Act 167 Watershed Stormwater Management Plan Phase I – Final Report Scope of Study for Phase Ii

ACT 167 WATERSHED STORMWATER MANAGEMENT PLAN PHASE I – FINAL REPORT SCOPE OF STUDY FOR PHASE II

VALLEY CREEK WATERSHED SWMP # 330:15

Chester County, Pennsylvania

Submitted to: PENNSYLVANIA DEPARTMENT OF ENVIRONMENTAL PROTECTION

June 30, 2004

ACT 167 WATERSHED STORMWATER MANAGEMENT PLAN FOR THE VALLEY CREEK WATERSHED

PHASE I FINAL REPORT SCOPE OF STUDY FOR PHASE II

June 30, 2004

Submitted to Pennsylvania Department of Environmental Protection

Prepared on Behalf Of County of Chester and Chester County Water Resources Authority

Prepared by: Borton-Lawson Engineering, Inc.

TABLE OF CONTENTS

I. INTRODUCTION ...... 1 Purpose...... 1 Stormwater Runoff - Its Problems and Its Solutions...... 1 Pennsylvania Storm Water Management Act (Act 167) ...... 2 II. VALLY CREEK WATERSHED CHARACTERISTICS...... 3 Valley Creek Watershed Municipalities and NPDES Phase II Involvement...... 5 Valley Creek Watershed Major Traffic Routes ...... 6 Valley Creek Watershed Geology ...... 6 Valley Creek Watershed Generalized Soils...... 10 Valley Creek Watershed Hydrology...... 10 Valley Creek Watershed Topography...... 14 III. ACT 167 PLANNING FOR THE VALLEY CREEK WATERSHED...... 14 Approach for the Development of the Valley Creek Watershed Integrated Stormwater Management Plan...... 17 Coordination with Other Projects/Studies...... 27 IV. PLAN PREPARATION STRATEGY...... 27 Stage A - Data Collection and Analysis...... 28 Stage B-I - Technical Analysis...... 37 Stage B-II - NPDES Phase II Activities...... 45 Stage C - Public/Municipal Participation...... 48 Stage D - Plan Preparation and Implementation ...... 51 V. LEVEL OF EFFORT, COST ESTIMATE, AND PROJECT ADMINISTRATION ...... 57 VI. PROPOSED PLAN DEVELOPMENT SCHEDULE ...... 59 VII. CONSULTANT CAPABILITIES...... 59 VIII. REFERENCES...... 62 References Cited...... 62 Additional References ...... 63

TABLES

Table 1. List of WPAC Members ...... 19 Table 2. Summary of Municipal Problem Area Survey ...... 24 Table 3. WPAC Meeting Topics and Schedule ...... 49

FIGURES

Figure 1. Base Map...... 4 Figure 2. Geology Map...... 8 Figure 3. Generalized Soils Map ...... 12 Figure 4. First Order Streams on a Digital Elevation Model (DEM) ...... 13 Figure 5. Topographic Relief – Triangulated Irregular Network (TIN)...... 15 Figure 6A. Stormwater Related Problems ...... 22 Figure 6B. Streambank Erosion Problems...... 23 Figure 7. Steep Slopes ...... 26 Figure 8. Technical Objectives (Desired)...... 41 Figure 9. Work Schedule ...... 59

APPENDICES

APPENDIX A Sample Municipal Invitation Letter and Questionnaire...... APPENDIX B Municipal Data Collection Forms ...... APPENDIX C Sample Municipal Ordinance Matrix ...... APPENDIX D Valley Creek Phase II Plan Cost Estimate ......

ACKNOWLEDGEMENTS

The preparation of this document was funded in part through a grant from the PA Department of Environmental Protection, Bureau of Watershed Conservation and the Chester County Board of Commissioners

I. INTRODUCTION

Purpose

This report was prepared under and in accordance with a grant from the DEP for Chester County to conduct an Act 167 Stormwater Management Plan Phase I for East Valley Creek in Chester and Montgomery Counties, PA. This report presents the final results of the Phase I effort, which includes:

• A summary of watershed characteristics • An inventory of relevant problems • A proposed Scope of Study, schedule and budget for completion of Phase II of the Act 167 Plan project.

The purpose of an Act 167 Study is to assess the current and future runoff conditions within a designated watershed and develop stormwater management standards, criteria and other ordinance provisions for adoption by the municipalities within the watershed to minimize adverse impacts from stormwater runoff associated with new or future development.

Stormwater Runoff - Its Problems and Its Solutions

The water that runs off the land into surface waters during and immediately following a rainfall event is referred to as stormwater. In a watershed undergoing land use conversion or urban expansion, the volume of stormwater resulting from a particular rainfall event increases because of the reduction in pervious land area (i.e., natural land cover being changed to pavement, concrete, buildings, or unmanaged cropland). It has also been proven that the water quality of the stormwater runoff can be substantially degraded, increasing the pollutant load to the rivers and streams. That is, the alteration of natural land cover and land contours to residential, commercial, industrial, and crop land uses results in decreased infiltration of rainfall, an increased rate and volume of runoff, and increased pollutant loadings to the water systems.

As land disturbance and development has increased, so has the problem of dealing with the increased quantity and decreased quality of stormwater runoff. Failure to properly manage this runoff has resulted in greater flooding, stream channel erosion and siltation, degraded water quality, as well as reduced groundwater recharge. These impacts can be minimized if the land use and development incorporates appropriate runoff and stormwater management systems and designs.

History has shown that individual land disturbance/development projects are often viewed as separate events and not necessarily a part of a “bigger picture.” This has also been the case when the individual land development projects are scattered throughout a watershed (and in many different municipalities). However, it is now being observed and verified that the cumulative nature of individual land surface changes dramatically affects

flooding conditions. This cumulative effect can, in some areas, result in increased flood of both small and large streams with property damages running into the millions of dollars and even causing loss of life. Therefore, given the distributed and cumulative nature of the land alteration process, a comprehensive (i.e., watershed-level) approach must be taken if a reasonable and practical management and implementation approach and/or strategy is to be successful.

Pennsylvania Storm Water Management Act (Act 167)

Recognizing the need to address this serious and growing problem, the Pennsylvania General Assembly enacted Act 167 of 1978. The statement of legislative findings at the beginning of the Pennsylvania Storm Water Management Act (Act 167) sums up the critical interrelationship among land development, accelerated runoff, and floodplain management. Specifically, this statement of legislative findings points out that:

1. Inadequate management of accelerated runoff of stormwater resulting from development throughout a watershed increases flood flows and velocity, contributes to erosion and sedimentation, overtaxes the carrying capacity of streams and storm sewers, greatly increases the cost of public facilities to carry and control stormwater, undermines floodplain management and floodplain control efforts in downstream communities, reduces groundwater recharge, and threatens public health and safety.

2. A comprehensive program of stormwater management, including reasonable regulation of development and activities causing accelerated runoff, is fundamental to the public health, safety, and welfare and the protection of the people of the Commonwealth, their resources, and their environment.

Until the enactment of Act 167, stormwater management had been oriented primarily towards addressing the increase in peak runoff rates discharging from individual land development sites to protect property immediately downstream. Management of stormwater throughout the state paid minimal attention to the effects on locations further downstream (frequently because they were located in another municipality) or to designing stormwater controls within the context of the entire watershed. Management of stormwater also was typically regulated on a municipal level with little or no designed consistency (concerning the types or degree of storm runoff control to be practiced) between adjoining municipalities in the same watershed.

Act 167 changed this approach by instituting a comprehensive program of stormwater planning and management -- on a watershed level. The Act requires Pennsylvania counties to prepare and adopt stormwater management plans for each watershed located in the county, as designated by the DEP. Most importantly, these plans are to be prepared in consultation with municipalities located in the watershed, working through a Watershed Plan Advisory Committee (WPAC). The plans are to provide for uniform technical standards and criteria throughout a watershed for the management of stormwater runoff from new land development sites.

The types and degree of controls that are prescribed in the watershed plan need to be based on the expected development pattern and hydrologic characteristics of each individual watershed. The management plan, specifically the standards and criteria, are to be developed from the technical evaluations performed in the planning process in order to respond to the “cause and effect” nature of existing and potential storm runoff impacts in the watershed. The final product of the Act 167 watershed planning process is to be a comprehensive and practical implementation plan, developed with a firm sensitivity to the overall needs (e.g., financial, legal, political, technical, etc.) of the municipalities in the watershed.

II. VALLY CREEK WATERSHED CHARACTERISTICS

The Valley Creek Watershed, as illustrated in Figure 1, is located in the northeastern section of Chester County and a small portion of southwestern Montgomery County, Pennsylvania. It drains a watershed area of approximately 23.4 square miles. Valley Creek and its tributaries include an estimated 34 miles of streams, and flow through the Valley Forge National Historical Park before joining with the Schuylkill River in the Delaware River Basin. Valley Creek and its tributary, Little Valley Creek, are the main water courses in the watershed. In addition to Little Valley Creek, the major tributaries to Valley Creek include Bacton Hill Tributary, Planebrook Tributary, Chester Valley Tributary, Warren Run, Cedar Hollow Tributary, Crabby Creek, and Wilson Run as can bee seen in Figure 1. Much has been written about the Valley Creek watershed in the references cited in this report, and therefore will not be duplicated here. A short synopsis of the factors important to Act 167 and stormwater management planning is, however, provided.

Valley Creek is designated as an Exceptional Value (EV) stream by the PA Code - Title 25, Chapter 93. Valley Creek and Little Valley Creek are both listed in the Pennsylvania Fish and Boat Commission’s “List of Pennsylvania Class A Wild Trout Streams” (February 2002). Both are also listed as “Surveyed Streams Having Verified Trout Reproduction” by the PA Fish and Boat Commission (February 2002).

Watersheds, An Integrated Water Resources Plan for Chester County, Pennsylvania and its Watersheds, was adopted in 2002 as the water resources component of the Chester County Comprehensive Plan Landscapes. One of the priority actions identified in Watersheds is to prepare a stormwater management plan to address flooding and related stormwater impacts in Valley Creek Watershed. The impacts of stormwater runoff on Valley Creek are well documented in Watersheds and elsewhere (see list of references), underscoring the need to develop a Stormwater Management Plan that addresses existing land use and watershed characteristics, as well as potential impacts from new land development and re-development.

Valley Creek Watershed Municipalities and NPDES Phase II Involvement

There are a total of seven municipalities within the Valley Creek watershed. Six of these municipalities are within Chester County, and one municipality is within Montgomery County as follows:

Chester County Charlestown Township Schuylkill Township East Whiteland Township Tredyffrin Township Malvern Borough Willistown Township

Montgomery County Upper Merion Township

East Whiteland and Tredyffrin Townships occupy about 90% of the watershed. The Valley Forge National Historical Park occupies the downstream, or northeastern, portion of the watershed, comprising about 10 percent of the watershed.

Each of the seven municipalities within the Valley Creek watershed is part of the Philadelphia Urbanized Area (UA) as designated by the U.S. Census 2000. Each municipality owning or operating a system of stormwater conveyance (including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels, or storm drains) within the designated UA is required to comply with the National Pollutant Discharge Elimination System (NPDES) Phase II requirements for operators of municipal separate storm sewer systems (MS4s), as specified by the U.S. Environmental Protection Agency (EPA). NPDES Phase II requires owners of these MS4s to develop, implement, and enforce a stormwater management program designed to reduce the discharge of pollutants from their MS4s to the “maximum extent possible” to protect water quality. Each stormwater management program must, at the least, address the following six minimum control measures (MCMs):

MCM Description 1 Public Education and Outreach 2 Public Participation / Involvement 3 Illicit Discharge Detection and Elimination (IDD&E) 4 Construction Site Runoff Control 5 Post-Construction Runoff Control 6 Pollution Prevention / Good Housekeeping

Many of the MCM tasks are required to be completed before the Phase II Act 167 Plan will be funded and completed. Therefore, the MCM activity of the Valley Creek Act 167 Study is anticipated to be very limited in scope. Section IV of this Scope of Study outlines how the County and municipalities plan on working together during the Act 167 planning process to coordinate these requirements.

Valley Creek Watershed Major Traffic Routes

The many traffic routes traversing the watershed have influenced the hydrology of Valley Creek. The major traffic routes in the Valley Creek watershed include I-76, U.S. Routes 30, and 202, and PA Routes 23, 29, 252, 352, and 401 as shown in Figure 1. Interstate 76 (East-West Pennsylvania Turnpike) runs through the northern portion of the watershed. US Route 202 runs through the lower middle portion of the watershed for approximately 5 miles. It follows the main stem of Little Valley Creek from Tredyffrin Township to East Whiteland Township and then runs through the southern headwaters of Valley Creek for approximately 2 miles. US Route 30 runs through the lower northern portion of the watershed from Willistown Township through East Whiteland Township. PA Route 23 crosses the watershed for a short distance in the upper northeast corner. Route 252 runs through several tributaries of Little Valley Creek in the lower eastern portion of the watershed. PA Route 29 runs through the middle portion of the watershed in a north- south direction. It crosses Valley Creek and PA Route 202 in East Whiteland Township and then joins PA Route 30 northwest of Malvern. PA 352 runs approximately 1 mile through the northwest portion of the watershed and joins PA Route 30 near Frazer. PA Route 401 runs from the northwest corner into the western portion of the watershed. PA Route 401 follows the upper stream corridor of Valley Creek for about 3 miles and continues in southeastern direction until joining PA Route 30 northwest of Malvern.

These major thoroughfares and crossroads provide a critical transportation and commuting link for Chester County residents. However, these routes create an increase of impervious surfaces throughout the watershed. These impervious surfaces create more surface runoff and are a source of nonpoint source pollution during precipitation events, which also increases the stress on the stormwater drainage systems in the watershed, reduces water quality, and exacerbates streambank erosion, especially at already-known problem areas.

Valley Creek Watershed Geology

The geology is important since it affects the watershed’s soils and hydrology, and surface and groundwater are integrally related. Improper stormwater management measures could diminish groundwater supplies or degrade groundwater quality. The ridges of the Valley Creek watershed are primarily crystalline rocks whereas the valley portion, where the main stem of the Little Valley Creek and Valley Creek flow, is underlain with carbonate rock with some crystalline rock as shown in Figure 2.

Carbonate rocks include limestone, dolomite and marble. According to Geology, Hydrology and Ground-Water Quality of Chester County, Pennsylvania (Sloto, 1994), groundwater in carbonate rocks flows through secondary openings in the rocks that are enlarged as the water dissolves the rock. This karst topography is prone to sinkhole formation, therefore if stormwater is not managed properly, the formation of sinkholes could result, providing a direct conduit to allow pollutants to enter the groundwater system. Protection of surface water quality in karst topography is therefore extremely important in maintaining a quality groundwater supply. 6

Well yields vary greatly in carbonate rocks. Yields can range from less than 1 to 1800 gpm (Gallons Per Minute) with a median output of 136 gpm for non-domestic wells and less than 1 to 500 gpm with a median of 20 gpm for domestic wells. Well yields from carbonate rocks are generally significantly higher than yields of other geologic groups with the exception of some wells in sedimentary rocks.

Crystalline rocks include quartzite, schist and gneiss. In crystalline geology, the groundwater moves through intergranular openings in weathered zones, and fractures and joints in un-weathered rock. According to Geology, Hydrology and Ground-Water Quality of Chester County, Pennsylvania (Sloto, 1994), well yields in crystalline geology is usually lower than in sedimentary or carbonate rocks. Non-domestic wells yield less than 1 to 650 gpm for the various crystalline rocks. Well yields are significantly lower than well yields in other geologic units.

A description of geologic units found in the Valley Creek watershed is listed below.

Geologic Units in Valley Creek Watershed

1. Antietam and Harpers Formations, undivided (Cah) - Includes, in descending order, the Antietam (Ca) and Harpers (Ch) Formations, which are described separately below.

2. Antietam Formation (Ca) – Light gray, buff-weathering quartzite and quartz schist; some ferruginous quartzite; fine grained; maximum thickness is about 300 feet; good surface drainage.

3. Harpers Formation (Ch) - Dark-greenish-gray phyllite and albite-mica schist; coarse- grained; abundant quartz; maximum thickness is about 1,500 feet; good surface drainage.

4. Octoraro Formation (Xo) - Includes albite-chlorite schist, phyllite, some hornblende gneiss, and granitized members.

5. Chickies Quartzite (Cch) – Coarse cobble conglomerate composed of well rounded cobbles 3 to 6 inches in diameter in a finer quartz matrix that firmly cements them; milky white quartz pebbles; pebbles up to one-half inch are common; interbedded with quartzite; approximately 600 feet thick; good surface drainage.

6. Elbrook Formation (Ce) – Light-gray to yellowish-gray, finely laminated, siliceous limestone having interbeds of dolomite; cherty; thickness is about 3,000 feet; good subsurface drainage; little surface drainage.

< Figure 2 Geology Map>

7. Kinzers Formation (Ck) - Dark-brown shale; contains the trilobite Olenellus; 150 feet thick; good surface drainage.

8. Ledger Formation (Cl) - Light-gray, locally mottled, massive, pure, coarsely crystalline dolomite; siliceous in middle part; beds weather to rust-stained, granular, cherty layers; approximately 2,000 feet thick; good surface and subsurface drainage.

9. Vintage Formation (Cv) - Dark-gray, knotty, argillaceous dolomite; impure light- gray marble at base; maximum thickness is 650 feet; good surface drainage; little subsurface drainage.

10. Conestoga Formation (OCc) - Medium-gray, impure limestone having black, graphitic shale partings; conglomeratic at base; in Chester Valley, includes micaceous limestone, phyllite, and alternating dolomite and limestone; total thickness is unknown, but is at least 300 feet thick; good surface drainage and minor subsurface drainage; few sinkholes.

11. Stockton Formation (Trs) - Light-gray to buff, coarse-grained, arkosic sandstone; includes red to purplish-red sandstone, shale, and siltstone; maximum thickness is approximately 3,300 feet; good surface drainage.

12. Felsic and intermediate gneiss (ggd) - Medium grained, light pink to green; largely quartz, feldspar, and mica; commonly gneissic; good surface drainage.

Valley Creek Watershed Generalized Soils

The soils in the Valley Creek watershed are arranged into four groups, or associations, based on the general patterns and characteristics of the major soil types as shown in Figure 3. The general soil groups were delineated and published by the U.S. Department of Agriculture in the 1963 Soil Survey, Chester and Delaware Counties, Pennsylvania. Since that time the names of the general soil groups have been changed but the delineated patterns are the same. Below are the general characteristics of the four soil groups within the watershed taken from the 1963 General Soil Map, Chester and Delaware Counties, Pennsylvania. For detailed soil characteristics, the information regarding the individual soil units should be examined.

The current soil group names and the map unit identification numbers (in brackets preceding the name) are provided along with the previous soil association names which are in parentheses. The characteristics described are from the 1963 soil survey.

[PA061] UNGER-PENN-KLINESVILLE (PENN-CROTON-BUCKS) – “Shallow to deep, silty soils on red shale and sandstone.”

[PA066] EDGEMONT-HIGHFIELD-BUCHANAN (EDGEMONT ASSOCIATION) - “Moderately deep channery soils on grayish quartzite and phyllite.” [PA058] CHESTER-GLENELG-MANOR (GLENELG-MANOR-CHESTER) – “Shallow to deep, silty and channery soils on grayish, brown shist and gneiss.”

[PA063] HAGERSTOWN-DUFFIELD-CLARKSBURG (HAGERSTOWN- CONESTOGA-GUTHRIE) – “Deep, silty soils on limestone.”

Valley Creek Watershed Hydrology

Valley Creek and its tributaries extend from the western edge of the watershed to its confluence with the Schuylkill River in the Valley Forge National Historical Park in the east. Little Valley Creek, the major tributary of Valley Creek, begins in the south-central portion of the watershed with its confluence with Valley Creek located about 1 mile west of the National Historical Park.

First order streams typically include over half of the total stream miles and drainage area of a watershed. They are highly vulnerable to impacts of pollutants, stormwater flow, and groundwater withdrawals. Several analyses were conducted for first order streams of Valley Creek watershed including analysis of total first order streams miles, drainage areas, and land use. The results indicate that of the 34 stream miles in the watershed , 56% or 19 miles are first order streams and 7,296 acres of 14, 941 acres (48.6%) of the land area within the Valley Creek watershed drains to first order streams (Chester County Water Resources Authority et al., 2002, Valley Creek Watershed Action Plan). Figure 4 shows first order streams of the Valley Creek Watershed on a Digital Elevation Model (DEM). A DEM shows topographic relief of the watershed.

The “Chester County, Pennsylvania Water Resources Compendium” (Chester County Water Resources Authority 2001) has reported (cited from Sloto, 1994) an average Valley Creek water budget from 1983 to 1987 as follows:

• Precipitation 47.3 inches per year • Runoff 5.3 inches per year • Evapotranspiration 23.0 inches per year • Baseflow 13.0 inches per year

The average width of Valley Creek after the confluence with its tributary, Little Valley Creek, ranges from about 20 feet to 50 feet at bank full level. The average width of Little Valley Creek is from 7 feet to 16 feet. The average width of Valley Creek above the confluence with Little Valley Creek, ranges from 13 feet to 26 feet. According to the “Draft Valley Creek Restoration Plan/Environmental Assessment” the width of the other tributaries ranges form 3 to 1 feet (Valley Creek Trustee Council, undated (circa March, 2004)). There are no major impoundments that would significantly affect the hydrology of the watershed, however, there are several quarries, which, due to pumping, affect low flow conditions and have affected the water table. In addition, several low head dams effect the localized hydraulics (backwater, sediment deposition, erosion and scour below

the dams), however, they do not provide significant storage potential to attenuate high flows. The karst topography results in significant baseflow oftentimes exiting the groundwater system via springs. There are several “loosing“ reaches (where water from the stream infiltrates through the stream bed as groundwater recharge) of tributaries within the watershed, which only have surface flow during storm events.

Valley Creek Watershed Topography

The Valley Creek Watershed lies within the Piedmont Physiographic Province of Pennsylvania. The Piedmont Province is characterized by folded and altered rocks. (Reif, 2002).

The topography of the watershed is characterized by a relatively flat to gently rolling hills in the stream valley with steep side slopes up to the watershed divide. This can be shown in the Triangulated Irregular Network (TIN) map, Figure 5, which uses color- coded indices to show terrain features and differences in elevation, and depicts the topographic relief of the watershed. The highest point in the watershed is close to the Union Chapel located in the northeast corner of East Whiteland Township with an elevation of 716 feet above sea level. The lowest point (65 feet above mean sea level) is at the confluence point where Valley Creek flows into Schuylkill River between Schuylkill Township in Chester County and Upper Merion Township in Montgomery County. Valley Creek has a typical streambed slope of 0.36 percent, while Little Valley Creek has a typical slope of 0.75 percent. The hydraulic grade line (slope) is, however, influenced by several on-line low level dams. By contrast, a typical side tributary, for example Wilson Run, has a channel slope of approximately 4.6 percent.

III. ACT 167 PLANNING FOR THE VALLEY CREEK WATERSHED

Given the above information on the Valley Creek watershed, the watershed planning process for this study area must be fitted to the watershed characteristics as well as the resources (technical, political, and economic) of this area. The Valley Creek Watershed is a very unique watershed in that it possesses many qualities of an undeveloped watershed yet is in an urban setting. Water quality is sufficient to support trout, and riparian forested buffers along the main stems are, up to this point in time, fairly well preserved. On the other hand, various water quality indicators and streambank erosion problems show the influence that land uses and development pressure are putting on the fragile ecosystem. The Act 167 Stormwater Management Plan is an opportunity to lay the framework for establishing management criteria to maintain or preserve the natural hydrologic regime of the watershed, through holistic analysis and coordination of the sciences that are integrated in a watershed, and through development of comprehensive management opportunities. Managing stormwater is the key to managing the watershed for sustainability. This section of the Phase I Scope of Study presents the concept and approach that has been developed to fully meet these requirements, as well as the specific requirements of Act 167 for this watershed stormwater management project.

Figure 5 Topographic Relief - Triangulated Irregular Network (TIN)

Benefits of the Plan

• Consistency in Stormwater Management Planning, Regulation, and Implementation

The purpose and benefit of the study and implementation plan is to provide all of the municipalities in the watershed with an accurate and consistent implementation strategy and procedures for comprehensive stormwater management. Currently, stormwater management regulations, strategies, and enforcement criteria vary between municipalities within the watershed. Given the nature of storm runoff and its impacts, as described earlier in this document, a critical objective of sound stormwater management planning is to provide for consistency of implementation requirements throughout the watershed. Therefore, the primary objective of the technical study and planning process is to develop a technical and institutional support document to encourage and/or support the consistency of regulations for implementation of effective stormwater management based on watershed-wide consideration.

• Integrated Stormwater Management Plan

Water resources are one integrated resource, connected through the hydrologic cycle. Stormwater runoff is a major component of this cycle. Surface water and groundwater are interconnected. The Valley Creek Integrated Stormwater Management Plan will not just address water quantity or peak flows, but will look at the holistic approach to watershed management by evaluating the interaction between surface water and groundwater and how to achieve sustainable ground and surface water supplies, where water quality concerns should be addressed, how stormwater management (or lack thereof) affects streambank erosion. The results will be a Plan to preserve and enhance Valley Creek’s water resources though proper stormwater management.

• Usable Technical Information in GIS Format

The technical and institutional watershed planning approach recommended by the DEP also provides the municipalities within this watershed with a considerable amount of usable technical information, such as a detailed watershed runoff simulation model, that can be used for numerous other associated purposes by participating municipalities. Therefore, as a result of developing the watershed plan, municipalities and the County will realize benefits and/or products that are usable for other planning and engineering purposes. For example, land use updates and environmental data management are functions that are necessary for effective planning in a watershed. The technical component of the plan, primarily the geographic information system (GIS) database created for the watershed, will provide the County and municipalities with a tool to perform a range of environmental assessments, such as future water quality impact studies after the plan is completed.

• Technical Information for Future Hydrologic and Hydraulic Analysis and Regulatory Activities

In addition, technical support information, provided as a part of the watershed modeling effort, can be useful in the analysis, design and regulatory permitting process for floodplain management and bridge replacement efforts. Further, the stream encroachment permit process, which involves the need to supply detailed stream flow data as a part of the application process, can be more efficiently and cost-effectively developed using the calibrated watershed model. Therefore, the benefits of the watershed planning process are wideranging, even beyond the important function of developing comprehensive stormwater management strategies and ordinance provisions.

The plan will not correct or provide funds to correct existing problems but will provide the framework or first step to solve those problems. Specifically, the plan will summarize problem areas, provide much of the hydrologic analysis that will be required in design of proposed solutions, provide potential solutions to correct these problems, and specify possible sources of funding to pursue.

Approach for the Development of the Valley Creek Watershed Integrated Stormwater Management Plan

In January 2004, the County of Chester initiated a multi-year study to develop an Integrated Stormwater Management Plan for the East Valley Creek Watershed. The Chester County Water Resources Authority leads the effort, with support from the Chester County Planning Commission, Chester County Conservation District, Montgomery County Planning Commission and Montgomery County Conservation District.

The East Valley Creek Watershed covers approximately 24 square miles and is located in the eastern part of Chester County with a few acres located in Montgomery County within the Valley Forge National Historic Park. Valley Creek and its tributaries total an estimated 34 stream miles. The East Valley Creek watershed is one of Chester County’s 21 watersheds. Watersheds, Chester County’s Integrated Water Resources Plan, ranked the East Valley Creek Watershed as one of the highest overall priority watersheds for water quality restoration and stormwater management countywide. East Valley Creek was selected as the first watershed to undergo a comprehensive stormwater management study based on this prioritization. Valley Creek is designated as an Exceptional Value stream with naturally reproducing trout waters per DEP’s Water Quality Standards. However, the Commonwealth of Pennsylvania has identified approximately 32 percent of the stream segments that are not meeting their designated water use due to runoff from developed lands.

The Integrated Stormwater Management Plan will integrate two distinct studies into a single comprehensive plan to manage stormwater from new development and redevelopment while identifying and providing recommendations for watershed restoration and preservation. One study will involve the development of a Phase I and

Phase II Stormwater Management Study based on Pennsylvania’s Stormwater Management Act of 1978, often referred to as an Act 167 Study. The purpose of an Act 167 Study is to provide a watershed-wide approach to the planning and management of stormwater from future development. The completed Act 167 Study will produce a model stormwater management ordinance. Each municipality in the watershed will adopt the ordinance to implement the results of the Study.

The Act 167 Study is conducted in two phases (I and II). Phase I began in January 2004 and was completed in June 2004. Upon completion of Phase I, Chester County will pursue PADEP Act 167 Grant Program funding for Phase II. Once initiated, Phase II will take an estimated two years to complete. The two phases will accomplish the following:

Phase I - Initial Watershed Assessment • Preliminary assessment of stormwater and physical condition of the watershed • Development of a Phase II Scope of Study

Phase II - Detailed Stormwater Study and Plan • Implement the Phase II Scope of Study established in Phase I, • Conduct watershed runoff modeling and analysis, • Development of a watershed-wide Stormwater Management Plan, • Development of a watershed-wide municipal stormwater ordinance that implements the results of the study consistently throughout the watershed.

In addition to (and simultaneously with) the Act 167 Study, a natural stream assessment was conducted on the streams of the watershed. The stream assessment (referred to as a fluvial geomorphology or FGM assessment) will identify stream reaches that are functioning well in addition to those reaches that are impaired and/or unstable due to excessive runoff. The stream characteristics evaluated included the stream’s geometry, water quality, habitat, stream bank stability, geology and topographic features. The results of the FGM assessment and Act 167 Phase I and II Study will be combined into a single Integrated Stormwater Management Plan, which will present the combined results, conclusions and recommendations for watershed restoration and stormwater management. The Integrated Stormwater Management Plan will also incorporate the results of various studies and planning efforts already completed by others in the watershed. The FGM stream assessment was started in January 2004 and completed in June 2004.

In order to implement watershed-wide comprehensive planning for and management of stormwater runoff, it was necessary to take a very close look at all portions of the watershed for this Phase I Study. Since the Act itself is very dependent on municipal coordination to provide for the total planning and management of stormwater throughout the watershed, it is necessary to get each municipality in the watershed involved in the planning process.

In order to initiate municipal level involvement in the overall development of the plan, an initial meeting with municipalities was held on March 17, 2004, as part of the Phase I Scope to obtain their general commitment to the project and to begin survey efforts to determine the extent and nature of issues and problems in the watershed (see Appendix A). A Watershed Plan Advisory Committee (WPAC) strategy and questionnaire was incorporated into the Phase I work approach for the watershed. The WPAC was formed by the Chester County Water Resources Authority, in conjunction with the Chester and Montgomery County Planning Commissions, Chester and Montgomery Counties Conservation Districts, and consists of the required municipalities, County Conservation Districts, and interested group representatives. Table 1 is a list of the WPAC members.

Table 1 – List of WPAC Members

Chester County

Charlestown Township Linda Csete, Administrator East Whiteland Township Terry Woodman, Manager Malvern Borough Sandra Kelley, Manager Schuylkill Township Mary Bird, Secretary Tredyffrin Township William Bryant, P.E., Engineer Willistown Township Hugh Murray, Manager Chester County Planning Commission Wayne Clapp, Assistant Director Chester County Conservation District Dan Greig, District Manager Chester County Water Resources Authority Janet Bowers, P.G. Executive Director

Montgomery County

Upper Merion Township Ronald Wagenmann, Manager Montgomery County Planning Commission Drew Shaw, Environmental Planner Montgomery County Conservation District Richard Kadwill, District Manager

Other Interested Parties

USEPA Region III Kelley Chase, Project Manager Natural Resources Conservation Service Sam High, District Conservationist Pennsylvania Department of Transportation Mike Rebert, Manager, District 6 Pennsylvania Turnpike Commission Walter Green U.S. Geologic Survey Kirk White Valley Forge National Historical Park Arthur Stewart, Superintendent Valley Creek Restoration Partnership Pete Goodman & Chuck Marshall Valley Creek Trustee Council Mark Hartle West Chester Fish & Game John Johnson

The questionnaire, which was distributed prior to and reviewed at the March 17, 2004 WPAC meeting, was designed to solicit input from each WPAC entity relative to specific

problems in the watershed as well as needs that they may see for stormwater management in their particular area. The questionnaire was distributed, along with a summary of the purpose of Act 167, which includes an emphasis on Act 167 goals as they relate to this watershed. The questionnaire package is included as Appendix B of this document.

Because the most important part of the Act 167 planning process is implementation of the plan, another consideration in utilizing this questionnaire strategy is that it should encourage municipalities to think about actively implementing stormwater management measures within their communities. A summary of the stormwater related problems in each municipality is an important product expected out of the Phase I Study.

There are many factors that influence stormwater runoff in the Valley Creek watershed. Other than being directly linked to a storms’ intensity, duration, and frequency, stormwater problems can also be influenced by or caused by (but not limited to) inadequate stormwater infrastructure, increased impervious surface due to increased development, and other landscape changes. Some problems associated with stormwater management are localized flooding and streambank erosion, which can impact roadways, private property, and historical structures. The input by the municipalities on the Act 167 questionnaire not only enabled the project team to gather the necessary data for this study and report, but it also enabled them to evaluate their stormwater problem areas, and see what areas are vulnerable to problems. This exercise might enable the municipalities to act accordingly to change current development plans and regulations, and try to fix inadequacies in the storm sewer system and fix other problems, or take the means to procure funding to do so.

There is sporadic flooding throughout the Valley Creek watershed and the immediate tributaries. The identification of the problem areas will help in assessing the stormwater management controls needed in the future for the watershed. Table 2 and Figure 6A summarize the flooding problems, causes, damages, etc from the Problem Area Survey Form, while Figure 6B summarizes the streambank erosion problems. Figure 6A also displays problems from the other studies researched for this report including:

• The wooded riparian buffer survey performed by the Heritage Conservancy (Heritage Conservancy, 2001) • Problems and concerns identified by the Valley Creek Watershed Action Plan (Chester County Water Resources Authority, 2002) • 100-year floodplains from Federal Emergency Management Agency (FEMA). • Draft Valley Creek Restoration Plan/Environmental Assessment Plan (Valley Creek Trustee Council, draft 2004)

The streambank erosion problems were recorded as part of the municipal survey, during field reconnaissance of the streams as part of the Fluvial Geomorphology assessment, and as supplied by the Valley Creek Trustee Council. As can be seen from Figure 6B, the dominant problem was streambank erosion, however, a large majority of the problems are also caused from regional flooding (stream) and from local flooding (inadequate infrastructure). Upper Merion Township in 20

Montgomery County and the Valley Forge National Historical Park reported regular regional and local flooding problems for every rainfall event. The Valley Creek Restoration Partnership reported local flooding problems along Crabby Creek.

During Hurricane Floyd in 1999, floodwaters reached the walkway immediately in front of Washington’s Headquarters in the National Park. Flooding also threatened the park’s historic covered bridge that is located about 1.25 miles upstream from Washington’s Headquarters. Downstream from the covered bridge that is located within the park, a footbridge over Valley Creek was destroyed by the floodwaters of Hurricane Floyd. High waters also caused the collapse of a portion of Route 252 that runs along the east side of Valley Creek between the covered bridge and Route 23, near Washington’s Headquarters. The Chester County Water Resources Authority’s Compendium also lists other places in the watershed where flooding is a chronic problem during smaller storms than hurricanes.

East Whiteland and Tredyffrin Townships, which comprise 90% of the Valley Creek watershed, have long had zoning laws prohibiting building in the floodplains (Draft Valley Creek Restoration Plan/ Environmental Assessment, Natural resources Trustee Council, undated (circa March, 2004)) and the Commonwealth of Pennsylvania requires permits for construction within the 100-year flood plain. In addition, the Open Land Conservancy has purchased or has conservation easements on riparian lands along several miles of stream corridor (Draft Valley Creek Restoration Plan/ Environmental Assessment). However, there are still several structures within the floodplains of the watershed.

There are numerous locations where streambanks receive excessive energy from flood flows as evidenced by highly eroded banks and deeply incised streams. The deeply cut stream channels do not allow high flow levels to reach their floodplains, and the adjacent stream banks become eroded from the force of more and faster water, which can be shown on Table 2 and Figure 6B. In addition, available floodplains are not well utilized to store and infiltrate stormwater. Stream channel stabilization is required to reconnect the floodplains to their streams to achieve flood management and reduce eroded banks.

Although studies specific to the streambank erosion problem are lacking, the prevailing opinion of local professionals is that the banks of the main stems of Valley Creek and its floodplains are not acting in a natural way to dissipate the energy of runoff waters and promote infiltration where possible. This condition is expected given the extensive development that has occurred in the contributing watershed, including the location of some structures in the floodplain.

Figure 6A. Stormwater Related Problems

Figure 6B. Streambank Erosion Problems

TABLE 2

SUMMARY OF MUNICIPAL PROBLEM AREA SURVEY

(A) (B) (C) (D) TYPE OF CAUSE OF OCCURRENCE TYPE OF MUNICIPALITY PROBLEMS PROBLEMS OF PROBLEMS DAMAGE Chester County Charlestown Township 1,2,6 1,2,5 1 3 East Whiteland 1,2,5,7, 1, N/I N/I Township Malvern Borough 1,7, 1,4 1 3 Schuylkill Township 1,2 1,2 1,2 3 Tredyffrin Township 1,2,8 1,2,5 1,2,3 3 Willistown Township 1,2,3,4,8 1,2,3,4 1,2 N/I Montgomery County Upper Merion 1,2,3,4,6,7,8 1,2,3,4,5 1 3 Township Others Valley Forge National 1,2,3,4,6,7,8 1,2,3,4,5 1 3 History Park Penn Turnpike N/I N/I N/I N/I Commission Valley Creek 2,3,4,7 1,2,3,4 1 3 Restoration Partnership

(A) 1. Flooding (B) 1. Stormwater volume 2. Accelerated erosion 2. Stormwater velocity 3. Sedimentation 3. Stormwater direction 4. Landslide 4. Water obstruction 5. Groundwater 5. Other contamination 6. Surface water pollution 7. Inadequate infastructure 8. Other

(C) 1. > 1 time per year (D) 1. Loss of life 2. < 1 time per year 2. Loss of vital services 3. Only major flood events 3. Property damage

N/I denotes that a problem area form was received from the municipality, and no problem areas were indicated. A blank after the municipality indicates that a problem area form was not returned to the County.

Many of the problems are caused by increased runoff from the built up areas. Some of the older areas have no stormwater management controls, while some of the newer developed areas have stormwater controls but the detention basins may have only been designed to manage the larger storms (Emerson, 2003). The smaller storms are the ones that cause the most streambank erosion damage. In addition, much of the development has occurred on the higher portions of the watershed and headwaters, allowing the increase in runoff to travel down the steep slopes to the valley floor. The problems in the Valley Creek watershed are not only caused by the increased runoff from developed areas, but the fact that the side slopes of the watershed are steep as shown in Figure 7, while the valley floor has a relatively gently slope. In addition, some of the other complications include the karst geology, the magnitude of the existing highway system and associated runoff, the influence of quarry pumping, and lack of forested buffers in some areas (Heritage Conservancy, 2001). In summary, the factors that complicate the hydrology of the Valley Creek watershed includes:

• The effect of karst geology on soils and surface hydrology • Steep valley walls and flatter valley floor • Lack of existing forested buffers thru out the corridor • Magnitude of existing highway system • Influence of quarry pumping • Areas without stormwater management controls • Areas of development at top of valley walls and steep slopes

Stormwater management planning is critical in the areas both currently affected and unaffected by stormwater problems in the Valley Creek watershed. The Act 167 plan will address future, more frequent flooding problems in these areas by managing runoff from newly developing areas. This plan will also provide the watershed communities with information essential in evaluating and upgrading current undersized stormwater systems. For areas currently unaffected by stormwater problems, the Act 167 plan will provide controls for future development to aid in preventing future stormwater runoff problems.

Although the identification of the problem areas will help in assessing the future stormwater management controls needed for the watershed, the Act 167 process will not correct nor will it provide funds to correct existing stormwater related problems. It will, however, provide for a systematic approach and information on sources of funding to correct the problems, and will, through the future implementation of stormwater ordinances, provide a means to prevent these problems from being aggravated by uncontrolled runoff from new development. The plan will make suggestions for other programs/activities to deal with the issues raised during the planning process.

Figure 7. Steep Slopes

Coordination with Other Projects/Studies

There are a number of projects/studies, old and new, undertaken within the Valley Creek watershed, which will be coordinated as part of the Phase II plan preparation. These studies include Watersheds, Valley Creek Watershed Action Plan, Valley Creek Draft Restoration Plan/Environmental Assessment (Valley Creek Trustee Council, undated (circa March, 2004), and the Grower Greener FGM and Water Quality Assessment project which is currently underway. A further summary of various studies can be found in Appendix VIII, References.

IV. PLAN PREPARATION STRATEGY

The plan will contain, at a minimum, the following items:

(1) A survey of existing runoff characteristics in small as well as large storms, including the impact of soils, slopes, vegetation, and existing development

(2) A survey of existing significant obstructions and their capacities

(3) An assessment of projected land development patterns and probable alternatives in the watershed and the potential impact of runoff quantity, velocity, infiltration, and quality

(4) An analysis of present and projected development in flood hazard areas and its sensitivity to damages from future flooding or increased runoff

(5) A survey of existing drainage problems and proposed solutions

(6) A review of existing and proposed stormwater collection systems and their impacts

(7) An assessment of alternative runoff control techniques and their efficiency in the particular watershed

(a) An assessment of alternative stormwater quality and infiltration techniques and their efficiency in the particular watershed

(b) An assessment of the existing stormwater management control sites that could be retrofitted to achieve the greatest enhancement to stormwater runoff quality and quantity control

(8) An identification of existing and proposed federal, state, and local flood control projects located in the watershed and their design capacities

(9) A designation of those areas to be served by stormwater collection and control facilities within a 10-year period, an estimate of the design capacity and costs of 27

such facilities, a schedule and proposed methods of financing the development, construction, and operation of such facilities, and an identification of the existing or proposed institutional arrangements to implement and operate the facilities

(10) An identification of floodplains within the watershed

(11) The development of criteria and standards for the control of stormwater runoff from existing and new development which are necessary to minimize dangers to property and life and to carry out the purposes of the Act

(12) The development of priorities for implementation of action within each plan

(13) The development of provisions for periodically reviewing, revising, and updating the plan

(14) The development of provisions as are reasonably necessary to manage stormwater such that development or activities in each municipality within the watershed do not adversely affect health, safety, and property in other municipalities within the watershed and in basins to which the watershed is tributary

(15) Consideration of consistency with other existing municipal, county, regional, and state environmental and land use plans

(16) Consideration of which, if any, of the National Pollution Discharge Elimination System (NPDES) Phase II Municipal Minimum Control Measures and permitting requirements will be addressed in the Phase II Study. The six minimum control measures to be considered are:

A. Public education/outreach B. Public involvement/participation C. Illicit discharge detection and elimination D. Construction site runoff control management E. Post-construction stormwater management F. Pollution prevention/good housekeeping for municipal operations

Most municipalities will have made substantial progress in implementing their MCMs by the time the Phase II Study is begun. Thus, Phase II will not address all MCMs. The WPAC process will address (at least in part) MCMs A and B. MCMs C, D, and F are beyond the scope of the Phase II Study and will not be addressed. MCM E will be addressed in detail in the Phase II Study.

The concept and approach presented in the previous discussions has been organized into stages that include the above indicated sixteen elements of the plan.

Stage A - Data Collection and Analysis

A.1 - Data Collection/Review/Analysis

This task will involve the necessary efforts to gather, review, and analyze the required data to complete the technical and institutional planning steps for the Valley Creek Watershed Act 167 Stormwater Management Plan. The Consultant, Chester County Water Resources Authority (CCWRA) and the Chester County Planning Commission (CCPC) will work jointly to collect data from Chester and Montgomery County offices, municipalities, and local, state, and federal agencies that will aid in preparation of the plan. The data will consist of information concerning existing and future conditions in the watershed. All data collection activities will be accomplished by gathering available information from either the agencies that will be contacted or from the data collection questionnaire that will be provided to the municipalities.

Data to be collected will include, but may not be limited to (and will be based on available information and/or questionnaire results):

• Comprehensive land use plans and current zoning ordinances to develop a build- out scenario for the future land use data layer for modeling purposes

• Existing municipal ordinances

• Existing and proposed flood control projects

• Existing and proposed stormwater control facilities

• Existing and proposed stormwater collection and control facilities, including a designation of those areas to be served by stormwater collection and control facilities within a 10-year period, an estimate of the design capacity and costs of such facilities, a schedule and the proposed methods of financing the development, construction, and operation of such facilities, and an identification of the existing or proposed institutional arrangements to implement and operate the facilities, where this information is readily available

• Soils

• Geology and Sinkholes

• Flow obstructions

• Topographic mapping

• Aerial photographs

• Engineering and planning studies

• Streamflow data

• Rainfall data required for use in calibration and development of design storm amounts

• Floodplain information

• Watersheds data from CCWRA,

• Water quality data

• Data from the completed FGM assessment

• Stormwater-related problems and proposed solutions.

The problem areas will be looked at in detail in the Phase II plan. Those problem areas identified as “significant” will be field evaluated, and the model will utilize these sites as points of interest to develop design storm flows. Local affected residents and municipal officials will be interviewed where appropriate to determine the problems that they have had in the past. A collection of past studies/investigations will be compiled and reviewed for proposed solutions and reasons why progress has not been made. The plan will summarize these problem areas, provide much of the hydrology that will be required in design of proposed solutions, and specify possible sources of funding to pursue. The plan will make suggestions for other programs/activities to address the issues raised during the planning process.

Review of stream gauge records from the U.S. Geologic Survey (USGS) indicates that there are historical flow values for one stream gauge located in the watershed as follows:

GAUGE YEAR OF LOCATION NO. RECORD 01473169 Valley Creek at PA Turnpike Br near Valley Forge 1982 – Current

The collected stream gauge data will be put in a format to be used in the model calibration process.

A collection of past studies/investigations was compiled during Phase I and will be reviewed for problem identification and proposed solutions. A comprehensive review of these related documents and/or programs will be performed, and a coordinated list of the goals and objectives from each of the project documents will be developed. Existing documents to be reviewed shall consist of, but not be limited to:

• Water supply and wellhead protection plans

• Flood mitigation plans

• Municipal Act 537 plans (various)

• Municipal flood insurance studies (various), as prepared by the Federal Emergency Management Agency (FEMA)

• Municipal ordinances

• Valley Creek Watershed Action Plan

• Valley Creek Restoration Plan / Environmental Assessment

• Landscapes, Managing Change in Chester County 1996-2020 Comprehensive Plan Policy Element

• Chester County, Pennsylvania Water Resources Compendium

• Watersheds, An Integrated Water Resources Plan for Chester County, Pennsylvania

• Any other relevant studies discovered during the Phase II process

• The references specified in Section VIII of this report.

This task effort will also coordinate closely with the initial Phase II WPAC meeting, which will involve the distribution of data questionnaires to the municipalities. In addition, a discussion of procedures to be followed in the completion of the questionnaires will be provided at the initial WPAC meeting. Finally, sources of funding to correct these stormwater related problems will be identified.

This task also involves the review and preliminary analysis of the technical data that have been obtained for consistency and usability. It also includes review of the institutional data collected through the municipal data questionnaire process for consistency and usability in the final implementation plan.

It is anticipated that in addition to the WPAC meetings, eight (8) coordination meetings will be required among the Counties, Consultant, and other affected parties throughout the duration of the Phase II Study. This includes approximately 3 meetings in Stage A, 3 meetings in Stage B, 2 meetings in Stage D. The purpose of these meetings is to coordinate data collection, administrative procedures, technical issues and analyses, plan development, scheduling, implementation and other various coordination as needed.

Project Team Responsibilities

COUNTY – is responsible for: • Distribution of municipal data questionnaire and instructions to municipalities • Receiving and compiling the municipal responses from the data questionnaires • Locate and collect field and other descriptive data of existing stream obstructions and stormwater problem areas, and compile data for evaluation • Collection of related available studies and data for other aspects of the study • Collection of flood insurance maps and reports from FEMA • Provide a summary of key results and conclusions from the municipal questionnaires and inventory of stream obstructions and problem areas to WPAC members

CONSULTANT – Is responsible for: • Preparation of municipal data questionnaires, with assistance from County. • Training the County for, and aiding the County in locating and collecting data for stream obstructions and stormwater problem areas. • Providing support for the actual data gathering and organizing efforts, as well as the preliminary review for consistency and content. • The review of gathered and organized data and the acceptability of the data, as well as for the preparation of a missing data list. • The final determination of data usability for completing the necessary technical and institutional planning efforts as well as for providing input and/or alternatives for the collection of missing data. • Prepare final data summary to catalog collected data.

Anticipated Product

The product will include the information listed above, gathered and organized in such a way as to be usable for both short- and long-term watershed planning activities (including updates). A final data summary will be prepared that will identify and/or catalogue the collected data. An interim summary of the inventory of stream obstructions and problems will be provided to the WPAC. This summary will be provided early in the planning process before the Phase 2 Act 167 Plan is complete. The goal is to put information in the hands of the WPAC and other interested parties as soon as possible in the Act 167 process.

A.2 - Municipal Ordinance Reviews/Evaluations

This task will involve the detailed evaluation of the municipal ordinances in order to prepare a municipal ordinance comparison matrix. This matrix is intended to display, for both the actual preparation of the implementation plan and also for the municipal education process, the current stormwater management provisions in the various municipal ordinances for all watershed municipalities. The objective of the preparation of the matrix is to easily and effectively see the similarities and differences, as well as the consistency/inconsistency, between the various municipal ordinances in the watershed. The matrix will be used to develop ordinance provision recommendations for the various municipalities that are based on the standards and criteria.

Municipal ordinance evaluation will be as comprehensive as possible. Typical ordinance standards related to stormwater management in local ordinances that will be reviewed for consistency with the Act 167 Plan will include:

• Erosion and sedimentation control provisions • Zoning Overlay Districts (e.g. floodplain, wetlands, steep slopes, prime agricultural lands, and other natural or environmental resource protection standards) • Zoning districts –bulk and area & impervious coverage requirements • Street and road geometry design standards • The complete plan submission, review and approval process • Water quality and runoff volume controls provisions • Wellhead protection provisions.

Appendix C shows an example of a municipal ordinance matrix.

Project Team Responsibilities

COUNTY - responsible for detailed evaluation of the municipal ordinances and the preparation of the municipal ordinance provisions matrix for the entire watershed.

CONSULTANT - responsible for providing insight and guidance to County staff in the formatting of the municipal ordinance provisions matrix. Also responsible for reviewing the completed municipal ordinance provisions matrix for consistency with the needs of the implementation provisions of the plan and ordinance.

Anticipated Product

The product will be a completed matrix of stormwater management ordinance provisions for the watershed municipalities which identifies the current status of ordinance provisions as they relate to stormwater management.

A.3 - Data Preparation for Technical Analysis

This task involves the engineering work necessary to transform the information collected under Task A.1 into a GIS that can be used for the later technical tasks. Included will be the preparation of “land characteristics” GIS data layers for modeling and display purposes.

The GIS data layers will include:

• Base Mapping - Existing base map information (roads, streams, municipal boundaries, text, etc.) will be collected from the Counties and PennDOT, and the most accurate data will be utilized to develop the watershed base map. All data will be projected into the coordinate system utilized by the Chester County. All data from the Counties will be merged into a seamless base map. The base map will also be utilized to show the location of obstructions and problem areas.

• Land Use/Land Cover Information - Existing Delaware Regional Planning Commission (DVRPC) 2000 land use data, and current tax parcel GIS files will be collected and evaluated for usability and consistency. Current digital aerials will be collected and utilized to update the land cover maps into the format required for hydrologic modeling (TR-55 land use classifications). Land development projects completed subsequent to existing data will be added from Planning Commission records as necessary. Prepared GIS layers will be field checked for accuracy. In addition, since there are severe streambank erosion problems in this watershed, it has been determined through the Phase I process that knowing the “predevelopment” flows of the watershed will be valuable as an aid in determining the impact that development has had on the Valley Creek hydrologic system and streambank erosion. Therefore a “predevelopment”, circa 1800 land cover map will be developed for use in the modeling. The circa 1800 map will be based upon the earliest available aerial photography and historical records of land cover of that time period.

• Future Land Use Conditions - Existing zoning information and the Counties comprehensive plans will be utilized to convert the existing land development conditions mapping to the future land use scenario for development for ultimate build-out conditions.

• Soils Information - Digital County soils data will be collected. The data collection effort will be coordinated with the County and NRCS to obtain “official soils data” where available. Overlay mapping will be necessary to prepare the hydrologic soils group map necessary for modeling. Erodibility classifications will be included in the GIS attributes so that an erodiblity map can be generated.

• Digital Elevation Models - Digital elevation models (DEMs) will be utilized and evaluated to assign flow paths, slopes, flow direction, and flow accumulation to the subareas for which detailed modeling will be completed. The County’s DEMs

will be utilized. Chester County’s DEMs will also be utilized for watershed and subwatershed delineation.

• Wetlands - Wetlands data will be compiled from the National Wetlands Inventory (NWI) maps.

• Geology - It was apparent from the field visitations that there were marked variations in streambank erosion throughout the watershed. This may be due to soils, geology (karst), stream profile, upgradient development, etc. To assist in the development of streambank erosion design criteria, the correlation between the recorded erosion problems and soil and geology should be established. Therefore an analysis will be performed within the GIS to determine if there is a correlation. Digital geologic maps developed for the watershed from existing County, USGS, Pennsylvania Geologic Survey (PGS), and Pennsylvania Spatial Data Access (PASDA) sources as part of the Phase I will be utilized . The locations of the various geologic features pertinent to the features of the watershed, i.e., limestone, gneiss etc., will be analyzed to establish trends and aid in portraying the goals of the plan. In addition, available sinkhole spatial data and public wells will be included on the map.

• Obstructions - Obstructions will be located on the appropriate base map and data or attributes attached or linked to the locations.

• Problem Areas - Flood Control Structures, Stormwater Management Facilities, etc. - These will be located on the appropriate base map and data or attributes attached or linked to the locations.

• Floodplains - FEMA Q3 Flood Data (or most current FEMA digital data, if available) will be transposed to the appropriate base map and displayed with the development in the watershed. FEMA is in the process of redelineating their floodplain mapping (GIS files) for the entire county. The product is expected in early 2005. If this data is available in time, it will be utilized in the Plan.

• Environmental Characteristics - Environmental characteristics such as open space, buffers, etc., will be displayed on a separate map where appropriate.

• Stream Profile data - As discussed under Geology, the streambank erosion may be a function of stream slope, or a combination of slope, soils, geology, increased stormwater flows, etc. Since the County has detailed topography, it is proposed to establish accurate stream reach profiles within the GIS, and compare slopes with streambank erosion to determine if a pattern exists. Profiles will be generated for the entire main stem length of Valley Creek, and Little Valley Creek in the valley and two typical side slope channels, for instance Crabby Creek and Cedar Hollow Creek. This information will assist in the development of streambank erosion standards and criteria.

A summary of data sources will be supplied (PASDA compliant metadata) and will include data type (coverage, shapefile, image) source, projection, and year.

Delineation of Subwatersheds

The watershed and subwatersheds will be delineated by the Consultant utilizing the DEM derived from the County-wide five foot digital topographic mapping. Subwatersheds will be established based on this Chester County topography and results of the field reconnaissance task. This breakdown of the watershed by major tributary drainage courses and points of interest will be the basis for the hydrologic and hydraulic analyses.

The subwatersheds will be further delineated to subareas based on the following:

• The location of existing problems, as identified by local officials in the municipal survey during the field reconnaissance or from data previously compiled in any earlier studies

• The location of major obstructions (primarily bridges), highway culverts, or stormwater control facilities

• Confluence points of tributaries, as deemed appropriate based on engineering judgment and good modeling practice

• First order streams

• Other points of interest, such as stream gauging or water quality monitoring stations, locations of water quality concerns, or outfall sections downstream of existing developments or where development is anticipated to occur

This task will also include mapping of relevant watershed planning information onto GIS data layers. This mapped information will include:

• Floodplain areas - the approximate floodplain limits plotted over the watershed base map or the highlighting of those stream segments for which detailed flood insurance studies are available

• Significant obstructions and their capacities – “significant” obstructions will be those that are identified in the municipal data questionnaires and which are confirmed by the Consultant as being areas where insufficient capacity exists for the necessary storm flows or those that would act as impoundments and affect watershed modeling

• Storm sewer systems - for significant system components, areas where storm sewering exists (service areas) will be indicated generally on the final watershed

base map. Storm sewer maps will be collected and included in the Technical Appendix.

• Existing federal, state, and local flood protection and stormwater management facilities

• Proposed stormwater facilities within the 10-year planning period - where known and confirmed by the municipalities through the municipal data questionnaire process

• Stormwater related “problems” - those areas indicated in the municipal data questionnaire and where confirmed by technical modeling/analysis (for example, flooding points or areas of streambank erosion

Project Team Responsibilities

COUNTY – responsible for development of the GIS existing land use coverage from aerial photographs and available land cover information (Chester County Planning Commission).

CONSULTANT – responsible for transposition of data relating to stream obstructions and stormwater problem areas into the GIS and digital spreadsheets. Responsible for the remaining map preparation work described above and the development of watershed base maps for use in both the technical planning process as well as the final plan presentation. Responsible for review and analysis of the land use data and the catalogued municipal data questionnaire information to help identify the data, as described above, that will be included on various maps. Responsible for final review of technical mapping information for use in the modeling efforts.

Anticipated Product

The product will be completed GIS watershed data layers and maps. The maps completed for this task will be preliminary in that they can and/or will be modified and finalized as a part of the final plan preparation efforts. The project team will provide as much of this data and mapping to the WPAC and other interested parties as soon as possible in the Phase 2 Study. A series of progress maps tailored to meet the WPAC’s needs will be prepared as a way to share the information gathered and mapped in a timely fashion during the project. Progress maps will be presented at the WPAC meetings and also distributed to all WPAC entities for their use and information.

Stage B-I - Technical Analysis

The technical analysis will describe the analytical processes involved with developing a strategy to manage stormwater runoff from new land development. Since stormwater runoff has a direct impact on flooding, water quality, infiltration and groundwater recharge, this analysis will consider the following objectives: 37

• Implementation of nonpoint source pollution removal methodologies • Maintaining infiltration and groundwater recharge • Reducing channel erosion • Managing overbank flood events • Managing extreme flood events

These objectives will be accomplished under Subtasks B.1 to B.4.

B.1 - Evaluate and Establish Water Quality Requirements

The water quality assessment performed under the Fluvial Geomorphology Assessment will be referenced and the results taken into account when developing the water quality standards. A water quality strategy to encourage nonstructural, low maintenance systems in conjunction with infiltration requirements will be provided. The strategy will be tied to the source to encourage innovative design practices. A water quality volume computational methodology will be provided. The water quality assessment information will be used to guide the selection of water quality and infiltration best management practices (BMPs). A matrix of BMPs verses pollutant will be developed as a guide.

B.2 - Evaluate and Establish Infiltration and Groundwater Recharge Requirements

Various approaches to achieve stormwater infiltration will be evaluated for suitability in the Valley Creek watershed including the a method based upon the water budget of the watershed, the method described in the Maryland Stormwater Management Manual (2000), the method described in the and the PA BMP Manual (CH2MHILL, 1998), the method described in Chester County’s Watersheds plan, the upcoming PA Stormwater Management Design manual (when available) and others.

Available water budgets (Sloto, 1990, Chester County Water Resources Authority 2001) will be analyzed for usable data and a final water budget determined for the watershed. The goals will be to establish base flow, low flow, trends and ultimately establish infiltration criteria to maintain the natural hydrologic regime. The results will also provide more accurate baseflow data for model input. Data will be collected on the quarries and the pumping/discharges that may influence the hydrologic regime. Infiltration criteria in karst areas will be analyzed for the prevention of sinkholes and to ensure long term groundwater quality. Final infiltration criteria may vary from non-karst to karst areas of the watershed.

Rainfall records for the watershed or region will be evaluated to identify a rainfall depth that produces 90% of the annual runoff volume. Hydrologic soil groups as well as natural and man-made features within the watershed will be analyzed to determine general areas of suitability for infiltration practices. The hydrologic model will be run with specific what-if scenarios to establish and verify the recommended computational methodology for infiltration. The final criteria may vary depending on location in the watershed, hydrologic soil group, karst verses non-karst geology etc.

B.3 - Evaluate and Establish Streambank Erosion Management Requirements

One product of the Fluvial Geomorphology assessment FGM assessment will be the bankfull discharge. This coupled with the recommended analyses in item B.1 above will be utilized to establish whether streambank erosion is being exacerbated by the increased runoff from land development.

Various streambank erosion standards (for example, detain 1-year, 24-hr storm event and drain over 24-hr period) will be evaluated and discussed and final criteria determined based upon the FGM assessment, soils erodibility, and profiles. This work will include an analysis of the critical velocity and erodibility of soils in and along streams within the watershed. Subareas will be created and grouped into management districts. Streambank erosion criteria will be analyzed on a management district basis with criteria established to minimize future streambank erosion based upon bankfull flow curve data. The final criteria may spatially vary in the watershed depending on the outcome of the analysis.

B.4 - Evaluate and Establish Overbank and Extreme Event Requirements (release rates)

This task involves the hydrologic modeling, quantitative computations, and evaluations necessary to analyze runoff characteristics of the watershed under existing and future conditions. It will also establish the need and extent of release rates for the 1-, 1.5-, 2-, 5- 10-, 25-, 50-, and 100-year 24-hour events. High intensity, low duration events such as a few of the most recent hurricane events will be evaluated and criteria possibly incorporated into the standards for management of these storms.

The process will follow the general outline in Figure 8.

Model Selection and Set Up

Several models are appropriate for stormwater management including SWMM, TR-20, HEC-HMS, and the Penn State Runoff Model. Each model has its advantages and disadvantages. Selection of the most appropriate hydrologic model will be determined during Phase II. This task includes the set-up of the hydrologic model for the analysis of the existing and projected land characteristics of those subareas. Input data including rainfall information, drainage network layouts and capacities, travel times within subareas and impoundments, and GIS-based data developed under Stage A will be input into the selected model.

Model Calibration and Verification

The model will be run to get preliminary results. It will then be calibrated to obtain a model that can predict the hydrologic response of the watershed with confidence and reliability. Calibration efforts will include the adjustment of model parameters to accurately simulate natural runoff conditions of the watershed. Consideration will be given to all calibration techniques including, but not limited to, use of any available

gauging information, comparison with rainfall and runoff information from similar watersheds, comparison with flood insurance study information, regression analyses, and short-term gauging. Calibration will be performed at multiple points within the watersheds to assure the most accurate modeling. Verification of the model will be performed.

Design Storm Selection

Subsequent to calibration of the model, the Consultant will run the model for the synthetic 1-, 1.5-, 2-, 5-, 10-, 25-, 50-, and 100-year 24-hour storms. Short duration storm events based upon actual rainfall records (approximately six (6) events) will also be analyzed to help analyze the flash flooding that takes place in the valley. An analysis of downstream impacts during the synthetic and actual storms will be performed to determine the required design storm(s) based on the watershed hydrologic response of the storms.

Model Runs

The calibrated model will be run for the selected subareas under the determined design storm(s) for the predevelopment, (circa 1800), existing, and future projected land cover and with future conditions with the recommended Valley Creek Act 167 Plan Standards and Criteria.

This task shall involve the detailed evaluation of modeling results to perform a problem identification analysis (i.e., a “cause and effect” analysis). This will concentrate on identifying the downstream storm runoff impacts of projected future land development projects. This evaluation will consider both the increase in current downstream storm runoff problems as well as new downstream runoff problems.

Act 167 Technical Objectives (Desired)

Prevent Manage Maintain Manage Maintain streambank overbank groundwater extreme events Water Quality erosion flooding recharge events

Release Water 1yr, 24 hr Release Recharge rates quality detained rates 2-5-10 Volume 25-50-100 volume 24 hrs yr events yr events

Meet with advisory committee

WPAC Input

Collect Inventory landuse/cover obstructions soils etc. data

Technical Analysis WPAC Input

Analysis of BMP analysis Problem area Analysis of current and State/fed identification and soils, natural future infiltration requirements analysis features needs

WPAC and MEC Input Streambank erosion Watershed modeling release rate analysis for overbank and extreme events Infiltration

WPAC and LAC Establish Water Input management Quality strategy

Overbank Standards flooding

Plan Extreme preparation event

Figure 8. Chart for analyzing five comprehensive management objectives

This work step consists of performing a technical evaluation of the hydrologic analysis for predevelopment (circa 1800), existing, future (build out) and future with Plan implementation conditions and recommending standards and criteria to regulate development activity which impacts stormwater runoff. This task also involves performing a release rate (or other similar) analysis and a preliminary distributed storage analysis and developing criteria and standards for proper control of stormwater from new developments. Recommended standards and criteria will accommodate various types of land development activities. The standards and criteria will provide for the application of management practices for the implementation of stormwater control measures. An additional analysis will then concentrate on identifying the downstream storm runoff impacts of projected future land development projects with and without the proposed

stormwater management criteria. A scenario will be developed incorporating the nonstructural design process, infiltration, water quality, streambank erosion, and stormwater quantity criteria developed as part of the Plan.

The above analyses may show that existing development in the watershed may already be overtaxing the carrying capacity of the streams and be a sufficient detriment to the natural hydrologic regime. Placing standards and criteria on new development may not be enough to prevent further stream degradation. In addition to managing stormwater from new development, this watershed may benefit from storage distributed in the most hydrologically and hydraulically advantageous locations. This may take the form of regional stormwater facilities for larger storms, smaller (streambank erosion) storms, to promote recharge, bypass facilities, etc. These options would not be the sole solution, but combined with promotion of nonstructural stormwater management from new development, may provide the comprehensive answer. It is proposed that several existing detention facilities be evaluated utilizing Emerson (2003) as to what impact they are having on the range of design storms. From existing data, several of the basins, which have a significant hydrologic impact on the watershed, will be evaluated and recommendations for retrofitting determined. A “retrofitting options” matrix will be compiled which will provide guidance on which types of retrofitting alternatives will benefit various factors i.e. water quality parameters, sediment, attenuation. In addition, regional basin locations will be determined, and high flow, low flow, infiltration and bypass scenarios modeled. This will include the possibility of utilization of the quarries and floodplains for temporary storage of stormwater.

B.5 - Compilation of All Technical Standards

This task involves the development of specific technical standards and criteria related to stormwater management control measures for new development as well as redevelopment sites. Recommended standards and criteria will accommodate various types of land development activities. The standards and criteria will provide for the application of management practices for the implementation of stormwater control measures.

The standards and criteria will address the following: a. Identification of all areas within the watershed where different criteria apply b. Recommended release rate percentages (if applicable) or other levels of control of accelerated runoff from the subareas identified in item a c. Recommended design flood frequencies and computational methodologies for stormwater management measures d. Management measures for infill/redevelopment areas e. A list of recommended alternate stormwater collection and control measures

f. Specifications for construction and maintenance of stormwater systems (if applicable)

g. Safety requirements for stormwater systems during and after construction

h. An identification of regional versus localized problems and generalized proposed solutions

i. Funding sources for correction of existing problems

j. Management measures unique to the tidal portions of the watershed (if applicable)

k. Coordinated efforts with the Phase II NPDES program

l. Coordinated efforts with concurrent studies. A summary of what tasks will be completed by what programs will be generated so as to avoid duplication of effort. Also, a recommended sequence for implementing the tasks will be developed

m. Feasibility of a stormwater utility or maintenance/management fund

n. Identification of repetitive loss structures in the floodplain

o. Evaluation of existing floodplain ordinances and their effect in the watershed and recommendations for improvement

The recommendations will be presented in layman’s language, keeping in mind that they are directed toward the local municipalities, are to address solutions to stormwater management needs, and will be read and interpreted by technical and nontechnical people. The technical standards and criteria developed as a part of this task will be watershed wide in their interpretation and/or application.

Structural water quality best management practices (BMP) information will be presented, including recommendations for the implementation of water quality BMPs for new land development activities to minimize impacts of nonpoint source pollution from land development activities. This educational effort will primarily involve discussions, presentations, and handouts on BMP technology to municipal officials during regularly scheduled WPAC meetings as described under Stage C. Information available from the DEP and other sources will be distributed.

Nonstructural methods of controlling stormwater runoff quantity and quality, such as innovative site planning, impervious area reduction, grading and protection of natural depression areas, buffer zones, temporary ponding on site, and other techniques will be evaluated and recommended for inclusion in the model ordinance.

Results from the data review and the field work indicate that the existing preservation of the Valley Creek floodplain is playing a large role in preserving the water quality of Valley Creek. In some of the undeveloped portions of the watershed, the absence of major flooding problems is due to minimization of building in the floodplain, absence of man-made channelization and impervious area encroachments in the riparian zone. Floodplain management and riparian buffer requirements specific to the watershed will be explored, coordinated with stormwater management requirements, and incorporated into the final standards and criteria. Buffer width standards will be incorporated into the model ordinance. Recommendations for floodplain management ordinance revisions to aid in achieving the goals of the Valley Creek Act 167 Plan will also be developed.

B.6 - Implementation of Technical Standards and Criteria

This task will involve the identification of the necessary ordinance provisions for each watershed municipality that will be required to be instituted in order to comply effectively with the technical standards and criteria. Included will be the preparation of a single-purpose or “model” ordinance and/or recommendations for updating existing municipal subdivision and land development ordinances to effectively implement the technical standards and criteria for stormwater management in this watershed. This will be accomplished in coordination with the WPAC.

Project Team Responsibilities (B.1-B.6)

COUNTY - responsible for; • Coordinating WPAC, consultant and County efforts to determine the provisions, technical standards and criteria to be included in the ordinance and plan (including NPDES Phase II components, per Task B.11. below). This will include evaluating existing ordinance language provided by the DEP and from other local and relevant ordinances (i.e., nearby recently completed Act 167 ordinances, etc.). • Coordinate review and comments on draft ordinance. • Compile and provide to the Consultant any questions and concerns regarding technical standards and criteria for resolution prior to the completion of the final plan.

CONSULTANT - responsible for: • Drafting and revising the Act 167 ordinance document, • Assisting in coordination and evaluation of ordinance language and identification of components needed to address NPDES Phase II requirements. • Modeling and the technical evaluation/analysis to be completed for the development and verification of technical standards and criteria as a part of this task. • Drafting and revising the Act 167 ordinance document, • Assisting in coordination and evaluation of ordinance language and identification of components needed to address NPDES Phase II requirements.

• Developing the legal and financial alternatives for stormwater management. • Responsible for visiting the “significant” problem areas sites, developing schematic proposed solutions, and aiding the County in identifying proposed methods of funding.

Anticipated Product

The product will be the charts, tables, and graphs to present the modeling results, the technical interpretation of the modeling results, and the definition of the technical standards and criteria for use in the preparation of the plan. The product will also include the identification of necessary recommended municipal ordinance provisions to implement the technical standards.

Stage B-II - NPDES Phase II Activities

All municipalities in the watershed were required to obtain permits in compliance with NPDES Phase II requirements for small MS4s by March 10, 2003. The permit requires each municipality to satisfy six Minimum Control Measures (MCMs). The six MCMs are:

• Public Education and Outreach • Public Involvement/Participation • Illicit Discharge Detection and Elimination (IDD&E) • Construction Site Stormwater Runoff Control • Post-Construction Stormwater Runoff Management • Pollution Prevention/Good Housekeeping for Municipal Operations and Maintenance

Since all of the municipalities will have addressed many of the MCM requirements by the time the Phase II Study gets underway, the scope of services under the Valley Creek Watershed Study is very limited. The role of the County will be limited to assisting the municipalities in addressing some aspects of certain MCMs and only within the Valley Creek Watershed. Subtasks B.7 through B.12 describe the activities relating to NPDES Phase II MS4 activities.

B.7 - Public Education and Outreach Program

The MCM for public education and outreach program involves educating homeowners, business owners, and developers on the effects of nonpoint source pollution on receiving water bodies. The DEP has developed much of the necessary educational material. This task will include aiding the municipalities in educating the public.

Task Distribute educational materials that are available from the DEP’s website or other sources, as appropriate during the regular WPAC meetings.

Project Team Responsibilities

COUNTY - responsible for supplying available educational materials and distributing same at the WPAC meetings.

CONSULTANT - responsible for assisting the County.

Anticipated Product

The product will be a variety of existing educational materials on non-point source pollution and stormwater management related topics.

B.8 - Public Participation and Involvement

This MCM involves engaging the public, including developers and contractors and other stakeholders, in understanding and reducing the impacts of stormwater runoff in the watershed. Public participation and involvement will occur during the WPAC meetings. The Act 167 WPAC meetings will address this MCM, at least in part. The mailing list for the Valley Creek Act 167 Study will be made available to the municipalities in the watershed in electronic format. Information on relevant stormwater management topics will be provided at the WPAC meetings (see Task B7).

Tasks

Information on relevant stormwater management topics will be made available at Act 167 WPAC meetings. The scope of work for WPAC process is discussed in Stage C in this report.

Project Team Responsibilities

COUNTY - Responsible for coordinating WPAC meetings.

CONSULTANT - Responsible for attending WPAC meetings and supporting County’s coordination efforts, and assisting in obtaining relevant educational materials .

B.9 - Illicit Discharge Detection and Elimination

This MCM requires mapping of municipal outfalls and IDD&E. This MCM is outside the scope of this study and will be left to the Municipalities to address.

B.10 - Construction Stormwater Management

This MCM addresses stormwater management during construction phases. The DEP’s NPDES Phase II – Construction Activities (PAG-2 Permit Program) and PA Chapter 102

already address thisMCM. This MCM is outside the scope of this study and will be left to the municipalities to address.

B.11 - Post-Construction Stormwater Management

The MCM for post-construction stormwater management involves enacting an ordinance that meets the requirements of NPDES Phase II regulations that is consistent with the DEP’s model ordinance, coordinating review of the post-construction BMPs simultaneously with erosion and sedimentation control plans, and ensuring long-term operation and maintenance of the BMPs. The Phase II Study will address the post- construction stormwater management ordinance component of this MCM.

Tasks

The Phase II Study will develop a post-construction stormwater management ordinance that includes components found necessary based on the Phase II analyses and WPAC input. The development of the ordinance will include consideration of other available ordinances (DEP’s NPDES Phase II model ordinance, existing municipal ordinance in the watershed, nearby recently completed Act 167/NPDES Phase II ordinances, etc.). The final ordinance will also be coordinated with and consistent with the DEP’s NPDES Phase II model ordinance and the requirements of Act 167.

Project Team Responsibilities

COUNTY - responsible for coordinating WPAC, consultant and County efforts to: • Determine the components to be included in the Act 167 ordinance, to address NPDES Phase II requirements • Evaluate ordinance language provided by the DEP and from other local and relevant ordinances (i.e., nearby recently completed Act 167 ordinances, etc.)

CONSULTANT - responsible for • Drafting and revising the Act 167 ordinance document • Assisting in coordination and evaluation of ordinance language and identification of components needed to address NPDES Phase II requirements

Anticipated Product

The product will be a comprehensive post-construction ordinance, which addresses both Act 167 and NPDES II requirements as appropriate.

B.12 - Pollution Prevention and Good Housekeeping for Municipal Operations

This MCM involves municipal pollution prevention and good housekeeping measures on municipal properties. This MCM is outside the scope of this study and will be left to the Municipalities to address.

Stage C - Public/Municipal Participation

Coordination efforts and/or activities will continue throughout the duration of the project and will be organized to include the necessary eight (8) meetings with the Counties, Consultant, and DEP.

A Watershed Plan Advisory Committee (WPAC) committee will be established to consist of the public, municipal governments (elected officials, engineers, and solicitors), Valley Forge National Historic Park, Counties, conservation districts and other interest groups such as watershed associations. Progress meetings will be conducted for the WAPC informing them of the progress of the Plan. Two subcommittees will be developed as part of the planning process 1) Municipal Engineers Committee (MEC); and 2) the Legal Advisory Committee (LAC).

The WPAC meetings will be held to provide information on the planning process and to receive advice from the WPAC membership to assure that the plan fits their needs, and to solicit valuable information through the distribution of the questionnaire for technical and institutional data. The advisory role of the WPAC during the development of the plan is vital to the ultimate adoption and implementation processes.

The MEC will consist of the municipal engineer from each municipality within the watershed (and any invited engineering, technical, or scientific individuals). The MEC will provide a technical forum to assist the County and Consultant during the preparation of the technical portions of the plan by evaluating the watershed modeling and water quality efforts and establishing overall technical standards.

The LAC will include the solicitors representing every municipality in the watershed. A meeting with the LAC will be convened one time to educate the municipal solicitors on the ordinance adoption and implementation requirements of the plan and to receive comments and direction in the finalization of the model ordinance.

The County will develop and conduct a stormwater quality/BMP workshop for the municipalities and municipal engineers within the watershed as part of a regularly scheduled WPAC meeting. The presentation of the workshop will reflect recent developments regarding the PA DEP Stormwater Best Management Practices (BMP) Manual (currently under development). The workshop will contain one or more examples showing the design and construction of BMPs, including design calculations.

Table 3 describes the proposed WPAC, MEC, and LAC meetings and public hearing schedules as well as the purpose of each meeting. Many of these meetings may be combined depending on timing of the completed tasks to aid in communication and efficiency of the project.

TABLE 3

WPAC MEETING TOPICS AND SCHEDULE

Meeting Purpose of Meeting Meeting Schedule WPAC 1 Phase II Start-up Meeting - to introduce the municipalities to Beginning of the the Phase II planning process and to establish the degree of project critical municipal involvement needed throughout the study. To present the data collection questionnaire and request assistance in gathering the required information. WPAC 2 To review the project status, the data questionnaire results, Subsequent to Stage A the prepared maps, and the institutional data (ordinance matrix), to solicit any additional comments or concerns from municipalities with respect to watershed data items, and to provide an overview of runoff problems in the watershed and the “cause and effect” of development on stormwater runoff. MEC 1 To review technical aspects of the plan, model Part way into Stage B selection/setup, initial modeling runs, and calibration efforts and to solicit ideas on technical standards and water quality issues. MEC 2 To review final modeling runs and determine final technical End of Stage B standards for water quantity and quality. WPAC 3 To present technical modeling results, to present technical After Stage B, MEC 2 standards and criteria for the watershed, and to discuss water quality issues and preliminary ordinance provisions for the municipalities (general and overall). WPAC 4 To present the draft plan and review municipal comments. Subsequent to draft (Initial draft sent to municipalities prior to the meeting.) preparation and WPAC 3 LAC To inform the municipal solicitors on the ordinance adoption After WPAC 3 and implementation requirements of the plan and to receive comments and direction in the development of the model ordinance. Stormwater To inform municipal officials, developers, and engineers on In conjunction with a Quality/BMP BMP construction techniques and implementation. The WPAC meeting Workshop purpose of this workshop is to acquaint municipal officials, engineers, and developers with the Plan and to provide them information regarding the engineering, economic, and other benefits resulting from the use of nonstructural implementation techniques. Consultant will coordinate content of the workshop with the DEP and County staff. Consultant will prepare the workshop handout and presentation materials that may include items such as maps, graphs, and handouts. County will arrange for the the facility and other logistics. Final To review comments from the WPAC, LAC, and MEC, to Following BMP WPAC present the final draft, and to review implementation. workshop Public Hearing To conduct the hearing as discussed in Stage D and as Upon completion of the required by Act 167 to present the final plan to the public. Final Draft Plan

In addition to the topics covered in Table 3, the Consultant will present one or more of the following implementation techniques at each WPAC meeting:

Nonstructural Stormwater Management Techniques

• Performance Zoning (if applicable) • Disconnected Impervious Area • Conservation Easements • Riparian Buffer Zones • Floodplain Overlay Districts • Cluster Development • Tree Planting

Infiltration

• Various Infiltration Facilities

Streambank Erosion Protection

• Streambank Restabilization and Revegetation • Restoration • Runoff volume reduction

Water Quality Management

• Stormwater Treatment Wetlands • Bioremediation Filters • Water quality inlets/inserts

Innovative Stormwater Management

• Conservation Design • Low Impact Development

Grant/Funding Programs for Specific Problem Areas

The subject matter may change as a result of issues identified in the WPAC meetings. This task will also involve the production and distribution of periodic Plan progress reports (updates) to the WPAC members, municipal officials, interest groups, and the public on the program and issues of the plan. Such updates will be provided in progress report format at least three times during the plan development process.

Project Team Responsibilities

COUNTY - responsible for: • Conducting activities necessary for coordinating and communicating with WPAC, MEC and LAC • Identifying and finalizing the WPAC, MEC, and LAC members • Providing logistical and facility arrangements for all WPAC, LAC, and MEC meetings • Preparing and distributing pre-meeting materials, agendas, meeting handouts, and meeting summaries (minutes) • Preparing and distributing three progress reports to WPAC

CONSULTANT - responsible for: • Supporting the County in coordination and communication activities with WPAC • Attending all WPAC, LAC, and MEC meetings • Preparation of committee meeting agendas, technical presentations (including graphics) • Prepare and present at each WPAC meeting a presentation on implementation techniques • Assist in addressing any technical, legal, and/or institutional issues raised by the WPAC and its subcommittees

Anticipated Product

The product will include WPAC correspondence, and meeting agendas, summaries (minutes), and handouts from the committee meetings, hardcopies of any technical topic presentation handouts/materials, and three progress reports.

Stage D - Plan Preparation and Implementation

The product of Phase II will be a truly Integrated Stormwater Management Plan including standards and criteria incorporated into a model ordinance which addresses water quantity, peak flows, infiltration requirements, water quality, and streambank erosion. The results will take into account the water quality and FGM assessment.

D.1 - Plan Report Preparation

Various components of the plan will be completed and incorporated into a draft Plan for distribution to the WPAC for review and then a Final Plan that will also be distributed to the WPAC. The Plan Report will be a blueprint for the future and recommendations in the report will build off of the recommendations in Watersheds and related documents and will provide the framework for “the next steps” for managing the watershed for sustainability. Components of each previous task will be included or at least referred to in the plan. In this way the plan shall contain such provisions as are reasonably

necessary to manage stormwater such that storm runoff from development or activities in each municipality within the watershed shall not adversely affect health, safety, and property in other municipalities within the watershed and in basins to which the watershed is tributary. In addition, the plan shall consider and be consistent with other existing municipal, county, regional, and state environmental and land use plans. The plan shall include the following:

• A description of the hydrologic characteristics of the watershed, the present and future land uses and their impacts on runoff, stormwater collection systems and their impacts on runoff, the available runoff control techniques and their efficiencies in the watershed, a list of significant obstructions, and a justification of their classification and available floodplain information. The available floodplain information will either be included in the plan or their sources referenced.

• Based upon the results of the watershed modeling, the technical evaluation will result in the criteria and standards governing the use of stormwater management controls throughout the watershed. An important aspect of the technical components of the plan will be the delineation of areas which should (and areas that should not) use stormwater detention to reduce peak flows. This determination will be made based upon an evaluation of subarea contributions to peak flows at the identified critical drainage points throughout the entire watershed. Each of the stormwater management alternatives as discussed earlier will be incorporated in the plan as appropriate, based upon the modeling results. Peak discharge tables will be compiled for the critical drainage points from the computer runs involved in the modeling effort.

• The tables for the rainfall depths for various frequency durations which are computed as part of the hydrologic modeling.

• Detailed flood insurance studies will be obtained and floodplain limits plotted for areas where available. The flood insurance studies will also be utilized to aid in flow comparison and determine obstructions. Where detailed flood control engineering plans for proposed remedial measures are available from municipal, County, or private agencies, a summary analysis and evaluation of those plans will be included in the Stormwater Management Plan. Where detailed plans are not available, preliminary recommendations relating to such measures will be provided.

• Recommendations for solutions to the existing drainage problems. Since Act 167 is not intended to solve existing problems, but to prevent their aggravation and also prevent other future problems, these recommendations for solutions to existing problems that are found to be relevant to the Plan will only be conceptual in nature, indicating the type of approach needed and inter-municipal cooperation issues. Sketch plans 52

will be developed for the highest two ranked priority sites and a surveying and engineering design cost estimate developed for each suitable for use in pursuit of funding (i.e., submission to DEP for Growing Greener grant, etc). This will be coordinated with the results of the FGM assessment results. Highest priority sites to be addressed may include stormwater facility repairs, retrofits, stream restoration projects, and or other.

• Recommendations for new regional drainage facilities to prevent future problems due to new development and a discussion regarding municipal arrangements for funding the projects.

• Priorities for implementation. The conclusions and recommendations of the plan will be summarized. Recommended actions will be listed according to agency, municipality, or individual responsible for each action. Priority of recommended actions would be based on chronological order, importance, hydrologic significance, or other factors as may be appropriate.

• As a part of the implementation strategy for the plan, specific steps and/or procedures will be established for pursuing and completing the necessary updates of the plan as required by Act 167. Specific circumstances that will “trigger” a decision to update will be identified and described in the plan document. For example, land development circumstances (such as major changes in the type and/or amount of proposed land development and in excess of that which was assumed for the preparation of the original plan) will be identified as reasons for pursuing an update of the plan prior to the required 5-year time frame identified in Act 167.

• The model ordinance.

• Any other items mentioned in this Scope of Study.

The preliminary outline for the plan is as follows:

Section I - Introduction including connection with Chester County’s Watersheds Plan and the Fluvial Geomorphology watershed assessment results.

Section II - Act 167 Watershed Level Stormwater Management Planning and Implementation

Section III - Watershed Characteristics • Present Land Use • Projected Land Developments

• Significant Obstructions • Floodplain and Drainage Problems • Proposed Solutions to and Funding for Existing Problems • Stormwater and Flood Management Systems

Section IV - Watershed Technical Analysis – Modeling

• Present/Ultimate Land Development Impacts on Storm Runoff

Section V - Modeling Results Interpretation and Development of Technical Standards and Criteria for Control of Stormwater Runoff

Section VI - Runoff Control Techniques and Their Efficiencies

Section VII - Existing Municipal Ordinance Information

Section VIII - Development of Model Stormwater Ordinance Provisions

Section IX - Priorities for Implementation of Technical Standards and Criteria

Section X - Plan Review Adoption and Updating Procedures

PLATES/FIGURES:

• a base map showing the watershed delineation and political subdivisions, roadway network, and the location as referenced to the County

• predevelopment land use

• existing land use

• future land use

• geology, karst areas, sinkholes and wells

• generalized soils, hydrologic soil groups, soils erodibility

• wetlands • development and floodplains

• stream profiles

• watershed subareas used for hydrologic analysis including information on applicable management strategies

• stream obstructions, flooding, and drainage problem areas

• areas where storm sewer networks exist (if available)

• additional information as determined by the County

TABLES:

• runoff characteristics of the watershed

• rainfall values for various frequency durations

• peak flow values at points of interest for a high intensity, short duration and mean annual 1-, 2-, 5-, 10-, 25-, 50-, and 100-year storm events for various durations and for present and future conditions

• subareas and corresponding management strategy information

APPENDICES:

• a list (or table) of all obstructions including their locations, sizes, calculated capacities, and any particular information which may seem helpful to the use of the plan

• recommended design storm(s)

• any special information concerning stormwater control facilities, BMPs, and other issues

Project Team Responsibilities

COUNTY - responsible for: • Providing support in the preparation of draft report. • Distribute draft report to WPAC members for review and receive and relay review comments to consultant. • Provide support in preparation of final plan document. • Distribute final plan to WPAC. • Also responsible for the overall review and approval of the plan documents and publication of the final plan.

CONSULTANT - responsible for: • Coordination and preparation of the draft Phase II project report, including model ordinance and sketch plans and engineering design cost estimates for two high priority sites. • Revise draft report to incorporate County and WPAC comments and prepare and provide final report. • Prepare the technical results, tables, maps and charts for presentation in the final plan document.

Anticipated Product

The product will be the final Integrated Stormwater Management Plan for the Valley Creek Watershed. The final plan will be prepared in three parts, Volume I - Executive Summary and Volume II - a document containing the full text and descriptions of the various plan contents as described above and Volume III, the technical Appendix which will contain the data collection forms, modeling results, technical analyses, etc. The report and data, including GIS files, will be supplied by the Consultant to the County in paper and digital format.

D.2 - Plan Adoption

The County will print 37 copies of the draft plan and transmit them to the official planning agency and governing body of each involved county, municipality, each member of the WPAC, and the DEP by official correspondence. The involved municipalities, WPAC, and DEP will then review the plan. Their review will include an evaluation of the plan’s consistency with other plans and programs affecting the watershed. The reviews and comments will be submitted to the County by official correspondence. The review comments will be received, tabulated, and responded to appropriately, and the plan will be revised accordingly.

A WPAC meeting will be held to identify specific ordinance changes and method(s) of incorporation of the standards and criteria into the municipalities’ existing ordinance framework. The County and Consultant will be available to answer municipal questions. In addition, the meeting(s) can also serve to provide clarification of any remaining questions or concerns that the municipality may have concerning the implementation of the plan.

Each County will hold a public hearing concerning the plan. A notice for the public hearing will be published at least two weeks before the hearing date. The public hearing notice will contain a brief summary of the principal provisions of the plan and a reference to the places within each affected municipality where copies of the plan may be examined or purchased at cost. The comments received at the public hearing will be reviewed by the County, and appropriate modifications in the plan will be made if applicable.

For the purpose of adoption, a resolution of adoption must be passed by official vote of the governing bodies of Chester and Montgomery Counties. The resolution will have to be carried by an affirmative vote of at least a majority of the members of the governing body and should refer expressly to the maps, charts, textual matter, and other materials intended to comprise the plan. This action will then be recorded on the adopted plan.

The County will then submit to the DEP a letter of transmittal and three copies each of the adopted plan, the review by the official planning agency and governing body of each municipality, the County Planning Commissions, regional planning agencies (Section 6(c) of Act 167), public hearing notice and minutes (Section 8(a) of Act 167), and the resolution of adoption of the plan by the Counties (Section 8(b) of Act 167). The letter of transmittal will state that the Counties have complied with all procedures outlined in Act 167 and will request that the DEP approve the adopted plan. Subsequent to DEP approval of the plan, 39 final copies of the plan will be printed and distributed.

All backup material including hydrologic and hydraulic analyses of the watershed will be retained at the County offices for future use during the future plan update or any other reference.

Project Team Responsibilities

COUNTY – responsible for: • Coordinate and conduct public hearing and final Chester County adoption • Coordinating with Montgomery County regarding the Montgomery County public hearing and adoption • Assist the Consultant with establishment of priorities for implementation of actions identified in the plan and update schedule • Print and distribute copies of final plan to WPAC members • Transmit final submission package to DEP for final approval

CONSULTANT - responsible for: • Support to the County during the plan adoption process • Identification of priorities for implementation of actions identified in the plan • Establish a Plan update schedule for inclusion in the Plan, in conjunction with County.

Anticipated Product

The products of this task will include the WPAC copies of final plan, documentation of final adoption by Chester and Montgomery Counties, County’s submission packet to the DEP.

V. LEVEL OF EFFORT, COST ESTIMATE, AND PROJECT ADMINISTRATION

This task covers the administrative work required to initiate the Agreement between the DEP and Chester County working in cooperation with Montgomery County (with Chester County taking the lead as in the Phase I Scope of Study). It involves initiating contracts between the County and the Consultant to lay out a framework for the critical coordination aspect with the municipalities. Activities include defining the framework for accomplishing various elements of the plan, scheduling of time, defining the budget, progress reporting procedures and formats, and finalizing the work schedule. It will also include the preparation for and holding of the Phase II start-up meeting with the DEP, Chester and Montgomery Counties, and the Consultant.

The previous stages were analyzed to determine the required level of effort, both by the County and the Consultant, to complete each stage. The estimated staff time for each project team member is presented in Appendix D. The cost estimates presented in Appendix D reflect the specific work step descriptions presented in Section IV, including the use of the particular procedures, methodologies, and estimates of direct costs that will be incurred.

Project Team Responsibilities

COUNTY - responsible for overall administration of the project, including: • Negotiating and executing the Phase II Grant Agreement with the DEP • Negotiating and executing a contract with a Consultant, • The establishment of the project coordination roles and procedures, • Finalize scope of work and detailed budget for Phase II • Finalize project scheduling, • Project team coordination meetings, • Grant and contract administration activities (invoice processing, progress reports, close-out, etc.).

CONSULTANT - responsible for:

• Negotiating and executing a contract with the County, • Assist County in the establishment of the project coordination roles and procedures, • Assist County in finalizing scope of work and detailed budget for Phase II • Assist County in finalizing project scheduling, • Attend project team coordination meetings, • Other contract administration activities (progress reports, etc.).

Anticipated Product

The anticipated products will be a summary or notes of project initiation and team coordination meetings. In addition, the finalized scope of work along with the associated budget and schedule will be documented for review by the DEP and for use as a project management guide. A project correspondence file will also be developed and organized and will be maintained throughout the total project duration. Progress reports will be prepared and submitted to PADEP.

VI. PROPOSED PLAN DEVELOPMENT SCHEDULE

A schedule has been developed for completing the work program described herein (Figure 9). It is felt that the developed time frame for this project is sufficient for all of the necessary contacts and follow-up correspondence, for each of the seventeen municipalities, and for the applicable tasks.

FIGURE 9

WORK SCHEDULE

MONTH 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 STAGE A BI BII C D

VII. CONSULTANT CAPABILITIES

The Consultant who assisted with the preparation of this Act 167 Phase I – Final Report, Scope of Study for Phase II for the Valley Creek Watershed and is anticipated to conduct the Phase II Study is Borton-Lawson Engineering of Wilkes-Barre and Bath, Pennsylvania.

A summary of specific experience related to watershed stormwater management modeling and planning is presented below. The detailed resumes of the individuals who may work on Phase II of the plan will be submitted to the DEP subsequent to the signing of the Phase II Agreements by the County and the DEP.

• Hydrologic Modeling

Borton-Lawson Engineering has extensive project experience in modeling study follow-up efforts, including stormwater management design projects.

Borton-Lawson Engineering has developed various hydrologic and hydraulic reports to determine waterway openings required for bridges and other obstructions.

• Stormwater Management Planning

Borton-Lawson Engineering has extensive experience in detailed planning and design for stormwater management aspects of land development projects (residential, commercial, and industrial).

Borton-Lawson Engineering has been the project Consultant for the following Act 167 Scope of Studies (Phase I):

Toby Creek Luzerne County Mill Creek Luzerne County Wapwallopen Creek Luzerne County Solomon Creek Luzerne County Conococheague Creek Franklin County Bobs & Dunning Creek Bedford County Chest Creek Cambria County Darby and Cobbs Creek Delaware County Crum Creek Delaware County Bull Run Update Union County White Deer Creek Union County Little Conemaugh River Update Cambria County McMichaels & Brodhead Creek Update Monroe County Wyalusing Creek Susquehanna County Shobers Run Bedford County Stonycreek River Cambria County Nescopeck Creek Luzerne County Maiden Creek Berks County Sacony Creek Update Berks County Schuylkill River Berks County

Borton-Lawson Engineering has been project Consultant for the following Act 167 Stormwater Management Plans (Phase II):

Toby Creek Luzerne County Mill Creek Luzerne County Wapwallopen Creek Luzerne County Solomon Creek Luzerne County Bowman’s Creek Wyoming County

Upper Mahoning Creek Jefferson County Tulpehocken Creek Berks County Conococheaque Creek Franklin County Bobs & Dunning Creek Bedford County Chest Creek Cambria County Darby and Cobbs Creek Delaware County East Branch Perkiomen Creek Bucks County Delaware River (South) Bucks County Little Conemaugh River Update Cambria County McMichaels & Brodhead Creek Update Monroe County Maiden Creek Berks County Sacony Creek Update Berks County Wyalusing Creek Susquehanna County Neshaminy Creek Update Bucks County Schuylkill River Berks County Crum Creek Delaware County

For the Phase II project, the following shall apply:

• Training and Education

Project Engineers shall be licensed by the State of Pennsylvania.

Project Engineers shall have specific training in hydrologic and hydraulic modeling and water quality assessment.

• Computer Facilities

The Consultant shall perform all calculations using software packages approved by the DEP.

All GIS information shall be compiled in an ESRI Arc Map or compatible format. GIS files shall be supplied in the State Plane, PA South coordinate system North American Datum (NAD) 1983. All GIS deliverables shall meet or exceed PASDA minimum standards for metadata documentation.

VIII. REFERENCES

References Cited

1. CH2MHILL, 1998, Pennsylvania Handbook of Best Management Practices for Developing Areas published for Pennsylvania Association of Conservation Districts, Inc.; Keystone Chapter, Soil and Water Conservation Society; DEP; Natural Resources Conservation Service

2. Chester County Board Of Commissioners, 2002, Chester County, Pennsylvania Water Resources Compendium, reported sited from Sloto, 1994

3. Chester County Planning Commission , 1996, Landscapes, Managing Change in Chester County 1996-2020, Comprehensive Plan Policy Element

4. Chester County Water Resources Authority, 2002, Watersheds, An Integrated Water Resources Management Plan for Chester County, Pennsylvania and its Watersheds

5. Chester County Water Resources Authority, 2002, Valley Creek Watershed Action Plan

6. Emerson, C.H., 2003, Evaluation of the Additive Effects for Stormwater Detention basins at the Watershed Scale, Thesis, Drexel University

7. Heritage Conservancy, 2001, Riparian Buffer Assessment of Southeastern Pennsylvania

8. Maryland Department of the Environment, 2000, Maryland Stormwater Management Manual

9. National Park Service, Valley Forge National Historic Park, (cited March 2004), Draft Valley Creek Restoration Plan/Environmental Assessment

10. Natural Resources Trustee Council, undated (circa March 2004), for Valley Creek Restoration Plan/Environmental Assessment

11. Pennsylvania Fish and Boat Commission, February 2002, List of Pennsylvania Class A Wild Trout Streams

12. Pennsylvania Fish and Boat Commission, February 2002, Surveyed Streams Having Verified Trout Reproduction

13. Reif, A.G, 2002, Assessment of Stream Conditions and Tends in Biological and Water-Chemistry Data from Selected Streams in Chester County, Pennsylvania, 1981-97, USGS, New Cumberland, PA.

14. Sloto, R.A., 1990, Chester County Water Resources Authority 2001

15. Sloto, R.A., 1994, Geology, Hydrology, and Ground-Water Quality of Chester County, Pennsylvania, USGS

Additional References

1. Advanced Biology Students of Conestoga Sr. High School, March, 1973, “Land Use Model for Predicting he Environmental Impact of Future Urbanization on the Valley Creek Watershed with Recommendations for Communities within the Watershed”

2. Bailey, J.F., Thomas, W.D., Wetzel, K.L., Ross, T.J., 1989, Estimation of Flood- Frequency Characteristics and the Effects of Urbanization for Streams in the Philadelphia, Pennsylvania Area, U.S. Geological Survey WRIR 87-4194.

3. Balmer, W.T., and D.K. Davis, 1996, U.S. Geological Survey, Groundwater Resources of Delaware County, Pennsylvania, Water Resource Report 66.

4. Cahill Associates and Compbell Thomas & Company, 2002, Draft Darby Creek Watershed River Conservation Plan.

5. Cahill Associates, 1999, Comprehensive Stormwater Management Ordinance, Prepared for Rockaway River Watershed Cabinet Sustainable Watershed Management Program.

6. Chester County Health Department Stream Quality Monitoring Program Data: August 1990 to April 2003 (unpublished).

7. Chester County Planning Commission, 1981, Urban Stormwater Runoff – Problem Area Inventory.

8. Chester County Planning Commission, 1997 & 1999, Community Planning Handbook Volume 1 and Volume 2.

9. Chester County Water Resources Authority, Chester County Planning Commission, Camp Dresser and McKee, and Gaadt Perspectives, LLC, 2002, Valley Creek Watershed Action Plan, Prepared as a Component of Chester County, Pennsylvania Water Resources Compendium.

10. Chester County Water Resources Authority, et al., 2001, Chester County, Pennsylvania Water Resources Compendium.

11. Chester County Water Resources Authority, March 2004, Post Construction Stormwater Management Ordinance (draft)

12. Delaware County Planning Department and Chester County Planning Commission, 2001, Act 167 Stormwater Management Plan Chester Creek Watershed.

13. DEP, Commonwealth of Pennsylvania, September 20, 2002, Comprehensive Stormwater Management Policy, Document number 392-0300-002,

14. DEP, Commonwealth of Pennsylvania, May 14, 1985, Stormwater Guidance and Model Ordinances, Document number 392-0300-001

15. DEP, Commonwealth of Pennsylvania, August 2, 2003, Guidance on MS4 Ordinance Provisions, document number 392-0300-003

16. Draft Valley Creek Restoration Plan/Environmental Assessment, Unpublished data.

17. Ehlke, M.H., and L.A. REED, 1999, Comparison of Methods for Computing Streamflow Statistics for Pennsylvania Streams, U.S. Geological Survey WRIR 99-4068.

18. Emerson, C.H., 2003, Evaluation of the Additive Effects for Stormwater Detention basins at the Watershed Scale, Thesis, Drexel University

19. Geyer, Alan R. and J. Peter Wilshusen, 1982, Engineering Characteristics of the Rocks of Pennsylvania, 2nd edition, Report Number Environmental Geology Report 1, Pennsylvania Geological Survey, 300 p.

20. Heritage Conservancy, 2001, Riparian Buffer Assessment of Southeastern Pennsylvania

21. Keystone Stream Team and Alliance for the Chesapeake Bay, 2003, Guidelines for Natural Stream Channel Design for Pennsylvania Waterways, (www.canaanvi.org/nscdguidelines/)

22. McCandless, T.L. and R.A. Everett, 2002, US Fish & Wildlife Service: Chesapeake Bay Field Office, Maryland Stream Survey: Bankfull Discharge and Channel Characteristics of Streams in the Piedmont Hydrologic Region, CBFO- S02-01.

23. Moore, C.R., 1987, USGS Water-Resources Investigations Reports 85-4177, Determination of Benthic-Invertebrate Indices and Water-Quality Trends of Selected Stream in Chester County, Pennsylvania, 1969-80.

24. PADEP, 2001, Comment and Response Document for Post Construction Storm Water Management in the Valley Creek Exceptional Value Watershed, DEP web site. http://www.dep.state.pa.us/dep/deputate/fieldops/se/Stormwater/ValleyCreek/PA DEP_PCSW_QA_02-08-02_Final1_Web.doc, accessed March 14, 2004. 64

25. PADEP, accessed March 14th, 2004, Online Valley Creek PCSWM PowerPoint Presentation, PADEP website,

http://www.dep.state.pa.us/dep/deputate/fieldops/se/Stormwater/ValleyCreek/PC SWM%20slideshow%20web.ppt

26. PADEP, accessed March 14th, 2004, Post-Construction Storm Water Control in the Valley Creek Exceptional Value (EV) Watershed, DEP website,

http://www.dep.state.pa.us/dep/deputate/fieldops/se/Stormwater/valleycreek.htm

27. PADEP, accessed march 14th, 2004, Valley Creek Settlement Agreement, 2000, Docket No. 2000-068-MG. PADEP web site,

http://www.dep.state.pa.us/dep/deputate/fieldops/se/Stormwater/ValleyCreek/VC Csettlement.pdf

28. DEP, 2001, Commonwealth of Pennsylvania - PA Code: Title 25. Environmental Protection – Chapter 93. Water Quality Standards.

29. DEP, Bureau of Engineering, February 1973, Hydrologic Study of Valley Creek at Valley Forge State Park.

30. Reif, A.G, 2002, Assessment of Stream Conditions and Tends (trends?) in Biological and Water-Chemistry Data from Selected Streams in Chester County, Pennsylvania, 1981-97, USGS, New Cumberland, PA.

31. Reif, A.G., 1999a, Physical, Chemical, and Biological Data for Selected Streams in Chester County, Pennsylvania, 1981-94, USGS, Lemoyne, PA.

32. Reif, A.G., 1999b, Physical, Chemical, and Biological Data for Selected Streams in Chester County, Pennsylvania, 1995-97, USGS, Lemoyne, PA.

33. Reif, A.G., 1999c, USGS Data from the Valley Creek Basin, USGS, Lemoyne, PA.

34. Reif, A.G., U.S. Department of the Interior, U.S. Geological Survey. (2003). USGS Data from the Valley Creek Basin, Malvern, PA.

35. Sloto, R.A., 1994, Chester County Water Resources Authority, Geology, Hydrology, and Groundwater Quality of Chester County, Water Resource Report 2, West Chester,

36. Sloto, R.A., Effects of Urbanization on Storm Runoff Volume and Peak Discharge of Valley Creek, Eastern Chester County, Pennsylvania, U.S. Geological Survey WRIR 87-4196.

37. Sloto, R.A., Geohydrology and Simulation of Ground-Water Flow in The Carbonate Rocks of The Valley Creek Basin, Eastern Chester County, Pennsylvania, U.S. Geological Survey WRIR 89-4169.

38. Steffy, Luanne Y., 2003, “Qualifications of the Impacts of urbanization and land use on fish communities in Valley Creek Watershed, Chester County, PA” (M.S. diss., Drexel University.)

39. The Advanced Biology Students of Conestoga High School, Tredyffrin-Easttown School District, under the direction of Dr. Ralph D. Heister, Jr., 1983, Valley Creek Watershed Revisited.

40. The Advanced Biology Students of Conestoga High School, Tredyffrin-Easttown School District, under the direction of Dr. Ralph D. Heister, Jr., 1979, The Impact of the Installation of Sewers on Valley Creek and It’s Surrounding Watershed.

41. U.S. Department of Agriculture, (1963) Revised (1972), Soil Conservation Service (sic NRCS), Soil Survey of Delaware and Chester Counties, PA

42. U.S. Department of Commerce, Bureau of the Census, 1992, Census of Agriculture, Volume 1 Geographic Area Series, Part 83 Pennsylvania state and County Data.

43. U.S. Geological Survey, 1975-2001, Water resources data for Pennsylvania, 1974-2001--volume 1: U.S. Geological Survey Water Data Reports PA-74-1 to PA-01-1 (published annually).

44. U.S. Geological Survey, 1975-2001, Water resources data for Pennsylvania, 1974-2001--volume 1: U.S. Geological Survey Water Data Reports PA-74-1 to PA-01-1 (published annually).

45. U.S. Geological Survey, 1981-97, Assessment of Stream Quality Using Biological Indices at Selected Sites in the Schuylkill River Basin, Chester County, Pennsylvania, in cooperation with the Chester County Water Resources Authority, December 2002, SGS Fact Sheet FS-114-02

46. U.S. Geological Survey, 1998, Effects of Urbanization on Storm-Runoff Volume and Peak Discharge of Valley Creek, Eastern Chester County, Pennsylvania”, Water-Resources Investigations Report 87-4196, 32 p *

47. U.S. Geological Survey, 1990, Geohydrology and Simulation of Ground-Water Flow in the Carbonate Rocks of the Valley Creek Basin, Eastern Chester County, Pennsylvania, Water-Resources Investigations Report 89-4169, 60 p *

48. U.S. Geological Survey, 2000, Physical, Chemical, and Biological Data for Selected Streams in Chester County, Pennsylvania, 1995-97”, Open-File report 00-238, 147 p.

49. U.S. Geological Survey, 2000, Physical, Chemical, and Biological Data for Selected Streams in Chester County, Pennsylvania, 1981-94, Open-File Report 99-216.

50. U.S. Geological Survey, 2003, Assessment of Stream Conditions and Trends in Biological and Water-Chemistry Data From Selected Streams in Chester County, Pennsylvania, 1981-97, Water-Resources Investigations Report 02-4242, 77 p. *

51. U.S.E.P.A, [cited 22 January 2004]: “Percent of Impaired Waters: 1998 (Region 3):” available from http://www.epa.gov/iwi/1999sept/iv22_r3map.html.

52. U.S.E.P.A, [cited 8 April 2004]: “Detailed TMDL Report”: available from http://oaspub.epa.gov/pls/tmdl/waters_list.tmdl_report?p_tmdl_id=6828.

53. U.S.E.P.A, [cited 8 April 2004]: “Detailed TMDL Report”: available from http://oaspub.epa.gov/pls/tmdl/waters_list.tmdl_report?p_tmdl_id=6827.

54. Unicorn Management Consultants, LLC, 2004, Final (100%) Design for Remedial Action Non-Rail Yard Site Property (Stream Sediment Portion of the Remedy), Paoli Rail Yard Superfund Site, Chester County, Paoli, Pa.

55. University of Virginia, Charlottesville, VA, (March 1, 1999). [Cited January 29, 2004], “The Stream Study (based on material developed by the Save Our Streams Program of the Izaak Walton League of America” [Online] Available from http://www.people.virginia.edu/∼sos-iwla/Stream- Study/StreamStudyHomePage/SteamStudy.HTML

56. Unpublished Summary of Biological Monitoring of Benthic Macroinvertebrates of East Valley Creek Watershed, unpublished, Results from Chester County-U.S. Geological Survey Stream Conditions of Chester County Biological Monitoring Network.