South Branch Patapsco River Watershed Characterization Plan

Figure 1-1 South Branch Patapsco Watershed Location Map........................................................ 2 Figure 2-1 South Branch Patapsco Subwatershed Locations ......................................................... 6 Figure 2-2 South Branch Patapsco Watershed Topography and Slope Categories........................ 9 Figure 2-3 South Branch Patapsco Watershed Hydrological Soil Groups................................... 12 Figure 2-4 South Branch Patapsco Watershed Geology............................................................... 14 Figure 2-5 South Branch Patapsco Watershed Wetland Acreage ................................................ 17 Figure 2-6 South Branch Patapsco Watershed Floodplains ......................................................... 19 Figure 2-7 South Branch Patapsco Watershed Forest Cover........................................................ 21 Figure 2-8 South Branch Patapsco Watershed Green Infrastructure............................................ 23 Figure 3-1 South Branch Patapsco Watershed Land Use and Land Cover .................................. 27 Figure 3-2 South Branch Patapsco Watershed Priority Funding Areas ....................................... 29 Figure 3-3 South Branch Patapsco Watershed Zoning................................................................. 30 Figure 3-4 South Branch Patapsco Watershed Build-Out Parcels................................................ 31 Figure 3-5 South Branch Patapsco Watershed Impervious Surface Area .................................... 33 Figure 3-6 South Branch Patapsco Watershed Stormwater Management Facilities .................... 36 Figure 3-7 South Branch Patapsco Watershed Public Drinking Water Supply............................ 38 Figure 3-8 South Branch Patapsco Watershed Wastewater Service Area.................................... 41 Figure 3-9 South Branch Patapsco Watershed Protected Lands .................................................. 45 Figure 3-10 South Branch Patapsco Watershed Rural Legacy Area ............................................ 46 Figure 3-11 South Branch Patapsco Watershed Agricultural BMP Locations............................. 48 Figure 4-1 South Branch Patapsco Watershed Tier II Water Segments....................................... 51 Figure 4-2 Shannon Run Monitoring Station................................................................................ 53 Figure 4-3 South Branch Patapsco Watershed DNR MBSS Locations ....................................... 55 Figure 5-1 South Branch Patapsco Watershed Carroll County MBSS Locations........................ 65 Figure 5-2 South Branch Patapsco Watershed Targeted Ecological Areas.................................. 68 Figure 5-3 SCA Landowner Participation .................................................................................... 69 Figure 5-4 Most Commonly Identified Impacts ........................................................................... 70

List of Tables

Table 1-1 South Branch Patapsco Watershed’s Subwatershed Acreages ..................................... 3 Table 2-1 South Branch Patapsco Watershed Slope Categories................................................... 8 Table 2-2 South Branch Patapsco Subwatershed Hydrologic Soil Group Categories................ 11 Table 2-3 South Branch Patapsco Watershed Wetland Acreage ................................................ 16 Table 2-4 South Branch Patapsco Watershed Forest Cover........................................................ 20 Table 3-1 South Branch Patapsco Watershed Baseline and Current Land Cover....................... 26 Table 3-2 South Branch Patapsco Watershed Estimated Impervious Surface Area ................... 32 Table 3-3 South Branch Patapsco Watershed Stormwater Facility Types.................................. 34 Table 3-4 South Branch Patapsco Watershed NPDES Permits .................................................. 42 Table 3-5 South Branch Patapsco Watershed Protected Lands .................................................. 43 Table 4-1 Water Quality Parameters and Methods ................................................................... 52 Table 4-2 South Branch Patapsco Watershed DNR’s MBSS Chemical Results ........................ 56 Table 4-3 South Branch Patapsco Watershed DNR’s MBSS Chemical Results Summary........ 58

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Table 5-1 South Branch Patapsco Watershed DNR’s MBSS Index of Biotic Integrity ............. 60 Table 5-2 South Branch Patapsco Watershed Carroll County MBSS Benthic IBI ..................... 62 Table 5-3 Stream Corridor Assessment – Identified Impacts...................................................... 67 Table 5-4 Linear Feet of Inadequate Buffer and Stream Erosion................................................ 71

List of Appendices

Appendix A South Branch Patapsco Watershed Stormwater Management Facilities ................ 75 Appendix B Agricultural Best Management Practices ................................................................ 86

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List of Acronyms

BMPs

best management practices

COMAR Code of Maryland Regulations DNR EPA FEMA GIS
Maryland Department of Natural Resources United States Environmental Protection Agency Federal Emergency Management Agency geographic information system
HSG IBI hydrological soil group Index of Biotic Integrity
MBSS MDE NLCD
Maryland biological stream survey Maryland Department of the Environment National Land Cover Database
NPDES national pollution discharge elimination system

PFA

priority funding area

RTE SW rare, threatened or endangered stormwater
TMDL TSS USDA WLA total maximum daily load total suspended sediments United States Department of Agriculture wasteload allocation

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I.

Characterization Introduction

A.

Purpose of the Characterization

The South Branch Patapsco Watershed Characterization Plan is intended to provide a background on the hydrological, biological and other natural characteristics of the watershed as well as discuss human characteristics that may have an impact within the watershed. The information provided in this report as well as information gathered during the South Branch Patapsco Watershed stream corridor assessment (SCA) will be used as a tool to help direct the watershed implementation plan for the South Branch Patapsco Watershed. The implementation plan will be used to identify opportunities for water quality improvements within the watershed

as required by the County’s National Pollutant Discharge Elimination System (NPDES) permit,

and is designed to meet approved Total Maximum Daily Loads (TMDLs) for the South Branch Patapsco Watershed.

B.

Location and Scale of Analysis

The South Branch Patapsco Watershed is located in southern portion of Carroll County, Maryland. The South Branch Patapsco Watershed is within the Piedmont Plateau Province of Maryland. The Piedmont Plateau province is characterized by gentle to steep rolling topography, low hills, and ridges (MGS 2009). The watershed area within Carroll County covers 38,736 acres within eleven sub-watersheds. Figure 1-1 depicts the location of the South Branch Patapsco Watershed and the several subwatersheds within Carroll County. The South Branch Patapsco Watershed drains to the Patapsco River Lower North Branch, which is a tributary to the Chesapeake Bay. Table 1-1 displays the distribution of acreage between the subwatersheds within South Branch Patapsco Watershed. The analyses presented in this report are done at the subwatershed scale. This allows for restoration and preservation efforts to be focused on smaller drainage areas where efforts can be prioritized and more easily monitored.

1

Figure 1-1: South Branch Patapsco Watershed Location Map

2

Table 1-1: South Branch Patapsco Watershed’s Subwatershed Acreages

DNR 12-digit Scale
021309081031 021309081030 021309081029 021309081021 021309081023 021309081024 021309081028 021309081025 021309081022 021309081020 021309081026
Subwatershed Gills Falls Upper
Acres
3,118.40 4,243.17 3,781.73 2,306.82 8,007.30 1,442.79 3,169.38 4,116.38 1,953.15 1,430.57 5,166.27

38,735.95

Gills Falls Lower
Middle Run
Piney Run Lower Piney Run Main
Piney Run Tributary South Branch Patapsco
South Branch Patapsco River South Branch Patapsco River South Branch Patapsco River
Tuckers Branch

South Branch Patapsco Watershed Total Report Organization

This report is organized into six different chapters: