Soapstone Watershed Quarry Gladwyne

WATERSHED ASSESSMENT FOR SOAPSTONE WATERSHED Gladwyne Lower Merion Township Montgomery County, PA

Prepared Prepared For: For:

Lower Merion Township 75 East Lancaster Avenue Ardmore, PA 19003-2323

Prepared By:

Office of the Township Engineer Pennoni Associates Inc. One Drexel Plaza 3001 Market Street Philadelphia, PA 19104 (215) 222 –3000

September 28, 2012

Scott A. Brown, PE PENNSYLVANIA PE 042215R LOWM093814

Table of Contents SECTION

PAGE

1.

EXECUTIVE SUMMARY ...........................................................................................................

1

2.

INTRODUCTION AND BACKGROUND ...............................................................................

2

2.1. WATERSHED DESCRIPTION .........................................................................................................

3

2.2. HISTORY OF DEVELOPMENT IN THE WATERSHED ...............................................................

3

2.3. SOILS

.................................................................................................................................................. 3

2.4. GEOLOGY

3.

.......................................................................................................................................... 4

FACTORS INFLUENCING ACCELLERATED CHANNEL EROSION ....................... 4 3.1. RAINFALL

......................................................................................................................................... 4

3.2. WATERSHED PHYSICAL CHARACTERISTICS ..........................................................................

5

3.3. SUMMARY CONCLUSIONS RELATED TO FACTORS FACTORS INFLUENCING EROSION ................ 7

4.

FIELD ASSESMENT AND STRATEGIES FOR EROSION MITIGATION ................. 7 4.1. PIPED SECTION – SCHUYLKILL EXPRESSWAY TO 200 RIVER ROAD ................................. 8 4.1.1. EXISTING CONDITIONS ............................ .......................................... ............................ ............................ ............................ ............................. ........................ .........8 4.1.2. SUGGESTED MITIGATION ACTIONS

........................... ......................................... ............................ ............................. ............................. ..............9

4.2. 1600 MONK ROAD AND 1619, 1621, AND 1624 WINSTON ROAD ............................................. 11 4.2.1. EXISTING CONDITIONS ............................ .......................................... ............................ ............................ ............................ ............................. ...................... .......11 4.2.2. EROSION MITIGATION APPROACH ........................... ......................................... ............................ ............................ ............................ ................ 11 4.2.3. ESTIMATE OF PROBABLE COST FOR EROSION MITIGATION............................ .................................. ......12 4.3. 1600 SOAPSTONE ROAD ................................................................................................................ 12 4.3.1. EXISTING CONDITIONS ............................ .......................................... ............................ ............................ ............................ ............................. ...................... .......12 4.3.2. EROSION MITIGATION APPROACH ........................... ......................................... ............................ ............................ ............................ ................ 13 4.3.3. ESTIMATE OF PROBABLE COST FOR EROSION MITIGATION............................ .................................. ......13 4.4. 1450 SOAPSTONE ROAD ................................................................................................................ 13 4.4.1. EXISTING CONDITIONS ............................ .......................................... ............................ ............................ ............................ ............................. ...................... .......13 4.4.2. EROSION MITIGATION APPROACH ........................... ......................................... ............................ ............................ ............................ ................ 14 4.4.3. ESTIMATE OF PROBABLE COST FOR EROSION MITIGATION............................ .................................. ......14 4.5. 1434 SOAPSTONE ROAD ................................................................................................................ 15 4.5.1. EXISTING CONDITIONS ............................ .......................................... ............................ ............................ ............................ ............................. ...................... .......15 4.5.2. EROSION MITIGATION APPROACH ........................... ......................................... ............................ ............................ ............................ ................ 15

i

4.5.3. ESTIMATE OF PROBABLE COST FOR EROSION MITIGATION............................ .................................. ......16 4.6. 1435 ABBEY LANE .......................................................................................................................... 16 4.6.1. EXISTING CONDITIONS ............................ .......................................... ............................ ............................ ............................ ............................. ...................... .......16 4.6.2. EROSION MITIGATION APPROACH ........................... ......................................... ............................ ............................ ............................ ................ 16 4.6.3. ESTIMATE OF PROBABLE COST FOR EROSION MITIGATION............................ .................................. ......16 4.7. 1418 MONK ROAD

.......................................................................................................................... 17

4.8. 1410 AND 1400 MONK ROAD ......................................................................................................... 17 4.8.1. EXISTING CONDITIONS ............................ .......................................... ............................ ............................ ............................ ............................. ...................... .......17 4.8.2. EROSION MITIGATION APPROACH ........................... ......................................... ............................ ............................ ............................ ................ 17 4.8.3. ESTIMATE OF PROBABLE COST FOR EROSION MITIGATION............................ .................................. ......17 4.9. DRAINAGE AT THE INTERSECTION OF MONK ROAD AND ABBEY LANE ....................... 18

5.

COST SUMMARY .......................................................................................................................

6.

GRANT AND OTHER FUNDING OPPORTUNITIES ................ .................. .................. .. 19

7.

SUMMARY ....................................................................................................................................

8.

CONCLUSIONS AND FUTURE DIRECTIONS ................................................................. 21

ii

18

20

Figures FIGURE 1 – Location Map

Aerial with Contours FIGURE 2 – Soapstone Watershed Aerial Photographs of the Soapstone Watershed Watershed FIGURE 3 – Historic Aerial Photographs Soapstone Watershed FIGURE 4 – Soil Survey of the Soapstone Philadelphia 1948 through through January 2012 FIGURE 5 – Daily Rainfall in Philadelphia

Appendices PHOTOGRAPHS APPENDIX A – KEY MAP AND PHOTOGRAPHS ILLUSTRATING RESTORATION APPROACHES APPENDIX B – EXHIBITS ILLUSTRATING

iii

Lower Merion Township, PA

Soapstone Watershed Assessment

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1. EXECUTIVE SUMMARY

The purpose of this study is to identify the probable cause of observed accelerated erosion within the watershed, and to develop mitigation strategies or approaches to control erosion and the resulting deposition of sediment and and debris. Order of magnitude cost estimates estimates for the proposed erosion mitigation mitigation strategies and potential funding sources (Grant programs, etc.) for projects of this nature are identified. Factors influencing accelerated erosion within the watershed are the erodible nature of local soils, the increase in frequency and magnitude or rainfall and runoff over the past 13 years, and development activities within the watershed watershed prior to the enactment of stormwater ordinances. ordinances. The dominant factor is the significant increase in rainfall frequency and magnitude over the past 13 years. This assessment has identified identified stream restoration strategies strategies that can be applied within the the watershed. In the eastern or lower portions of the watershed, strategies included the use of a sediment/debris basin near the Schuylkill Expressway, toe stabilization using local materials, bank grading, and construction of floodplain benches. In the upper or western western portions of the watershed, watershed, the dominant strategy is to use bank grading and the creation of vegetated floodplain benches to stabilize the channel. Bank armoring at a bend, installation of cross vane drop structures, and other energy dissipation strategies are also used to address localized problem areas. Conceptual design level order of magnitude estimates of probable cost f or mitigation measures have been developed and are summarized as follows: Upper Watershed

$ 350,000

Lower Watershed Alternative 1a - Erosion Mitigation Alternative 1b - Sediment/Debris S ediment/Debris Trap Alternative i. Access from Schuylkill Expressway ii. Access from Soapstone Road Alternative 2 – Conveyance Improvements Schuylkill Expressway to River

$ 415,000 $ 370,000 $ 460,000 $ 455,000

Grant and other funding opportunities applicable to the watershed restoration and erosion mitigation identified include:        

Schuylkill River Restoration Fund Emergency Watershed Protection Assistance Program Growing Greener Program The National Fish and Wildlife Foundation’s Five Star Restoration Program William Penn Foundation PennVEST Urban Waters Small Grants Program US Army Corps of Engineers Snagging and Clearing for Flood Control Program

In addition, key stakeholders including PennDOT, Norfolk Southern Corporation, and the Township will need to play a role in project funding. funding. Affected property owners will will also need to participate. 1



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2. INTRODUCTION AND BACKGROUND

The purpose of this investigation was to identify the cause or causes of the stream instability and erosion occurring along the Soapstone Watershed stream valley and to develop schematic design options to restore the stream valley to a more stable condition. In addition, order of magnitude cost estimates have been developed for the recommended stream stabilization measures along with potential sources of funding. The Soapstone watershed is located in the north eastern portion of Lower Merion Township as illustrated in Figure 1. The watershed is generally bounded by the Schuylkill Schuylkill River to the east, Monk Road to the south, Youngsford Road to the west, west, and Waverly Road to the north. The watershed gets its name from a historic soapstone soapstone quarry, the remnants of which are located near the middle of the watershed. The stream within this watershed is an unnamed tributary to the Schuylkill River. Photographs taken throughout the stream valley are provided in Appendix A. On August 1, 2004 a localized high intensity, short duration storm caused flooding and severe erosion along the stream corridor, above the Schuylkill Expressway. Expressway. With erodible soils and steep slopes, slopes, a large volume of stony sediment and debris was washed downstream, partially clogging the Schuylkill Expressway culvert and clogging clogging the culverts under the Norfolk Norfolk Southern railroad and River Road. As a result of the culvert clogging stormwater overflowed the railroad, eroding its embankment and cascading onto River Road. Along with the embankment debris, sediment sediment and debris were forced through through the Expressway and railroad culverts and onto River Road cr eating a five foot tall debris pile (see Photograph 1 in Appendix A). In addition to this initial event, similar events occurred in April 2005 and August 2009, and on a number of other occasions. In addition, it has been reported that erosion and sedimentation in the upper watershed has resulted in significant sediment deposition in the pond located at 1450 1450 Soapstone Road. If this pond were were to be completely filled or damaged, sediment from upstream would be transported to downstream waterway segments and ultimately to River Road aggravating the situation there. The erosion and sedimentation problems in the watershed have resulted in significant costs to the Township and its residents. It is reported that river road clean-up after these events costs the township approximately $4,000 per per event. The cost in flood damage damage repair to residents along river road and throughout the watershed is estimated to be significantly significantly greater. In addition these events pose a significant threat to public safety, rail and vehicular traffic, and emergency vehicle access in the vicinity of River Road. Erosion of this railroad bed could result in a derailment on this active active freight line not not only causing damage to the railroad and River Road but to residents and the environment. The Schuylkill River is a source of drinking water for the City C ity of Philadelphia, which could be contaminated in a spillage from derailed freight car. The objective of this watershed assessment is to identify mitigative actions that will reduce the erosion and resulting sediment and debris transport within the watershed, to reduce the r esulting public safety risk and financial impacts to the property owners, PennDOT, Norfolk Southern Corporation, and the Township. The approach to this study involved extensive field observations, assessments, and review of historic data and events. Field investigations investigations were used to evaluate site-specific erosion erosion issues along the stream 2



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corridor. These issues are keyed to the eight (8) individual individual properties which the stream traverses. The outcome of this study is a set of recommendations to mitigate the observed erosion and debris transport in the watershed. 2.1. WATERSHED DESCRIPTION

The Soapstone Watershed encompasses 176-acres in the north eastern portion of Lower Merion Township (See Figure 1). As illustrated in Figure Figure 2, the current land use within the watershed watershed is mostly large lot (2 acres or greater) suburban residential. The stream draining the watershed begins as an ephemeral (intermittent) (intermittent) channel at a storm sewer pipe discharge at Abbey Lane. Lane. This discharge discharge pipe collects runoff from watershed areas upstream of Abbey lane and from a portion of Monk Road. From the stormwater outlet the channel flows flows through residential residential yards. The stream gains perennial flow from a spring located on or near 1438 and 1439 Abby Lane. The perennial flow continues continues into a pond located on the property at 1450 Soapstone Road. From the pond outfall the stream continues across 1600 Soapstone Road and then through a steep undeveloped ravine on 1600 Monk Road. Flow within the stream remains perennial and gains water from two additional springs along its lower reach. Just upstream of the the Schuylkill Expressway, Expressway, the stream enters a 6 foot by 4 foot concrete culvert which conveys conveys the discharge under the Expressway. Just downstream of the Expressway the the discharge enters a 36 inch diameter culvert under the Norfolk Southern Corporation’s Harrisburg Line, and then under under River Road and across 200 River Road in a second 36” diameter culvert after which discharges into the Schuylkill River. 2.2. HISTORY OF DEVELOPMENT IN THE WATERSHED

Historic aerial photographs from 1942, 1958, 1971, and 2010, and information from the Lower Merion Historical Society was evaluated to determine the development sequence within the Soapstone watershed. The aerial photographs reviewed reviewed are illustrated in Figure 3. In the early 20th Century the majority of the watershed was occupied by the Soapstone Farm, Waverly Farm, and the Shipley School Farm. In 1948 there were approximately approximately 10 homes homes in the watershed (see Figure 3). By 1958, one and two acre lots had been subdivided subdivided along the edges of the farmland and the number of residences had increased increased to approximately 38. By 1971 the total number of homes in the watershed had increased to approximately 60. Today, there are approximately 62 residences in the watershed. In addition, since 1971 a number number of homes in the watershed have have been replaced or enlarged, and surface amenities have been added (pools, tennis courts, enlarged driveways, etc.). 2.3. SOILS

The majority of the the watershed is covered by by the Glenville Glenville and Manor soil series series (Figure 4). The Glenville silt loam series is located in the central portion of the watershed in the stream valley. These soils soils are common common in drainage drainage ways. The soils have a moderate saturated hydraulic conductivity and are typically typically well drained. The upper 3 feet of a typical soil profile has a silt loam texture. Below 3 feet the the soil is a massive massive channery loam. Mottles are common at 1 foot depth, depth, suggesting some seasonal saturation. This soil series can have a fragipan at 15 to 30 inches. The importance of fragipans is that they restrict re strict the vertical movement of water migrating through the soil. The depth to bedrock in Glenville soils is generally 5 feet or greater. 3



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The soils in the stream valley below the pond pond are in the Manor very stony silt loam. This soil is deep and highly erodible. A typical Manor soil profile has a sandy loam texture that extends through an A and Bw horizon to a depth of approximately approximately 2 feet. Below the Bw horizon are a series of C horizons with increasing sand content. content. Depth to bedrock in the the Manor series is typically at 6 feet or greater and channery rock fragments fragments are commonly 20 to 50% of the soil soil profile. These soils soils do not typically have a seasonal high water table as they drain rapidly. Closer to the Schuylkill River, River, soils within the stream stream corridor are classified as Stony Land. Land. The Montgomery County Soil Survey (1967) classifies the Stony Land soils in association with other series, in the case case of this location, location, with Manor soils. soils. The distinction between between the stony land association and Manor soils is that the soils are generally shallower. The surface runoff and internal drainage of Stony Land is rapid. These soils soils are not suitable for development development or agriculture. The Soil Survey recommends that these soils be used for watershed protection or recreational purposes. Keeping these soils planted with trees and shrubs will minimize erosion. The soils in the upper parts of the watershed are in the also mapped as being in the Manor soil series. Compared to the Manor soils mapped in the stream corridor, the Manor soils in the upper parts of the watershed are less stony. 2.4. GEOLOGY

The digital geology map of Pennsylvania produced by the Department of Conservation and Natural Resources maps two geological geological formations within within the Soapstone watershed. watershed. The central portion of of the watershed, corresponding to the stream corridor is mapped as being ultramafic (dark igneous rock). The upper portions of the watershed are mapped as being in the the Wissahickon Formation which consists primarily of schist, gneiss and quartzite. 3. FACTORS INFLUENCING ACCELLERATED CHANNEL EROSION

Erosion within a watershed is dependent upon rainfall amounts and physical characteristics such as soils, geology, land slope, slope, and land cover conditions conditions (surface characteristics). characteristics). Physical characteristics characteristics within the watershed are important because they define how much storm runoff is generated by a particular amount or rainfall. 3.1. RAINFALL

Regional rainfall data was evaluated for trends that might be influencing observed erosion within the watershed. Daily data for a 64 year period was available from the National Oceanic and Atmospheric Administration for a station at the Philadelphia Philadelphia Airport. This data is plotted in Figure 5. It is noted that the time scale in Figure 5 coupled with the line width representing individual rain events obscures days with no rain. However this plotting technique permits clearer representation representation of the less frequent, larger rain events. A significant visual observation from Figure 4 is the large number of daily rain events greater than 2 inches that occurred during the period from 1999 through 2011. The following comparisons and

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observations are made from the data for this period as they relate to the entire data set from 1948 through 2011:    

Of the 32 daily rainfall events greater than 3 inches, 13 occurred during the last 13 years; Of the 12 daily rainfall events greater than 4 inches , 7 occurred during the last 13 years; Of the 5 daily rainfall events greater than 5 inches, 3 occurred during the last 13 years; The single largest daily rainfall event, 6.6 inches, occurred in September of 1999.

While the data from the rainfall reporting station at the Philadelphia Airport provides good daily and annual trend analysis, localized high intensity storms of short duration occurring in suburban areas like Lower Merion Township Township may not be reflected in the data. For example, On August 1, 1, 2004 a high intensity storm dropping over 6 inches of rain in 90 minutes occurred locally causing heavy flooding and damage in the Township. Township. This localized storm was not reflected reflected in the data recorded by the Airport rain gage which reported 1.7 inches for that date. date. It is noted that some researchers believe that the heat island affect in the vicinity of large cities influences local weather patterns by deflecting higher intensity storms to the surrounding suburbs. Therefore, during wet years, Lower Merion Township may receive more frequent higher intensity rain events than are recorded at the airport. Erosion is a natural process in all watersheds. It is also known that natural erosional processes accelerate or increase during flow events equal to or greater than about the 1-year frequency runoff event. The PennDOT Drainage Manual reports that the 1-year frequency frequency 24-hour rain event for the the area is about 2.6 inches. As illustrated in Figure 5, the rainfall data for the region document that there has been a larger than normal number of rainfall events equal to or greater than 2.6 inches per day during the period from 1999 through 2011. It would be expected that this recent significant increase in the frequency of large rainfall events would produce an equally significant increase in erosion within the watershed. 3.2. WATERSHED PHYSICAL CHARACTERISTICS

Watershed physical characteristics characteristics include include soils, geology, geology, land slope, and cover cover condition. Cover condition characterizes the land surface as it relates relates to runoff generation. generation. Typical classifications classifications include imperious areas (building roofs, pavement and other hardscape that typically sheds most runoff), lawn, meadow, forest, forest, etc. These later classifications classifications represent different different pervious surface conditions. Land slope is important because water will run off of steeper slopes faster than it runs off mild slopes. It is also noted that that changes to any of the items items described above will result result in a change in the rainfall-runoff relationship within the watershed. The permeability of the soil soil and underlying geology geology also influence runoff runoff generation. As described above, soils within the watershed are well drained and are made up of silts, sands, and stony/rocky material. Once exposed, exposed, these materials are highly erodible. erodible. Therefore, runoff events events that might might only cause minor erosion in soils with higher clay content can cause significantly more erosion here. As described previously and illustrated in Figure 2, prior to 1942 there was very little development within the watershed and the cover conditions were primarily meadow and forest lands with some agricultural development in the western portions of the watershed. Under these conditions, most of 5



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the annual rainfall in upper portions portions of the watershed would have infiltrated infiltrated into surface soils. This is why there is no evidence of a surface channel in the upper and middle watershed in the 1942 photograph in Figure Figure 2. It is noted that even in the watershed’s relatively undeveloped condition in 1942, there would have been erosion occurring in the watershed during larger rainfall r ainfall events. This is particularly true in the lower portions of the watershed due to the steepness of the valley slope and the susceptibility of the local soils to erosion. The existence of the valley itself is the strongest evidence of past erosion. As the watershed developed through the 1950’s and 1960’s, additional impervious area was added to the watershed as a result of road improvements and the development of residential properties (roofs, driveways, etc.). It is estimated that that the impervious area in the watershed increased, from less than than 1 percent pre-1942 to approximately approximately 10% in 1971. In addition to the increase in impervious area, some drainage patterns in the watershed were altered as a result of the development of roads and driveways. driveways. For example road construction construction and improvements during this period along Abby Lane and Monk Road resulted in interception and concentration of runoff runoff from upslope areas that previously previously discharged in a dispersed fashion. This concentrated runoff is discharged through the culvert under Abbey Lane. The development of roadside ditches along Soapstone Road has also contributed to the concentration of runoff tributary to the stream channel. The impact of the development activities in the 1950’s and 1960’s was to increase the frequency and magnitude of runoff reaching the stream corridor. The natural response to this increase in runoff would be an acceleration of naturally occurring erosion within the watershed. As indicated previously, from the early 1970’s to today there has been some additional development within the watershed. A few new homes have been built, and a number of homes have been replaced or enlarged, and amenities amenities such as tennis courts and pools have have been added. This additional additional development is estimated to have created less than 3 percent additional impervious area within the watershed. Stormwater and erosion controls were implemented through new Township Ordinances and codes regulating development development of the land beginning in the mid 1970’s. Therefore, runoff from development activities since the mid 1970’s has been controlled through the installation of seepage beds or other on-lot stormwater controls. A field review of the on-lot stormwater controls constructed after implementation of Township stormwater regulations was conducted to determine if they were constructed in conformance with the approved design. Although most were found to be in conformance, several were in need of maintenance. The township is in the process of notifying notifying affected property owners regarding the necessary maintenance items. items. In addition, one property property was found to be out of compliance compliance with township regulations. regulations. This property owner has been contacted contacted about correcting correcting this situation. It has

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been determined that none of the maintenance or compliance issues identified have had measurable impact on erosion or storm runoff in the watershed. In the discussion above, impervious area is used as the measure of development impacting the quantity of runoff. runoff. It is noted that site grading grading and other construction activities activities which compact compact natural soils also have an impact on runoff runoff rates and volumes. However, the re-establishment of vegetation on these surfaces causes the resultant increase in runoff to be much less significant than the impact from impervious surfaces. 3.3. SUMMARY CONCLUSIONS CONCLUSIONS RELATED TO FACTORS INFLUENCING INFLUENCING EROSION

As mentioned previously, erosion is a natural process in all watersheds and these natural erosional processes accelerate or increase during flow events equal to or greater than about the 1-year frequency runoff event. The 1-year runoff event corresponds corresponds with a 24 hour hour rain event of a little little more than 2 inches. As discussed above, above, the rainfall data for the the region demonstrates that that there has been a significant increase in rainfall r ainfall events over about 2 inches per day during the period from 1999 through 2011. As discussed above, development in the watershed before implementation of stormwater controls resulted in an estimated estimated 10% increase of impervious surface area in the watershed. However, runoff from most of this impervious area is tributary to pervious landscape (lawns and other open space) where some of the runoff can be absorbed. absorbed. Therefore the increase in runoff is less pronounced than in in cases where the runoff from impervious surfaces is piped directly directly to watercourses. It is acknowledged that the runoff from a small portion of Monk Road and Abby Lane is directly connected to the waterway by storm drains and a nd roadside drainage swales. While development activities in the watershed may have resulted in a minor increase in runoff, no evidence was uncovered during this study that would suggest that the imperviousness associated with development in the watershed caused erosion comparable to what has been evidenced in recent years. It is concluded then, that the increased frequency of large rainfall events and associated runoff during the past 13 years, has been the primary contributor to the acceleration of natural erosion observed in the watershed. 4. FIELD ASSESMENT AND STRATEGIES FOR EROSION MITIGATION

As discussed above, the stream channel through the watershed begins as an ephemeral channel, just downstream of a storm sewer pipe discharge east of Abbey Lane. From this point, the channel crosses 10 properties before reaching the culverts under the Schuylkill Schuylkill Expressway, Norfolk Southern Railroad Railroad lines, River Road, and the Lot at 200 River Road. The stream channel conveyance conveyance culverts were field viewed viewed and evaluated to assess site-specific capacity and channel erosion characteristics, and to identify recommended restoration techniques to mitigate the observed erosion, flooding, and debris deposition issues. In the following sections, sections, the evaluation and recommendations recommendations are keyed to eight (8) individual properties and the piped section from the expressway to the Schuylkill Sc huylkill River. The analysis is presented beginning with the piped section continuing upstream through each referenced property to Abby Lane. For property locations in relation to the stream channel, refer to Figure 1. For each stream reach, 7



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conveyance and erosion characteristics are presented followed by a description of the recommended mitigation measures. Conceptual design level level order of magnitude estimates of probable cost are also also presented. 4.1. PIPED SECTION – SCHUYLKILL EXPRESSWAY TO 200 RIVER ROAD

The piped section represents the downstream limit of the study reach and includes the piped conveyance systems under the Schuylkill Expressway, Norfolk Southern Corporation railroad rightof-way, River Road, and the side yard of 200 River Road. 4.1.1. EXISTING CONDITIONS

The existing condition for this reach is illustrated in Exhibit 12 (Appendix B) and consists of a 4 foot by 6 foot box culvert under the Schuylkill Expressway, Expressway, a 48 inch circular reinforced concrete pipe (RCP) under the Norfolk Southern Corporation railroad, and a 36 inch oval pipe under River Road and through the property at 200 River River Road. Photo a on Exhibit 12 illustrates the Township Junction Box along the west side of of River Road. Photo b and c illustrate the junction junction configuration between the PennDOT culvert under the Schuylkill Expressway and the inlet to the culvert under the Norfolk Southern Corporation railroad. Discharges from the culvert under the Schuylkill Expressway are controlled by a 9” by 20” low flow opening at the bottom of the box, and a grate covering its top. The inlet end of the the 48 inch RCP under the railroad right-of-way is screened with a vertical mesh screen and a horizontal steel grate (See Photo c on Exhibit 12.). It is noted that the mesh or wire screen was installed installed to replace a vertical steel screen (similar to the top grate) sometime after November 2011 after the Township requested requested that the steel screen be removed. removed. This request was in response to information received from the Pennsylvania Department of Environmental Protection that flow and debris restrictions such as this were a violation of State Code. The discharge end of the culvert under the railroad connects to the culvert under River Road via a Township installed installed junction box. When this junction junction box was initially initially constructed, a vertical vertical steel grate was installed at its outlet side to trap debris and facilitate maintenance of the pipe under river road. This grate was removed in November November of 2011 when when the Township Township became aware that the obstruction caused by the grate was a violation of State Code. C ode. Both the discharge configuration of the PennDOT culvert and the inflow configuration of the railroad culvert, as well as the grate in the junction box along River Road restricted flow and debris movement through through the system. In addition, the fact that the the culvert under the railroad is is smaller than the box culvert under the Expressway causes an additional restriction of flow at this junction. The restriction of flow and debris movement caused by the described conveyance elements has contributed to past flooding and erosion/debris deposition on and along River Road.

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4.1.2. SUGGESTED MITIGATION ACTIONS

Mitigation actions to reduce the risk of flooding, erosion, and debris deposition in the vicinity of River Road would involve trapping or otherwise removing the sediment and debris load (Alternative 1) and/or improving the conveyance capacity of the piped discharge system (Alternative 2). Alternatives for removing removing or reducing the transported transported sediment and debris load include stabilizing the upstream stream reach (Alternative 1a) or constructing a sediment/debris trap just upstream of the Expressway Expressway (Alternative 1b). Alternative 1a, stabilizing stabilizing the upstream channel is considered in Section 4.2 below. 4.1.2.1.

ALTERNATIVE 1B - SEDIMENT/DEBRIS TRAP

This alternative involves the construction of a debris trap upstream of the Schuylkill Expressway. During large storm storm events eroded material material from the watershed watershed is transported into and through through the culvert system as described described previously. Some of this material is deposited in the various pipe segments and at the junction of the pipe segments partially or fully blocking the portions of the pipes causing flood waters and debris to flow out the top of the discharge box at the downstream end of the expressway culvert and the junction box at River Road, and flood across the railroad tracks causing flooding, erosion, and significant debris deposition. deposition. The result has been property property damage and economic loss, as well as a significant safety hazards for rail traffic. One alternative to reduce or eliminate clogging of these culverts would be to construct a sediment and debris trap just upstream of the Expressway to capture transported sediment and debris before it enters the system. This alternative, alternative, investigated by by the Township Township in 2010/2011, involves construction of a riser pipe on the upstream end of the PennDOT culvert under the Expressway and excavation of debris basin immediately upstream (See Exhibit 11 in Appendix B). In addition, an access road and staging area for maintenance of the debris debris basin would need to be constructed. constructed. Construction of the access road will be the most significant challenge for this alternative. There are two options for providing access to the area adjacent to the Expressway embankment. The first is to construct the access road from the Expressway (with locked and controlled access). The second would be to construct the access from Soapstone Road. Both options pose challenges but warrant further investigation. A concept level order of magnitude estimate of probable cost for both access alternatives are provided below. It is noted that these costs reflect initial construction and do not include include cost associated with maintenance and operation. Access from Schuylkill Expressway Access from Soapstone Road

$ 370,000 $ 460,000

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4.1.2.2.

ALTERNATIVE 2 - CONVEYANCE SYSTEM IMPROVEMENTS

Actions that would improve flow and sediment/debris movement through the culvert system include: a. Construction of a more efficient transition between the PennDOT culvert and the culvert under the Norfolk Southern railroad. This would involve involve some or all of the following items: Completely remove the wire screen and grate at the upstream end of the 48 inch culvert under the railroad right-of way and replace it with a structural headwall with wingwalls; enlarging the opening in the side of the PennDOT culvert outlet box; or 



improving the flow transition between the PennDOT box culvert and the Norfolk Southern culvert through installation of a junction box joining these culverts. b. Installation of a larger pipe under the Norfolk Southern railroad. c. Installation of a larger pipe under River Road and across the property at 200 River Road. d. Removing the pipe under the property at 200 River Road and replacing it with an open drainage channel. 

As indicated above, the Pennsylvania Department of Environmental Protection has indicated that any screen or conveyance element which might hinder free flow of water and transported sediment and debris through the piped conveyance system is a violation of State Code. Therefore, the wire screen at the upstream end of the culvert under the railroad grade should be removed immediately by Norfolk Southern Corporation. In addition, State Code also requires that clear conveyance be maintained through closed conveyance systems constructed to carry waters of the Commonwealth. Commonwealth. Therefore, PennDOT, Norfolk Southern, and the the Township have an obligation to inspect and if necessary clean any debris deposited in the subject culverts following all significant flow events. An order of magnitude estimate of probable cost for the construction of the conveyance elements identified above is as follows: Improved transition structure – PennDOT to Norfolk Southern Corporation culverts Install larger pipe under Norfolk Southern Corporation railroad Install larger pipe/drain under River Road and replace pipe across 200 River Road with an open channel Total

$

85,000

$ 250,000

$ 120,000 * $ 455,000

* Previously designed, designed, permitted and bid by Township. Fee is average bid amount 15% inspection/oversight inspection/oversight + plus 10% contingency 10



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4.2. 1600 MONK ROAD AND 1619, 1621, AND 1624 WINSTON ROAD

These properties are located just upstream of the Schuylkill Expressway and just downstream of 1600 Soapstone Road. It includes the portion portion of the channel channel which flows through through 1600 Monk Road and also a small section section of channel channel that that flows through 1621 1621 and 1619 Winston Winston Road. Road. The lot at 1624 Winston Road is included as its southern property line is immediately adjacent to the stream channel. 4.2.1. EXISTING CONDITIONS

This section of the stream valley valley is steep and the channel is deeply incised. As indicated in Photographs 4 and 5, the stream banks are steep cut, near vertical and incised incised 8 to 15 feet. In many locations the stream banks, composed of erodible soils and stony material, are exposed and susceptible to erosion as a result of past erosion. A significant number of large trees have been undermined by the erosion and many have fallen across the stream channel. The valley sides are steep with 25% to 50% slopes. slopes. Though the stream flow is tranquil on sunny sunny days, the erosive and forceful nature of rainy day flows are evidenced by the loose boulders, rocks, and debris along the channel length (Photograph (Photograph 5). In many locations the stream stream has eroded to the underlying underlying platy bedrock (Photograph 6). The stream reach through 1600 Monk Road discharges to the culvert under the Schuylkill Expressway. As shown in Photograph 3, the channel area just upstream of the Expressway functions as a sediment sediment and debris trap. A significant volume volume of sediment, stones, large rocks, downed trees and branches, and other debris have accumulated in this area. ar ea. 4.2.2. EROSION MITIGATION APPROACH

The inaccessibility of this reach, coupled with the deeply incised nature of the channel are significant challenges challenges to stabilizing stabilizing this reach. Access can be achieved via Soapstone Road, or from the Schuylkill Expressway. It is acknowledged that gaining the permissions necessary to access this reach via the Expressway will be challenging since it is a Federally regulated limited access highway. Therefore, access from Soapstone Road has been assumed. The recommended mitigation approach for stabilizing actively eroding portions of this reach is illustrated in Appendix Appendix B, Exhibits 1 and 2. The approach involves stabilizing stabilizing the toe (bottom) (bottom) of the stream bank, and, where possible, grading the bank to create a small floodplain bench immediately adjacent to to the channel. When used, the floodplain floodplain bench would be be created on one side or both sides of the channel depending depending on site specific field conditions. conditions. Where conditions would permit, the floodplain bench would be vegetated with woody or brushy vegetation to help reduce the velocity of flood flows and overall erosion potential. To the extent possible, toe armoring would be accomplished by repurposing existing site materials. In areas where trees have toppled toppled over, it is proposed that that the upper trunks and/or root wads be used to armor the toe and lower lower portions of eroding banks banks as scour protection. In other locations, large rocks could be harvested and used for armoring. Stream restoration techniques will not be applied along the entire length of this reach, but rather they will be applied only in areas exhibiting active erosion or other areas deemed to be vulnerable to lateral erosion.

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The steepness of the watershed and erosive power of flood flows coupled with the highly erodible nature of the soils in this reach imposes a degree of uncertainty relative to the success of any erosion mitigation strategy. strategy. In addition, the erosion mitigation mitigation approach suggested will in and of itself result in short term disturbance which could result in an increased susceptibility to erosion. Access for equipment will require grading activities and removal of trees and other existing vegetation, and vegetation planted as part of the erosion mitigation strategy, will require time to become established. Also, there are no homes or other infrastructure that would be threatened by erosion in this reach. For these reasons, consideration consideration of an alternative alternative approach is warranted. Normally the construction of a sediment/debris basin is just upstream of the Expressway. This alternative is presented in Section 4.1.4 below. 4.2.3. ESTIMATE OF PROBABLE PROBABLE COST FOR EROSION EROSION MITIGATION MITIGATION

The cost of implementing the erosion mitigation approach suggested in the previous section is influenced by the limited site access for equipment and ruggedness of the terrain. The order of magnitude estimate of probable cost to implement the described erosion mitigation measures described is $270,000. This estimated cost is based on the following assumptions: assumptions:   

Stabilization of approximately 700 LF of stream using the r estoration methods described; Access is via Soapstone Road; Soapstone Road will require significant restoration as a result of damage from construction traffic.

4.3. 1600 SOAPSTONE ROAD

This property is located just upstream of 1600 Monk Road at the end of Soapstone Road. 4.3.1.

EXISTING CONDITIONS

Approximately two-thirds of the stream reach through this property is deeply incised similar to the conditions described for the upper portions of the stream reach through 1600 Monk Road. However, as the stream flows through the home site near the center of the property, the stream banks fall away as though though they may have been cut to provide provide a more suitable building site. Photographs 7 through 11 illustrate the stream condition in the vicinity of the home site. Although steeply cut, the stream banks here are relatively shallow shallow (0.5 to 3 feet). A portion of the home spans the stream (Photograph 7), and the yard area upstream of the addition has been terraced forming a stepped floodplain floodplain area (Photograph (Photograph 8). The stream banks are steep cut, evidencing past erosion. An erosion control blanket installed installed to stabilize the stream stream banks and adjacent lawn lawn area is exposed exposed at the cut banks banks where where it has been undermined. The channel consists of stony material and rocks. Downstream of the turfgrass area, the stream enters the deep forested valley and is geometrically similar to that described described above for the property property at 1600 Monk Road. In this section, the cut stream banks are steep cut with bank heights up to about 5 feet. Within this lower portion of 1600 Soapstone Road, some channel segments appear stable and some are heavily eroded.

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Upstream of the home site, the stream banks are continuously exposed, evidencing past erosion activity (Photograph (Photograph 10). Cut banks in this area range from about 5 feet, to more more than 10 feet in height, west of the barn. The channel becomes very deeply incised at the western edge or the the property. 4.3.2. EROSION MITIGATION APPROACH

In the forested sections of the stream reach upstream and downstream of the house site, restoration techniques techniques similar to those described for for 1600 Monk road would be appropriate. The approach is illustrated in Exhibit 4, in Appendix B. To mitigate the erosion within within the stream segment crossing the home site, armoring the stream banks with riprap or some other material is the suggested restoration restoration technique. This technique is illustrated illustrated in Exhibit Exhibit 3. Due to the proximity of the house, any installed installed bank armor will require inspection inspection following each storm and prompt maintenance, as needed, between storms. The Township was recently notified that the damages on this property are eligible and have been selected for funding through the US Department of Agriculture’s (USDA) emergency watershed protection program (see Section 6 for a description of this program). program). Mitigation measures have been designed designed by PA DEP for USDA. The Township is assisting as the sponsor and contracting agency will full reimbursement of the construction costs. 4.3.3. ESTIMATE OF PROBABLE PROBABLE COST FOR EROSION EROSION MITIGATION MITIGATION

The order of magnitude estimate of probable cost to implement the described erosion mitigation measures in the upstream and downstream downstream incised channel channel areas on this property is is $ 68,000. The riprap bank protection proposed for the center portion of the property is being funded through a USDA grant and, therefore therefore is not included. included. The estimated cost cost is based on the the following assumptions: 



Stabilization of approximately 100 LF of the stream valley downstream of the house site using techniques as described for the stream segment through 1600 Monk Road. Stabilization of approximately 200 LF of stream valley upstream of the house site using techniques described above.


This property sits at the transition from the steeply sloped stream channel in the lower portion of the watershed and the more mildly sloping upper channel channel reaches. Remnants of the former soapstone soapstone quarry are visible near the center of the property and the quarry pond occupies a large portion of the site (Photograph 13). 4.4.1. EXISTING CONDITIONS

The stream on this property consists of a previously stabilized steeply sloped pond outlet channel (See photograph on Exhibit 5, Appendix B), a mildly sloping pond inflow channel, and the in-line pond in the middle. There is also a short section of steeply incised channel just j ust downstream of

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the pond outlet channel (refer to the photograph on Exhibit 4 in Appendix B) extending into the property at 1600 Soapstone Soapstone Road. The steeply sloped pond outlet channel was previously stabilized by the property owner and a gabion basket retaining wall topped with a segmented block retaining wall, was also installed along the north side of the channel (Photograph (Photograph 12 and Exhibit 5 in Appendix B). As illustrated in Exhibit 5, there is active erosion at the downstream downstream end of the stabilized outlet channel. This erosion is a result of the abrupt flow transition between the outfall channel and the natural stream channel below. The pond on this property is in-line with the stream. Therefore, any sediment transported transported from upstream areas as a result of natural or accelerated erosion is captured in the pond. There is evidence of deposited sediment at the point where the upstream channel enters the pond (See Photo 14). The pond serves as a sediment trap for all material eroded and transported from from the upstream stream segments. It this pond were to fill it it would no longer prevent the the movement of this material to downstream reaches and ultimately to River Road. The short stream segment on the property just upstream of the pond has steep cut 3 to 4 foot near vertical channel bank slopes as illustrated illustrated in Figure 14 and the top left photo in Exhibit 6. Small stony alluvial deposits along this reach provide evidence of sediment transport through the reach. Photograph 14 illustrates an exposed pipe located in this section of the stream which indicates that there has been historic erosion within the reach that resulted in a general lowering of the channel bed. 4.4.2. EROSION MITIGATION APPROACH

As indicted above, the property owner has already made a substantial investment in stabilizing the pond outlet channel. channel. However, where the stabilized stabilized channel and adjacent gabion retaining retaining wall end, there is an area of significant scour. A photograph documenting the scour in this area and a cross section documenting the mitigation approach are illustrated in Appendix B Exhibit 5. The mitigation approach involves the construction of a large rock energy dissipater apron extending for an appropriate length into the milder downstream channel. The cut stream banks in the segment of channel upstream of the pond should be stabilized the bank toe and installation of an adjacent floodplain bench as illustrated in Exhibit 6 for the downstream channel segment on 1434 Soapstone Road. 4.4.3. ESTIMATE OF PROBABLE PROBABLE COST FOR EROSION EROSION MITIGATION MITIGATION

The order of magnitude estimate of probable cost to implement the described erosion mitigation measures described is $77,000. This estimated cost is based on the following assumptions: assumptions: 



Installation of an energy dissipation apron downstream of the stabilized pond outlet channel; Stabilization of approximately 100 LF of stream channel upstream of the pond using techniques as illustrated in Appendix B, Exhibit 6. 14



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The property at 1434 Soapstone is the geometric center of the watershed. Perennial stream flow begins here as a result of spring flows from 1449 and 1439 1439 Abby Lane. Upstream of this property the streamflow is ephemeral/ intermittent. 4.5.1. EXISTING CONDITIONS

There are three distinctly unique stream segments on on this property. The downstream segment segment flows parallel to the properties driveway in a linear fashion and then curves sharply to the north, near the north eastern corner of the house. Photographs 15 through through 21 illustrate illustrate channel conditions in this reach. The channel is moderately to deeply incised in this reach with cut banks ranging from 3 to 6 feet high. high. The deepest channel cut cut is near the sharp bend just mentioned. The linear stream channel in the lower portion of this reach is located approximately 5 to 12 feet from the driveway. driveway. The pipe illustrated illustrated in Photograph Photograph 15 is approximately 1.5 feet above the bottom of the stream channel. This provides evidence that the stream has eroded vertically over time. The center channel section, which flows mostly along the northern property line, appears stable as illustrated in Photographs Photographs 22 and 23. Along this portion portion of the channel the property owner graded the streambanks to create a gentle connection with the floodplain in a fashion similar to the mitigation measures illustrated in Appendix B Exhibit 6. Upstream of the stable channel reach (near the darn and property boundary with 1435 Abbey Lane) there is an area ar ea that exhibits significant erosion at and just downstream of an 8 foot vertical headcut (sudden drop in stream elevation). This headcut section is currently being stabilized by the roots of large trees that extend across the channel from both sides. Immediately downstream of the headcut the channel channel is approximately 10 10 feet deep (Photograph 27). Just upstream of the headcut the channel depth is less than 2 feet deep with gently sloping stable banks as illustrated in Photograph 29. 4.5.2. EROSION MITIGATION APPROACH

Restoration options are presented for the downstream channel reach and headcut ar ea. The restoration option for the downstream channel reach is illustrated in Appendix B Exhibit 6. The solution consists of grading the bank to a more stable angle and constructing a vegetated floodplain bench on one or both sides sides of the channel depending depending on specific site conditions. conditions. In areas where there isn’t adequate room to lay the bank back to a stable slope, the toe of the slope should be armored using stone/riprap or other means such as logs or root wads. Additional stabilization stabilization will be required at the sharp bend, near the north east corner of the house. At this location, an earth retention system or similar technique should be used to stabilize the outside of the bend. A vegetated floodplain bench on the north and east of the channel should also be extended through this this bend. This mitigation approach approach is illustrated in Appendix Appendix B Exhibit 7.

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The recommended solution for mitigation of erosion at that headcut is illustrated in Appendix B Exhibit 8. The solution includes includes installation of of eight cross vane drop structures structures spaces 15 feet apart. In addition, the the channel banks should be laid back and stabilized stabilized with grass grass or other vegetation. 4.5.3. ESTIMATE OF PROBABLE PROBABLE COST FOR EROSION EROSION MITIGATION MITIGATION

The order of magnitude estimate of probable cost to implement the described erosion mitigation measures is $122,000. This estimated cost is based on the following following assumptions:   

Installation of 375 LF of stream restoration using techniques in Appendix B Exhibit 6. Installation of rock filled gabion bank protection as illustrated in Appendix B Exhibit 7. Construction of 8 cross vane stabilization structures illustrated in Appendix B Exhibit 8.

4.6. 1435 ABBEY LANE 4.6.1. EXISTING CONDITIONS

Photographs 30 through 32 illustrate channel characteristics on the property at 1435 Abbey Road. Natural erosion on this property has created c reated an eroded stream channel with an average width of about 2.5 feet and an average average depth of about 2 feet. This channel appears to be generally stable although some erosion probably does occur during high flows. A sizable scour hole exists just just downstream of the upstream property line (Photograph 32). This scour hole has been formed in response to energy dissipation as flow transitions from the rock lined channel on the upstream property to the natural condition on this property. 4.6.2. EROSION MITIGATION APPROACH

Improving the channels erosion resistance would involve minor grading along the existing channel to improve floodplain connectivity and create a broader distribution of flow across the property during high high flows. Exhibit 9 in Appendix Appendix B illustrates this concept. concept. In addition, some form of energy dissipation should be implemented at the upstream property line to eliminate the the accelerated erosion at that location. location. This could be accommodated accommodated on this property or on 1418 Monk Road. 4.6.3. ESTIMATE OF PROBABLE PROBABLE COST FOR EROSION EROSION MITIGATION MITIGATION

The order of magnitude estimate of probable cost to implement the described erosion mitigation measures described is $108,000. This estimated cost is based on the following assumptions: assumptions:  

Stream restoration for 400 LF using techniques in Appendix B Exhibit 9. Installation of a rock apron/energy dissipater at the upstream property line.

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4.7. 1418 MONK ROAD

As shown in Photograph 33, 33, the stream corridor at 1418 Monk Road is entirely entirely lined with rock. At this time, no restoration is proposed at this location. However as discussed previously, a scour hole has formed at the point where the stream discharges from the 1418 Monk Road property to the property at 1435 Abbey Road. The alternative to installing an energy dissipation apron at 1435 Abbey Road would be to install a stilling basin or other form of energy dissipation on this property. 4.8. 1410 AND 1400 MONK ROAD

Since the channel section and observed erosion are similar on the properties at both 1410 and 1400 Monk Road, these properties will be considered together. 4.8.1. EXISTING CONDITIONS

Existing channel conditions conditions on these properties are illustrated illustrated in Photographs 34, 35, and 37. The channel through both of these properties properties is cut through very erodible soils. Stream banks are near vertical with an average height of approximately four feet. The top of bank width within this reach varies from about 5 feet to 15 feet. Large section of undermined undermined turfgrass can be observed observed on these properties properties (Photograph 34). Photograph 37 illustrates the beginnings beginnings of the the defined stream channel just downstream of the culvert under Abbey Lane. As time progresses, this headcut will continue continue to advance until it reaches the culvert outfall. outfall. Photograph 38 illustrates flow entering the culvert on the upstream side of Abbey Lane. This culvert also carries flows from the inlets on Monk Road at its intersection with Abbey Lane (photographs 39 and 40). 4.8.2. EROSION MITIGATION APPROACH

The preferred mitigation approach across these properties would be to grade the streambank to a more appropriate slope and create vegetated floodplain benches where possible and appropriate. It is acknowledged that the large trees along the stream will make creation of a continuous floodplain bench difficult. Bank Toe armor should also be installed in locations were active bank undermining is occurring. These mitigation techniques are illustrated in Appendix B Exhibit 10. 4.8.3. ESTIMATE OF PROBABLE PROBABLE COST FOR EROSION EROSION MITIGATION MITIGATION

The order of magnitude estimate of probable cost to implement the described erosion mitigation measures described is $120,000. This cost is about evenly split between the two properties. properties. This estimated cost is based on the following f ollowing assumptions: assumptions: 

Stream restoration for 600 LF using techniques in Appendix B, Exhibit 10.

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4.9. DRAINAGE AT THE INTERSECTION OF MONK ROAD AND ABBEY LANE

Drainage conditions at the intersection of Monk Rod and Abbey Lane are illustrated in Photographs 39 and 40. The water illustrated in the photographs is runoff from a curbed portion of Monk Road extending both east and west of Abbey Lane. As illustrated in Photograph 39, some of the runoff tributary to this location runs down the west side of Abbey Lane (see also Photograph 38) contributing to erosion adjacent to this private driveway. driveway. This condition could could be mitigated mitigated by modifying the driveway apron/roadway apron/roadway transition transition to create a positive flow line to the inlet. inlet. It is suggested that the Township Public Works Department work with the land owner to facilitate this modification. 5. COST SUMMARY

Costs associated with mitigation strategies were presented in the last section for each property the stream channel traverses across. Costs are summarized below as they relate to erosion and and depositional processes in the upper and lower lower watershed. The upper watershed includes includes all properties upstream upstream of the pond at 1450 Soapstone Soapstone Road, and the lower watershed is everything everything to the east of the the pond. The pond traps all sediment generated generated from the upper watershed. The lower watershed is the the source of the sediment and debris that gets transported to the culverts under the Schuylkill Expressway, Norfolk Southern Railroad, and River Road. Upper Watershed

$ 350,000

Lower Watershed Alternative 1a - Erosion Mitigation Alternative 1b - Sediment/Debris S ediment/Debris Trap Alternative i. Access from Schuylkill Expressway ii. Access from Soapstone Road Alternative 2 – Conveyance Improvements Schuylkill Expressway to River

$ 415,000 $ 370,000 $ 460,000 $ 455,000

It is noted that the lower watershed alternatives alternatives are intended as either/or alternatives. alternatives. Also, alternative 1a represents an estimate of the cost to stabilize the channel in the lower watershed and includes costs presented for mitigation of erosion from 1600 Soapstone Road to the Expressway. There are also additional costs associated with operation and maintenance of the sediment/debris trap that were not considered here. As identified in Section 4.2.2, the steepness of the watershed and erosive power of flood flows coupled with the highly erodible nature of the soils in the lower reach imposes a degree of uncertainty relative to the success of any erosion mitigation strategy. In addition, the need to cut access roads and disturb additional land within this highly erodible portion of the watershed makes this an undesirable alternative. For these reasons, Alternative 1a is considered the least preferred alternative for mitigation of sediment and debris transport from this portion of the watershed. It is further noted that in addition to construction costs, all cost estimates presented in this report include an estimate of permitting and engineering fees.

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6. GRANT AND OTHER FUNDING OPPORTUNITIES

Grant and other funding opportunities applicable to watershed restoration and erosion mitigation within the Soapstone Watershed are described below: Schuylkill River National National and State Heritage Heritage Area was was Schuylkill River Restoration Fund: The Schuylkill designated by the United United States Congress Congress as an area where historic historic and recreational recreational resources come together to define a distinctive landscape. The Heritage Area is managed by the Schuylkill River Greenway Association. Association. In cooperation cooperation with Exelon Nuclear and the Philadelphia Philadelphia Water Department, the Heritage Area administers the Schuylkill Schuylkill River Restoration Fund. Available to non-profit organizations organizations and municipal governments, the grant finances projects that mitigate water quality problems resulting from acid mine drainage, agricultural runoff, and stormwater issues. Grant applications are by invitation after a Letter of Interest is submitted and reviewed. A letter of interest was submitted for this watershed but an invitation has not been extended at the time of this writing. writing. Grant allocations range from $25,000 and $100,000 and a 25% match is required. Department of Agriculture Emergency Watershed Protection Assistance Program: The United States Department (USDA) Emergency Watershed Protection (EWP) program in cooperation with Pennsylvania Emergency Management Association is currently offering technical and financial assistance to stabilize streams that became damaged following the hurricane Irene and Tropical Storm Lee. Lee . To qualify for this funding the unstable stream reach must be within 50 feet of improved improved property. The program stabilizes stabilizes streams by armoring the stream with rock. One property owner in the Soapstone Soapstone Watershed Watershed has qualified for funding under this program. Growing Greener Program began in 1999. One of the the program’s program’s Growing Greener Program: The Growing missions is to restore and protect Pennsylvania’s rivers rivers and streams. To fulfill this mission, mission, Growing Green offers Watershed Watershed Protection Protection Grants. Projects that improve waters quality of impaired watersheds watersheds polluted by urban runoff qualify for funding under this program. At this time , Growing Greener is not accepting applications. In 2011 the program accepted applications in August. The next round of applications for Growing Greener Funding is expected after the 2012-2013 budget is approved. The National Fish and Wildlife Foundation’s Five Star Restoration Program: This program provides competitive funding for community-based community-based restoration project. project. The program is focused on both restoration restoration and community partnerships. partnerships. The average grant award is is $25,000. A one-to-one in-kind match of goods and services is required to qualify for this program. Grant applicants applicants must address how their project achieves on-the-ground on-the-ground restoration, environmental education, and measurable measurable results. The applicant applicant must also demonstrate demonstrate that the project project will engage engage multiple partners partners within a community. community. The program is not accepting applications at this time, but is expected e xpected to reopen in 2012. William Penn Foundation: The William fund Foundation funds programs that protect, conserve and restore water resources in the Philadelphia Philadelphia region. The Foundation prioritizes prioritizes funding to projects that promote policies and practices that facilitate green infrastructure approaches to stormwater management. The first step in applying for a grant from the Foundation is to submit a letter of inquiry to the Foundation. The letter should address how the project meets the objective objective of the Foundation. Foundation. If the Foundation considers the letter of inquiry favorably, the applicant will be invited to submit a full application.

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PennVEST: The Pennsylvania Infrastructure and Investment Authority (PennVEST) provides low interest loans to finance design, engineering, and construction for municipal stormwater projects through the Clean Water State Revolving Fund. The interest interest rates range from 1 to 4%. Examples of of stormwater stormwater projects that PennVest has financed in the past include infiltration system, swales, and tree plantings. Penn Vest Board meetings are currently scheduled for May 16, 2012 and August 22, 2012.

Small Grants Program is administered by the Urban Waters Small Grants Program: The Urban Waters Small Environmental Protection Protection Agency. It finances projects that contribute to improved improved water quality and community revitalization. revitalization. Funded projects must demonstrate demonstrate community-led efforts that promote economic, environmental, environmental, and social benefits. Local watershed planning, water water quality monitoring, and public education are examples of projects funded in the past. The 2012 application deadline was January 23, 2012. It is expected that applications applications for 2013 will will also be accepted in January. January. US Army Corps of Engineers Snagging and Clearing for Flood Control Program: The Snagging and Clearing for Flood Control program is administered by by the Army Corps of Engineers Engineers (ACOE). Through this program the ACOE designs designs and constructs projects projects that provide flood control. control. Removal of snags and debris in a waterway in the interest of of flood control is the focus of this program. The maximum funding amount is $500,000. The project sponsor is required to contribute a minimum minimum of 5% of the project cost in cash. Obtaining this this funding requires the the applicant to request the Army Corps of Engineers Engineers to conduct a planning and design analysis (PDA) study. study. If the study concludes that the project is acceptable acceptable from an engineering feasibility, environmental acceptability, or economic basis, it will be funded.

stakeholders will also need to play a role in project funding. Other Sources of Funding: Key project stakeholders This includes PennDOT, Norfolk Southern Corporation, the Township, and affected property owners. Both PennDOT and Norfolk Southern Corporation have operations, maintenance, and safety responsibilities related to the erosion and sediment/debris transport issues in the eastern end of the watershed. Therefore, they should participate as responsible partners partners in helping to fund erosion mitigation projects in the eastern end of the watershed. 7. SUMMARY

This watershed assessment has identified the probable causes of observed accelerated erosion within the watershed, and has advanced mitigation strategies, or approaches to control the erosion, or manage erosion and the the resulting deposition of of sediment and and debris. Preliminary order of magnitude cost estimates for the proposed erosion erosion mitigation strategies strategies were also developed. In addition, research was conducted to identify grant and other funding sources available for projects of this nature. The two factors influencing accelerated erosion within the watershed are the increase in frequency and magnitude or rainfall and runoff over the past 13 years, and development activities within the watershed prior to the enactment of stormwater ordinances. The dominant factor responsible for the recently observed accelerated erosion is the significant increase in rainfall frequency and magnitude over the past 13 years. Identified stream restoration restoration strategies were also also identified. In the eastern or lower lower portions of the watershed strategies included use of a sediment/debris basin near the Schuylkill Expressway, toe stabilization using local local materials, bank grading, and construction construction of floodplain benches. In the upper or western portions of the watershed the dominant strategy is to use bank grading and the creation of 20



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vegetated floodplain benches benches to stabilize the channel. Bank armoring at a bend, installation of cross vane drop structures, and other energy dissipation strategies are also used to address localized problem areas. Conceptual design level estimates of probable cost for implementation of the erosion mitigation strategies were also developed and were summarized above. 8. CONCLUSIONS AND FUTURE DIRECTIONS

In conclusion, this study has identified erosion and sedimentation/debris mitigation strategies that can be applied within the watershed to mitigate the physical, financial, and safety impacts caused by accelerated erosion within the watershed. watershed. This study serves as a foundation for implementation implementation of these mitigation strategies. Future efforts should include include involving the property owners and key stakeholders (PennDOT (PennDOT and Norfolk Southern Corporation) in a dialogue related to advancing this project. Key discussion items should include project prioritization and phasing, and funding. It is critical that PennDOT and Norfolk Southern Railroad be brought into these discussions at the earliest possible opportunity to assist in advancing solutions particularly in the western watershed areas.

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APPENDIX A KEY MAP AND PHOTOGRAPHS

A-1



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APPENDIX B EXHIBITS ILLUSTRATING RESTORATION APPROACHES

B-1

1 inc h = 2,000 feet

´

ip Township Lower Merion Merion Townsh Study Watershed Study oapston e Watershed Soapstone Figur e 1 d Watershed Soaps tone Watershe Location Locati on of th e Soapstone

2 3 5 0 2 4 5 2 4

0 2 4

2 7 5

245 245

3 2 0

5 2 7 2 9 0

0 5 2 5 5 2

2 8 8 0

5 2 9

2 8 85 5 2 9 9 0 0

1 5 0 202 RIVER RD 200 RIVER RD

300

198 RIVER RD 1552BRIAR HILLRD 1548BRIAR HILLRD

1622WINSTON RD

1557BRIAR HILLRD 1601WINSTON RD

1540BRIAR HILLRD

1611WINSTONRD

1534BRIAR HILLRD

0 4 2

1551BRIAR HILLRD

3 4 0

5 4 2 0

6 2

5 4 1

1607WINSTON RD

1619WINSTON RD

1545BRIAR HILLRD

3 4 45 5

3 4 5

1 1 0 1 1 5

1600SOAPSTONERD

1533BRIAR HILLRD

1525BRIAR HILLRD

3 5 0

1600MONKRD

1 3 0

0 2 4

2 1 0

1455ABBEYLN

2 6 6 5

255 25

1447WAVERLYRD 1450SOAPSTONERD

1400WAVERLYRD

5 3 5

280

1441WAVERLYRD

1550MONKRD

1449ABBEYLN

5 2 2

1530MONKRD

2 9 5

1439ABBEYLN 1433WAVERLYRD

5 2 8

1415WAVERLYRD

5 3 2

1520MONKRD

1421WAVERLYRD

1407WAVERLYRD

0 5 3

0 3 0

5 1 3

9 0 2

3

1543MONKRD

1510MONKRD 1500MONKRD

5 2 9

0 1 5 3 0

1347WAVERLYRD

1 3 5

5 3 2

1435ABBEYLN

5 3 0 3 3 3 0 2 3

1411WAVERLYRD 1401WAVERLYRD

1 1 2 5 5 1 5 2 0

5 3 4

1434SOAPSTONERD

0 2 3

y d p u i t h S s n d e w h o s T r e n t o a i r W e M e r n o e t w s o p L a o S

140

1520BRIAR HILLRD

0 8 2

1 0 5

1539BRIAR HILLRD

1501WAVERLYRD

5 5 2

5

9 0

1621WINSTON RD

0 5 6 6 2 2 0 0 5 0 7 8 3 2 2

194 RIVER RD

9 5 6 5 7 0 5 8 8

1624WINSTON RD

1615WINSTON RD

1530BRIAR HILLRD

1 0 0

0 5 3

1432MONKRD

1356MONKRD

5 3 5 3 6 0

MONK RD

1509MONKRD

1501MONKRD

1345WAVERLYRD

1426MONKRD

1499MONKRD

1418MONKRD

y h p a r g o p o T d 2 n a e w r u i e g v i r F e v O d e h s r e t a W

1435MONKRD 1325WAVERLYRD 1410MONKRD

2 7 5

1429MONKRD 1343WAVERLYRD

5 5 3 0 3 6 5 3 6

1415MONKRD

1335WAVERLYRD

3 7 0

5 0 1 6 0 1 2 1 3

0 3 5

1350MONKRD

5 75 3 7

0 2 6 5 0 2

1423MONKRD

1400MONKRD 1225YOUNGSFORD RD

1326MONKRD

1407MONKRD 1342MONKRD

2 1 5

1401MONKRD

0 8 3

1336MONKRD 1351MONKRD 1332MONKRD

1348BEAUMONTDR

1317MONKRD

1328BEAUMONTDR

1311MONK RD

3 6 0

1310MONKRD

1334BEAUMONTDR

1320BEAUMONTDR 1321BEAUMONTDR

5 0 3

3 4 5

355 35 5 4 3

5 7 3

3 7 0

5 6 3

2 7 0

5 4 2

2 3 0

2 0 0

0 2 2

7 5

140

170 190

2 0 05 5 2 1 5 5 2 2 5

2 3 5

2 4 0

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Philadelphia, PA Daily Precipitation Data 7

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Figure 5. Daily Rainfall in Philadelphia 1948 through January 2012



LOWM093814

September 28, 2012

APPENDIX A KEY MAP AND PHOTOGRAPHS

A-1

A-2

Photograph 1. Rocks, debris

and sediment deposited on River Road following a storm event in 2004.

Photograph 2. Same location on River Road as Photo 1. Center foreground foreground is the junction box connecting the 48” RCP culvert under the Norfolk Norfolk Southern Railroad to the Township’s 36” oval culvert under River Road. (11/03/2011)

Office of the Township Engineer PENNONI ASSOCIATES INC. One Drexel Plaza, 3001 Market Street Philadelphia, PA 19104 Job No.

LOWM093814

Date Taken:


As indicated

Lower Merion Township, Montgomery County, PA

A-3

Photograph 3. Deposition of debris upstream upstream of the 6’ wide and 4’ high culvert under the

Schuylkill Expressway.

Photograph 4 . Stream bank just upstream upstream of

the Schuylkill Schuylkil l Expressway. Note the deeply incised banks and and large boulders boulders on adjacent, steep slopes.


LOWM093814

Date Taken:


8/31/2009


A-4

Photograph 5. Representative Representative channel section at

1600 Monk Road. Vertical Vertical banks and the collapse collapse of trees is noted. Rock similar to that that deposited on the roadway in Photograph 1, is being actively transported down the stream channel.

Photographs 6 . There are

several locations within 1600 Monk Road where the stream has incised to bedrock.


LOWM093814

Date Taken:


8/31/2009


A-5

Photograph 7. Channel looking

upstream to the location of where the stream is routed under the home.

Photographs 8. Channel looking upstream

of where the stream is routed under the home. Side-slopes are terraced downward at approximately 1:1, using landscape rock. Erosion evident along stream banks.


LOWM093814

Date Taken:


2/22/2012


A-6

Photograph 9. Sediment

deposition where stream goes under home.

Photographs 10. Bank

sloughing evident as fine sediment in the channel.


LOWM093814

Date Taken:


2/22/2012


A-7

Photograph 11. Attempts to stabilize banks with

landscaping landscapi ng material. material . Photograph take take n upstream of Photograph 10.

Photographs 12. Gabion basket

installed to stabilize stream bank downstream of the pond.


LOWM093814

Date Taken:


2/22/2012


A-8

Photograph 13. Pond that

remains from former quarry operation. The pond is inline with the stream.

Photograph 14. Stream inflow channel to to pond on 1450 Soapstone. Sediment deposition

evident in pond in vicinity of stream inflow. Office of the Township Engineer PENNONI ASSOCIATES INC. One Drexel Plaza, 3001 Market Street Philadelphia, PA 19104 Job No.

LOWM093814

Date Taken:


2/22/2012


A-9

Photographs 15. The streambed

parallel to the driveway at 434 Soapstone Road has incised to 1.5 feet below an existing water pipe.

Photograph 16. View of stream where it parallels the

1434 Soapstone Road driveway, looking upstream. The channel is approximately approximately 3.5 feet deep on one side and 7.5 feet deep on the other.


LOWM093814

Date Taken:


2/22/2012


A-10

Photographs 17. Stream where it makes a sharp turn to the north at 1434 Soapstone Road.

Photograph 18. View from within the channel, looking downstream. Road is located at the right edge of the photograph.


LOWM093814

Date Taken:


2/22/2012


A-11

Photographs 19. View from

within the channel looking upstream where the stream curves to the north.

Photograph 20. Looking

upstream of stream bend.


LOWM093814

Date Taken:


2/22/2012


A-12

Photographs 21. Looking

downstream of stream bend banks show evidence of recent sloughing.

Photograph 22. Stream just

downstream of where it gains perennial flow from a spring.


LOWM093814

Date Taken:


2/22/2012


A-13

Photographs 23 . Location where

homeowner graded the channel to connect it to the floodplain. This photograph was taken just upstream of where the channel gains perennial flow from the spring.

Photograph 24. Upstream of restored channel channel section is an area of extreme erosion and headcutting.


LOWM093814

Date Taken:


2/22/2012


A-14

Photographs 25. Evidence of

former attempts to armor the streambank.

Photograph 26. Looking downstream across across the property at 1434 Soapstone Road.


LOWM093814

Date Taken:


2/22/2012


A-15

Photographs 27 . Channel incised

8 feet, photograph taken immediately upstream of Photograph 26.

Photograph Photograph 28. Photograph taken just upstream of Photograph 27 looking down into gully.


LOWM093814

Date Taken:


2/22/2012


A-16

Photographs 29 . Channel as it

approaches gully, gully, here it i t is shallow with moderately sloped banks.


downstream, channel as it exists in the western section of 1434 Abbey Lane.


LOWM093814

Date Taken:


2/22/2012


A-17


downstream, channel as it exists in the eastern section of 1434 Abbey Lane.


upstream at the property line between 1435 Abbey Lane and 1418 Monk Road.


LOWM093814

Date Taken:


2/22/2012


A-18

Photographs 33. Stream looking upstream

as it exists at 1418 Monk Road.

Photograph 34. Sloughed banks at 1410

Monk Road.


LOWM093814

Date Taken:


2/22/2012


A-19

Photographs 35. Stream approximately at

1400 Monk Road looking downstream towards 1410 Monk Road.

Photograph 36. Storm water

outfall at the stream headwaters on Abbey Road.


LOWM093814

Date Taken:


2/22/2012


A-20

Photographs 37. Looking downstream

across 1400 Monk Road stormwater discharge point.

at

the

Photograph 38. Stormwater runoff at 1350 Monk Road. Upstream of the Abbey Road outfall.


LOWM093814

Date Taken:


Unknown


A-21

Photograph 39 . Stormwater

inlet at the intersection of Monk and Abbey Roads.

Photograph 40. Stormwater

along Monk Road.


LOWM093814

Date Taken:


Unknown


A-22



LOWM093814

September 28, 2012

APPENDIX B EXHIBITS ILLUSTRATING RESTORATION APPROACHES

B-1

B-2

B-3

B-4

B-5

B-6

B-7

B-8

B-9

B-10

B-11

B-12

B-13

Soapstone Watershed Quarry Gladwyne

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