Temperature Standards Review and Development

Review and development of temperature standards for marine and freshwater environments

Dr AWH Turnpenny Dr KE Liney

Document control sheet Client: Project:

SNIFFER Review and development of temperature Job No: standards for marine and freshwater environments

Title:

Report Prepared by

ORIGINAL

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Dr Kat Liney Dr Andy Turnpenny

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Reviewed by

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Dr Andy Turnpenny SIG NAT U RE

SIG N AT U RE

20/09/2006

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NAME

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NAME

Dr Kat Liney DATE

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REVISION

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NAME

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DATE

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This report, and information or advice which it contains, is provided by Jacobs Ltd solely for internal use and reliance by its Client in performance of Jacobs Ltd’s duties and liabilities under its contract with the Client. Any advice, opinions, or recommendations within this report should be read and relied upon only in the context of the report as a whole. The advice and opinions in this report are based upon the information made available to Jacobs Ltd at the date of this report and on current UK standards, codes, technology and construction practices as at the date of this report. Following final delivery of this report to the Client, Jacobs Ltd will have no further obligations or duty to advise the Client on any matters, including development affecting the information or advice provided in this report. This report has been prepared by Jacobs Ltd in their professional capacity as Consulting Engineers. The contents of the report do not, in any way, purport to include any manner of legal advice or opinion. This report is prepared in accordance with the terms and conditions of Jacobs Ltd‘s contract with the Client. Regard should be had to those terms and conditions when considering and/or placing any reliance on this report. Should the Client wish to release this report to a Third Party for that party's reliance, Jacobs Ltd may, at its discretion, agree to such release provided that: (a) Jacobs Ltd's written agreement is obtained prior to such release, and (b) By release of the report to the Third Party, that Third Party does not acquire any rights, contractual or otherwise, whatsoever against Jacobs Ltd, and Jacobs Ltd accordingly assume no duties, liabilities or obligations to that Third Party, and (c) Jacobs Ltd accepts no responsibility for any loss or damage incurred by the Client or for any conflict of Jacobs Ltd's interests arising out of the Client's release of this report to the Third Party.

Use of this report

The development of UK-wide classification methods and environmental standards that aim to meet the requirements of the Water Framework Directive (WFD) is being sponsored by UK Technical Advisory Group (UKTAG) for WFD on behalf its member and partners. This technical document has been developed through a collaborative project, managed and facilitated by SNIFFER and has involved the members and partners of UKTAG. It provides background information to support the ongoing development of the standards and classification methods. Whilst this document is considered to represent the best available scientific information and expert opinion available at the stage of completion of the report, it does not necessarily represent the final or policy positions of UKTAG or any of its partner agencies.

Contents

1

Introduction

1-1

1.1

Temperature and Aquatic Life

1-1

1.2 1.3

Background to Study Sources of Data

1-1 1-2

2

The Physical Environment

2-3

2.1 2.1.1 2.1.2 2.1.3 2.1.4 2.1.5 2.1.6

Thermal Status of UK Water Bodies Insolation and Cooling Thermal Discharges Seasonality Effect of Latitude and Longitude Diurnal and Tidal Effects Global Warming

2-3 2-3 2-4 2-7 2-7 2-8 2-9

2.2 Dissolved Oxygen (DO) in Relation to Water Temperature 2.2.1 Solubility of Oxygen 2.2.2 Natural Decay Processes & Photosynthesis

2-10 2-10 2-11

2.2.3 Sewage Sedimentand Resuspension 2.2.4 Other Organic Discharges- Oxygen ‘Sag’ 2.2.5 Significance of DO in Relation to Temperature Standards

2-11 2-12 2-13

2.3

Frequency of Sampling Required to Characterise DO and Temperature 2-13

3

Review of International Temperature Standards

3-15

3.1

Introduction

3-15

3.2 3.2.1 3.2.2 3.2.3

USA Regulations Feedback on effectiveness Oregon

3-15 3-15 3-16 3-17

3.3 3.3.1 3.3.2 3.3.3 3.3.4

Canada Regulations Feedback on effectiveness British Columbia Alberta

3-18 3-18 3-19 3-19 3-20

3.4 South Africa 3.4.1 Regulations 3.4.2 Feedback on Effectiveness

3-20 3-21 3-21

3.5 New Zealand 3.5.1 Regulations 3.5.2 Feedback on Effectiveness

3-21 3-21 3-22

3.6

3-22

Netherlands

3.6.1 Regulations 3.6.2 Feedback on Effectiveness

3-22 3-23

3.7 Germany 3.7.1 Regulations 3.7.2 Feedback on effectiveness

3-23 3-23 3-23

3.8 Denmark 3.8.1 Regulations 3.8.2 Feedback on effectiveness

3-23 3-24 3-24

3.9 Austria 3.9.1 Regulations 3.9.2 Feedback on effectiveness

3-24 3-24 3-25

3.10 Belgium 3.10.1 Regulations 3.10.2 Feedback on Effectiveness

3-25 3-25 3-25

3.11 Switzerland 3.11.1 Regulations 3.11.2 Feedback on Effectiveness

3-25 3-25 3-26

3.12 Finland 3.12.1 Regulations 3.12.2 Feedback on Effectiveness

3-26 3-26 3-26

3.13 3.13.1 Sweden Regulations 3.13.2 Feedback on effectiveness

3-26 3-27 3-27

3.14

Summary of International Regulations

3-27

4

Water Body Typology

4-1

4.1

Typology for Rivers

4-1

4.2

Typology for Lakes

4-4

4.3

Typology for Coastal and Transitional Waters

4-5

5

Existing UK Guidelines and Standards

5-7

5.1

EC Freshwater Fish Directive (FFD)

5-7

5.2

EC Shellfish Directive

5-7

5.3

Feedback on Current UK Water Temperature Standards and Approach to Regulation 5-9 Professor Terry Langford, author of “ Ecological Effects of Thermal Discharges”, University of Southampton 5-9 Neil Edwards, Environmental Specialist, RWE Npower 5-9 Les Watson, Regulatory Area Manager, Scottish Environmental Protection Agency 5-11 Tim Jacklin, Fisheries Technical Specialist, Environment Agency, Midland Region 5-11

5.3.1 5.3.2 5.3.3 5.3.4

6

Review of Temperature Requirements of UK Fish Species

6-13

6.1

Introduction

6-13

6.2

Upper Lethal Temperature

6-14

6.3

Ultimate Temperature Preferenda

6-14

6.4

Preferred Spawning Temperatures

6-15

6.5

Migration

6-15

6.6

Temperature Requirements of Key UK Species

6-16

6.7

Water Framework Directive Normative Definitions

6-16

6.8

Macroinvertebrates

6-17

7

Derivation of Draft WFD Water Temperature Standards

7-1

7.1

Key Biological Criteria

7-1

7.2 7.2.1 7.2.2 7.2.3 7.2.4

Adequacy of Existing Standards Surface water temperature standards Maximum Allowable Temperature Uplift and Plume Spread Maximum Allowable Temperature Decrease Spawning temperature

7-1 7-1 7-2 7-3 7-3

7.3

Provisional WFD Standards

7-3

7.4

Modifying Role of Dissolved Oxygen in Estuaries

7-4

7.5

Basis of Regulation

7-5

8

References

8-1

Appendix A - QUESTIONNAIRE AND LIST OF RESPONDANTS

1

Introduction 1.1

Temperature and Aquatic Life

Water temperature exerts a major influence on the biological activity, growth and survival of aquatic organisms. The effects of temperature on organisms can be observed to act from a cellular level, in the regulation of biochemical processes, through to effects on growth and development, tolerance and metabolism of toxic substances, reproductive success, disease resistance and ultimately survival or death. Aquatic species have preferred temperature ranges in which physiological processes operate at an optimum but have certain limits of physiological flexibility and will have some capacity to adapt to changing temperatures with time. Water temperature is also important because of its influence on water chemistry and, importantly, on its effects on the solubility and metabolic consumption of oxygen. Surface water temperatures are influenced by many factors including solar radiation, ambient air temperatures, shading, channel morphology, water velocity and water depth as well as by inflows to a water body. Anthropogenic factors may influence surface water temperatures, for example, by discharge of heated effluents, abstraction of water, alterations in channels resulting in altered flows, and land-use changes. The European Water Framework Directive (WFD) (2000/60/EC) requires that all inland and coastal waters within defined river basin districts must reach at least good ecological status by 2015 and indicates how this should be achieved through the establishment of environmental objectives and ecological targets for surface waters. 1.2

Background to Study

The present report was commissioned by SNIFFER 1 as a step in the process of developing water quality standards for temperature, suitable for application to UK water bodies. These are intended to supersede UK existing standards based on the European Freshwater Fish Directive (78/659/EEC), which arose from EIFAC water quality criteria first published in the 1960s (Alabaster and Lloyd, 1981). It is the first time that temperature standards will have been formulated specifically to cater for fish species and climatic conditions in the UK. This is an important step forward since many have viewed certain aspects of the European standards as being poorly targeted on UK conditions. New water quality standards, combined with metrics of biotic performance, will form the basis of environmental regulation in the context of the WFD. Several recent studies underlie the present work. A principle of the WFD is that different water body types should be categorised into ‘typologies’ according to their physico-chemical, geomorphological and biotic attributes, so that regulation can be more effectively matched to their characteristics. The simplest subdivisions include lakes, rivers, transitional waters and coastal water; further subdivisions can be made according to the varied characteristics within each of these fundamental types. The UK Water Quality Technical Advisory Group (UKTAG) and other groups have advanced a number of typological definitions that may suit different aspects or targets of regulation (e.g. benthic macroinvertebrates, fish, etc.). In setting standards, the fewest number of typologies for effective environmental regulation

1

The Scotland and Northern Ireland Forum for Environmental Research

Temperature standards review and development/Jul-07

1-1

should be chosen. The distinction of typologies relevant to setting temperature standards is one of the subjects of this report. Other recent relevant work has included a review of water temperature effects on fish living in transitional waters, commissioned by the Environment Agency (Turnpenny et al., 2006), and UKTAG guidance (WQTAG160) on temperature standards for application to transitional waters lying within Special Areas of Conservation (SACs) designated under the European Habitats Directive (92/43/EEC). The findings from these studies will also be reviewed and, where appropriate, incorporated into the recommendations of the present study. Other preceding information worthy of consideration may be found in the regulations of other national and regional jurisdictions where temperature standards for water quality have been established. Many of these may not be directly relevant, perhaps through being outdated, based on little or inadequate science, from different climatic zones or markedly different fish biotopes, but even in these cases it may help to learn from principles (e.g. what typologies were distinguished), past mistakes and user-feedback. Well-conceived modern standards may come close to what we are trying to achieve in the UK. 1.3

Sources of Data

The referenced data are taken as far as possible from peer-reviewed scientific publications but inevitably there has been a need to reference ‘grey literature’, for example unpublished scientific reports, from sources including; the Environment Agency (EA), the former National Rivers Authority (NRA), Central Electricity Generating Board (CEGB), Ministry of Agriculture, Fisheries and Food (MAFF) and Fawley Aquatic Research Laboratories Ltd (FARL). Generally these reports are available from the srcinating body or its successor or from the British Lending Library. Internet references are shown where used (as URLs), although these have been kept to a minimum owing to the volatility of Internet content.


1-2

2

The Physical Environment 2.1

Thermal Status of UK Water Bodies

The temperature regime of any water body is controlled by the temperature of water entering the system, as rainfall, surface drainage, groundwater inputs or anthropogenic discharges, and gains or losses caused by radiation, conduction, evaporation, condensation and friction. These processes vary in space and time. Examples of spatial variation can be seen, for example, within river systems, where summer temperatures generally increase from headwater to estuary, and across geographic ranges where climate changes; on a smaller scale, local variations can occur as a result of thermal discharges, and vertical changes are found within lakes and estuaries where stratification occurs. Temporal variations are associated with diurnal and (in coastal waters) tidal effects, seasonal changes, longer-term climatic cycles, changes of land use and channel morphology and (potentially) “global warming“ effects; short-term temperature fluctuations can also result from anthropogenic causes, such as thermocycling of power generating plant, regulation of flow within rivers or aeration of lakes to break up stratification. Effective regulation of surface water temperatures requires an understanding of these natural and anthropogenic factors in order to avoid the development of unrealistic standards. 2.1.1 Insolation and Cooling

Insolation (solar heat input) and radiative cooling affects the surface layers of all natural waters, along with evaporative and condensation effects. Heat absorbed or lost from surrounding land areas is transferred into water bodies by conduction, especially on tidal shores and via runoff. The effect is therefore subject to seasonal, diurnal and, in coastal waters, tidal variations. Direct insolation is the most important natural means of warming in most UK river and lake systems (Webb and Zhang, 1997). Studies of thermal budgets of a number of rivers in southern England have shown that between 44% and 94% of heat input is solar, accounting for temperature rises between source and sea often in excess of 10 °C in summer (Solomon et al., 2005). On the Dorset Avon, Solomon et al. attribute 90% of the heat gain to direct solar radiation and suggests that the thermal regime of the river must have been radically altered over the past 2000 years by the progressive removal of once-ubiquitous marginal tree cover; he shows that such tree cover can reduce solar radiation reaching the water by up to 100%. The effect of insolation onradiation river temperature directlyofproportional theraise riverthe depth: for example, solar striking a is channel 0.5 m depthtowill temperature by twice as much as the same energy level striking a channel of 1 m depth for a given flow rate (Solomonet al., 2005). Changes in the surface area to volume ratio of a channel or water body will effect the amount of heat lost or added due to energy exchange at the water surface. Consequently, changes to channel morphology or abstraction regime can affect temperature considerably. River systems can also collect solar heat from off-line sources such as fish farms and water meadows. Solomon et al. (2005) recorded a September temperature rise of +5 °C at the outfall from Britford water meadows (Salisbury) on the R. Avon and Temperature standards review and development/Jul-07

2-3

refers to previous report of a +8.3 °C rise. The water meadows are managed through a system of periodic flooding to maintain biodiversity. The effect of channels and ponds on fish farms similarly is to increase the surface area for solar absorption. Temperature rises are usually less dramatic but flows may be larger, so that the impact on thermal budget may still be significant. In estuaries, heating and cooling of mudflats and other intertidal areas can cause strongly fluctuating temperatures on a tidal/diurnal timescale. The effects are most marked where intertidal areas form a high proportion the total estuary area and in summer; particularly in estuaries where freshwater run-off and exchange is low and low water of low range tides occurs around midday. On clear, still summer nights significant re-radiation of heat can occur, at times resulting in local groundfrost. Spencer (1970a) recorded a 15°C variation in the near-surface temperature of a Milford Haven (Dyfed) mudflat over a 48 hour period in September 1968 but only 3 °C in March of that year. In the Blackwater estuary (Essex) the heat rejected by Bradwell 300 MWe nuclear power station was equivalent to about 20% of the incoming solar radiation on an average summer’s day but about 200% on an average winter’s day. It was calculated that for every 3 °C through which the top 10 mm of mudflat was cooled by the returning tide, a quantity of heat equivalent to that rejected by the power station in one hour was rapidly transferred to the water (Hawes et al,.1974). As these authors note, the sensitivity of estuarine water temperatures to changing weather conditions can make interpretation of water temperature data difficult. The stresses to biota are compounded by fluctuations in other environmental factors such as salinity and DO levels. 2.1.2 Thermal Discharges

Langford (1990) defines a ‘thermal discharge’ as having the following characteristics: • • •

the disposal of heat is the primary purpose; the heat srcinates from a man-made heat exchanger; any contaminants srcinate from additives, water treatments or corrosion in the system, rather than from a manufacturing process.

Thermal power stations (nuclear and fossil-fuelled) are the largest sources of waste heat, thermodynamic processes dictating that for many traditional plants, over 60% of the energy input as fuel is lost to the environment via cooling water or stack emissions (Turnpenny and Coughlan, 2003). In newer combined cycle gas turbine (CCGT) stations and combined heat and power (CHP) plants much higher heat recovery can be obtained, in which case thermal discharges (per unit of generation) are reduced (Turnpenny and Coughlan, 2003). Many larger thermal power stations are located on the coast or on estuaries to take advantage of the large heat sink available, possibly avoiding or minimising the need to use cooling towers. Petrochemical refineries associated worksNonetheless, are also commonly located estuaries and many haveand thermal discharges. there are manyon instances, particularly in more recently constructed plant, of plant authorisations issued under IPPC or PPC 2 placing limits on plant discharge temperatures which have the effect of requiring either the seasonal operation of cooling towers or seasonal limits on heat output to avoid breach of temperature consents. Recently constructed power stations on the Thames Tideway, for example, have been required to switch to tower cooling when the bulk temperature of the water exceeds 2

PPC= Pollution Prevention & Control; IPC = Integrated Pollution Control. PPC is the current consenting procedure in England & Wales Temperature standards review and development/Jul-07

2-4

21.5oC. This policy is based on an Environmental Quality Standard (EQS) intended primarily to protect salmonid migration. Cooling systems which use freshwater sources are now limited to indirect (towercooled) types; the once-through cooling that was common in older coal-fired stations has now been entirely phased out in the UK. The cooling water requirements for indirect cooling are much more modest, being required only for make-up and purge water: typically few per cent of their direct-cooled counterparts. In some locations where water is short, plant air-cooling is the only option. However, this is less energy efficient that water cooling and results in higher carbon dioxide emissions. The area surrounding a thermal discharge is known as the ‘mixing zone’ or ‘thermal plume’. The dictionary definition of a mixing zone is the “zone separating regions of two different fluids through which a gradient exists to mix the fluid properties3 ”. The concept of the mixing zone is applied to allow consent conditions to be related to environmental temperatures: in regulatory terms, the mixing zone is an area of receiving water around the discharge point within which an EQS can be exceeded. Langford (1990) suggests that a useful ecological definition for a thermal mixing zone is a volume of water which has a temperature differential (∆T) of >0.5 °C above ambient. However, this definition will not work for regulatory standards which state that a certain temperature should not be exceeded beyond the outside of the mixing zone. The choice of the size of a mixing zone is therefore somewhat arbitrary. A diameter of 100 m is often adopted in the UK by the Environment Agency and SEPA, although this is not necessarily appropriate in tidal waters; Environment Agency guidance in Appendix 5 of the Dangerous Substances Act Guidance states that, for discharges to tidal waters, the mixing zone has been defined as “the area of water within which we are prepared to accept EQS exceedance”.

For European Marine Sites designated under the Habitats Directive, separate guidance is given by the Habitats Directive Advisory Group on Water Quality 4 . This requires that where an effluent whose contents exceed the EQS discharges across an intertidal zone it will require an Appropriate Assessment; alternatively, where the discharge is subtidal, it will require an Appropriate Assessment if, taking into account receiving water quality and initial dilution, there is not a 95% confidence that the EQS will be met. ‘Initial dilution’ in this context means the dilution that occurs as the buoyant plume rises from the point of discharge to the sea surface, entraining dilution water on its way. The term ‘thermal plume’ is often used synonymously with ‘mixing zone’ but is a more graphic description. Thermal plumes are often visible at the water surface owing to the different refractive index of warmer water or, for instance, due to differing suspended sediment concentrations between the discharge and the receiving water. The hydraulic behaviour thermal is instrumental in determining its for ecological effects. There of arethe two broad plume engineering approaches: one is to aim rapid initial mixing and dilution, typically using diffusers to create a large volume of slightly warmed water; the other is to allow the plume, which in most cases will be buoyant, owing to the lower density of warm water, to rise virtually unmixed to the surface and spread horizontally (Figure 2.1) where it will lose heat to atmosphere and slowly mix downward. In an estuary, the horizontal dispersion will be primarily due to tidal movement. At slack water, a plume will tend to spread symmetrically, 3 4

amsglossary.allenpress.com/glossary WQTAG083e, January 2004


2-5

and in narrow estuarine corridors may temporarily fill out the entire channel width. It has often been asserted (though never properly established) that this could create a thermal block, inhibiting fish migration. The risk of the plume washing onto shallow marginal habitat is also greatest under these conditions when the discharge is midchannel.

Figure 2.1 Vertical slice of a modelled thermal discharge showing rise and spread of the buoyant plume. Note cool area beneath plume.

The positioning andthe design of comes the thermal discharge willbed largely determine the habitats with which plume into contact. The beneath the discharge point will often be protected by the plume buoyancy (Figure 2.1), provided the openings are sufficiently above bed level to avoid hydraulic friction. If the outfall is located close to the shore then it is likely that the plume will hug the shoreline (Figure 2.2), increasing the impact on intertidal areas. Where navigation permits, a mid-channel position is generally preferable unless discharge temperatures are low. Diffuser outlets can be fitted to improve mixing and dispersion, thereby reducing the size of the mixing zone. A variety of 1-D, 2-D and 3-D hydraulic models is available and these are now routinely used in siting and design of outfalls to ensure that consentable conditions can be achieved.


2-6

Figure 2.2 Modelled thermal plume showing thermal contours hugging the foreshore (lower boundary of plot). In this case, plume temperatures are <1.5 oC above ambient. Tidal flow is left to right.

Good practice design objectives for a thermal discharge can be summarised as follows: •

the outfall should be located and designed so as to minimise contact of warmed water with sensitive habitats under all hydraulic conditions;

•

recirculation of the plume into the plant CW intake should be minimised (recirculation reduces plant thermal efficiency);

•

in a river or estuarine channel, the plume should not occupy more than a certain percentage of the channel cross-section for more than a stated percentage of the time (e.g. a maximum of 25% of the cross-section for 95% of the time); the actual percentage figures may vary between regulatory agencies.

2.1.3 Seasonality

Whereas river water temperatures in the UK may range from 0 °C in winter to over 30 °C in a hot summer, marine temperatures away from the shoreline are more stable, ranging from 5 °C to 17 °C (MAFF, 1981). Seasonal temperatures in the deeper partsinofestuaries estuarieswill willallow fall between thetemperature riverine andtomarine salt content the winter fall to aconditions degree orbut twothe below zero in shallow areas before freezing takes place (Friedrich, 1969). 2.1.4 Effect of Latitude and Longitude

Mean surface temperatures in British coastal waters range from around 12-13 °C in northern Scotland to 16-17 °C in southern England; the highest temperatures occur in the south-east (Thames Estuary) (MAFF, 1981). Winter sea surface temperatures (SST) range from around 5 °C along much of the east coast to 9 °C off the western tip of Cornwall and western Ireland, where the Gulf Stream holds up winter Temperature standards review and development/Jul-07

2-7

temperatures. Thus there can be a 3-4 °C differential in mean temperatures between different parts of the UK at any one time. On a larger geographic scale, latitude is the more important determinant of temperature, east-west being more a function of ocean current structures than longitude per se. Summer SSTs in the Bay of Biscay, for example, reach around 20 °C, 3-4 °C warmer than southern Britain. River temperatures similarly reflect climatic conditions related to latitude. The example in Figure 2.3 compares seasonal temperature cycles for a river in Norway and one in(Salmo France; these represent northerly and southerly parts of the Atlantic salar salmon’s ) latitudinal range. It shows how a y-axis shift in the temperature cycle can affect the duration of the growth season and the match to the optimum growth temperature.

Figure 2.3 Average monthly water temperatures for two rivers from northerly (R. Alta, Norway) and southerly (R. Nivelle, France) parts of the salmon’s geographic range. The lower horizontal dotted line represents the minimum growth temperature and the upper dashed line represents the optimum growth temperature (adapted from McCarthy and Houlihan, 1997). 2.1.5 Diurnal and Tidal Effects

In UK rivers, temperature over the course of a summer’s day can change by up to 8-10 °C. Daily fluctuations in estuaries result from a combination of solar heating during the day, tidal movements, over heated or cooled intertidal substrata and the mixing of river and sea waters. Spencer (1970b) found a daily temperature fluctuation of up to15 °C in the top few centimetres of an intertidal mudflat in Milford Haven, (Dyfed) with heat being transferred to and from the incoming tide edge. In deeper water, Spencer reported surface temperatures to vary rather less, typically by <0.5 °C in winter and <1.5 °C in summer. Pickett and Pawson (1994) refer to bass (Dicentrarchus labrax) being present in tidal creeks when the tide has risen over of sun-heated substrate, raising the temperature by +2 to +3 °C; they also report temperature drops of a similar magnitude when morning tides inundate frosted creek beds. Temperature standards review and development/Jul-07

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2.1.6 Global Warming

Temperature rises caused by ‘global warming’ predicted by The UK Climate Impacts Programme (UKCIP 5 ) suggest that that by 2050, mean annual SSTs in British waters will have increased by 1-1.5°C or 1.5-2 °C, (for a greenhouse gas ‘Low Emission’ and ‘High Emission’ scenario, respectively); over the next century sea surface temperatures are forecasted to increase by 0.5 to 4 °C (Hulme et al. 2002). Although fish have a strong adaptivity to temperature, such changes are likely to have a significant impact on fish distribution and community structure as some species of Arctic-Boreal zoogeography are replaced by more Lusitanean species. The effects first become noticeable at the fringes of their geographic ranges (southern fringe for Arctic-Boreal species, northern for Lusitanean). In Britain, there have been increased sightings of Lusitanean vagrants such as red mullet (Mullus surmuletus), on power station cooling water (CW) screens in Severn Estuary, for example (Holmes and Hendersonet al. 1990). The converse effect is also implied, viz. increasing rarity of some cold-water species in southern parts of Britain. While the decline of migratory salmonids in some southern English rivers can be blamed on many factors, high summer estuarine temperatures may be a factor in some cases. Adult salmon returns to the River Thames have declined heavily since 1997. Salmon are sensitive to poor oxygen and high temperature conditions (Alabasteret al, 1991) and reduced adult returns are thought to be a consequence of such conditions. While the average monthly temperature of the River Thames appears to have remained fairly constant over the last 15 years (Figure 2.4), maximum monthly temperature over the same time period followed a more pronounced upward trend (Figure 2.5). Temperature rises in the Thames may be due in part to the global warming phenomenon and may result in southern rivers like the Thames eventually becoming unsuitable habitat for salmonid species. Conversely, interventions to improve DO levels are likely to extend the viability of salmonids in southern rivers . 24 22

TEMPERATURE

20 18

C o 16 re u t 14 a r e 12 p m10 e T

8

O conc

6 4 2

'91 '92 '93 '94 '95 '96 '97 '98 '99 '00 '01 '02 '03 '04 '05

Year

Figure 2.4 Average monthly temperature of the River Thames over a fifteen year period

5

http://www.ukcip.org.uk/


2-9

26

o

) C ( 25 e r u t a r e p 24 m te l a u n n 23 a m u im x 22 a M

21 '91 '92 '93 '94 '95 '96 '97 '98 '99 '00 '01 '02 '03 '04 '05

Figure 2.5 Maximum annual temperature of the River Thames

In July 2006 the temperature in Lake Windermere reached 24°C, the highest recorded temperature since recording began in 1933 (Freshwater Biological Association). Lakes such as Windermere provide valuable habitat for cold water coregonid fish species such as vendace and Arctic char. There is mounting concern that the increase in lake temperatures attributed to global warming may lead to the extinction of the UK populations of these fish (Maitland et al., in press). 2.2 Dissolved Oxygen (DO) in Relation to Water Temperature 2.2.1 Solubility of Oxygen

Dissolved gases of particular interest are oxygen and carbon dioxide. These constitute around 21% and 0.03%, respectively, of the air but in seawater there is seldom more than about 8.2 mL/L of oxygen against 35-55 mL/L of carbon dioxide. This is in part due to the higher solubility (28 times as great at 20 °C) of carbon dioxide but also to the fact that much of this gas is present as carbonate and bicarbonate, rather than as free CO 2 and H2CO3. The solubility of a gas depends primarily on the concentration (salinity) of dissolved material in the water, the concentration (partial pressure) of the gas in the atmosphere over the water and, particularly, on water temperature (Tables 2.1, 2.2).


2-10

Table 2.1

Solubility of oxygen [mgL-1] in water in equilibrium with air (=100% saturation) at 760 mm barometric pressure and 100% humidity

Temperature C 0 5 10 15 20 25 30 35

°

Solubility of oxygen in Freshwater Seawater (35 ppt) mgL-1 mgL-1 14.6 11.3 12.7 10.0 11.3 9.0 10.1 8.1 9.1 7.4 8.2 6.7 7.5 6.1 6.9 5.7

Correction for Salinity. Factor to be subtracted * 0.0925 0.0771 0.0653 0.0559 0.0481 0.0415 0.0362 ≈0.035

* EXAMPLE: Find solubility of oxygen at 32 ppt and 20 °C Correction at 20 °C is 0.0481 for each salinity unit (ppt) [32 x 0.0481] = 1.54. Deduct this from the freshwater value So 9.1 mgL-1 minus 1.54 = 7.6 mgL-1 Table 2.2

Temp °C 0 5 10 15 20 25 30 35

Solubility of oxygen [mgL-1] in freshwater at various temperatures and atmospheric pressures (after Weiss,1970)

Atmospheric mm mm Hg and760 as millibars mbmm 800 mm 650 675 700 pressure 725 as 750 mm 775 mm mm mm mm 867 mb 900 mb 933 mb 967 mb 1000 mb 1013 mb 1033 mb 1067 mb 12.46 10.88 9.62 8.58 7.72 7.01 6.39 5.87

12.95 11.31 9.99 8.92 8.03 7.29 6.65 6.11

13.43 11.73 10.37 9.25 8.33 7.56 6.91 6.35

13.91 12.15 10.74 9.59 8.64 7.84 7.17 6.59

14.39 12.58 11.12 9.93 8.95 8.12 7.43 6.83

14.59 12.74 11.27 10.06 9.07 8.24 7.53 6.93

14.88 13.00 11.49 10.26 9.25 8.40 7.69 7.07

15.36 13.42 11.87 10.60 9.56 8.68 7.95 7.31

For seawater use the correction method for Table 2.1. Solubility increases with depth since 1.0 m of water is approximately 100 mbars. 2.2.2 Natural Decay Processes & Photosynthesis

Many aquatic habitats suffer natural hypoxia as a result of diurnal photosynthetic cycles or seasonal decomposition cycles (Diaz and Rosenberg, 1995; Breitberg, in press). These are temperature and/or daylight driven and are maximal in the summer months. 2.2.3 Sediment Resuspension

This applies mainly to macrotidal estuaries which are characterised by strong tidal currents and very high suspended sediment concentrations. Suspended sediments Temperature standards review and development/Jul-07

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generally have a high oxygen demand and lead to stripping of DO from the water column. Hypoxia due to suspended sediment oxygen demand occurs principally during warm summer months when biological activity is high and oxygen solubility is at its lowest. On warm summer days and spring tides in the R. Wye estuary at Chepstow the author has seen adult salmon ( Salmo salar) gasping at the surface amongst the dipnet fisheries, probably due to a combination of low DO and very high sediment levels clogging the gills. 2.2.4 Sewage and Other Organic Discharges- Oxygen ‘Sag’

The organic load introduced into water bodies by sewage treatment works (STW) effluents, combined sewer overflow (CSO) discharges and by other organic wastes, generates a biochemical oxygen demand (BOD) similar to that caused by resuspended sediments. The resulting depression in DO levels is known as ‘oxygen sag’. The extent and magnitude of the oxygen sag depends on the organic load, the water temperature and the amount of freshwater entering the system, as well as the tidal excursion. In larger estuaries such as the Thames, a standard 5-day BOD test does not take account of the slower oxygen-consuming process of nitrification, which normally takes 8-10 days to become apparent. Potentially long retention times in transitional waters mean that this effect cannot be ignored and a measure known as the Effective Oxygen Load (EOL) is used instead. This is calculated as: EOL= (1.5 BOD mg L-1 + 4.5 (ammoniacal + organic N) mg L-1 * flow ML d-1) / 1000. The impact of the EOL on water quality is seasonal, depending on the freshwater input and the water temperature, and therefore is at its worst during the warmer, dryer summer months. Oxygen sags occurs when natural re-oxygenation processes (mainly through mixing with the surface-aerated layers) do not balance the effect of the EOL. As an example: the typical summer oxygen sag curve for the Thames Tideway is shown in Figure 2.3. A sag in the upper Tideway is due mainly to the input from Mogden STW. A greater effect is created by the discharges below central London from the main STWs at Beckton and Crossness. The minimum DO level, known as the Critical Point, occurs in this region, about 20 km below London Bridge; the effects extend upstream of this point due to the tidal movement. Storm discharges from CSOs can cause acute hypoxic events. The situation on the Thames Tideway has been monitored over many years (Turnpenny et al., 2005). All surface drainage within central London is directed into the sewerage system. The capacity of the trunk sewers is inadequate to carry the runoff from heavy rainfall events, so at times of overloading the excess is discharged into the Tideway by a complex of CSOs. The effluent from these CSOs contains a mixture of the untreated sewage normally carried by the trunk sewers and the urban runoff. During the winter months, increased freshwater input to the estuary and lower water temperatures prevent any noticeable harm to fish. From May to October, higher temperatures and lower freshwater inputs reverse this situation and it is during or following heavy rainfall events during this period that fish kills have been observed.


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Figure 2.7 Typical summer dissolved oxygen profile in the Thames Tideway (source: Environment Agency, 1997).

2.2.5 Significance of DO in Relation to Temperature Standards

Temperature standards are invariably required to deal with the ecological threat of excess temperatures rather than of low temperatures, owing to the fact that most anthropogenic processes do not tend to remove energy from the environment. Warm summer temperatures are naturally accompanied by lower DO concentrations in the water, resulting from a combination of reduced oxygen solubility and increased BOD. On the other hand, since fish are poikilotherms, their metabolic oxygen demand rises at warmer temperatures and at a certain point will become critical. Under natural conditions, there may be sufficient headroom between the natural maximum temperature and this critical point but any thermal additions to the water can reduce the metabolic headroom available to them. The highest risk occurs in organically polluted or sediment-rich waters, notably in estuaries. When considering maximum temperatures suitable for fish, therefore, it is also necessary to consider the DO regime: where there is a risk of chronically low -1

DO values occurring (e.g. <5 mg DO L ), the maximum allowable temperature may need to be reduced to maintain adequate metabolic headroom. 2.3 Frequency of Sampling Required to Characterise DO and Temperature

Strong seasonal, tidal and diurnal cycles of temperature and DO make frequent sampling essential. Some larger UK rivers and estuaries such as the Thames employ a network of AQMS (automated quality monitoring station) sites that measure and record DO, temperature, salinity and other characteristics. The Thames Tideway AQMS network telemeters information at 15 min intervals to a Temperature standards review and development/Jul-07

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control centre. The spacing of the AQMS sites ensures that water passes 2-3 monitoring points during a single tidal excursion (±13km). This allows a virtually continuous model of water quality to be maintained. The system is used to provide advance warning of hypoxic episodes that might cause fish kills, allowing specially designed oxygenation boats to be deployed. Many UK water bodies do not have sophisticated monitoring equipment of this type and rely on spot sampling programmes. The ability to monitor effectively against WFD temperature and DO standards will require careful consideration in these cases. In particular, diurnality will mean that the time of day when a reading is taken will markedly affect the statistics gathered and regulation cannot be effectively applied using single readings for each sampling date. Kirchneret al (2004) illustrate this point with data from studies of water quality parameters, measured at monthly, weekly, daily and hourly measurements. The study demonstrates the dramatic loss of information that occurs at lower sampling frequencies.


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3

Review of International Temperature Standards 3.1

Introduction

A review of international water temperature standards was carried out through a combination of literature review, Internet search and correspondence with international specialists. The list of specialists was drawn up in consultation with the Project Steering Committee and contacted by e-mail. The questionnaire sent out them and the list of respondents is shown in Appendix A. Table 3.1 lists the countries researched and whether or not they currently have relevant regulations for freshwater or marine water bodies. The following sections summarise the regulatory position in each country. Table 3.1

Summary of countries with surface water temperature regulations

Country

USA Canada South Africa New Zealand Netherlands Germany Denmark Austria Belgium Switzerland Finland Sweden 3.2

Surface water temperature regulations Freshwater Marine Yes No Yes Yes No Yes Yes No Yes Yes Yes Yes Yes Yes No

Yes No Yes N/A Yes N/A No No

USA

Regulatory body: Environmental Protection Agency (EPA) Document: EPA Region 10 Guidance for Pacific Northwest States and Tribal

Temperature Water Quality Standards (2003) URL:http://yosemite.epa.gov/R10/water.nsf/6cb1a1df2c49e4968825688200712cb7/ b3f932e58e2f3b9488256d16007d3bca/$FILE/TempGuidanceEPAFinal.pdf 3.2.1 Regulations

The US EPA provides guidelines for water temperature standards specifically for the freshwater habitat of salmon and trout species. The EPA does not have guidance or recommended temperature criteria for lakes, oceans and bays or cool water species (Oregon DEQ). The Clean Water Act (CWA, amended 2002) requires States and Tribes to adopt water quality standards and requires the EPA to approve or reject these standards. States and Tribes also have obligations to conserve Pacific Northwest salmon and trout species under the Endangered Species Act (ESA, 1973). The EPA issue Temperature standards review and development/Jul-07

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guidance to assist with the development and adoption of water quality standards by individual states to fulfil the obligations of both the CWA and ESA. The guidance is optional and States and Tribes may develop and submit alternative water quality standards. However, compliance with the EPA guidelines eases progress through the approval process. The guidelines are based on a review of scientific literature (EPA, Scientific Issues Relating to Temperature Criteria for Salmon, Trout and Char Native to the Pacific Northwest, 2001). Recommended temperature criteria to protect salmon and trout (US EPA)

(Criteria are based on the 7 day average of maximum values). Summer maximum temperatures •

12 °C for bull trout rearing (upper river basin).

•

16 °C for salmon and trout “core” juvenile rearing (high density, mid to upper river basin).

•

18 °C for salmon and trout migration and “non-core” juvenile rearing (low density, middle to lower reaches).

•

20 °C for salmon and trout migration (lower reaches).

Spring/Autumn maximum temperatures •

9 °C for bull trout spawning.

•

13 °C for salmon and trout spawning.

•

14 °C for steelhead smoltification. In addition, the guidance document provides the following recommendations: The protection of existing cold waters: states and tribes should adopt mechanisms to protect waters that are currently colder than the maximum summer criteria to protect species covered by the ESA. Thermal plumes: water temperatures of point-source discharges may exceed the recommended temperature criteria providing there is no harm to fish. It is recommended that measures be put in place to prevent lethal temperatures (more than 10 seconds at ≥32 °C), prevent thermal shock (prohibit sudden increases to higher than 26 °C in more than 5% of the river), prevent blockage to migration (prevent water temperature of more than 21 °C in more than 25% of the crosssection) and to prevent discharge to spawning ground and egg incubation areas. The guidelines recognise that the temperature criteria may not be appropriate or attainable all recommended waters and advise that(when if the natural background temperature is the higher thaninthe criteria anthropogenic factors are absent) natural background temperature may be established as a standard. Federal regulations (40 CFR 131.20a) requires that water quality standards should be reviewed at least every three yearsand that public hearings be part of the process of modifying andadopting standards. 3.2.2 Feedback on effectiveness

Feedback from practitioners is that the regulations are generally perceived to be appropriate (R. Zabel, National Marine Fisheries Service, pers comm.). However, Temperature standards review and development/Jul-07

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some regulators believe that the standards should be more ecologically based and should involve more ecological monitoring, such as relative species abundances (R. Zabel, pers comm.). 3.2.3 Oregon Regulatory body: Department of Environmental Quality. Document: OAR 340-041-0028 URL: http://www.deq.state.or.us/wq/wqrules/Div041/OAR340Div041.pdf

The standards for the state of Oregon are based on US EPA guidance combined with a review of scientific literature. The standards are designed to protect the freshwater habitat of salmonid species and make species- and site- specific recommendations. Monitoring of stream temperature is carried out by means of continuous recording temperature sensors, placed at well mixed water locations in streams during the seasons when maximum temperatures are expected. Determining whether the stream temperature is above or below the temperature standard is based on the average of the maximum daily water temperatures for the stream’s warmest, consecutive seven-day period during the year. Summary of Oregon water temperature standards (Criteria are based on the 7

day average of maximum values): Temperature criteria for salmonid species: the regulations summarised below make

species and site specific recommendations (fish habitat use maps and tables are provided here). within the regulations. For clarity, specific site information is not given a) Temperature of a stream identified as having salmon and steelhead spawning may not exceed 13 °C. b) Temperature of a stream identified as having core cold water habitat use may not exceed 16 °C. c) Temperature of a stream identified as having salmon and trout rearing and migration use may not exceed 18°C. d) Temperature of a stream identified as having a migration corridor use may not exceed 20 °C. In addition these water bodies must have sufficiently distributed cold water refuges and the seasonal thermal pattern must reflect normal seasonal water temperature patterns. e) Temperature a stream as °having Lahontan cutthroat trout or redband trout of use may notidentified exceed 20 C. f) Temperature of a stream identified as having bull trout spawning and juvenile rearing may not exceed 12°C. Unidentified tributaries – for waters not identified on fish habitat-use maps or tables,

the criteria to be applied is that of the nearest downstream water body.


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Natural lakes – Natural lakes may not be warmed more than 0.3°C above the

ambient condition unless a greater increase would not reasonably be expected to adversely affect fish or other aquatic life. Oceans and bays – Ocean and bay water may not be warmed by more than 0.3°C

above the ambient condition unless a greater increase would not reasonably be expected to adversely affect fish or other aquatic life. The regulations also state that when the natural temperature of a water body exceeds the guidelines given, that the natural temperature for that water body should be taken as the standard. There is also provision to protect the habitat of the borax lake chub and water bodies that are habitat for this species may not be cooled by more than 0.3 °C than the ambient temperature. 3.3

Canada

Regulatory Body: Canadian Council of Ministers of the Environment (CCME) Document: Canadian (CCME) Environmental Guidelines for Aquatic Life URL: http://www.ccme.ca/publications/ceqg_rcqe.html 3.3.1 Regulations

In common with regulation of surface water temperatures in the USA, national guidelines for water temperature are provided by the Canadian Council of Ministers of the Environment. These guidelines are developed and standards set by individual states. The national guidelines do make distinction between freshwater and marine environments and make recommendations that potentially sensitive species be considered. Freshwater

1.

Thermal Stratification

Thermal additions to receiving waters should be such that thermal stratification and subsequent turnover dates are not altered from those existing prior to the addition of heat from artificial srcins. 2.

Maximum Weekly Average Temperatures (MWAT)

Thermal additions to receiving waters should be such that the MWAT is not exceeded. In the warmer months, the MWAT is determined by adding to the physiological optimum temperature (usually for growth) a factor calculated as onethird of the difference between ultimate upper incipient the optimum temperature for thethe most appropriate life stagelethal of thetemperature sensitive and important species that normally is found at that location and time. Some MWAT values are shown in US EPA (1976). In the colder months, the MWAT is an elevated temperature that would still ensure that important species would survive if the temperature suddenly dropped to the normal ambient temperature. The limit is the acclimation temperature minus 2 °C when the lower lethal threshold temperature equals the ambient water temperature.


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During reproductive seasons, the MWAT meets specific site requirements for successful migration, egg incubation, fry rearing, and other reproductive functions of important species. At a specific site, the MWAT preserves normal species diversity or prevents undesirable growths of nuisance organisms. 3.

Short-term Exposure to Extreme Temperature

Thermal additions to receiving waters should be such that the maximum temperatures are not exceeded. Exposures should not be so lengthy or frequent as to adversely affect the important species. For growth, the short-term maximum temperature is the 24-h median tolerance limit, minus 2 °C at an acclimation temperature approximating the MWAT for that month. The short-term maximum temperature for the season of reproduction should not exceed the maximum incubation temperature for successful embryo survival, or the maximum temperature for spawning. Marine

Water temperature should not exceed a 1 °C change from natural background temperature. 3.3.2 Feedback on effectiveness

No feedback has been received on the effectiveness of these regulations. 3.3.3 British Columbia Regulatory body: The Ministry of Water, Land and Air Protection Document: Ambient water quality guidelines for temperature : overview URL: http://www.env.gov.bc.ca/wat/wq/BCguidelines/temptech/temperature.html

The guidelines are based on a review by Oliver and Fidler (2001). A major use of the guidelines is to set ambient water quality objectives, which are the guidelines modified or adopted to protect the most sensitive designated water use in a particular body of water. The objectives are used in the preparation of waste management plans, pollution prevention plans, waste management permits, orders or approvals. These waste management permits, orders and approvals are the only documents that have legal standing. Currently, monitoring is only undertaken if a problem is identified (for example, a fish kill – L. Fidler, Aspen Environmental Ltd, pers comm). Guidelines: Streams by bull trouthave Salvelinus confluentus and/or varden Salvelinusfrequented malma (These species been demonstrated to havedolly the highest

thermal sensitivity of native BC fish species tested). •

The maximum daily temperature should not exceed 15 °C

•

Maximum spawning temperature should not exceed 10°C

•

Preferred incubation temperatures should range from 2 to 6 °C

All Other Streams


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•

The guidelines for streams and rivers other than those frequented by bull trout and dolly varden are based on temperature tolerance data for adult salmonids.

Streams with Unknown Fish Distribution •

The mean weekly maximum temperature (MWMT) = 18 °C

•

The maximum daily temperature = 19 °C

•

The maximum daily incubation temperature (Spring and Fall) = 12 °C

Streams with Known Fish Distribution •

•

± 1 °C beyond the optimum temperature range for each life history phase of the most sensitive salmonid species present. The hourly rate of change ≤1 °C.

Lakes •

± 1 °C change from the natural condition.

Marine and Estuarine •

± 1 °C change from the natural condition.

The natural temperature cycle characteristic of the site should not be altered in amplitude or frequency by human activities The maximum rate of any human-induced temperature change should not exceed 0.5 °C per hour 3.3.4 Alberta Regulatory body: Environmental Assurance Division, Government of Alberta. Document: Surface Water Quality Guidelines for Use in Alberta URL: http://www3.gov.ab.ca/env/protenf/publications/surfwtrqual-nov99.pdf

The current guidelines have been compiled from previous guidelines, CCME guidelines (see section 2.1) and US EPA guidelines (see section 2.2). Freshwater temperature

Not to be increased by more than 3 °C above ambient water temperature. The guidelines also state that Thermal additions should not alter thermal stratification or turnover dates, exceed maximum weekly average temperatures, nor exceed maximum short-term temperatures. 3.4

South Africa

Regulatory body:

Department of Environmental Affairs and Tourism Department of Water Affairs and Forestry Document: South African Water Quality Guidelines, Second Edition, 1996 URL: www.dwaf.gov.za/documents


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3.4.1 Regulations

The Republic of South Africa provide separate water quality guidelines for fresh and marine waters. There are currently no regulations in place that refer to thermal discharges to fresh water bodies. Coastal marine standards state that ‘the maximum acceptable variation in ambient temperature is ± 1 C’. °

Discharge of water into the environment is subject to granting of licence which may or may not include a monitoring programme. 3.4.2 Feedback on Effectiveness

In practice it is reported that the water temperature standards are rarely implemented due to resource constraints (S. Taljaard, Council for Scientific and Industrial Research, pers. comm.). 3.5

New Zealand

Regulatory body: Ministry for the Environment and regional councils. Document: Australian and New Zealand Guidelines for Fresh and Marine Water

Quality (ANZECC / ARMCANZ 2000) and the Resource Management Act 1991 (amended 2005). URL: http://www.mfe.govt.nz/publications/water/anzecc-water-quality-guide02/anzecc-water-quality-guide-02-pdfs.html http://www.qualityplanning.org.nz/legislation/rma-consolidated.pdf 3.5.1 Regulations

Regulation of thermal discharges in New Zealand is carried out on a regional basis with site-specific standards recommended by regional councils. Guidelines for the derivation of these standards are given in the Australian and New Zealand Guidelines for Fresh and Marine Water Quality (2000). These guidelines state that: “The maximum permissible increase in the natural temperature of any inland waters should not exceed the 80th percentile of ecosystem reference data or for cooled discharges go below the 20th percentile”.

The guidelines for water quality in New Zealand are also specified in Schedule 3 of the Resource Management Act 1991 (amended 2005). The schedules (including water quality classes) were transferred from previous legislation (The Water and Soil Conservation Act 1967).The regulations state that the natural temperature of the water may not be changed by more than 3 °C. Water bodies managed for fisheries purposes may not be changed by more than 3°C and the water temperature may not exceed 25 °C. In addition, the temperature of waters managed for fish spawning purposes or cultivation of shellfish for human consumption may not be changed by more than 3 °C. A ‘resource consent’ or discharge permit is granted by the Regional Councils and legally enforceable conditions (including temperature standards) may be included. Breaches can lead to fines, imprisonment and/or closure of the facility. Temperature standards are set site-specifically by regional councils. Water body type and species inhabiting the receiving water are factors taken into account when standards are set (James Court, Ministry for the Environment, pers. comm.). The Resource Management Act (1991) is not a national standard and regional councils have the discretion to choose their own classification systems and set appropriate standards. Temperature standards review and development/Jul-07

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Regional councils are also responsible for monitoring and enforcement of their standards and to prosecute need to provide evidence of significant adverse effects on ecology. 3.5.2 Feedback on Effectiveness

Feedback from practitioners is that most (if not all) Regional Councils ignore the water quality guidelines given in the Resource Management act because it is perceived that they are dated (James Court, Ministry for the Environment, pers. comm.). The conditions of resource consents are often reported to be difficult to apply, monitor and report on and it has been reported that operators of thermal discharges sometimes choose to ignore the fish monitoring conditions of their resource consent until someone complains (J. Boubee, National Institute of Water and Atmospheric Research, pers. comm.). The devolution of regulation to regional councils and setting site-specific standards is perceived by some to be an appropriate approach (James Court, pers. comm.). However, other practitioners believe that the national Resource Management Act guidelines are too open to interpretation and appropriate national standards need to be set which include limits based on indigenous fish as well as invertebrate populations (J. Boubee, pers. comm.). 3.6

Netherlands

Regulatory body: Ministerie van Verkeer en Waterstaat Document: CIW beoordelingssystematiek warmtelozingen 3.6.1 Regulations

The Dutch guidelines relating to thermal discharges are presented in the Dutch language but are summarised in Table 3.2. Table 3.2 Dutch surface water temperature regulations Parameter

Guidelines

Temperature of cooling Fresh: ≤ 30 ºC water discharge Saline: ≤ 30 ºC ∆T

cooling water within discharge Uplift over ambient

Fresh:

7 ºC (Summer) 15 ºC (Winter) Saline: ≤ 10 ºC (Summer) ≤ 15 ºC (Winter) ≤ 3 ºC Deviation from ambient temperature to a maximum of 28 ºC ≤

≤

In addition, the guidelines specify waters inhabited by cyprinids the increase in ambient water temperature should be no more than 3°C up to a maximum water temperature of 28 °C; in waters inhabited by shellfish the increase in temperature may be 2 °C up to a maximum of 25 °C; in waters inhabited by salmonids the increase in temperature may be 1.5 °C up to a maximum of 21.5 °C. There is guidance that water abstractions and thermal discharges to canals, tidal harbours, rivers, estuaries and the North Sea should not cause significant effects to spawning areas, juvenile fish rearing areas or affect fish migration. The guidance also states Temperature standards review and development/Jul-07

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that the mixing zone of any thermal discharge may not be more than 25% of the cross-sectional area of the river. 3.6.2 Feedback on Effectiveness

New thermal discharge consents are based on modelling using a 3D hydraulic model called “Threetox” (H. Jenner, KEMA, pers. comm.) Thermal modelling has indicated that the regulations may be too stringent and that there may be more scope for discharging heated water into Dutch water bodies (H. Jenner, pers. comm.). 3.7

Germany

Regulatory body: Federal Ministry for the Environment and State Ministries of

Environment. Document: Allgemeine Guteanforderungen für Fließgewaesser URL: www.stua-mi.nrw.de/Pdf/AGA.pdf 3.7.1 Regulations

Germany has a federal structure and government is divided among federal, state and municipal levels. The German Federal Government is responsible for devising and circulating a water framework policy which each of the 16 state governments is responsible for implementing and regulating. Therefore, each State can set its own water quality standards. A state-wide working group harmonises the guidelines set by the Federal government (M. Redeker, Ruhrverband, pers comm.). The Federal guidelines (Allgemeine Guteanforderungen für Fließgewaesser) provide recommendations for freshwater bodies but not for transitional or marine waters. There is a distinction made between “summer cool waters” and “summer warm waters”. The maximum temperature (Tmax) for summer cool waters is recommended as 25 °C; ∆T = 3 °C and for summer warm waters, Tmax = 28 °C; ∆T = 5 °C. The compliance of a thermal discharge with temperature regulations has to be proven mathematically during the licence application process. Furthermore, the state water & environmental authorities may require site-specific monitoring before and during discharge; however, there is no national programme of surface water temperature monitoring in place. 3.7.2 Feedback on effectiveness

The federal regulations are currently in the amendment process and a tightening of the regulations is being discussed (M. Redeker, pers. comm.). Feedback from regulators suggests the regulations shouldofbe site-specifically taking into account factors suchthat as natural temperatures theset water body and local climate and hydrology (M. Redeker, pers. comm.). 3.8

Denmark

Regulatory body: Danish Ministry of the Environment Document: Vejledning i recipientkvalitetsplanlægning , 1983 URL: http://www.mst.dk/udgiv/Publikationer/1983/87-503-4476-5/pdf/87-503-4476-

5.PDF


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3.8.1 Regulations

Responsibility for environmental regulation of Danish waters is in the process of being transferred. Currently regional authorities have responsibility, but from 1st January 2007 the Danish Ministry of the Environment will have responsibility for water management planning and local authorities will have responsibility for daily administration and detailed regulation. The guidelines for Danish freshwater temperature are based directly on the Freshwater Fish Directive. For coastal waters, the guidelines specify a maximum temperature increase of 1 °C at the edge of the mixing zone. Discharge authorisations are granted according to the Danish Environmental Protection Act and penalties are applied in case of non-compliance. Monitoring of environmental impact is at the discretion of the regional authorities (J. BrøggerJensen, Danish Environmental Protection Agency, pers. comm). 3.8.2 Feedback on effectiveness

No feedback was received on the effectiveness of these regulations as currently the responsibility for regulation of Danish waters is in the process of being transferred. 3.9

Austria

Regulatory body: Federal Ministry of Agriculture, Forestry, Environment and Water

Management Documents: Allgemeine Abwasser Emissions Verordnung , BGBl 1996/ 186;

Fischgewässer Verordnung , Amtsbl.z.Wiener Zeitung, 15.12.2000 3.9.1 Regulations

The Austrian water temperature standards are based on the Freshwater Fish Directive and scientific reviews commissioned by the Ministry of Forestry, Environment and Water Management (Humpesch et al., 1982 and Dokulil et al., 1993). The standards are summarised in Table 3.3. Table 3.3 Austrian surface water temperature regulations Maximum allowed increase in water temperature downstream from thermal discharge mixing zone Maximum permitted water temperature Maximum permitted water temperature during breeding season

Salmonid Waters 1.5 °C

Cyprinid Waters 3 °C

21.5 °C

28 °C

10 °C

10 °C

The Austrian water temperature regulations also provide a list of rivers and defined stretches of river and their official classification as either cyprinid or salmonid waters. There is no regulation regarding lakes in Austria.


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3.9.2 Feedback on effectiveness

These water temperature regulations are perceived to be appropriate except in cases where rivers are warmed in summer time to above the maximum permissible temperature (A. Jagsch, Institute for Water Ecology, Fisheries and Lake Research, pers comm.). 3.10

Belgium

Regulatory body: Departement Leefmilieu, Natuur en Energie (Department of the

Environment, Nature and Energy) Document: For Flanders: VLAREM II (Flemish legislation regarding environmental management and environmental licenses) URL:http://www.emis.vito.be/navigator/Scripts/item.asp?id_boek=53&volgnr=1&id_i nhoud=880&AddInfo=False 3.10.1 Regulations

In Belgium the responsibility for environmental policy has been devolved to regional governments (Flanders, Wallonia and Brussels Capital Region). The regulations are based on the FFD and make distinctions between waters inhabited by salmonids and cyprinids. The Shellfish Directive applies to marine waters. The Environment Inspection Section (EIS) is the enforcement body for environmental health legislation in the Flemish Region. Enforcement is carried out by means of temperature monitoring and monitoring of ecological status. When noncompliance is discovered the inspector seeks remediation and evaluates any damage. If the problem is more serious, the inspector may send the case to the prosecutor which can result in fines, imprisonment or may result in the closure of a facility. 3.10.2 Feedback on Effectiveness

The regulations are perceived as stringent but appropriate (Caroline Polders, VITO (Flemish Institute for Technological Research) pers. comm.). Revisions are prepared through a BAT (Best Available Techniques) approach which involves participation and feedback from both regulators and industry. 3.11

Switzerland

Regulatory body: Federal Office for the Environment Document: Gewässerschutzverordnung URL: http://www.admin.ch/ch/d/sr/8/814.201.de.pdf 3.11.1 Regulations

The Swiss water temperature standards are based on the Freshwater Fish Directive and on regulations set in other countries (E. Staub, Federal Office for the Environment, pers. comm.). Switzerland has no estuarine or marine waters, therefore the standards apply only to freshwater rivers and lakes. Increase in surface water temperature due to thermal discharge is accepted up to +1.5 °C for salmonid waters and +3.0°C for all other waters and the maximum allowable water temperature is 25°C.


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Switzerland has national water discharge monitoring stations that also collect water temperature data (E. Staub, pers. comm.). All operators of thermal discharges (e.g. nuclear power plants cooled with river water, warm water from transalpine tunnels) are obliged to measure temperature of both the discharged water and of river water downstream of discharge. This data is reported annually to the authority that grants discharge consent. 3.11.2 Feedback on Effectiveness

It is perceived that the regulations are appropriate although it is suggested that the maximum temperature of 25 °C may be too high for salmonid species (E. Staub, pers comm.). 3.12

Finland

Regulatory body: Ministry of the Environment and Ministry of Agriculture and

Forestry Document: Environmental Protection Act (86/2000), Environmental Protection

Decree (169/2000) and Government Decision on the Quality of Certain Fishwaters (1172/1999) URL: http://www.finlex.fi/en/laki 3.12.1 Regulations

The Government Decision on the Quality of Certain Fishwaters (1172/1999) designates certain salmonid and cyprinid waters (a total of 23 rivers and lakes) in accordance with the requirements of the EC Freshwater Fish Directive. The same temperature limit values specified in the Directive are specified in the Finnish legislation (for salmonid and cyprinid waters). Thermal discharges into water bodies are regulated according to the provisions laid down in the Environmental Protection Act (86/2000) and Environmental Protection Decree (169/2000). The specific permit conditions on thermal discharges from point sources e.g. power stations, are agreed on a case-by-case basis. The issue of discharge permits and the enforcement of the regulations is carried out by Environmental Permit Agencies, Regional Environment Centres and Municipal Environmental Authorities. The operators of thermal discharges are obliged to monitor the temperature of the discharge as well as and ecological status e.g. impacts on benthic fauna and fisheries. The monitoring requirements are set up case-by-case during the permitting procedure. 3.12.2 Feedback on Effectiveness

Feedback from Finnish practitioners is that the thermal regulations are perceived to be appropriate. Importance is placed on theare regular review of environmental conditions and thermal discharge permits reviewed regularly within 7 topermit 10 years. The results of the emission and impact monitoring and the ecological and use objectives for the water body are examined in the permit review process (S. Kimmo, Finnish Environment Institute, pers. com). 3.13

Sweden

Regulatory body: Swedish Environmental Protection Agency


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3.13.1 Regulations

Sweden does not have any national water temperature regulations for either fresh or marine water bodies. There is neither a national programme of temperature monitoring nor of monitoring of the effects of temperature on ecological status. There may be discharge temperature standards attached as part of the consent permit for thermal discharges and if the temperature criteria are not fulfilled the permit may be withdrawn, however, there is no routine monitoring of surface water temperature. 3.13.2 Feedback on effectiveness

Thermal discharges are not perceived to be of concern in Sweden (M. Gönczi, Swedish Environmental Protection Agency, pers. comm.). 3.14

Summary of International Regulations

Table 3.4 summarises the key numerical temperature standards used in the countries reviewed. This reveals a general consistency of approach in which regulation aims to protect spawning temperatures for coldwater species (ranging from 10 °C to 13 °C maxima), maximum allowable temperatures for the water body (after mixing) and a maximum temperature change (uplift). Some countries also limit the maximum temperature of the discharge water in thermal effluents. Most European countries follow the Freshwater Fish Directive, distinguishing between salmonid (cold-water) and cyprinid (warm-water) habitats, with temperature maxima of 21.5 °C and 28 °C respectively, and allowable temperature rises of 1.5 °C and 3 °C respectively. Germany and Switzerland differ in specifying a 25 °C maximum temperature for cold-water habitats but, according to WWF, Atlantic salmon have “all but disappeared from these countries”6 . It is interesting to note the Swiss comment that this limit is “may be too high for salmonids”. Marine limits, where specified, range from a +1 ° to +2 °C uplift. The review of European standards gives little suggestion that regulations in any of the countries questioned have developed beyond the FFD position, nor indeed does it seem that they have been subject to any rigorous scrutiny. There is no evidence from our enquiries of case histories being examined. Generally the respondents appear to show little confidence in the standards adopted. Feedback on standards including that from UK sources - ranged from a bland statement (“appears to be adequate”) to, more commonly, “too stringent” or even “not implemented”. This perhaps stems from the “one size fits all” approach engendered by the FFD. In contrast, the USA and Canada adopt a more flexible approach, tailored to particular species’ requirements, allowing for the application of more regional or local criteria. Such an approach is more suitable on a continental scale where regional climatic differences may be considerable. A common factor in European standards is the inclusion of a maximum allowable temperature change (uplift) standard. This does not appear to be adopted in the US regulations.

6

http://www.wwf.org.uk/news/n_0000000293.asp Temperature standards review and development/Jul-07

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Table 3.4 Summary of International Surface Water Temperature Regulations

Country

USA

Canada

South Africa New Zealand

Spawning temperatures

Cold water species Maximum water Maximum temperature permitted change in temperature

Warm water species Maximum water Maximum temperature permitted change in temperature

12 °C for bull trout rearing (upper river basin) 16 °C for juvenile salmonid rearing (mid to upper river basin) 18 °C for salmonid migration (middle to lower reaches) 20 °C for salmonid migration No absolute values are given in the national guidelines. The guidelines describe methods for calculating appropriate values for standards based on sensitive species and life stages present. 9 °C for bull trout spawning 13 °C for salmonid spawning 14 °C for steelhead smoltification

3 °C change from natural background temperature

Lakes

-

Marine

-

These are natio which are used standard settin -

+1 °C natural temperature +1 °C natural temperature -

-

-

-

-

-

25 °C

3 °C

25 °C

3 °C

-

Netherlands

-

21.5 °C

1.5 °C

28 ºC

3 ºC

-

Germany

-

25 °C

3 °C

28 °C

5 °C

-

Denmark

10 °C

21.5 °C

1.5 °C

28 °C

3 °C

-

Austria

10 °C

21.5 °C

1.5 °C

28 °C

3 °C

-

+1 ºC maximum temperature increase (at edge of mixing zone of a discharge N/A

Belgium Switzerland

10 °C -

21.5 °C 25 °C

1.5 °C 1.5 °C

28 °C 25 °C

3 °C 3 °C

As rivers

N/A

Finland

10 °C

21.5 °C

1.5 °C

28 °C

3 °C

-

-

Sweden

-

-

-

-

-

-

-


3-1

Natural may be establis if this is higher anthropogenic recommended

25 °C maximum with a +2 °C change -

These are natio which are used standard settin

Water of shellfish for h may not be cha 3 °C

These which are used standard settin Freshwater reg on FFD

Freshwater on FFD Freshwater on FFD Freshwater on FFD

4

Water Body Typology The Water Framework Directive (WFD; article 5 annex II) requires member states to characterise waters including the identification of water bodies and typology of surface waters. The UK Water Quality Technical Advisory Group (UKTAG) has produced guidance for typology of UK rivers (UKTAG, 2003a), lakes (UKTAG, 2003b) and coastal and transitional waters (2003c). A review of typologies of rivers and lakes is also given in SNIFFER, 2005. The paragraphs below provide a summary of several of the typologies currently in use. 4.1

Typology for Rivers

The characteristics of natural rivers used in devising the typology under Section 1.2.1, annex 5, system A of the WFD are given in Table 4.1 (UKTAG 2003a). Table 4.1 Typology for rivers given by the WFD Mean catchment altitude (m)

Catchment size (km2)

Dominant geology

Lowland <200 Mid-altitude 200-800 High-altitude >800

10-100

Siliceous

100-1 000

Calcareous

1 000-10 000

Organic

This table generates a potential 27 typological river types, however, in application 18 of these types are significant in Scotland, England and Wales and these are given in Table 4.2 (adapted from UKTAG 2003a). Table 4.2 UK river types given by UKTAG (2003a) Type

Mean catchment altitude (m)

Catchment size (km2)

Dominant geology

1 2 3 4 5 6 7 8

<200 <200 <200 <200 <200 <200 <200 <200

10-100 10-100 10-100 100-1 000 100-1 000 100-1 000 >1 000 >1 000

Siliceous Calcareous Organic Siliceous Calcareous Organic Siliceous Calcareous

9 10 11 12 13 14 15 16 17 18

<200 200-800 200-800 200-800 200-800 200-800 200-800 200-800 200-800 >800

>1 000 10-100 10-100 10-100 100-1 000 100-1 000 100-1 000 >1 000 >1 000 10-100

Organic Siliceous Calcareous Organic Siliceous Calcareous Organic Siliceous Calcareous Siliceous


4-1

A typology of UK rivers based on ecological data has been defined using macrophyte communities (Holmes et al. 1998). This classification was simplified to give 8 generic river water body types (summarised in Table 4.3, adapted from Holmes et al, 1998). This typology has been deemed appropriate for setting standards for macro-invertebrates and macrophyte communities (SNIFFER, 2006). Table 4.3 River typology given by Holmes et al. (1998) Type A

A1 - lowland, low gradient, clay

substrate river A2 - lowland chalk stream Type B

B1 – low/medium altitude,

low/medium gradient, sandstone, mudstone or hard limestone substrate B2 – shallower than B1, low/medium altitude, low/medium gradient sandstone, mudstone or hard limestone substrate Type C C1 - medium altitude, medium slope, more silt and sand than C2, shale, hard limestone and hard sandstone substrate river C2 – steeper than C1, medium altitude, medium slope, shale, hard limestone and hard sandstone substrate river Type D D1 – medium gradient, lowland, finegrained substrate river D2 - steep, upland, coarse-grained

substrate river

e.g. Wissey, Lark, Nar, Wensum, Avon e.g. Test, Piddle, Frome, Itchen, Hull e.g. Tamar, Torridge, Exe, Lugg e.g. Ribble, Wharfe, Eden, Tweed Scattered around UK e.g. Lower Findhorn, Dee, Usk, Spey e.g. Lowland acid heaths, New Forest, Western Isles e.g. Dartmoor, Exmoor, Pennines

There is currently no precise method for predicting which fish communities would be present in a particular river (SNIFFER, 2006). The Environment Agency Resource Assessment and Management Framework (RAM, Environment Agency, 2002) is a typology designed to be sensitive to ecological consideration. The RAM fisheries scoring system is given in Table 4.4. Table 4.4 RAM framework as given by the Environment Agency (2002) RAM score 5 4 3

2 1

Description

Salmonid fish – spawning/nursery area Adult salmonids residents (wild) and/or rheophile coarse fish – barbel, grayling Salmonid fish passage (smolts or adults) and/or flowing water cyprinid fish – dace, chub, gudgeon, bullhead and/or shad spawning/rearing/passage Slow/still water cyprinid fish – roach, bream, tench, carp Minimal fish community e.g. eels and stickleback only or no fish

The EU FAME project aimed to develop fish-based ecological status assessment methods for European rivers. Each fish species has preferred habitat requirements and this results in changes in community structure along the upstream- downstream Temperature standards review and development/Jul-07

4-2

gradient of a river. Cowx et al. (2004) grouped fish species with similar habitat requirements and defined eight fish community types and identified the key (most abundant) fish species within each type. In broad terms, types 1, 2, 3 and 8 can be considered as salmonid waters and types 4, 5, 6, 7 as cyprinid waters (see Table 4.5, adapted from Cowx et al. 2004). Table 4.5 Typology based on fish community t ypes given by Cowx et al. (2004) Type

Key species

Complementary species

Abundance / comments

1

Brown trout

Very high abundance of trout

2

Salmon Brown trout Brown trout

Salmon Bullhead Bullhead Stone loach Eel Bullhead Stone loach Lamprey Flounder Grayling Stone loach Gudgeon Chub Dace Perch

Presence of bleak high abundances of pikeand andrelatively bream indicative of larger lowland rivers Relatively high abundances of grayling, salmon and pike. Constitutes sites from Hampshire chalk rivers Test and Itchen

3

Brown trout Eel Barbel Chub Roach Bream

4 5 6

7

Pike Bleak

Roach

8

Salmon Grayling

Brown trout Pike

Very high abundance of salmon Very high abundances of minor species and high abundance of trout Relatively high abundance of diadromous species plus some coastal species Relatively high abundance of barbel, indicative of main river stem of large rivers Relatively high abundances of common cyprinid species

These eight fish community types were further distilled into five fish community types by SNIFFER (2006) when considering the development of environmental standards, in that instance specifically in relation to water abstraction. River velocity and flow volume may influence river water temperature, therefore it may be appropriate to adopt this typology. The community types given by SNIFFER (2006) are: • • • • •

Chalk stream communities Eurytopic/limnophilic – roach, bream, tench, pike, bleak Rheophilic – dace, chub, adult resident trout Salmonids cyprinids – adult salmon Salmonids – spawning and nursery areas.

UKTAG (2006), when recommending dissolved oxygen standards, proposed a basic typology for rivers based on just alkalinity and altitude. The rationale behind this typology is linked to the organic pollution tolerance of aquatic invertebrate species, for example, high alkalinity lowland rivers have invertebrate communities dominated by taxa less sensitive to organic pollutants.


4-3

Given the intrinsic link between dissolved oxygen and temperature it may be suitable to consider these two parameters with the same typology. The typology used for setting dissolved oxygen standards is summarised in Table 4.6 (taken from UKTAG, 2006). Table 4.6 Typology used in the setting of dissolved oxygen standards for surface waters (UKTAG, 2006)

Site altitude Under 80 metres Over 80 metres

Alkalinity (as mgL-1 CaCO3) Less than 10

Type 1

10 to 50

Type 2

50 to 100

100 to 200

Type 3

Type 5

Type 4

Type 6

Over 200

Type 7

This typology was condensed further to produce a final typology as summarised in Table 4.7 below: Table 4.7 Final typology used in the setting of dissolved oxygen standards for surface waters (UKTAG, 2006)

Upland and low alkalinity Lowland and high alkalinity

Types 1, 2, 4 and 6 Types 3, 5 and 7

These typologies approximate to the typology of the existing Freshwater Fish Directive(lowland standards Salmonid Waters (upland and low alkalinity) and Cyprinid Waters andofhigh alkalinity). 4.2

Typology for Lakes

The typology applied to UK lakes uses Section 1.2.2, annex 5, system B of the WFD is given in Table 4.8 (adapted from UKTAG 2003b). Table 4.8 UK lake t ypes given by UKTAG (2003b) Catchment geology

Depth

Altitude

Size

Organic

Very shallow (<3 m) Deep (>3 m)

Lowland (<200 m)

Calcareous

Mid-altitude (200800 m) High-altitude

Very small (1-9 ha) Small (10-49 ha) Large

Brackish

(>800 m)

(20-10 000 ha)

Siliceous

UKTAG (2006) dissolved oxygen standards for lakes divide lakes into only two categories; those that support natural populations of salmonids and those that support natural populations of cyprinids. This typology does not take into account lakes that support populations of charr ( Salvelinus alpinus) and coregonid fish; vendace (Coregonus albula) and powan (Coregonus lavaretus).


4-4

For the purposes of this review we propose three lake typologies based on a similar structure to the typology for rivers based on fish community structure given by Cowx et al. (2004). This typology is detailed in Table 4.9. Table 4.9 Proposed UK lake types based on fish community structure Type L1

L2 L3

4.3

Key species

Complementary Species

Charr Vendace Powan Brown trout Salmon Bream Roach

Brown trout Eel Perch Pike

Typology for Coastal and Transitional Waters

The typology applied to UK transitional waters uses Section 1.2.3, annex 5, system B of the WFD (given in Table 4.9, adapted from UKTAG 2003c). Table 4.10 UK transitional water types given by UKTAG (2003c)

Mixing characteristics

Salinity

Mean

TW1

Partly mixed/stratified

Mesohaline or polyhaline

TW2


TW3 TW4

Type

Name

Exposure

Depth

Substratum

Macrotidal

Sheltered

Intertidal/shall ow sub-tidal

Sand and mud

Mesohaline or polyhaline

Strongly mesotidal

Sheltered

Intertidal/shall ow sub-tidal

Sand and mud

Fully mixed

Polyhaline

Macrotidal

Sheltered

Extensive intertidal areas

Fully mixed

Polyhaline or Euhaline

Mesotidal

Sheltered

Extensive intertidal areas

Sand or mud

Polyhaline

Mesotidal

Sheltered

Oligohaline - polyhaline

N/A

Sheltered

Shallow

Mud

tidal range

TW5

Transitional sea lochs

TW6

Transitional lagoons


Thermal regimes will differ between the types, depending on e.g. the proportion of intertidal the degree mixing and the relative influence of freshwater Each typearea, will also favour aofdifferent balance of fish community. However, ininput. each case there is likely to be representation of each of the ecological guilds, with the exception of transitional lagoons (typology TW6): these generally have limited opportunity for migratory species and may not therefore need to be regulated to a level suitable e.g. for salmonids or smelt. Turnpenny and Coughlan (2006) proposed that temperature regulation in transitional waters should be applied by condensing the typology given by UKTAG (2003c) in two groups as follows:


4-5

Group A: estuaries and sea lochs (TW1-TW5) Group B: brackish lagoons (TW6). This distinction implies that all Group A waters in England and Wales should have the potential to support cold-water migratory species such as smelt, salmon and sea trout. Retention of the older categorisation into ‘salmonid’ and ‘non-salmonid’ waters would maintain the status quo rather than encourage improvement to Good Ecological Status or Potential and is therefore to be avoided within the WFD context. The typology applied to UK coastal waters uses Section 1.2.4, annex 5, system B of the WFD are given in Table 4.10 (adapted from UKTAG 2003c). Table 4.11 UK coastal water types given by UKTAG (2003c) Type

4.4

Mean tidal range

Exposure

CW1

Name

Macrotidal

Exposed

CW2

Mesotidal

Exposed

CW3

Microtidal

Exposed

CW4

Macrotidal

Moderately exposed

CW5

Mesotidal

Moderately exposed

CW6

Microtidal

CW7

Macrotidal

Moderately exposed Sheltered

CW8

Mesotidal

Sheltered

CW9

Microtidal

Sheltered

CW10

Coastal lagoon

N/A

Sheltered

CW11

Sea lochs (shallow)

Mesotidal

Sheltered

CW12

Sea lochs (deep)

Mesotidal

Sheltered

Summary

The selected typologies were grouped and condensed according to the temperature preferences of the fish species present and two categories were distinguished; coldwater (formerly ‘salmonid’) and warm-water (formerly ‘cyprinid’), suggesting that the two level typology grouping given by the FFD remains adequate. Table 4.12 indicates the grouping and gives the final typology proposed. Table 4: Final temperature water body typology Cool water R1, R2, R3, R4, R8, L1, L2, TW1-6, CW1-12 Warm water R5, R6, R7, L3


4-6

5

Existing UK Guidelines and Standards

5.1 EC Freshwater Fish Directive (FFD)

The EC Freshwater Fish Directive (78/659/EEC) requires that certain designated stretches of water (rivers, lakes or reservoirs) meet quality standards that should enable fish to live or breed in that water. While legally applicable only to fresh waters, standards have been applied to transitional waters in the absence of more suitable standards. In England and Wales, the EC standards are implemented via The Surface Waters (Fishlife) (Classification) Regulations 1997. The Directive identifies two categories of water; those suitable for: •

salmonid fish or

•

cyprinid fish.

It also distinguishes ‘imperative standards’, which must be met in order for a designated water to be compliant with the Directive, from ‘guideline standards’ which should be met ‘where possible'. Table 4.1 shows imperative standards for DO and temperature. Under Article 11 of the Directive, Member states may derogate from the Directive because of exceptional weather, special geographical conditions or where "natural enrichment" makes it impossible to respect the values for the Standards. Table 4.1 Imperative Standards for Temperature and DO from the EC Freshwater Fish Directive Parameter Salmonids Temperature Imperative (I.) value – (°C) Increment above upstream temperature should not exceed 1.5°C at the edge of the mixing zone.

Cyprinids Imperative (I.) value Increment above upstream temperature should not exceed 3.0 °C at the edge of the mixing zone.

Remarks Sudden variations in temperature should be avoided.

Imperative (I.) value –

Imperative (I.) value –

The temperature should not exceed 21.5 °C at the edge of the mixing zone for more than 98%

The temperature should not exceed 28 °C at the edge of the mixing zone for more than 98% of

Regional derogations from this standard are permitted. Species that require cold water for reproduction are protected by an upper limit of 10 °C

of the time.

the time.

during the breeding season.

5.2 EC Shellfish Directive

The 2 ºC degree temperature rise specified in the 79/923 Shellfish Waters Directive has become a surrogate EQS for marine waters generally. WQTAG160 (version 4) "...incorporates temperature thresholds defined in existing EC directives (namely the Shellfish Waters and Freshwater Fish Directives)...". The critical point is that this new usage accepts the definition given in the Shellfish Directive without clarification or re-definition even though: Temperature standards review and development/Jul-07

5-7

• • •

•

•

it is a Guideline, not a Mandatory, value; the minimum sampling frequency is quarterly; the comparison is with "..waters not so affected.." with no limit on where these might be; Member states can vary or derogate from the Directive in the event of "exceptional weather" that presumably includes any hot summer; Member states can vary or derogate from the Directive in the event of "geographical conditions" that presumably include confined waterways.

In January 1980 a DoE circular on the implementation of the Shellfish Directive advised Water Authorities (at para 6b) that there “is no obligation to use the G (guideline) value given in the Annex or even to set a figure close to it. A G value is no more than an indication of what the Community regards as an ideal ”. In

November 1980 further DoE advice stated (at para 9.1): “Evidence from the CEGB and UKAEA7 has shown that the thermal discharges from power stations are unlikely to produce major temperature differentials except in areas close to discharge points. There may be local variations and in certain circumstances a larger layer of warm water near the surface may occur, but in general the Working Group felt that water authorities should be able to observe the G value of a 2 C variation in designated shellfish waters. °

The CEGB/UKAEA representations had drawn attention to the natural establishment and continued development of clam (Mercenaria mercenaria) and oyster ( ) beds in transitional waters around power station outfalls (e.g. Ostrea edulis and Fawley) where excess temperatures >2 °C were routinely Bradwell, Marchwood encountered. During consideration of an application for a thermal discharge into the middle of a designated oyster ground, the advice further stated that: “The Shellfish Directive, as published, does not say whether the 2 C is to be measured at the surface, at one metre depth (as in the 1976 draft), throughout the water column, on the seabed or is a depth-averaged value. This is to be determined by the competent authority. There is no evidence that any coordinated attempt has been made to determine or clarify this for its srcinal or new, surrogate, role. In 1988 the (then) Southern Water Authority, in consultation with MAFF, determined that it applied to the seabed beyond the limits of an agreed tidally determined footprint.” °

The “waters not so affected” issue leads to potential problems in selecting a reference location. The concept of a stable background (or ambient) temperature is particularly difficult in an estuary or embayment. In 1956 the thermal survey for Bradwell nuclear station used Clacton Pier (10 nautical as a local(Essex) control and the power Sunk lightship (30 nm) as the ultimate controlmiles to tryaway) to escape potential long-term build up of heat. Pembroke (Milford Haven) power station thermal surveys (1960s/’70s) were referenced against St Gowan lightship off the south coast of Pembrokeshire, which turned out to be a bad choice since temperatures there were found to be decreasing by about 0.2 °C/decade. The widespread use of thermal hydraulic modelling nowadays perhaps simplifies this issue from a consenting point of view, as results are usually expressed in terms of the temperature rise relative to background. 7

United Kingdom Atomic Energy Authority Temperature standards review and development/Jul-07

5-8

5.3

Feedback on Current UK Water Temperature Standards and Approach to Regulation

The Project Steering Group wished to seek the views of a number of specialists representing different viewpoints on regulation. A list of contacts was agreed (Appendix B), with whom face-to-face meetings or teleconferences are to be held. The views of those contacted so far are summarised below. Text shown in italic typeface is a written summary provided by the contact following the discussion. 5.3.1 Professor Terry Langford, author of “Ecological Effects of Thermal Discharges”, University of Southampton Thermal standards must be reasonable. Maxima or averages should not in any season be less than the potential natural temperature which the water reaches or has reached over available records. For rivers and lakes this would be around 2425 C and 22-24 C for estuaries (transitional waters) and marine waters, depending upon the depth of water and tidal flow, but irrespective of migratory fish. °

°

Thermal standards must take into account temporal and spatial criteria. Variations should allow for time-temperature relationships, i.e. short term exposures to defined maxima may not be generally harmful. This will also allow for short-term operations of plant which could be severely disadvantaged by too stringent constraints. Seasonal variations can also be allowed such that vulnerable species may be protected or not if they are not present at that time. Vertical and/or horizontal stratification and avoidance can allow higher temperatures from some installations at least for some of the year. Sometimes slow mixing may be the best protection, depending upon the species exposed and their ecological "value". It must be assured that temperature is the real danger in any discharge and not contaminants for example chlorine. This is why some of the earlier work on thermal discharges came up with widely variable constraints as the scientists and regulators did not recognise the effects were caused by chlorine in both freshwater and marine habitats. There will be pressure to simplify regulations as regulators are not able to cope with complexity. Blanket criteria should be avoided and consideration given to the industries and their responsibilities to society as well as to fish. 5.3.2 Neil Edwards, Environmental Specialist, RWE Npower The existing standards/guidance for temperature are not complete and some have not been subject to full technical review and regulatory impact analysis. This leads to difficulty in developing acceptability arguments for thermal discharges, resulting in potentially excessive costs and extended project development time for stakeholders, including plant owners, regulators and statutory and non-statutory consultees. In particular, from the owner perspective, this results in uncertainty in project planning (for new plant with operation life up to 40 years from now and site considerations beyond that – use of grid and existing plant infrastructure). There is a risk that if an over-precautionary approach is applied, especially in conjunction with climate change concerns, it will become harder to operate/develop direct-cooled plant. This would lead to reduction in thermal efficiency in electricity production and increase in all gaseous emissions/MWh supplied (including CO 2), which is not necessarily an appropriate outcome from a societal perspective.


5-9

The EU-wide standards will have been derived to protect EU as a whole (e.g. using EIFAC work of the 1960s in the case of the Freshwater Fish Directive) and may be over precautionary for UK species/habitats. There is currently no general standard to protect aquatic life with respect to temperature/ temperature rise in nondesignated rivers, lakes, estuaries or seas – this makes each assessment potentially more subjective than it need be, though depending on species/habitat sensitivity it may be that each assessment has to be unique based on species/habitats potentially affected. However, in the absence of standards, some stakeholders invoke the ‘precautionary principle’ and seek to invoke the most restrictive standard ‘number’ from other settings which could potentially apply (e.g. widespread use of +1.5°C, 21.5°C to protect salmonid migration in estuaries). This could result in inappropriate outcomes from a societal perspective. There is no standard to protect migratory fish passage (especially fish of conservation importance e.g. salmon, lamprey, shad, eel etc). Often regulators/stakeholders seek to apply the EU FFD salmonid standard +1.5°C and 21.5°C or apply ‘findings’ of recent tagging studies in a precautionary way with respect to temperature or temperature rise which does not acknowledge the study author’s own interpretation, which is often cautious or tentative, of causal relationships (e.g. DO, salinity, freshwater flow, light cues, olfactory cues. No principles of mixing zone extent acceptability are laid out. It may well be entirely appropriate that the acceptable extent is case-specific. However, some consideration within the review may be helpful. Some stakeholders, perhaps those most familiar with the small volume flux discharges from sewage treatment works, do not appreciate the scale of power station direct-cooled discharges (e.g. 1060m3s-1) which leads to a difference in the nature of physical mixing within the regulatory mixing zone compared with STW discharges. See for example PPG28. The H1 methodology on ‘initial dilution’ for estuarine and marine situation is inappropriate for most power station thermal discharges evaluation. The recent Commission draft directive on EQS for PS/PHS (priority and priority hazardous substances) introduces a concept of Transitional Area of Exceedence (TAoE) for these substances and the Commission appears to reserve the right to ‘set up the method to be used for identification of the TAoE.’ Depending on what this means, ideas emerging may influence stakeholder expectation regarding mixing zones in other contexts. In particular, the draft Directive seeks to achieve progressive reduction in extent of the TAoE for PS/PHS. There should be no expectation of through life progressive reduction on extent of a thermal mixing zone for a power station. There is no explicit recognition of robustness of biota on intertidal areas with respect to water temperature change. Water temperature is not a strong contributor to the ‘stress envelope’ experienced by intertidal residents especially those of the upper intertidal areas (for example; air/water, rain (freshwater), frost, wind, solar radiation). The application of standards designed to be protective of subtidal ecology may well be significantly over precautionary for the protection of the ecology of intertidal areas. In absence of ‘general ecosystem standard’, assessment of acceptability or otherwise of general ecosystem effects is not straightforward and tends to be sitespecific. Whilst this may be inevitable some standard/guidance would be helpful if technically feasible. (Such guidance would deal with species succession (i.e. balance of species in communities changing in response to temperature changes while ecosystem functioning remaining not significantly affected).


5-10

“Exotics” risk is always an assessment issue for stakeholders but often appears to receive undue attention given the limited evidence of temperature effects being a contributory factor in the actual occurrence of exotic species. However, given the UKCIP02 forecasts of temperature rise related to climate change effects, some consideration of ecosystem response would be helpful in the context of overall adaptation policies. A further issue is how to treat climate change temperature rises in the context of temperature standards? For many of the power stations being considered now, the committed climate change temperature rise (e.g. 0.15-0.3°C/decade 1990-2030 based on UKCIP02) would lead, away from the immediate vicinity of the outfall, to greater temperature rises than that due to the long-term heat field the station. Some guidance/statement here dealing with the integration with climate change adaptation policies in a wider policy context may be helpful for all parties. 5.3.3 Les Watson, Regulatory Area Manager, Scottish Environmental Protection Agency

Les Watson described a case study of thermal discharges from distilleries in Scotland. The distilleries had been operating thermal discharges for many years under operating consents that pre-dated the FFD. Monitoring specific to their operating conditions was routinely carried out by the distillery operators. The discharges have been at temperatures higher than standards set by FFD, however, no real concerns were raised as no apparent impact on fish populations was found. However, work by the Freshwater Fisheries Laboratory (Faskally) has suggested that salmon parr downstream of these discharges may be maturing more quickly. 5.3.4 Tim Jacklin, Fisheries Technical Specialist, Environment Agency, Midland Region

Tim Jacklin Since 1969 it is clear that species composition in the River Trent has shifted from being dominated by roach to become increasingly diverse with chub, bream, eels and perch all becoming more important in anglers' catches (Jacklin, 2000; Cowx & Broughton, 1986; Cowx, 1991). This has been attributed to an improvement in water quality and its implications for inter-specific competition (Cowx & Broughton, 1986). The aspects of water quality that have changed since 1969 are water clarity which has increased due to smaller quantities of organic suspended solids entering the river and temperature which has decreased due to less heated effluent from power stations being discharged. Improvements in dissolved oxygen, ammonia and biochemical oxygen demand have also occurred resulting in an increase in the diversity of the invertebrate community which was previously dominated by a small number of species resistant to organic pollution (Jacklin, 2000). Changes in the fish community are the result of complex interactions between changing water quality and the compromised habitat of the River Trent resulting from impoundment, land drainage and flood defence. Changes that have been attributed mostly to reduced temperature include increased variability in year-class strengths resulting from climatic influences. Studies on fish affected by power station cooling discharges in the Trent (Sadler, 1979; Alabaster, 1962) and other British rivers (Brown, 1975; 1973; Cragg-Hine, 1971) have generally recorded an extension of the growth period and an increased growth rate. Artificially elevated temperatures in the Trent causing faster growth could therefore have lead to strong year classes occurring more frequently than under a natural temperature regime (Jacklin, 2000). Temperature standards review and development/Jul-07

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More recent research has indicated food availability and growth rate at specific developmental stages may be more important than ultimate over-winter size, the speed at which fish outgrow vulnerability to certain forms of predation being the implied mechanism (Mann et al., 1997). An aspect of inter-specific competition described by Persson (1986) is the influence of temperature on foraging ability. Roach displayed a longer handling time and lower capture rate of prey than perch at lower temperatures (12 – 18 C), whilst the reverse was true at higher temperatures (18 – 21 C). Reduced input of heated effluent from power stations has generally lowered the temperatures in the Trent. The lower temperature regime may have influenced competitive interactions between many species resulting in changes in relative abundance. °

°

Since 1998 migratory salmonids have returned to the Trent after an absence of 70 years. The return is largely because of annual stocking with juvenile salmon into Trent tributaries, but relies upon a migration route through the main river with water quality parameters suitable for the survival of this species. Feasibility studies on salmon re-introduction in 1985 and 1995 (STWA, 1985; Cowx & O’Grady, 1995) highlighted low dissolved oxygen and elevated water temperatures in the tidal river and Humber Estuary as having the potential to bar the upstream movement of salmon, particularly in the summer. Whilst this problem was reduced by the decommissioning of many coal-fired power stations, potential problems remain and the renaissance of power generation in the Trent valley using gas-fired turbines currently gives cause for concern.


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6

Review of Temperature Requirements of UK Fish Species

6.1

Introduction

Initially, the aim is to review the temperature preferences of the key and secondary species in each of the water body typologies. The typology of UK waters selected has been based on the typology of fish communities developed by Cowx et al. (see Table 4.5, adapted from Cowxet al. 2004). The typologies selected for each water body are as follows; eight river typologies based on fish community structure given by Cowx et al. (2004), the three lake typologies proposed in section 3.2 and the two coastal and transitional water body types proposed by Turnpenny and Coughlan (2006)(referred to as TCW1 and TCW2). This typology with key and complementary species and their temperature preferences are shown in Table 6.2. The temperature preferences selected for consideration are spawning temperature, ultimate temperature preferenda and lethal temperatures. In selecting data on which to base standards, a distinction must be drawn between scientific studies which are carried out to gain a better understanding of processes, normally at the individual level, and those which are designed to understand biological response thresholds at the population level. Research on processes helps to determine suitable methods of measurement and what parameters need to be measured but for setting standards, we are concerned with questions of how response thresholds vary among species and lifestages, how they are influenced by environmental variables and the magnitude of the population variance. Effective standards must protect the most vulnerable lifestages of the most vulnerable species. This dimension is lacking in many studies. When reviewing literature on thermal effects on fish, terminology can be confusing. Jobling (1981) provides the following explanation. “Acclimation temperature” refers to the temperature to which the fish have become adapted in the short-term (i.e. days). The thermal responses of fish relative to acclimation temperature, can be divided into zones of tolerance, resistance and preference. The upper boundary is represented by the critical thermal maximum (CTM), which is a measure of thermal resistance determined by increasing the water temperature at a rate of 1 °C min-1 until the fish lose equilibrium with survival times above CTM being close to zero. The upper and lower incipient lethal temperatures (UILT and LILT) represent the temperatures at which, theoretically, 50% of the population could survive indefinitely. The ultimate upper incipient lethal temperature (UUILT), LILT and CTM vary with acclimation temperature and the previous thermal exposure. These form the boundaries of the thermal tolerance zone. By choice, fish will spend as much time as possible within a certain preferred temperature range (thermal preferenda) at which they function best. Acute thermal preferenda are usually determined over a short period by their acclimation temperature but, left in a temperature gradient for a long period, they will gravitate towards the optimum for the species (final preferendum). When applying species-specific lethality data to standards-setting, it is preferable to choose a metric which is protective of the majority of the population; thus the UILT (based on a median response – it would better perhaps be called the UILT 50) would be a more suitable measure than the CTM (not survivable by any of the population). On the other hand, the “UILT90” (the highest temperature that 90% of the population could survive) would be better still. In practice, data based on uniform measurement Temperature standards review and development/Jul-07

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standards and metrics are not available for a wide range of species and for the present, a rather looser definition will have to suffice. Jobling (1981) also recognised this problem: in trying to define upper limits of temperature tolerance, Jobling found that different authors presented either CTM, UILT or UUILT values and in his own review was obliged to adopt the term ‘upper lethal temperature’ as a catch-all. Although this inevitably reduces the precision of the data, for the purposes of standards-setting, a safety margin can be added. The term ‘upper lethal temperature’ (ULT) is used in this sense in this document. 6.2

Upper Lethal Temperature

A temperature of around 40-41 °C can be regarded as the limiting CTM for all temperate fish. At lethal temperatures, proteins begin to denature and enzyme systems fail (Somero andHofmann, 1997). Sudden changes in temperature may kill fish due to "thermal shock". In British waters no species would tolerate temperatures as high as 40°C, although eel can survive to 38 °C and some freshwater cyprinids can tolerate temperatures in the high-thirties (Langford, 1990). Since bulk temperatures (i.e. outside any thermal plume) in Britain are unlikely to exceed around 25 °C outside the mixing zone of thermal discharges, it is unlikely that fish kills would occur due to temperature alone. Even within thermal plumes, where temperatures can reach +10-14 °C above background (which might reach ≥22 °C in an estuary during a warm summer), Langford’s (1990) review, ‘ Ecological Effects of Thermal Discharges’, concludes that ‘in view of the vast amount of literature dealing with thermal discharges, very few large-scale mortalities have occurred which can unequivocally be related to high temperature’. Summer

temperatures in the warmest southern English estuaries (e.g. the Thames) can °

Temperatures have been reported reach 23-24 25 °C inC.Scotland during in lowsmall flow headwater conditions streams (I Malcolm, pers. comm.). Forto most warm-water species, ULTs in the high twenties to thirties °C provide adequate headroom for survival under these conditions, although the situation is more marginal for some cold-water species such as the salmonids and probably smelt. However, it is clear that the temperature could become critical for survival of these species under the more severe global warming scenarios. Although locally higher temperatures may occur around thermal discharges, fish are usually able to avoid exposure to lethal temperatures, provided that the plume does not pervade the full channel width and depth. When reviewing the published literature on lethal temperatures of fish species it is important to consider the thermal responses of fish relative to acclimation temperature. Studies where fish were subjected to a large change in water temperature in a very short period of time may not determine the true lethal temperature for that species nor reflect environmental conditions fish are likely to experience in their natural habitat. Therefore, studies where the acclimation °

temperature was less than 15 C have not been included in this review. 6.3 Ultimate Temperature Preferenda Since lethal temperatures are seldom reached in UK surface waters, thermal preferenda are the most important criteria in relation to thermal standards development. Brett’s classic 1971 study of the thermobiology of sockeye salmon (Oncorhynchus nerka) demonstrated that the preferred temperature in this species (15 °C) coincided with the optimum temperature for metabolic scope, cardiac scope, swimming performance and growth. Magnuson et al. (1979) proposed the concept of fish occupying a “thermal niche”, a band of temperatures in which they prefer to Temperature standards review and development/Jul-07

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live: they found that most fish will spend two-thirds of their time at within ±2 °C of their temperature preferendum and all of their time within ±5 °C. This no doubt serves to keep fish within their optimum physiological temperature range (but note that while each species will exhibit a final preferendum, their preferendum at any one time will be governed by acclimation temperature, which will alter seasonally). Magnuson et al. (1979) also proposed that fish will compete for resource use within a particular thermal niche. At the individual river basin level, therefore, the dynamics of preference-competition will be a major factor in determining fish community structure; on a global scale, it will determine the geographic range of the species. An important consideration is whether water temperature rises might push species living close to the upper limit of their thermal niche to move away or become impoverished. In the case of cold-water anadromous species such salmonids or smelt, it is possible, but by no means proven, that they would fail to penetrate areas where the temperature is raised above their thermal niche limit to reach spawning grounds. The outcome in such cases will be a function of, e.g. their ability to detect and avoid thermal changes, their motivation to spawn and their ability to swim through the affected area. The experimental method used to determine temperature preferenda usually involves some form of gradient or choice chamber apparatus that allows fish to select from a range of offered temperatures. As with lethality data, preferred temperatures depend on the acclimation temperature and therefore will vary seasonally. 6.4

Preferred Spawning Temperatures

Temperatures suitable for spawning fall within a narrow range in some UK species such as dace and smelt. However, it is important to note that for many species the observed spawning temperature range may not necessarily represent spawning temperature limits. If the temperature in a spawning area is artificially elevated then spawning and early development could fail, since embryonic stages have narrower thermal niche than older lifestages. Discrete spawning grounds of substrate spawners deserve particular attention because, if they happen to be close to a thermal discharge, any effect such as thermal avoidance by adult spawners or mortality of eggs could be catastrophic, as compared with pelagic-spawning fish where only those eggs that drift into the way of the thermal plume would be affected. The thermal tolerance zone of eggs is narrower than for later developmental stages. Effective regulation of temperatures in spawning areas is therefore critical. Once hatched, warmer temperatures can be beneficial, increasing developmental rates and shortening the time for larvae to pass through critical lifestages. This would be true (within limits) for all warm-water species and possibly in cold-water species too, early in the season; however, this may have knock-on ecological effects. 6.5

Migration

The majority of laboratory work on fish behaviour in response to temperature choices has concentrated on determining thermal preferenda and some avoidance of high water temperatures is implicit in these measurements. However, a more specific concern is as to how fish will behave when confronted with a step change or sharp gradient in temperature on meeting a thermal plume or far-field temperature rises caused by a thermal discharge. This is one of the most important regulatory aspects for consenting thermal discharges. In relation to European sites, WQTAG160 (WQTAG, 2006) takes a precautionary approach and assumes that fish will be reluctant to pass through thermal plumes: “Migratory fish species will be an important element of estuarine habitat structure and functioning, and may even be cited as specific Temperature standards review and development/Jul-07

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interest features in their own right. They require a significant “window of opportunity” to migrate upstream. The mixing zone is likely to be surface-biased but should not form a barrier to migration across the whole estuary, or block areas of the estuary through which fish are known to pass.”

Blockage by thermal plumes appears to be an intuitive rather than observed concept. The reasoning is that salmonids (the main migratory species of interest) are cold-water stenotherms and therefore avoid warm water. In fact, fish tracking studies carried out in rivers and estuaries in the UK and elsewhere in the world do not provide any clear evidence of thermal barriers (Langford,by1990) where evidence suggests possible effects it has been confounded otherand issues such as changes in - or absolute levels - of freshwater discharge and the levels of dissolved oxygen. A lesser known issue concerns juvenile migrations through estuaries. A common mechanism by which young fish undertake migrations in transitional waters is known as selective tidal stream transport (STST). STST was first demonstrated in plaice (Pleuronectes platessa) by Greer-Walker et al. (1978) as a means by which flatfish can save energy by ‘hitching a ride’ on the tide when it is flowing in the desired direction, whilst sitting out the reverse tide on the bed. The process is one of vertical modulation of movement between slow moving water at the bed and faster moving water above or to one side. STST has since been demonstrated for many other species; it is known to be important within the Thames Tideway as a fish dispersal mechanism (Naismith and Knights, 1988; Colclough et al., 2002). The phenomenon is seen regularly during the summer months when a ‘ribbon’ of small fish such as dace (Leuciscus leuciscus), flounder (Platichthys flesus), elvers (Anguilla anguilla) and smelt (Osmerus eperlanus) occupies the very shallow water margins of the channel. During migration, they may be heading either upstream or downstream, depending on species and habitat conditions. For example, in the case of elvers, the migration is towards freshwater, where eels spend most of their life growing to maturity. For other species the purpose may be simply to disperse the population over the available habitat. The recently proposed consenting of a thermal discharge on the Thames Tideway has raised questions about whether intrusion of the plume into shallow marginal areas might cause a barrier to juvenile migrations. To resolve this, it is necessary to show either (a) that the plume does not impinge on the intertidal foreshore or (b) that the temperature rise is not sufficient to cause a barrier or (c) that there are sufficient remaining migration paths or temporal windows of opportunity to ensure that the fish can pass. At present there is no scientific information on thermal avoidance thresholds in these species and the argument therefore hinges on opportunity. In considering this question it should be recognised that fish living in such marginal areas will experience substantial temperature changes that occur naturally there. 6.6

Temperature Requirements of Key UK Species

The reported temperature requirements for the key and secondary species for each typology are given in Table 6.2. 6.7

Water Framework Directive Normative Definitions

The Water Framework Directive (WFD) sets environmental objectives for the whole aquatic ecosystem. The aim is to achieve ‘good ecological and chemical status’ in surface waters by 2015. Section 1.2, Annex 5 of the WFD gives normative definitions of high, good, moderate, poor and bad ecological status classifications. Temperature standards review and development/Jul-07

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The normative definitions for ‘high’, ‘good’ and ‘moderate’ are based on biological quality elements e.g. flora and fauna, hydromorphological quality elements and physico-chemical quality elements. Generally, only water bodies with very minor anthropogenic alterations from undisturbed conditions may be classified under the WFD definitions as being of ‘high’ ecological status. Water bodies with low levels of anthropogenic alteration may be classified as ‘good’ and the ‘moderate’ classification is applied to water bodies with moderate levels of alteration with significant observed deviations from undisturbed conditions. Water bodies showing evidence of major alterations to the values of the biological quality elements for the surface water body type, and in which the relevant biological communities deviate substantially from those normally associated with the surface water body type under undisturbed conditions, are classified under the directive as ‘poor’. Water bodies showing evidence of severe alterations and in which large portions of the relevant biological communities normally associated with the water body type are absent are classified as ‘bad’. In developing suitable standards for water body temperature it is necessary to interpret the key normative definitions of ‘high’, ‘good’, ‘moderate’ and ‘poor’ and to identify the positions of temperature boundaries between high/good, good/moderate moderate/poor and poor/bad status. The boundary values should be based on the best available scientific information that demonstrates the performance limits of key indicator fish species living under different thermal regimes. Table 6.1 – Summary of normative definitions Normative Definition High

Good

Moderate

Poor

Bad

6.8

Fish community

Species present and their abundance consistent with undisturbed conditions. Key life stages of ‘disturbance sensitive species’ are present e.g. salmonids. Slight deviations in expected species abundance and/or community structure, for example age class, some age classes may be underrepresented. Disturbance to sensitive species e.g. salmonids, shads, lamprey, eels and smelt. Some disruption to migration patterns in transitional waters. Non-native species may be present. Moderate disturbance, some expected species may be present in reduced abundance or absent, especially sensitive species e.g. salmonids, shads, lamprey, eels and smelt. Disruption in population structure e.g. some age classes may be under-represented or absent. Major disruption to migratory species. Non-native species may be present. Fish communities deviate substantially from those normally associated with the surface water body. Major disruption to fish migration. Key species may be absent and non-native species present. Severe disruption to fish community. Many fish species absent and severe disruption to migratory species. Non-native species often present.

Macroinvertebrates

This review has focussed on the temperature preferences of fish species. However, fish may not be the most sensitive community present in an ecosystem. Lethal temperatures of freshwater invertebrate species have not been thoroughly studied. The upper temperature limits for species of Coleoptera and Chironomidae are thought to be 45-50 °C (for species inhabiting hot springs, Brock, 1975, cited by Langford, 1990). The responses of macroinvertebrate communities to changes in thermal regime include: reduction in abundance, changes in community structure Temperature standards review and development/Jul-07

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and reduced year to year stability in invertebrate community similarity (Bradley and Ormerod, 2001). Water temperature increases of 2-3.5 °C during the experimental manipulation of an Ontario stream system resulted in decreased total macroinvertebrate densities, advanced the timing of adult emergence, changed sex ratios and altered growth rates and size at maturity in some species (Hogg and Williams, 1996). Macroinvertebrate species are generally thought to have broad temperature tolerances and may be able to tolerate temperatures above temperature preferenda for short periods of time (Carvalho et al. 2002). Large increases in temperature over the short term may have less impact on macroinvertebrate communities than smaller increases in temperature over the longer term (Cairns and Pratt, 1993). Langford’s (1990) review of the ecological effects of thermal discharges indicated that the evidence for direct effects of temperature on macroinvertebrate communities was inconclusive. The consequences of water temperature increase on macroinvertebrate communities will be further investigated by the PRINCE (Preparing for Climate Change Impacts on Freshwater Ecosystems) project which is to report its findings in 2007.


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Table 6.2 Temperature preferences for spawning, temperature preferendum and lethal temperatures for key UK fish species (acclimation temperatures for lethal temperature studies also indicated). Acclimatio n temperatur e 15-25 °C

Type

Key species

Spawning temperature

Ultimate temperature preferendum

Lethal temperature

R1

Brown trout

2-6 °C1

12.2-17.6 °C2

25-27.2 °C1

Salmon Brown trout Brown trout

1

1-6 °C 2-6 °C1 2-6 °C1

9-17 °C 12.2-17.6 °C2 12.2-17.6 °C2

27.8 °C 25-27.2 °C1 25-27.2 °C1

16-20 °C 15-25 °C 15-25 °C

Brown trout Eel Barbel Chub Roach Bream

2-6 °C1

12.2-17.6 °C2

25-27.2 °C1 38 °C 4

15-25 °C 29 °C

R7

Pike Bleak

4-17 °C1 14 °C1

R8

Salmon Grayling Charr Vendace Powan

1-6 °C1 6-10 °C1

R2 R3

R4 R5 R6

1

1

15.6-20 °C 12 °C1 8-19.4 °C1 12-20 °C1

3

1

37.9-38.8 °C 27.3-37.8 °C1 30.2-35.7 °C1

25.7-31 °C 15-28.4 °C 20-25.7 °C

23-24 °C2

30-34 °C1 37.7 °C1

? 25.7-26.2

9-17 °C1

27.8 °C2

20-25 °C1 19 °C1

Complementary species

Spawning temperature

Ultimate temperature preferendum

Lethal temperature

Salmon Bullhead Bullhead Stone loach Eel Bullhead Stone loach Lamprey Flounder Grayling Stone loach Gudgeon Chub Dace Perch

1-6 °C1 7.5-13.5 °C5 7.5-13.5 °C5 18-20 °C1

9-17 °C1

27.8 °

38 °C

7.5-13.5 °C5 18-20 °C1 9-16 °C6

26-27

Roach

6-10 °C1 18-20 °C1 12 °C1 12 °C1 5-9 °C1 6-15 °C1 8-19.4 °C1

23.7/26.8 °C2 20-25 °C1

23.2-35.8 27.3-37.8

Brown trout Pike Brown Trout

2-6 °C1 4-17 °C1 2-6 °C1

12.2-17.6 °C2 23-24 °C2 12.2-17.6 °C2

25-27.2 30-34 25-27.2

1

2

C

27.2-36.7 37.9-38.8

°

L1

4.5-7.7 °C 1 1-3 °C 1

16-20 °C

23-30.2 °C1 25-31 °C1

10.5-14.8

C

°

L2 L3

1

TCW 2

1

Brown Trout Salmon Bream

2-6 °C 1-6 °C1 12-20 °C1

12.2-17.6 °C 9-17 °C1 19 °C1

25-27.2 °C 27.8 °C2 30.2-35.7 °C1

15-25 °C 16-20 °C 20-25.7 °C

Eel Perch

6-15 °C

Roach

8-19.4 C

20-25 C

27.3-37.8 C

15-28.4 °C

Pike

4-17 C

Salmon Sea/Brown trout Smelt

1-6 °C1 2-6 °C1 6-9 °C8

9-17 °C1 12.2-17.6 °C2

27.8 °C2 25-27.2 °C1

16-20 °C 15-25 °C

10-17 °C10

Bass Sand smelt

10-17 °C10

Sand smelt Flounder Dace Common goby Flounder

1

TCW 1

2

°

1

°

1

°

30-32 °C9

38 °C 1

°

5-9 °C1 10-20 °C11

23.7/26.8 °C

23.2-35.8

23-24 C

30-34

2

°

26-27 26-27

Alabaster and Lloyd, 1980, Jobling, 1981, Garside, 1973 Sadler, 1979, Fox,1978, Hardisty, 1986, Waede, 1954 in Fonds et al. 1992, Lyle and Maitland, 10 11 6-1 Temperature standards review and1981, development/Jul-07 Barnabe, 1991, Turnpenny, Fonds and Von Burt, 1974

7

Derivation of Draft WFD Water Temperature Standards 7.1

Key Biological Criteria

The biological data presented in Section 6 identifies the three key biological criteria that appear most relevant to standards setting: upper lethal temperatures, ultimate preferenda and preferred spawning temperatures. Maintaining temperature values within the animal’s preferred range ensures that other biological requirements such as feeding growth, locomotion and disease resistance will also be met. During period of high temperatures it will also be necessary to ensure that DO levels are adequate, particularly in waters receiving organic wastes such as STW and CSO discharges. Turnpenny and Coughlan (2006) propose that for estuaries, for every 1 mg L-1 drop in DO level below 5 mg DO L-1, the maximum allowable temperature should be de-rated by 4°C 8 . In some recent power station applications, the Environment Agency have drawn attention to the potential risk of selective tidal stream transport in juvenile estuarine migrants being disturbed by warm water flowing across the foreshore. It is not known at present what (if any) temperature differentials might cause avoidance behaviour in different species and therefore a precautionary approach may be taken when granting plant authorisations. The only scientific evidence relates to salmonids, which are actually rather insensitive (∆t> 4 °C), and this may turn out to be the case for other species. A further issue of concern is that the reported lethal temperatures of some species span a wide range. One possibility is that this reflects the use of test procedures in which fish were exposed to high temperatures when acclimated to low ambient temperatures; whilst there may be a case for undertaking such tests when researching physiological tolerance, using data from such tests in relation to standards development would clearly be misleading. A second possibility is that observations of fish deaths at the lower temperatures reported may in some cases be associated with low DO concentrations. These values may therefore need to be investigated further before firm conclusions can be drawn. 7.2

Adequacy of Existing Standards

7.2.1 Surface water temperature standards

The data from Table 6.2 are graphically represented in Figure 7.1, which also indicates current UK surface water temperature standards. It is important to note that temperature preference data is not available for all of the key and complementary species. Spawning temperatures and approximate spawning season are indicated on Figure 7.2. These plots allow the existing FFD standards (also used as the UKTAG transitional and coastal water standards for SPAs and SACs in WQTAG160) to be compared with biological data on the key indicator species. It is seen that in general, the existing FFD standards for maximum and spawning temperatures should be protective of the relevant salmonid and cyprinid categories. In view of the common assertion in feedback responses that they may be too stringent, it is interesting to note that the maximum temperatures in the salmonid 8

subject to review pending Jacobs analysis of new data for the Thames Tideway Temperature standards review and development/Jul-07

7-1

category fall only slightly below the lower end of the reported lethal ranges and that in the case of some cyprinids, actually overlap the lethal ranges. This emphasises the importance of checking the basis of the lethality values as suggested in Section 7.1. 7.2.2 Maximum Allowable Temperature Uplift and Plume Spread

A function of the maximum allowable temperature uplift value is to prevent deterioration in the quality or status of surface waters. When considering allowable temperature rises, it should be noted that any rise at all is only permissible if absolute upper temperature limits for the class of water are not exceeded with the temperature rise included. However, without a maximum uplift value this would potentially allow increases in temperature which may change the status of a water body within a classification. For example, for the standards presented in this document, without a maximum uplift value in force, a water body classified as cold water of moderate quality could potentially increase in temperature up to 5 °C and remain in the moderate classification. Although the classification of the water body remains the same, this temperature increase would arguably result in deterioration in status, as the water body would be shifted from the good/moderate boundary to the moderate/poor boundary. Maximum uplift temperatures are of vital importance in waters where species are at the limits of their physiological tolerance. For example, in poor status waters, temperature may be a critical factor when considering survival of fish during events such as CSO discharges, due in part to knock on effects to DO concentration. Maximum temperature uplift value also serves to prevent seasonal advancement which may result in mismatches in ecology. The validity of the uplift values given in the FFD standards of 1.5 °C and 3 °C for salmonid and cyprinid waters respectively and of the 2 °C uplift used in the WQTAG160 guidance, is less clear. Principally they are designed, in the case of fish, to ensure that a step rise or sharp gradient in temperature does not act as a thermal barrier to fish movement. Turnpenny et al. (2006) reviewed evidence of thermal barriers to fish and were unable to find firm evidence of the reality of thermal barriers in rivers and estuaries, except near to the lethal limit (already protected by the maximum temperature standards). Experiments with salmon and sea trout smolts have shown that, while some individuals may detect and avoid temperature fronts having a ∆T of ≤1 °C, the median avoidance threshold was ∆T=+6 °C in sea trout and ∆T=+4 °C in salmon, while adult salmon have been found in telemetry studies to pass through a ∆T of 9°-10 °C at an estuarine salt-wedge. On this basis, the FFD ∆T of 1.5 °C for salmonid waters appears excessively stringent and the 3 °C uplift used for cyprinid waters appears adequate for most cases. In view of advice and case-history feedback reported in Section 5.1, it would seem appropriate to apply this less stringent value to designated shellfish waters also. The normative definition of high ecological status waters are those that show only minor anthropogenic influence from undisturbed conditions and arguably an uplift of 3 °C represents more than a minor influence. Therefore it is proposed that for water of high ecological status an uplift of 2 °C is applied. A number of countries reviewed in this study place limits on the allowable spread of the plume within river and estuarine channels, limiting the plume to 25% of the cross-sectional area of the channel. This is a sensible precaution to protect migratory channels. It is proposed that this limit should also be included in UK standards, such that the mixing zone should be contained within ≤25% of the channel cross-sectional area for 95% of the time. The 5% time allowance Temperature standards review and development/Jul-07

7-2

recognises the uncontrollable spread of the plume in estuarine channels under slack water conditions; this should allow ample opportunity for migratory fish to pass. 7.2.3 Maximum Allowable Temperature Decrease

Release of cooled water, for example, from the hypolimnion of reservoirs may result in reduced downstream river temperatures, which may lead to adverse effects upon ecology including changes to spawning seasons and reduction in fish growth rates. It is therefore proposed that a value for maximum allowable temperature drop be considered. Studies have shown that the mean annual water temperature of water in rivers downstream of reservoirs is higher than in the same rivers prior to impoundment. However, in general, summer downstream water temperature is cooler, owing to the thermal inertia of the reservoir (reviewed by Cassie, 2006). Water temperature of rivers subject to reservoir releases are therefore prone to alterations in the annual temperature cycle, and also may be subject to alterations in the diel cycle, depending on patterns of usage (Web and Walling, 1996). Reduced summer temperatures may result reduction in growth rates of fish (Robinson and Childs, 2001). Jenson (2003) studied the growth of Atlantic salmon parr in the River Alta in Norway, a river which is subject to flow regulation due to a hydropower plant. The plant has resulted in a decrease in downstream river water temperature during June, July and August of 1-2 °C and the author reports that this has resulted in a minor decrease in growth rate of parr down stream. 7.2.4 Spawning temperature

Embryonic stages have narrower thermal niche than older lifestages. Following a recent review of winter river water temperatures in the Republic of Ireland (ROI), the case for increasing the maximum temperature to 14 °C for salmonid spawning waters was examined (Fiona Murphy, South Eastern River Basin District, Pers. Comm.). However, the evidence was not deemed to be conclusive and the ROI spawning temperature standard currently remains at 10 °C in line with the FFD. A review of the spawning temperatures of UK species indicates that general, the existing FFD standard of maximum 10 °C during the spawning season would be protective of the relevant cold water spawning species (detailed in section 6.4) and therefore retention of this value is proposed. No spawning temperature limit should be applied to warm water bodies. 7.3

Provisional WFD Standards

The typologies were grouped according to the temperature preferences of the fish species present and two categories were distinguished; cold-water (formerly ‘salmonid’) and warm-water (formerly ‘cyprinid’), suggesting that the two level typology grouping given by the FFD remains adequate. Table 7.1 indicates the grouping and gives the final typology. Table 7.1 Final water body typology Typology Cool water Warm water

Water body types

R1, R2, R3, R4, R8, L1, L2, TW1-2, CW1-12 R5, R6, R7, L3

WFD standards must attempt to distinguish normative boundary values for the ‘high’, ‘good’, ‘moderate’, ‘poor’ and ‘bad’ classes of fishery status (Figure 7.3). Temperature standards review and development/Jul-07

7-3

Temperature preferences have been represented according to the concept of “thermal niche” (Magnuson et al., 1979) i.e. that most fish will spend two-thirds of their time at within ±2 °C of their temperature preferendum. Temperature preferendum is indicated on Figure 7.3 as a solid green line and the thermal niche of the species extends 2 °C either side of this as a dashed green line. The high/good class boundary has been set at the upper limit of the thermal niche in which most fish will spend two-thirds of their time (±2 °C of the thermal preferendum), whilst the ‘good/moderate’ class boundary has been set at the upper limit of the thermal niche in which most fish will spend all of their time (±5 °C of the thermal preferendum). The ‘moderate/poor’ boundary has been set at the lower limit of the lethal temperature range and the ‘poor/bad’ boundary has been set at the upper limit of the lethal temperature range. These values are represented on Figures 7.3 and 7.4 and given in Table 7.2. The proposed absolute standards are based on the 98 percentile values at the edge of the mixing zone. It is proposed that 3 °C uplift limit is used for all cases except for waters of high ecological status where a 2 °C uplift limit is proposed (Table 7.3 and discussed in section 7.2.2). There is concern that release of water from the hypolimnion of reservoirs may result in reduced downstream river temperatures which may lead to adverse effects to ecology. It is therefore proposed that a maximum allowable temperature drop be applied to mirror the maximum uplift values i.e. 3 °C to be used for all cases except waters of high ecological status where a maximum allowable temperature drop of 2 °C is proposed (Table 7.3). . Table 7.2 Proposed boundary values Typology High/good Cold water Warm water

Normative definition boundary positions Good/moderate Moderate/Poor Poor/bad

20 °C

23 °C

28 °C

30 °C

25 °C

28 °C

30 °C

32 °C

Table 7.3 Maximum allowable temperature uplift and drop for all normative definitions Typology High Cold water Warm water

7.4

Normative definition classes Good Moderate Poor

Bad

2 °C

3 °C

3 °C

3 °C

3 °C

2 °C

3 °C

3 °C

3 °C

3 °C

Modifying Role of Dissolved Oxygen in Estuaries

It is tentatively proposed that in estuaries where the median DO level is expected to fall below 5 mg L-1 during the months of July to August, the maximum allowable temperature should be reduced by 4°C for every drop of 1 mg L-1 below 5 mg L-1, or pro rata.


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7.5

Basis of Regulation

It will be necessary for the regulatory agencies to develop standard temperature sampling methods that can be applied across the UK. Monitoring method and frequency should take into account, for example seasonal and diurnal differences. The Directive states that derogations may be granted if it can be demonstrated that there are is no evidence of deterioration of fish populations. The FFD states that: “Derogations limited in geographical scope may be decided by Member States in particular conditions if the competent authority can prove that there are no harmful consequences for the balanced development of the fish population”.


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Figure 7.1 Temperature preferences for spawning, temperature preferendum and lethal temperatures for key UK fish species. Current UK temperature standards are indicated by dashed vertical lines. SPAWNING

ULTIMATE PREFERENDUM 10 C °

R1 R R

LETHAL 21.5 C

28 C

°

°

Brown trout Salmon

Bullhead

Salmon Brown trout Bullhead Stone loach

Brown trout Eel Bullhead Stone loach

Brown trout Eel

R4 R5

Barbel Chub

R6

Roach Bream

R7

Pike Bleak

R8

Salmon Grayling

Lamprey Flounder

Grayling Stone loach

Gudgeon Chub Dace Perch

Roach

Brown trout Pike

L1

Charr Vendace Powan

L2

Brown trout Salmon

L3

Bream Roach

Brown trout

Eel

Perch Pike

Salmon

TC

Brown trout Smelt

TC W2

Bass Sand smelt

Sand smelt Flounder Dace Common goby

Flounder

0

5

10

15

20

25

30

Temperature °C


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35

40

Figure 7.2 Temperature preferences for spawning. The current UK temperature standard for salmonid waters is indicated by a dashed vertical line. SPAWNING

R1

Brown trout Nov to Jan Salmon Nov to Jan Bullhead Mar to May

R2

Salmon Brown trout Bullhead Stone loach

R3

Brown trout Nov to Jan Eel Bullhead Mar to May Stone loach Apr to May

R4

Brown trout Nov to Jan Eel

R8

L1

L2 TCW1

TCW2

10 C °

Nov to Jan Nov to Jan Mar to May Apr to May

Lamprey Flounder

Apr to Apr May Jan

Salmon Grayling Brown trout Pike

Nov to Jan Mar to May Nov to Jan Feb to May

Charr Vendace Powan Brown trout

Nov to Feb Dec to Jan Dec to Feb Nov to Jan

Brown trout Nov to Jan Salmon Nov to Jan Eel Nov to Jan Salmon Brown trout Nov to Jan Smelt M art oA r Sand smelt Flounder Mar to May Common ob Apr to Aug Bass Mar to Jun Sand smelt Apr to Jul Flounder Jan to Apr

0

2

4

6

8

10

12

14

16

18

20

Temperature °C

Figure 7.3 Temperature preferenda and lethal temperatures for key UK fish species. Current UK temperature standards are indicated by vertical dashed black lines. Provisional WFD normative class boundaries are indicated by coloured dashed lines.


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ULTIMATE PREFERENDUM

LETHAL

HIGH/GOOD

GOOD/MOD

MOD/POOR

POOR/BAD

21.5 °C

R1

Brown trout

R2

Salmon Brown trout

R3 R4

Salmon Bullhead

Bullhead Stone loach

Brown trout Eel

Bullhead Stone loach

Brown trout Eel Lamprey Flounder

R8

Salmon Grayling

L1

Charr Vendace Powan

L2

Brown trout Salmon

Brown trout Pike

Brown trout

TCW1 TCW2

Eel

Salmon Brown trout Smelt Sand smelt Flounder Dace Common goby

Bass Sand smelt

28 °C

Flounder

R5 R6 R7 L3

Barbel Chub

Grayling Stone loach

Roach Bream Gudgeon Chub Dace Perch

Pike Bleak

Roach

Bream Roach Perch Pike

6

8

10

12

14

16

18

20

22

24

26

28

30

32

Temperature °C


7-2

34

36

38

40

Figure 7.4 Proposed boundary values

R E T A W D L O C

HIGH

R E T A W M R A W

10

GOOD

MOD

HIGH

12

14

16

18

GOOD

20

22

24

26

BAD

POOR

MOD POOR

28

30

32

BAD

34

36

Temperature °C


7-1

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Colclough, S.R., Gray, G., Bark, A. and Knights, B. (2002). Fish and fisheries of the Tidal Thames: management of the modern resource, research aims and future pressures. J. Fish Biol. 61 (Suppl. A), 64-73. Cowx, I.G. (1991). The use of angler catch data to examine potential fishery management problems in the lower reaches of the River Trent, England. In Catch Effort Sampling Strategies, their application in freshwater fisheries management (Ed. I.G. Cowx), Fishing News Books, Blackwell Scientific

Publishers, 154-165. Cowx, I.G. & Broughton, N.M. (1986). Changes in the species composition of anglers catches in the River Trent (England) between 1969 and 1984.J. Fish Biol. 28, 625-636. Cowx, I.G., Noble, R.A., Nunn, A.D. Harvey, J.P. (2004) Flow and level criteria for coarse fish and conservation species. Environment Agency R&D report W6-096, Bristol UK. Cowx, I.G. & O’Grady, K.T. (1995). Feasibility study for the re-introduction of Atlantic salmon (Salmo salar L.) into the River Dove, via the River Trent. Report to the National Rivers Authority, Severn Trent Region, April 1995. Cragg-Hine, D. (1971). Coarse fish populations in the electricity cut, Peterborough. Proc. 5th Brit. Coarse Fish Conf., Univ. Liverpool, pp 19-28. Dokulil, M.T., Humpesch, U.H., Schmidt, R. & Pöckl, M. (1993) 5.Limnologie – Auswirkungen geänderter Klimaverhältnisse auf die Ökologie von Oberflächengewässern in Österreich. 5.1 – 5.84 In: Bestandsaufnahme anthropogene Klimaänderungen: Mögliche Auswirkungen auf Österreich – Mögliche Massnahmen in Österreich. Verlag der Österreichischen Akademie der Wissenschaften, Wien. Environment Agency (2002) Resource Assessment and Management Framework. Report and User manual (version 3). W6-066M. Environment Agency, Bristol, UK. EPA (2003) Region 10 Guidance for Pacific Northwest state and Tribal temperature water quality standards. EPA (2001), Scientific Issues Relating to Temperature Criteria for Salmon, Trout and Char Native to the Pacific Northwest. Fonds, M. Cronie, R. Vethaak, A.D. Van der Puyl, P. (1992) Metabolism, food consumption, and growth of plaice (Pleuronectes platessa) and flouder (Platichthys flesus) in relation to size and temperature. Netherlands Journal of Sea Research. 29(1-3) 127-143. Fonds, M. & van Buurt, G., 1974. The influence of temperature and salinity on the development and survival of goby eggs (Pisces, Gobiidae). Hydrobiological Bulleting (Amsterdam), 8, 110-116. Fox, P.J. (1978) Preliminary observations on different reproduction strategies in the bullhead (Cottus gobio L.) in northern and southern England. Journal of Fish Biology 12(1) pp 5-11


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Garside E.T. (1973) Ultimate upper lethal temperature of Atlantic salmon Salmo salar L. Canadian Journal of Zoology.51, 898-900. Greer Walker, M., Harden Jones, F. R., and Arnold, G. P. (1978). The movements of plaice (Pleuronectes platessa L.) tracked in the open sea. Journal du Conseil International pour l’Exploration de la Mer , 38: 58–86. Hardisty, M.W., (1986). Lampetra fluviatilis (Linnaeus, 1758).. p. 249-278. In J. Holcík (ed.) The Freshwater fishes of Europe. Vol. 1, Part 1. Petromyzontiformes. Hogg. I.D. and Williams, D.D. (1996) Response of stream invertebrates to a globalwarming thermal regime: An ecosystem-level manipulation. Ecology. 77(2) 395-407. Holmes, R. H. A. and P. A. Henderson. 1990. High fish recruitment in the Severn Estuary: The effect of a warm year? J. Fish Biol., 36 (6), 961-963. Holmes, NTH, Boon, PJ, Rowell, TA (1998). A revised classification system for British rivers based on their aquatic plant communities. Aquatic Conservation: Marine and Freshwater Ecosystems. Vol. 8(4) pp555-578. Humpesch U.H., M.Dokulil, J.M.Eliott & A.Herzig (1982) Ökologische Auswirkungen der thermischen Gewässerbeeinflussung. Österreichische Wasserwirtschaft: 34, 123-136. Jacklin, T.E. (2000). Aspects of fishery management on the River Trent – a large lowland river. Ph.D. Thesis, University of Nottingham. Jensen, A.J. (2003). Atlantic Salmon ( Salmo salar) in the regulated river Alta: Effects of altered water temperature on Parr growth. River Res. Applic. 19: 733-747. Jobling, M. (1981) Temperature tolerance and the final preferendum; rapid methods for the assessment of optimum growth temperatures. Journal of Fish Biology, Vol. 19 pp439-455. Kirchner, J.W., Feng, X., Neal, C., Robson, A.J. (2004). The fine structure of water quality dynamics: the (high frequency) wave of the future. Hydrological Processes. 18 pp 1353-1359. Langford, T.E.L. (1990). Ecological effects of thermal discharges. Elsevier Applied Sciences, London. Lyle, A.A., Maitland, P.S. (1997) The spawning migration and conservation of smelt Osmerus eperlanus in the River Cree, southwest Scotland. Biological Conservation 80:3 pp. 303-311. Magnuson, J.J, Crowder, L.B. and Medvick, P.A. (1979). Temperature AS an ecological resource. American Zoologist, 19, 331-343. Maitland, P.S., Winfield, I.J., McCarthy, I.D., Igoe, F. (In press) The status of Arctic charr Salvelinus alpinus in Britain and Ireland. Ecology of Freshwater Fish.


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Mann, R.H.K. (1997). Temporal and spatial variations in the growth of 0 group roach (Rutilus rutilus) in the River Great Ouse, in relation to water temperature and food availability. Regulated Rivers: Research & Management13, 277286. Mann, R.H.K., Bass, J.A.B., Leach, D. & Pinder, A.C. (1997). Temporal and spatial variations in the diet of 0 group roach (Rutilus rutilus) larvae and juveniles in the River Great Ouse in relation to prey availability. Regulated Rivers: Research & Management 13, 287-294. McCarthy, I.D. and Houlihan, D.F. (1997). The effect of temperature on protein metabolism in fish: the possible consequences for wild Atlantic salmon (Salmo salar L.) stocks in Europe as a result of global warming. In: Global warming: Implications for freshwater and marine fish. (Ed. Wood, C.M and McDonald, D.G.) Soc. Exp. Biol. Sem. Ser. 61, 51-78. Naismith, I.A. and Knights, B. (1988). Migrations of elvers and juvenile European eels, Anguilla anguilla L., in the River Thames. J. Fish Biol. 33 (Suppl. A). Oliver and Fidler (2001). Towards a Water Quality Guideline for Temperature in the Province of British Columbia and the CCMA guidelines. Persson, L. (1986). Temperature-induced switch in foraging ability in two fish species, roach (Rutilus rutilus) and perch (Perca fluviatilis): implications for coexistence between poikilotherms. J. Anim. Ecol. 55, 829-839. Robinson. A.T and Childs, M.R. (2001). Juvenile growth of native fishes in the Little Colorado River and in a thermally modified portion of the Colorado River. North American Journal of Fisheries. 21, 809-815. Sadler, K. (1979). "Effects of temperature on the growth and survival of the European eel, Anguilla anguilla L." Journal of Fish Biology 15: 499-507. Sadler, K. (1979). Effect of the warm water discharge from Castle Donington power station on fish populations in the River Trent. Lab. Note RD/L/N 11/79 Central Electricity Research Laboratories. Severn Trent Water Authority (1985). Re-introduction of salmon to the River Trent. A preliminary feasibility study. Severn Trent Water, Directorate of Technical Services, Birmingham 64 pp. SNIFFER (2005) Development of Environmental Standards (Water resources) Stage 2: Typology Review. Project WFD48, July 2005. SNIFFER (2006) Development of Environmental Standards (Water resources) Stage 3: Environmental Standards. Project WFD48, January 2006. Solomon, D.J., Acornley, R. and Lightfoot, G.W. (2005 in press). Anthropogenic influences on chalkstream temperature. Paper presented to the Institute of Fisheries Management Annual Meeting, Lancaster, September 2005. Somero, G.N., Hofmann, G.E. 1997. Temperature thresholds for protein adaptation: when does temperature start to ‘hurt’? In: “Global Warming: Implications for freshwater and marine fish” (Ed. Wood, C.M. and McDonald, D.G.), University Press, Cambridge, 1-24. Temperature standards review and development/Jul-07

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Turnpenny, A.W.H., Clough, S.C., Holden, S.D.J., Bridges, M., Bird, H., O’Keeffe, N., Johnson, D., Edmonds, M. and Hinks, C. (2004). Thames Tideway Strategy: experimental studies on the dissolved oxygen requirements of fish. Babtie Aquatic Contractors report to the Thames Tideway Strategy Group, Report No. FCR 374/04, April 2004. Turnpenny, A.W.H, Coughlan, J and Liney, K.E. (2006) Review of temperature and dissolved oxygen effects on fish in transitional waters. Environment Agency report (In press) Turnpenny A.W.H., Bamber , R.N., & Henderson, P.A., (1981) - Biology of the sandsmelt (Atherina presbyter Valenciennes) around Fawley Power Station.J. Fish Biol. 18, 417-427. UKTAG (2006) UK Environmental standards and conditions (phase 1). SR1-2006 Draft, January 2006. Webb, B.W. and Walling, D.E. (1996) Long term variability in the thermal impact of river impoundment and regulation. Applied Geography. 16, 211-227 Webb, B.W. and Zhang, Y. (1997) Spatial and seasonal variability in the components of the river heat budget. Hydrological Processes. 11 pp 79101. WQTAG (2003a) Guidance on Typology for Rivers for Scotland, England and Wales. Final working paper. WQTAG (2003b) Guidance on Typology for Lakes in the UK. Draft. WQTAG (2003c) Guidance on Typology for Coastal and Transitional Water of the UK and Republic of Ireland. Final


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APPENDIX A: QUESTIONNAIRE AND LIST OF RESPONDANTS Name: Organisation: Country: 1. In your country/state - What body/organisation is responsible for environmental regulation of waters?

2. Is there regulation of thermal discharges into water bodies?

3. Were the regulations formulated on the basis of scientific criteria? If so, is there a document that summarises the scientific data?

4. Are these regulations available electronically? (Please provide a copy of regulations if possible or a URL)

5. Is any distinction made in your regulations between discharges to different types of water body, i.e. between freshwater lakes and rivers or estuarine or marine waters?

6. Is any distinction made between waters inhabited by different fish species – for example those inhabited by cyprinids or salmonids?

7. How are these regulations enforced? Do penalties apply?

8. What monitoring procedures are applied for enforcement? E.g. monitoring of temperature, monitoring of ecological status.


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9. In your opinion, are these regulations perceived to be appropriate? Is there evidence/ feedback to suggest that the regulations are (a) too stringent or (b) too lax?

10.

If you had the opportunity to revise the standards, what changes would you wish to make?

List of questionnaire respondents Country

Name

Organisation

USA Germany Netherlands Austria

Rich Zabel Marq Redeker Henk Jenner Albert Jagsch

Denmark Belgium

J. Brøgger-Jensen Caroline Polders

National Marine Fisheries Service Ruhrverband KEMA Institute for Water Ecology, Fisheries and Lake Research, Danish Environmental Protection Agency VITO (Flemish Institute for Technological Research)

Sweden Finland South Africa Canada New Zealand

Mikaela Gonczi Silvo Kimmo Susan Taljaard Larry Fidler James Court Jacques Boubee Erich Staub

Switzerland


Swedish Environmental Protection Agency Finnish Environment Institute Council for Scientific and Industrial Research Aspen Environmental Ministry for the Environment NIWA Federal Office for the Environment

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Appendix B: UK Specialists Contacted for Feedback on Standards

Willie Duncan - SEPA Peter Moorehead - DOENI Neil Edwards - Environmental specialist, RWE Npower Steve Colclough - Environment Agency Rodger Proudfoot – Environment Agency Prof Terry Langford - Southampton (ex-industry Iain Malcolm - Freshwater FisheriesUniversity Laboratory, Faskally specialist) Tim Jacklin – Environment Agency


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Temperature Standards Review and Development

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