Christina Basin Watershed Plan August 2012 Table of Contents List of Terms ................................................................................................................................. 3 Executive Summary ...................................................................................................................... 4 Chapter 1: Introduction ............................................................................................................... 7 1.1 What Is a Pollution Control Strategy? ................................................................................................................. 7 1.2 Tributary Action Teams ....................................................................................................................................... 7 1.3 The Christina Basin Tributary Action Team Process .......................................................................................... 8 1.4 Christina Basin Tributary Action Team Public Forum ........................................................................................ 8 Chapter 2: The Christina Basin ................................................................................................ 11 2.1 A Unique Watershed.......................................................................................................................................... 11 2.2 Land Use ............................................................................................................................................................ 12 2.3 Population .......................................................................................................................................................... 15 2.4 Geology ............................................................................................................................................................. 16 2.5 Water Supply ..................................................................................................................................................... 16 2.6 Recreational Resources ...................................................................................................................................... 16 2.7 Historic and Cultural Resources ........................................................................................................................ 17 2.8 Economic Resources .......................................................................................................................................... 17 2.9 Ecological and Natural Functions ...................................................................................................................... 18 2.10 Watershed Organizations ................................................................................................................................. 19 Chapter 3: Water Quality and Total Maximum Daily Loads ................................................ 20 3.1 Water Quality Concerns .................................................................................................................................... 20 3.2 Nutrient Trends .................................................................................................................................................. 20 3.3 Dissolved Oxygen Trends .................................................................................................................................. 26 3.4 Bacteria Trends .................................................................................................................................................. 29 3.5 Total Suspended Sediment................................................................................................................................. 32 3.6 Stream Habitat and Biological Health of the Streams ....................................................................................... 34 3.7 Contaminated Substance Sites ........................................................................................................................... 36 3.8 Fish Consumption Advisories ............................................................................................................................ 37 3.9 Total Maximum Daily Loads in the Delaware Portion of the Christina Basin .................................................. 38 Chapter 4: Recommendations to Achieve the TMDLs ............................................................ 43 4.1 Background ........................................................................................................................................................ 43 4.2 Stormwater Recommendations .......................................................................................................................... 43 4.3 Open Space Recommendations ......................................................................................................................... 59 4.4 Wastewater Recommendations .......................................................................................................................... 79 4.5 Agriculture Recommendations .......................................................................................................................... 98 4.6 Education Recommendations .......................................................................................................................... 102 Chapter 5: Monitoring ............................................................................................................. 109 5.1 Christina Basin Water Quality Monitoring ...................................................................................................... 109 5.2 Stream Watch Technical Monitoring Program ................................................................................................ 110 Chapter 6: Economic Analysis ................................................................................................. 112 6.1 The Cost of Implementing the Christina Basin Pollution Control Strategy ..................................................... 112 6.2 The Benefits of the Christina Basin and Meeting the TMDLs ........................................................................ 121 6.3 Discussion of the Costs and Benefits of the Christina Basin ........................................................................... 126 Chapter 7: Analysis for TMDL Achievement ........................................................................ 127 References .................................................................................................................................. 136 List of Terms BMP – Best Management Practice CRP – Conservation Reserve Program CSO – Combined Sewer Overflow CSS – Combined Sewer System DelDOT – Delaware Department of Transportation DNREC – Delaware Department of Natural Resources and Environmental Control DO – Dissolved Oxygen EQIP – Environmental Quality Incentives Program ERU – Equivalent Residential Unit ESU – Equivalent Stormwater Unit GAMN – General Assessment Monitoring Network GIS – Geographic Information Systems HOA – Homeowner Association LID – Low Impact Development LIP – Landowner Incentive Program LTCP – Long-Term Control Plan LUST – Leaking Underground Storage Tank MGD – Million Gallons Per Day MS4 – Municipal Separate Storm Sewer System NCC – New Castle County NCCD – New Castle Conservation District NMP – Nutrient Management Plan NPDES – National Pollutant Discharge Elimination System NRCS – Natural Resources Conservation Service OWTS – Onsite Wastewater Treatment System PAH – Polycyclic Aromatic Hydrocarbons PCBs – Polychlorinated Biphenyls PCS – Pollution Control Strategy RCRA – Resource Conservation and Recovery Act SIRB – Site Investigation and Restoration Branch TAT – Tributary Action Team TMDL – Total Maximum Daily Loads TN – Total Nitrogen TP – Total Phosphorus TSS – Total Suspended Sediment UDC – Unified Development Code USDA – United States Department of Agriculture USEPA – United States Environmental Protection Agency USGS – United States Geological Survey UST – Underground Storage Tank WHIP – Wildlife Habitat Incentives Program WRA – Water Resources Agency WRP – Wetlands Reserve Program WRPA – Water Resource Protection Area WWTP –Wastewater Treatment Plant 3 Executive Summary The Christina Basin is a 565 square mile basin contained in the larger Delaware River Basin. The Christina Basin spans three states, Delaware, Pennsylvania, and Maryland, and includes four watersheds: Brandywine Creek, Red Clay Creek, White Clay Creek, and the Christina River. On April 8, 2005, the U.S. Environmental Protection Agency (USEPA) assigned Total Maximum Daily Loads (TMDLs) to the Christina Basin. Total Maximum Daily Loads (TMDLs) are the maximum amount of a pollutant that a waterbody can assimilate and still achieve water quality standards. These TMDLs called for a reduction in nitrogen, phosphorus and bacteria loading. An implementation plan was developed by a Tributary Action Team, a diverse group of citizens and government agency personnel and presented to DNREC for promulgation to reach the prescribed TMDLs. This document, the Pollution Control Strategy (PCS), reflects those recommendations made by the Tributary Action Team for the Delaware portion of the Christina Basin based on a consensus-seeking process. Each group of recommendations is intended to reduce the levels of nitrogen, phosphorus, and bacteria from nonpoint sources of these pollutants