Soapstone Watershed Quarry Gladwyne

8/20/2019 Soapstone Watershed Quarry Gladwyne

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WATERSHED ASSESSMENTSOAPSTONE WATER

Lower Mer

Montgome

Lower Merion75 East Lan

Ardmore, P

Office of the TownshPennoni AO

30Philade



Table of ContentsSECTION

1. EXECUTIVE SUMMARY .......................................................................................

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

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

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

2.3. SOILS ............................................................................................................................

2.4. GEOLOGY ....................................................................................................................

3. FACTORS INFLUENCING ACCELLERATED CHANNEL EROSION ..

3.1. RAINFALL ....................................................................................................................

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

3.3. SUMMARY CONCLUSIONS RELATED TO FACTORS INFLUENCING EROSI

4. FIELD ASSESMENT AND STRATEGIES FOR EROSION MITIGATIO

4.1. PIPED SECTION – SCHUYLKILL EXPRESSWAY TO 200 RIVER ROAD ..........

4.1.1. EXISTING CONDITIONS ...................................................................................

4.1.2. SUGGESTED MITIGATION ACTIONS ...........................................................

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


4.2.2. EROSION MITIGATION APPROACH .............................................................

4.2.3. ESTIMATE OF PROBABLE COST FOR EROSION MITIGATION ...........

4.3. 1600 SOAPSTONE ROAD ............................................................................................




4.4. 1450 SOAPSTONE ROAD ............................................................................................




4.6. 1435 ABBEY LANE ......................................................................................................




4.7. 1418 MONK ROAD ......................................................................................................

4.8. 1410 AND 1400 MONK ROAD .....................................................................................




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

5. COST SUMMARY .....................................................................................................

6. GRANT AND OTHER FUNDING OPPORTUNITIES ...................................

7. SUMMARY ..................................................................................................................

8. CONCLUSIONS AND FUTURE DIRECTIONS ...............................................



Figures

FIGURE 1 – Location Map

FIGURE 2 – Soapstone Watershed Aerial with Contours

FIGURE 3 – Historic Aerial Photographs of the Soapstone Watershed

FIGURE 4 – Soil Survey of the Soapstone Watershed

FIGURE 5 – Daily Rainfall in Philadelphia 1948 through January 2012

Appendices

APPENDIX A – KEY MAP AND PHOTOGRAPHS

APPENDIX B – EXHIBITS ILLUSTRATING RESTORATION APPROACHES



Lower Merion Township, PALOWM093814

Soapstone WatersheSep

1.

EXECUTIVE SUMMARY

The purpose of this study is to identify the probable cause of observed accelerated eros

watershed, and to develop mitigation strategies or approaches to control erosion and

deposition of sediment and debris. Order of magnitude cost estimates for the proposed ero

strategies and potential funding sources (Grant programs, etc.) for projects of this nature are

Factors influencing accelerated erosion within the watershed are the erodible nature of

increase in frequency and magnitude or rainfall and runoff over the past 13 years, an

activities within the watershed prior to the enactment of stormwater ordinances. The domthe significant increase in rainfall frequency and magnitude over the past 13 years.

This assessment has identified stream restoration strategies that can be applied within the

the eastern or lower portions of the watershed, strategies included the use of a sediment/de

the Schuylkill Expressway, toe stabilization using local materials, bank grading, and c

floodplain benches. In the upper or western portions of the watershed, the dominant str

bank grading and the creation of vegetated floodplain benches to stabilize the channel. Ba

a bend, installation of cross vane drop structures, and other energy dissipation strategies a

address localized problem areas.

Conceptual design level order of magnitude estimates of probable cost for mitigation measu

developed and are summarized as follows:

Upper Watershed $ 350,000

Lower WatershedAlternative 1a - Erosion Mitigation $ 415,000

Alternative 1b - Sediment/Debris Trap Alternativei. Access from Schuylkill Expressway $ 370,000ii. Access from Soapstone Road $ 460,000

Alternative 2 – Conveyance Improvements

Schuylkill Expressway to River $ 455,000

Grant and other funding opportunities applicable to the watershed restoration and erosion midentified include:

Schuylkill River Restoration Fund

Emergency Watershed Protection Assistance Program

Growing Greener Program





2.

INTRODUCTION AND BACKGROUND

The purpose of this investigation was to identify the cause or causes of the stream instabili

occurring along the Soapstone Watershed stream valley and to develop schematic des

restore the stream valley to a more stable condition. In addition, order of magnitude cost

been developed for the recommended stream stabilization measures along with poten

funding.

The Soapstone watershed is located in the north eastern portion of Lower Merion Townshi

in Figure 1. The watershed is generally bounded by the Schuylkill River to the east, Mo

south, Youngsford Road to the west, and Waverly Road to the north. The watershed gets i

historic soapstone quarry, the remnants of which are located near the middle of the w

stream within this watershed is an unnamed tributary to the Schuylkill River. Phot

throughout the stream valley are provided in Appendix A.

On August 1, 2004 a localized high intensity, short duration storm caused flooding and

along the stream corridor, above the Schuylkill Expressway. With erodible soils and steep

volume of stony sediment and debris was washed downstream, partially clogging Expressway culvert and clogging the culverts under the Norfolk Southern railroad and Riv

result of the culvert clogging stormwater overflowed the railroad, eroding its embankment

onto River Road. Along with the embankment debris, sediment and debris were forc

Expressway and railroad culverts and onto River Road creating a five foot tall debris pile (s

1 in Appendix A). In addition to this initial event, similar events occurred in April 2005 an

and on a number of other occasions.

In addition, it has been reported that erosion and sedimentation in the upper watershed significant sediment deposition in the pond located at 1450 Soapstone Road. If this po

completely filled or damaged, sediment from upstream would be transported to downstr

segments and ultimately to River Road aggravating the situation there.

The erosion and sedimentation problems in the watershed have resulted in significant costs

Township and its residents. It is reported that river road clean-up after these events costs th

approximately $4,000 per event. The cost in flood damage repair to residents along river ro

throughout the watershed is estimated to be significantly greater. In addition these events p

significant threat to public safety, rail and vehicular traffic, and emergency vehicle access in

of River Road. Erosion of this railroad bed could result in a derailment on this active freig

only causing damage to the railroad and River Road but to residents and the environment.

River is a source of drinking water for the City of Philadelphia, which could be contaminate





corridor. These issues are keyed to the eight (8) individual properties which the stream

outcome of this study is a set of recommendations to mitigate the observed erosion and deb

the watershed.

2.1.

WATERSHED DESCRIPTION

The Soapstone Watershed encompasses 176-acres in the north eastern portion of

Township (See Figure 1). As illustrated in Figure 2, the current land use within th

mostly large lot (2 acres or greater) suburban residential. The stream draining the water

an ephemeral (intermittent) channel at a storm sewer pipe discharge at Abbey Lane.

pipe collects runoff from watershed areas upstream of Abbey lane and from a portion

From the stormwater outlet the channel flows through residential yards. The stream

flow from a spring located on or near 1438 and 1439 Abby Lane. The perennial flow c

pond located on the property at 1450 Soapstone Road. From the pond outfall the str

across 1600 Soapstone Road and then through a steep undeveloped ravine on 160

Flow within the stream remains perennial and gains water from two additional springs

reach. Just upstream of the Schuylkill Expressway, the stream enters a 6 foot by 4

culvert which conveys the discharge under the Expressway. Just downstream of the E

discharge enters a 36 inch diameter culvert under the Norfolk Southern Corporatio

Line, and then under River Road and across 200 River Road in a second 36” diamete

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 fro

Merion Historical Society was evaluated to determine the development sequen

Soapstone watershed. The aerial photographs reviewed are illustrated in Figure 3.

In the early 20th Century the majority of the watershed was occupied by the Soapstone

Farm, and the Shipley School Farm. In 1948 there were approximately 10 homes in

(see Figure 3). By 1958, one and two acre lots had been subdivided along the edges o

and the number of residences had increased to approximately 38. By 1971 the total nu

in the watershed had increased to approximately 60. Today, there are approximately 6the watershed. In addition, since 1971 a number of homes in the watershed have be

enlarged, and surface amenities have been added (pools, tennis courts, enlarged drivew

2.3.

SOILS





The soils in the stream valley below the pond are in the Manor very stony silt loam. T

and highly erodible. A typical Manor soil profile has a sandy loam texture that extend

and Bw horizon to a depth of approximately 2 feet. Below the Bw horizon are a serie

with increasing sand content. Depth to bedrock in the Manor series is typically at 6

and channery rock fragments are commonly 20 to 50% of the soil profile. Thes

typically have a seasonal high water table as they drain rapidly.

Closer to the Schuylkill River, soils within the stream corridor are classified as Sto

Montgomery County Soil Survey (1967) classifies the Stony Land soils in associat

series, in the case of this location, with Manor soils. The distinction between association and Manor soils is that the soils are generally shallower. The surface runo

drainage of Stony Land is rapid. These soils are not suitable for development or agricu

Survey recommends that these soils be used for watershed protection or recreatio

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 Ma

Compared to the Manor soils mapped in the stream corridor, the Manor soils in the upp

watershed are less stony.

2.4.

GEOLOGY

The digital geology map of Pennsylvania produced by the Department of Conservatio

Resources maps two geological formations within the Soapstone watershed. The cen

the watershed, corresponding to the stream corridor is mapped as being ultramafic

rock). The upper portions of the watershed are mapped as being in the Wissahickon Fo

consists primarily of schist, gneiss and quartzite.

3.

FACTORS INFLUENCING ACCELLERATED CHANNEL EROSION

Erosion within a watershed is dependent upon rainfall amounts and physical characteristic

geology, land slope, and land cover conditions (surface characteristics). Physical charac

the watershed are important because they define how much storm runoff is generated b

amount or rainfall.

3.1. RAINFALL

Regional rainfall data was evaluated for trends that might be influencing observed ero

watershed. Daily data for a 64 year period was available from the National Oceanic an

Ad i i t ti f t ti t th Phil d l hi Ai t Thi d t i l tt d i Fi





observations are made from the data for this period as they relate to the entire data

through 2011:

Of the 32 daily rainfall events greater than 3 inches, 13 occurred during the last

Of the 12 daily rainfall events greater than 4 inches , 7 occurred during the last

Of the 5 daily rainfall events greater than 5 inches, 3 occurred during the last 1

The single largest daily rainfall event, 6.6 inches, occurred in September of 199

While the data from the rainfall reporting station at the Philadelphia Airport provides

annual trend analysis, localized high intensity storms of short duration occurring in

like Lower Merion Township may not be reflected in the data. For example, On Au

high intensity storm dropping over 6 inches of rain in 90 minutes occurred locally

flooding and damage in the Township. This localized storm was not reflected in the da

the Airport rain gage which reported 1.7 inches for that date. It is noted that some rese

that the heat island affect in the vicinity of large cities influences local weather pattern

higher intensity storms to the surrounding suburbs. Therefore, during wet years, L

Township may receive more frequent higher intensity rain events than are recorded at th

Erosion is a natural process in all watersheds. It is also known that natural erosi

accelerate or increase during flow events equal to or greater than about the 1-year fre

event. The PennDOT Drainage Manual reports that the 1-year frequency 24-hour rai

area is about 2.6 inches. As illustrated in Figure 5, the rainfall data for the region docum

has been a larger than normal number of rainfall events equal to or greater than 2.6 i

during the period from 1999 through 2011. It would be expected that this recent signi

in the frequency of large rainfall events would produce an equally significant incre

within the watershed.

3.2. WATERSHED PHYSICAL CHARACTERISTICS

Watershed physical characteristics include soils, geology, land slope, and cover con

condition characterizes the land surface as it relates to runoff generation. Typical

include imperious areas (building roofs, pavement and other hardscape that typical

runoff), lawn, meadow, forest, etc. These later classifications represent different pe

conditions. Land slope is important because water will run off of steeper slopes faster

mild slopes. It is also noted that changes to any of the items described above will res

in the rainfall-runoff relationship within the watershed.





the annual rainfall in upper portions of the watershed would have infiltrated into surfac

why there is no evidence of a surface channel in the upper and middle watershe

photograph in Figure 2.

It is noted that even in the watershed’s relatively undeveloped condition in 1942, the

been erosion occurring in the watershed during larger rainfall events. This is particul

lower portions of the watershed due to the steepness of the valley slope and the susce

local soils to erosion. The existence of the valley itself is the strongest evidence of past

As the watershed developed through the 1950’s and 1960’s, additional impervious arethe watershed as a result of road improvements and the development of residential pro

driveways, etc.). It is estimated that the impervious area in the watershed increased, f

percent pre-1942 to approximately 10% in 1971.

In addition to the increase in impervious area, some drainage patterns in the watershed

a result of the development of roads and driveways. For example road co

improvements during this period along Abby Lane and Monk Road resulted in inconcentration of runoff from upslope areas that previously discharged in a dispersed

concentrated runoff is discharged through the culvert under Abbey Lane. The d

roadside ditches along Soapstone Road has also contributed to the concentration of run

the stream channel.

The impact of the development activities in the 1950’s and 1960’s was to increase the

magnitude of runoff reaching the stream corridor. The natural response to this incr

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 additiona

within the watershed. A few new homes have been built, and a number of homes have

or enlarged, and amenities such as tennis courts and pools have been added. T

development is estimated to have created less than 3 percent additional impervious a

watershed.

Stormwater and erosion controls were implemented through new Township Ordinan

regulating development of the land beginning in the mid 1970’s. Therefore, runoff from

activities since the mid 1970’s has been controlled through the installation of seepage

on-lot stormwater controls.





been determined that none of the maintenance or compliance issues identified have h

impact on erosion or storm runoff in the watershed.

In the discussion above, impervious area is used as the measure of development

quantity of runoff. It is noted that site grading and other construction activities w

natural soils also have an impact on runoff rates and volumes. However, the re-es

vegetation on these surfaces causes the resultant increase in runoff to be much less s

the impact from impervious surfaces.

3.3.

SUMMARY CONCLUSIONS RELATED TO FACTORS INFLUENCING E

As mentioned previously, erosion is a natural process in all watersheds and these na

processes accelerate or increase during flow events equal to or greater than ab

frequency runoff event. The 1-year runoff event corresponds with a 24 hour rain e

more than 2 inches. As discussed above, the rainfall data for the region demonstrate

been a significant increase in rainfall events over about 2 inches per day during the pe

through 2011.

As discussed above, development in the watershed before implementation of storm

resulted in an estimated 10% increase of impervious surface area in the watershed. H

from most of this impervious area is tributary to pervious landscape (lawns and oth

where some of the runoff can be absorbed. Therefore the increase in runoff is less pron

cases where the runoff from impervious surfaces is piped directly to waterc

acknowledged that the runoff from a small portion of Monk Road and Abby La

connected to the waterway by storm drains and roadside drainage swales.

While development activities in the watershed may have resulted in a minor increase

evidence was uncovered during this study that would suggest that the imperviousness a

development in the watershed caused erosion comparable to what has been evidenced i

It is concluded then, that the increased frequency of large rainfall events and associated

the past 13 years, has been the primary contributor to the acceleration of natural erosi

the watershed.

4.

FIELD ASSESMENT AND STRATEGIES FOR EROSION MITIGATION

As discussed above, the stream channel through the watershed begins as an ephemera

downstream of a storm sewer pipe discharge east of Abbey Lane. From this point, the chan





conveyance and erosion characteristics are presented followed by a description of the

mitigation measures. Conceptual design level order of magnitude estimates of probabl

presented.

4.1.

PIPED SECTION – SCHUYLKILL EXPRESSWAY TO 200 RIVER ROAD

The piped section represents the downstream limit of the study reach and inclu

conveyance systems under the Schuylkill Expressway, Norfolk Southern Corporation

of-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

foot by 6 foot box culvert under the Schuylkill Expressway, a 48 inch circular reinf

pipe (RCP) under the Norfolk Southern Corporation railroad, and a 36 inch oval pi

Road and through the property at 200 River Road. Photo a on Exhibit 12 illustrate

Junction Box along the west side of River Road. Photo b and c illustrat

configuration between the PennDOT culvert under the Schuylkill Expressway and

culvert under the Norfolk Southern Corporation railroad.

Discharges from the culvert under the Schuylkill Expressway are controlled by a

flow opening at the bottom of the box, and a grate covering its top. The inlet end

RCP under the railroad right-of-way is screened with a vertical mesh screen an

steel grate (See Photo c on Exhibit 12.). It is noted that the mesh or wire screen w

replace a vertical steel screen (similar to the top grate) sometime after November Township requested that the steel screen be removed. This request was i

information received from the Pennsylvania Department of Environmental Protec

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 Ri

Township installed junction box. When this junction box was initially constru

steel grate was installed at its outlet side to trap debris and facilitate maintenan

under river road. This grate was removed in November of 2011 when the Tow

aware that the obstruction caused by the grate was a violation of State Code.

Both the discharge configuration of the PennDOT culvert and the inflow config

railroad culvert, as well as the grate in the junction box along River Road restr





4.1.2.

SUGGESTED MITIGATION ACTIONS

Mitigation actions to reduce the risk of flooding, erosion, and debris deposition in

River Road would involve trapping or otherwise removing the sediment an

(Alternative 1) and/or improving the conveyance capacity of the piped dis

(Alternative 2). Alternatives for removing or reducing the transported sediment a

include stabilizing the upstream stream reach (Alternative 1a) or constructing a s

trap just upstream of the Expressway (Alternative 1b). Alternative 1a, stabilizin

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

Expressway. During large storm events eroded material from the watershed

into and through the culvert system as described previously. Some of t

deposited in the various pipe segments and at the junction of the pipe segmen

fully blocking the portions of the pipes causing flood waters and debris to flow

the discharge box at the downstream end of the expressway culvert and the jRiver Road, and flood across the railroad tracks causing flooding, erosion,

debris deposition. The result has been property damage and economic los

significant safety hazards for rail traffic.

One alternative to reduce or eliminate clogging of these culverts would be

sediment and debris trap just upstream of the Expressway to capture transporte

debris before it enters the system. This alternative, investigated by the

2010/2011, involves construction of a riser pipe on the upstream end of the Pen

under the Expressway and excavation of debris basin immediately upstream (

in Appendix B). In addition, an access road and staging area for maintenanc

basin would need to be constructed.

Construction of the access road will be the most significant challenge for t

There are two options for providing access to the area adjacent to th

embankment. The first is to construct the access road from the Expressway (wcontrolled access). The second would be to construct the access from Soapsto

options pose challenges but warrant further investigation.

A concept level order of magnitude estimate of probable cost for both access a

provided below. It is noted that these costs reflect initial construction and do n





4.1.2.2.

ALTERNATIVE 2 - CONVEYANCE SYSTEM IMPROVEMEN

Actions that would improve flow and sediment/debris movement through the include:

a.

Construction of a more efficient transition between the PennDOT c

culvert under the Norfolk Southern railroad. This would involve som

following items:

Completely remove the wire screen and grate at the upstream

inch culvert under the railroad right-of way and replace it w

headwall with wingwalls;

enlarging the opening in the side of the PennDOT culvert outle

improving the flow transition between the PennDOT box c

Norfolk Southern culvert through installation of a junction bo

culverts.

b.

Installation of a larger pipe under the Norfolk Southern railroad.

c.

Installation of a larger pipe under River Road and across the propert

Road.

d.

Removing the pipe under the property at 200 River Road and replac

open drainage channel.

As indicated above, the Pennsylvania Department of Environmental Protection

that any screen or conveyance element which might hinder free flow of water a

sediment and debris through the piped conveyance system is a violation

Therefore, the wire screen at the upstream end of the culvert under the railroad

be removed immediately by Norfolk Southern Corporation. In addition, S

requires that clear conveyance be maintained through closed conveyance syste

to carry waters of the Commonwealth. Therefore, PennDOT, Norfolk Sou

Township have an obligation to inspect and if necessary clean any debris d

subject culverts following all significant flow events.

An order of magnitude estimate of probable cost for the construction of th

elements identified above is as follows:

Improved transition structure – PennDOT

to Norfolk Southern Corporation culverts $ 85,000

Install larger pipe under Norfolk Southern

Corporation railroad $ 250,000





4.2.

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

These properties are located just upstream of the Schuylkill Expressway and just downSoapstone Road. It includes the portion of the channel which flows through 1600 M

also a small section of channel that flows through 1621 and 1619 Winston Road. T

Winston Road is included as its southern property line is immediately adjacent to the st

4.2.1. EXISTING CONDITIONS

This section of the stream valley is steep and the channel is deeply incised. A

Photographs 4 and 5, the stream banks are steep cut, near vertical and incised 8

many locations the stream banks, composed of erodible soils and stony material, ar

susceptible to erosion as a result of past erosion. A significant number of large t

undermined by the erosion and many have fallen across the stream channel. The v

steep with 25% to 50% slopes. Though the stream flow is tranquil on sunny days,

forceful nature of rainy day flows are evidenced by the loose boulders, rocks, and d

channel length (Photograph 5). In many locations the stream has eroded to the u

bedrock (Photograph 6). The stream reach through 1600 Monk Road dischargesunder the Schuylkill Expressway. As shown in Photograph 3, the channel area ju

the Expressway functions as a sediment and debris trap. A significant volum

stones, large rocks, downed trees and branches, and other debris have accumulated

4.2.2.

EROSION MITIGATION APPROACH

The inaccessibility of this reach, coupled with the deeply incised nature of th

significant challenges to stabilizing this reach. Access can be achieved via Soapfrom the Schuylkill Expressway. It is acknowledged that gaining the permission

access this reach via the Expressway will be challenging since it is a Federally reg

access highway. Therefore, access from Soapstone Road has been assumed.

The recommended mitigation approach for stabilizing actively eroding portions o

illustrated in Appendix B, Exhibits 1 and 2. The approach involves stabilizing the

the stream bank, and, where possible, grading the bank to create a small flo

immediately adjacent to the channel. When used, the floodplain bench would be

side or both sides of the channel depending on site specific field conditions. Wh

would permit, the floodplain bench would be vegetated with woody or brushy veg

reduce the velocity of flood flows and overall erosion potential.

T th t t ibl t i ld b li h d b i





The steepness of the watershed and erosive power of flood flows coupled with the h

nature of the soils in this reach imposes a degree of uncertainty relative to the

erosion mitigation strategy. In addition, the erosion mitigation approach suggested

itself result in short term disturbance which could result in an increased susceptibi

Access for equipment will require grading activities and removal of trees and

vegetation, and vegetation planted as part of the erosion mitigation strategy, will r

become established. Also, there are no homes or other infrastructure that would be

erosion in this reach. For these reasons, consideration of an alternative approac

Normally the construction of a sediment/debris basin is just upstream of the Exp

alternative is presented in Section 4.1.4 below.

4.2.3.

ESTIMATE OF PROBABLE COST FOR EROSION MITIGATION

The cost of implementing the erosion mitigation approach suggested in the prev

influenced by the limited site access for equipment and ruggedness of the terrain

magnitude estimate of probable cost to implement the described erosion mitiga

described is $270,000. This estimated cost is based on the following assumptions:

Stabilization of approximately 700 LF of stream using the restoration meth

Access is via Soapstone Road;

Soapstone Road will require significant restoration as a result of

construction traffic.

4.3.

1600 SOAPSTONE ROAD

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

4.3.1.

EXISTING CONDITIONS

Approximately two-thirds of the stream reach through this property is deeply inc

the conditions described for the upper portions of the stream reach through 160

However, as the stream flows through the home site near the center of the prope

banks fall away as though they may have been cut to provide a more suitable build

Photographs 7 through 11 illustrate the stream condition in the vicinity of t

Although steeply cut, the stream banks here are relatively shallow (0.5 to 3 feet). A

home spans the stream (Photograph 7), and the yard area upstream of the add

terraced forming a stepped floodplain area (Photograph 8). The stream banks

evidencing past erosion. An erosion control blanket installed to stabilize the stre





Upstream of the home site, the stream banks are continuously exposed, evidencin

activity (Photograph 10). Cut banks in this area range from about 5 feet, to more

height, west of the barn. The channel becomes very deeply incised at the weste

property.

4.3.2.


In the forested sections of the stream reach upstream and downstream of t

restoration techniques similar to those described for 1600 Monk road would be ap

approach is illustrated in Exhibit 4, in Appendix B. To mitigate the erosion wi

segment crossing the home site, armoring the stream banks with riprap or some ot

the suggested restoration technique. This technique is illustrated in Exhibit 3

proximity of the house, any installed bank armor will require inspection following

prompt maintenance, as needed, between storms. The Township was recently n

damages on this property are eligible and have been selected for funding th

Department of Agriculture’s (USDA) emergency watershed protection program (se

a description of this program). Mitigation measures have been designed by PA D

The Township is assisting as the sponsor and contracting agency will full reimbuconstruction costs.

4.3.3.


The order of magnitude estimate of probable cost to implement the described eros

measures in the upstream and downstream incised channel areas on this property is

riprap bank protection proposed for the center portion of the property is being fun

USDA grant and, therefore is not included. The estimated cost is based onassumptions:

Stabilization of approximately 100 LF of the stream valley downstream of

using techniques as described for the stream segment through 1600 Monk R

Stabilization of approximately 200 LF of stream valley upstream of the ho

techniques described above.

4.4.

1450 SOAPSTONE ROAD

This property sits at the transition from the steeply sloped stream channel in the lower

watershed and the more mildly sloping upper channel reaches. Remnants of the for

quarry are visible near the center of the property and the quarry pond occupies a large





the pond outlet channel (refer to the photograph on Exhibit 4 in Appendix B) exte

property at 1600 Soapstone Road.

The steeply sloped pond outlet channel was previously stabilized by the propert

gabion basket retaining wall topped with a segmented block retaining wall, was

along the north side of the channel (Photograph 12 and Exhibit 5 in Appendix B).

in Exhibit 5, there is active erosion at the downstream end of the stabilized outlet

erosion is a result of the abrupt flow transition between the outfall channel and the

channel below.

The pond on this property is in-line with the stream. Therefore, any sediment tra

upstream areas as a result of natural or accelerated erosion is captured in the p

evidence of deposited sediment at the point where the upstream channel enters

Photo 14). The pond serves as a sediment trap for all material eroded and transp

upstream stream segments. It this pond were to fill it would no longer prevent th

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

vertical channel bank slopes as illustrated in Figure 14 and the top left photo in Ex

stony alluvial deposits along this reach provide evidence of sediment transport thro

Photograph 14 illustrates an exposed pipe located in this section of the stream w

that there has been historic erosion within the reach that resulted in a general lo

channel bed.

4.4.2.


As indicted above, the property owner has already made a substantial investmen

the pond outlet channel. However, where the stabilized channel and adjacent g

wall end, there is an area of significant scour. A photograph documenting the sco

and a cross section documenting the mitigation approach are illustrated in Append

The mitigation approach involves the construction of a large rock energy di

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

bank toe and installation of an adjacent floodplain bench as illustrated in Exh

downstream channel segment on 1434 Soapstone Road.

4 4 3 ESTIMATE OF PROBABLE COST FOR EROSION MITIGATION





4.5.

1434 SOAPSTONE ROAD

The property at 1434 Soapstone is the geometric center of the watershed. Perenni

begins here as a result of spring flows from 1449 and 1439 Abby Lane. Upstream of th

streamflow is ephemeral/ intermittent.

4.5.1.

EXISTING CONDITIONS

There are three distinctly unique stream segments on this property. The downs

flows parallel to the properties driveway in a linear fashion and then curves sharplnear the north eastern corner of the house. Photographs 15 through 21 illu

conditions in this reach. The channel is moderately to deeply incised in this reach

ranging from 3 to 6 feet high. The deepest channel cut is near the sharp bend j

The linear stream channel in the lower portion of this reach is located approximate

from the driveway. The pipe illustrated in Photograph 15 is approximately 1.5

bottom of the stream channel. This provides evidence that the stream has eroded

time.

The center channel section, which flows mostly along the northern property line, ap

illustrated in Photographs 22 and 23. Along this portion of the channel the p

graded the streambanks to create a gentle connection with the floodplain in a fas

the mitigation measures illustrated in Appendix B Exhibit 6.

Upstream of the stable channel reach (near the darn and property boundary wit

Lane) there is an area that exhibits significant erosion at and just downstream of anheadcut (sudden drop in stream elevation). This headcut section is currently bein

the roots of large trees that extend across the channel from both sides. Immediatel

of the headcut the channel is approximately 10 feet deep (Photograph 27). Just u

headcut the channel depth is less than 2 feet deep with gently sloping stable banks a

Photograph 29.

4.5.2. EROSION MITIGATION APPROACH

Restoration options are presented for the downstream channel reach and headcut ar

The restoration option for the downstream channel reach is illustrated in Appendi

The solution consists of grading the bank to a more stable angle and constructin

floodplain bench on one or both sides of the channel depending on specific site





The recommended solution for mitigation of erosion at that headcut is illustrated

Exhibit 8. The solution includes installation of eight cross vane drop structures

apart. In addition, the channel banks should be laid back and stabilized with

vegetation.

4.5.3.


The order of magnitude estimate of probable cost to implement the described eros

measures is $122,000. This estimated cost is based on the following assumptions:

Installation of 375 LF of stream restoration using techniques in Appendix B Installation of rock filled gabion bank protection as illustrated in Appendix

Construction of 8 cross vane stabilization structures illustrated in Appendix

4.6.

1435 ABBEY LANE

4.6.1.

EXISTING CONDITIONS

Photographs 30 through 32 illustrate channel characteristics on the property at 143

Natural erosion on this property has created an eroded stream channel with an av

about 2.5 feet and an average depth of about 2 feet. This channel appears to be g

although some erosion probably does occur during high flows.

A sizable scour hole exists just downstream of the upstream property line (Photog

scour hole has been formed in response to energy dissipation as flow transitions

lined channel on the upstream property to the natural condition on this property.

4.6.2.


Improving the channels erosion resistance would involve minor grading alon

channel to improve floodplain connectivity and create a broader distribution of f

property during high flows. Exhibit 9 in Appendix B illustrates this concept.

In addition, some form of energy dissipation should be implemented at the upstreamto eliminate the accelerated erosion at that location. This could be accomm

property or on 1418 Monk Road.

4.6.3. ESTIMATE OF PROBABLE COST FOR EROSION MITIGATION





4.7.

1418 MONK ROAD

As shown in Photograph 33, the stream corridor at 1418 Monk Road is entirely linedthis time, no restoration is proposed at this location.

However as discussed previously, a scour hole has formed at the point where the stre

from the 1418 Monk Road property to the property at 1435 Abbey Road. The alternati

an energy dissipation apron at 1435 Abbey Road would be to install a stilling basin o

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

1400 Monk Road, these properties will be considered together.

4.8.1.

EXISTING CONDITIONS

Existing channel conditions on these properties are illustrated in Photographs 34, 3

channel through both of these properties is cut through very erodible soils. Streamvertical with an average height of approximately four feet. The top of bank wid

reach varies from about 5 feet to 15 feet. Large section of undermined turfgrass c

on these properties (Photograph 34). Photograph 37 illustrates the beginnings

stream channel just downstream of the culvert under Abbey Lane. As time p

headcut will continue to advance until it reaches the culvert outfall. Photograph

flow entering the culvert on the upstream side of Abbey Lane. This culvert also

from the inlets on Monk Road at its intersection with Abbey Lane (photographs 39

4.8.2. EROSION MITIGATION APPROACH

The preferred mitigation approach across these properties would be to grade the st

more appropriate slope and create vegetated floodplain benches where possible an

It is acknowledged that the large trees along the stream will make creation of

floodplain bench difficult. Bank Toe armor should also be installed in locations w

undermining is occurring. These mitigation techniques are illustrated in Appendix B

4.8.3.


The order of magnitude estimate of probable cost to implement the described erosio

measures described is $120 000 This cost is about evenly split between the two pr





4.9.

DRAINAGE AT THE INTERSECTION OF MONK ROAD AND ABBEY LA

Drainage conditions at the intersection of Monk Rod and Abbey Lane are illustrated 39 and 40. The water illustrated in the photographs is runoff from a curbed portion

extending both east and west of Abbey Lane. As illustrated in Photograph 39, some

tributary to this location runs down the west side of Abbey Lane (see also P

contributing to erosion adjacent to this private driveway. This condition could b

modifying the driveway apron/roadway transition to create a positive flow line to

suggested that the Township Public Works Department work with the land owner to

modification.

5. COST SUMMARY

Costs associated with mitigation strategies were presented in the last section for each prope

channel traverses across. Costs are summarized below as they relate to erosion and deposit

processes in the upper and lower watershed. The upper watershed includes all properties up

pond at 1450 Soapstone Road, and the lower watershed is everything to the east of the pond

traps all sediment generated from the upper watershed. The lower watershed is the source o

and debris that gets transported to the culverts under the Schuylkill Expressway, Norfolk So

Railroad, and River Road.

Upper Watershed $ 350,000

Lower Watershed

Alternative 1a - Erosion Mitigation $ 415,000

Alternative 1b - Sediment/Debris Trap Alternativei. Access from Schuylkill Expressway $ 370,000ii. Access from Soapstone Road $ 460,000

Alternative 2 – Conveyance Improvements

Schuylkill Expressway to River $ 455,000

It is noted that the lower watershed alternatives are intended as either/or alternatives. Also

represents an estimate of the cost to stabilize the channel in the lower watershed and

presented for mitigation of erosion from 1600 Soapstone Road to the Expressway. additional costs associated with operation and maintenance of the sediment/debris trap

considered here.

As identified in Section 4.2.2, the steepness of the watershed and erosive power of flood

with the highly erodible nature of the soils in the lower reach imposes a degree of uncerta





6.

GRANT AND OTHER FUNDING OPPORTUNITIES

Grant and other funding opportunities applicable to watershed restoration and erosion mitthe Soapstone Watershed are described below:

Schuylkill River Restoration Fund: The Schuylkill River National and State Herit

designated by the United States Congress as an area where historic and recreational re

together to define a distinctive landscape. The Heritage Area is managed by the Sc

Greenway Association. In cooperation with Exelon Nuclear and the Philadelphia Water D

Heritage Area administers the Schuylkill River Restoration Fund. Available to non-profi

and municipal governments, the grant finances projects that mitigate water quality prob

from acid mine drainage, agricultural runoff, and stormwater issues. Grant applications ar

after a Letter of Interest is submitted and reviewed. A letter of interest was submitted for

but an invitation has not been extended at the time of this writing. Grant allocations rang

and $100,000 and a 25% match is required.

Emergency Watershed Protection Assistance Program: The United States Department

(USDA) Emergency Watershed Protection (EWP) program in cooperation with PennsylvanManagement Association is currently offering technical and financial assistance to stabiliz

became damaged following the hurricane Irene and Tropical Storm Lee. To qualify for t

unstable stream reach must be within 50 feet of improved property. The program stabili

armoring the stream with rock. One property owner in the Soapstone Watershed ha

funding under this program.

Growing Greener Program: The Growing Greener Program began in 1999. One of

missions is to restore and protect Pennsylvania’s rivers and streams. To fulfill this misGreen offers Watershed Protection Grants. Projects that improve waters quality of impai

polluted by urban runoff qualify for funding under this program. At this time, Growing

accepting applications. In 2011 the program accepted applications in August. The

applications for Growing Greener Funding is expected after the 2012-2013 budget is appro

The National Fish and Wildlife Foundation’s Five Star Restoration Program: This pro

competitive funding for community-based restoration project. The program is focused on b

and community partnerships. The average grant award is $25,000. A one-to-one in-kind m

and services is required to qualify for this program. Grant applicants must address ho

achieves on-the-ground restoration, environmental education, and measurable results.

must also demonstrate that the project will engage multiple partners within a community.

not accepting applications at this time, but is expected to reopen in 2012.





PennVEST: The Pennsylvania Infrastructure and Investment Authority (PennVEST)

interest loans to finance design, engineering, and construction for municipal stormwater p

the Clean Water State Revolving Fund. The interest rates range from 1 to 4%. Examples

projects that PennVest has financed in the past include infiltration system, swales, and

Penn Vest Board meetings are currently scheduled for May 16, 2012 and August 22, 2012.

Urban Waters Small Grants Program: The Urban Waters Small Grants Program is admi

Environmental Protection Agency. It finances projects that contribute to improved wa

community revitalization. Funded projects must demonstrate community-led efforts

economic, environmental, and social benefits. Local watershed planning, water quality m

public education are examples of projects funded in the past. The 2012 application deadli

23, 2012. It is expected that applications for 2013 will also be accepted in January.

US Army Corps of Engineers Snagging and Clearing for Flood Control Program: The

Clearing for Flood Control program is administered by the Army Corps of Engineers (AC

this program the ACOE designs and constructs projects that provide flood control. Remov

debris in a waterway in the interest of flood control is the focus of this program. The max

amount is $500,000. The project sponsor is required to contribute a minimum of 5% of tin cash. Obtaining this funding requires the applicant to request the Army Corps of Engin

a planning and design analysis (PDA) study. If the study concludes that the project is acce

engineering feasibility, environmental acceptability, or economic basis, it will be funded.

Other Sources of Funding: Key project stakeholders will also need to play a role in projec

This includes PennDOT, Norfolk Southern Corporation, the Township, and affected proper

Both PennDOT and Norfolk Southern Corporation have operations, maintenance, and safet

responsibilities related to the erosion and sediment/debris transport issues in the eastern endwatershed. Therefore, they should participate as responsible partners in helping to fund ero

mitigation projects in the eastern end of the watershed.

7.

SUMMARY

This watershed assessment has identified the probable causes of observed accelerated eros

watershed, and has advanced mitigation strategies, or approaches to control the erosio

erosion and the resulting deposition of sediment and debris. Preliminary order of mestimates for the proposed erosion mitigation strategies were also developed. In addition

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

magnitude or rainfall and runoff over the past 13 years and development activities within





vegetated floodplain benches to stabilize the channel. Bank armoring at a bend, installatio

drop structures, and other energy dissipation strategies are also used to address localized pro

Conceptual design level estimates of probable cost for implementation of the erosion mitig

were also developed and were summarized above.

8. CONCLUSIONS AND FUTURE DIRECTIONS

In conclusion, this study has identified erosion and sedimentation/debris mitigation strateg

applied within the watershed to mitigate the physical, financial, and safety impacts caused

erosion within the watershed. This study serves as a foundation for implementation of th

strategies. Future efforts should include involving the property owners and key stakehold

and Norfolk Southern Corporation) in a dialogue related to advancing this project. Key di

should include project prioritization and phasing, and funding. It is critical that PennDO

Southern Railroad be brought into these discussions at the earliest possible opportuni

advancing solutions particularly in the western watershed areas.





APPENDIX A

KEY MAP AND PHOTOGRAPHS

i i A S





APPENDIX B

EXHIBITS ILLUSTRATING RESTORATION APPROACHES



202 RIVER RD

200 RIVER RD 2 5 0

55

2 7 5 2 9

0

1 5 0

2 7 5 2 8 0

2 8 5 2 9 0

2 9 5

300

2 3 5 2 4 0

245 2 4 0

2 4 53 2 0



1520MONKRD

1400WAVERLYRD

1622WINSTON RD1552BRIAR HILLRD

1548BRIAR HILLRD 1557BRIAR HILLRD

1601WINSTON RD

198 RIVER RD

1540BRIAR HILLRD

1551BRIAR HILLRD

194 RIVER RD

1534BRIAR HILLRD

1607WINSTON RD

1624WINSTON RD

1545BRIAR HILLRD

1611WINSTON RD

1615WINSTON RD

1530BRIAR HILLRD 1619WINSTON RD

1621WINSTON RD

1539BRIAR HILLRD

1600MONKRD

1501WAVERLYRD1600SOAPSTONE RD

1533BRIAR HILLRD

1520BRIAR HILLRD

1525BRIAR HILLRD

1550MONKRD

1450SOAPSTONE RD

1455ABBEYLN

1530MONKRD

1447WAVERLYRD

1441WAVERLYRD1449ABBEYLN

1433WAVERLYRD

1439ABBEYLN

1434SOAPSTONE RD

1421WAVERLYRD

1415WAVERLYRD

1435ABBEYLN

1510MONKRD

1500MONKRD1411WAVERLYRD

1407WAVERLYRD

1543MONKRD

1401WAVERLYRD

1356MONKRD

MONK RD

1432MONKRD1347WAVERLYRD

1418MONKRD

1345WAVERLYRD1426MONKRD

1509MONKRD

1325WAVERLYRD1410MONKRD

1501MONKRD

1499MONKRD

1343WAVERLYRD

1435MONKRD

1400MONKRD

1429MONKRD

1225YOUNGSFORD RD1335WAVERLYRD

1423MONKRD

1350MONKRD

1415MONKRD

1342MONKRD1407MONKRD1326MONKRD

1401MONKRD

1336MONKRD

1351MONKRD1348BEAUMONTDR

1316MONKRD

1332MONKRD1341MONKRD

MONK RD 1344BEAUMONTDR

1331MONKRD

1211YOUNGSFORD RD 1317MONKRD1328BEAUMONTDR

1334BEAUMONTDR

1320BEAUMONTDR1310MONKRD

1311MONK RD

1321BEAUMONTDR 1 2 5

140

1 4 5

170

1 7 5

1 8 5

1 9 0

2 4 0

2 4 5

2 5 5

2 6 0

2 6 5

2 7 0

2 8 0

2 8 5

2 9 5

3 0 0

1 1 0

1 1 5

1 3 0

140

1 4 5

2 4 0

2 3 5 230

2 2 5 2 20

2 1 5 210

2 0 5

2 0 0

3 5 5

3 3 5

3 3 0

3 2 5

3 2 0

3 1 5

3 1 0

3 0 5

3 0 0

2 9 5

2 9 0

2 8 5

280

2 7 5

2

7 0

3 8 0

3 75 3 7 0

3 6 5

3 6 0

3 5 5

3 5 0

300

2 0 0

2 3 0

2 3 5

2 4 0

2 4 5

1 0 0

1 01 1 0

9 0 9 5

2 1 0

2

2 2 0

2 2 5

3 4 5

3 4 0

3 7 5

3 7 0 3

6 5

3 5 5 3 5

0

355

3 6 0

7 5

8 0

195

190

1 8 5

9 0

9 5

1 0 5

3 5 0

3 5 0

3 2 0

3 4 5

2 5 0

255

2 6 0

2 6 5

6 5

1 9

2 5 5

2 6 0

8 5

1 0 0

1 5 0

3 4 5

3 5 0

3 4 5

3 4 5

3 6 0

1942 1958



1942 1958

1971 2010

Mb



W

MhC2

GnB2

MdD

MhE2

G

MdD

StE

StEHa

Ch

MhE2

MdB

MnD

Ru

StE

MhC2

Ha

Ch

MnD

GsB2

GsB2

MdB

CgB2

StE

GnC2

GnC2

MhC2

StE

GsB2

MhC2

MhE2

MhB2

MhC2

GsB2

Mh

MdB

MhE2

MdD

MdB

MdB

MhE2

MdB

GnC2

Mb

MhB2

MnD

Bo

MhE2

MhE2Symbol Soi l Type

StE Stony Land

MhE2 Manor channery silt loam, 15 to 35 percent slopes, moderately erode

MnD Manor very stony silt loam, 8 to 25 percent slopes

MhC2 Manor channery silt loam, 8 to 15 percent slopes, moderately eroded

MdD Made land, schist and gneiss materials, strongly slopingGsB2 Glenville silt loam, 3 to 8 percent slopes, moderately eroded

GnB2 Glenelg silt loam, 3 to 8 percent slopes, moderately eroded



Figure 5. Daily Rainfall in Philadelphia 1948 through January 2012

0

1

2

3

4

5

6

7

2 / 1 / 1 9 4 8

2 / 1 / 1 9 5 0

2 / 1 / 1 9 5 2

2 / 1 / 1 9 5 4

2 / 1 / 1 9 5 6

2 / 1 / 1 9 5 8

2 / 1 / 1 9 6 0

2 / 1 / 1 9 6 2

2 / 1 / 1 9 6 4

2 / 1 / 1 9 6 6

2 / 1 / 1 9 6 8

2 / 1 / 1 9 7 0

2 / 1 / 1 9 7 2

2 / 1 / 1 9 7 4

2 / 1 / 1 9 7 6

2 / 1 / 1 9 7 8

2 / 1 / 1 9 8 0

2 / 1 / 1 9 8 2

2 / 1 / 1 9 8 4

2 / 1 / 1 9 8 6

2 / 1 / 1 9 8 8

2 / 1 / 1 9 9 0

2 / 1 / 1 9 9 2

2 / 1 / 1 9 9 4

2 / 1 / 1 9 9 6

2 / 1 / 1 9 9 8

2 / 1 / 2 0 0 0

2 / 1 / 2 0 0 2

2 / 1 / 2 0 0 4

Philadelphia, PA

Daily Precipitation Data

Lower Merion Township, PA Soapstone Watershe



p,LOWM093814

pSep

APPENDIX A

KEY MAP AND PHOTOGRAPHS





Photograp

and sedim

River Road

event in 20

Photograph 2. Same location on

River Road as Photo 1. Center

foreground is the junction boxconnecting the 48” RCP culvert

under the Norfolk Southern

Railroad to the Township’s 36”

oval culvert under River Road.

(11/03/2011)



Photograph 4 . Stream bank just upstream of

the Schuylkill Expressway. Note the deeply

incised banks and large boulders on adjacent,

steep slopes.

Photograph

debris upstre

and 4’ high c

Schuylkill Exp



Photograph 5. Representative

1600 Monk Road. Vertical bank

of trees is noted. Rock similar t

on the roadway in Photograph 1

transported down the stream ch

Photographs 6 . There are

several locations within 1600Monk Road where the stream

has incised to bedrock.



Photograph 7.

upstream to th

where the strea

under the hom

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.



Photographs 10. Bank

sloughing evident as fine

sediment in the channel.

Photogra

depositio

under ho



Photograph 11. Attempts to stab

landscaping material. Photograp

upstream of Photograph 10.

Photographs 12. Gabion basket

installed to stabilize stream bank

downstream of the pond.



Photog

remain

operatline wi

Ph t h



Photograph 16. View of stream where it parallels the

1434 Soapstone Road driveway, looking upstream.

The channel is approximately 3.5 feet deep on one

side and 7.5 feet deep on the other.

Photograph

parallel to t

Soapstone R

1.5 feet belo

pipe.



Photograph 18. View from

within the channel, looking

downstream. Road is located

at the right edge of thephotograph.

Photogra

where it

the north

Road.

Photograph



Photograph 20. Looking

upstream of stream bend.

Photograph

within the c

upstream w

curves to th

Photograp



Photograph 22. Stream just

downstream of where it

gains perennial flow from a

spring.

downstrea

banks show

sloughing.

Photographs



Photograph 24. Upstream of

restored channel section is an area

of extreme erosion and head-cutting.

homeowner

connect it to

photograph w

upstream of gains perenn

spring.

Photogra

former a

th t




downstream across the property

at 1434 Soapstone Road.

the strea

Photographs

8 f t h t



Photograph 28. Photograph

taken just upstream of

Photograph 27 looking downinto gully.

8 feet, photog

immediately u

Photograph 2

Photographs

approaches g




downstream, channel as it exists

in the western section of 1434Abbey Lane.

pp g

shallow with

banks.

Photograph

downstream




upstream at the property linebetween 1435 Abbey Lane and

1418 Monk Road.

in the easte

Abbey Lane



Photograph 34. Sloughed banks at 1410

Monk Road.

Photographs 33. Stream looking

as it exists at 1418 Monk Road.

Photographs 35. Stream approxi



Photograph 36. Storm water

outfall at the stream headwaters

on Abbey Road.

1400 Monk Road looking downst

towards 1410 Monk Road.

Photographs 37. Looking do

across 1400 Monk Road

t t di h i t



Photograph 38. Stormwater

runoff at 1350 Monk Road.

Upstream of the Abbey Roadoutfall.

stormwater discharge point.

Photogr

inlet at t



Photograph 40. Stormwater

along Monk Road.

Monk an





APPENDIX B

EXHIBITS ILLUSTRATING RESTORATION APPROACHES

















B-9







B-12



B-13

Documents

Soapstone Watershed Quarry Gladwyne