Conestoga River Watershed
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20296.qxp 6/23/08 10:12 AM Page 1 Publication 257 July 2008 Conestoga River Watershed Total Maximum Daily Loads Development - An Interim Data Report - Introduction Description of Watershed SRBC was contracted by PADEP to The Conestoga River Watershed develop a TMDL for the Conestoga River encompasses 475 square miles in Watershed because several segments — Lancaster County, with small portions about 330 stream miles — of the of the watershed located in Chester, Conestoga River and its tributaries have Lebanon, and Berks Counties. In addition been listed as impaired on the Clean to the mainstem Conestoga River, the Water Act Section 303(d) List, primarily watershed can be divided into five for nutrients and sediment. PADEP subwatersheds: Little Conestoga Creek, assesses all Pennsylvania waters to Mill Creek, Muddy Creek, Cocalico ABOUT TMDLS AND THIS determine if water quality standards are Creek, and Lititz Run. The Conestoga being met. Waterbodies not meeting River originates in Caernarvon Township, INTERIM DATA REPORT water quality standards are The Susquehanna River Basin placed on the 303(d) List. The Commission (SRBC), under contract with the nutrients of concern in the Pennsylvania Department of Environmental Conestoga River Watershed are Protection (PADEP), is developing Total nitrogen and phosphorus. Excess Maximum Daily Loads (TMDLs) for the nutrients can cause nuisance Conestoga River Watershed. SRBC began this algal growth, deplete oxygen TMDL project in 2005 and is scheduled to levels, and decrease aquatic complete it by April 2010. A TMDL calculates populations. The primary sources the maximum amount of a pollutant that of nutrients include agricultural/ urban runoff, construction activities, a waterbody can receive and still meet wastewater, septic systems, water quality standards, and allocates that industrial discharges, and soil amount to the pollutant's sources. (streambank/bed) erosion. Conestoga River. As part of the assessment, SRBC staff conducted water quality sampling in the Conestoga River Watershed (Figure 1) during the 2005 and 2006 summer months to characterize nutrient loads during base flow conditions. This interim data report focuses exclusively on the nutrient data collected and analyzed from samples collected from the water column under these base flow conditions. A separate report will be issued later focusing on the water quality data collected and analyzed from biological samples, such as macroinvertebrates and periphyton, as well as any water quality data collected under different flow regimes. This interim data report was produced by: Dawn Hintz Water Quality Specialist (717) 238-0426, ext. 103 [email protected] Figure 1. Conestoga River Watershed 20296.qxp 6/23/08 10:12 AM Page 2 Berks County, near the PA Turnpike, areas. However, agricultural land use Cocalico Creek Watershed (55 percent), flows southeast towards New Morgan has led to higher amounts of soil and with the majority of this land situated Borough, and then bends and streams nutrients running off and reaching the in the middle of the watershed. Forests southwest towards the Susquehanna waterways (WRAS, 2001). In addition cover about 35 percent of the area River, flowing about 65 miles. to agricultural runoff, the mainstem and are located in the northern The watershed contains a varied Conestoga River receives nutrients from portion of the watershed. The Middle landscape including large tracts of point-source discharges, urban runoff, Creek Wildlife Refuge is located along forested, urban, and rural land (Figure 2). groundwater, and its tributaries. the Lancaster/Lebanon County line, From 1990 to 2000, the population protecting a large area of natural in the Conestoga River Watershed Subwatersheds vegetation. Seven percent of the increased by more than 11 percent (U.S. Muddy Creek is the first major Cocalico Creek Watershed is developed Census Bureau, 2000). Between 1994 tributary to enter the Conestoga River. land, with the heaviest concentration and 2002, 11,100 acres of land were Muddy Creek begins in State Game being around Ephrata Borough. developed, with the greatest development Land No. 52, Berks County, and flows The next tributary to enter the concentration taking place in the 12 miles southwest to its confluence with Conestoga River is Lititz Run. Lititz central Lancaster County area. The the Conestoga River near Hinkletown, Run begins near the town of Lititz, largest acreage converted to development Lancaster County. Two notable tributaries Lancaster County. A large tributary, during that time frame took place in entering Muddy Creek include Little Santo Domingo Creek, flows into Lititz Warwick Township (Lancaster County Muddy Creek and Black Creek. The Run in Lititz Borough. A TMDL for the Planning Commission, 2004). Today, watershed is dominated by agriculture Lititz Run Watershed was completed and more than 13 percent of the Conestoga and forested land (50 and 43 percent, approved by the U.S. Environmental River Watershed is developed. respectively). Protection Agency (USEPA) in 2005. While the area’s population continues Cocalico Creek enters the Conestoga The Lititz Run Watershed is dominated to grow, agriculture remains the dominant River near Talmage, Lancaster County. by agriculture, but is heavily developed land use at 60 percent. Lancaster Cocalico Creek flows through the around the Lititz area. County’s soils are among the most population center of Ephrata Borough Mill Creek flows into the Conestoga productive in the country. These rich and drains about 139 square miles. River south of the City of Lancaster. soils sustain traditional farming in many Agriculture dominates the land use in the The watershed comprises the southern side of the Conestoga River Watershed and flows through open farmland and receives nutrient inputs from several discharges. A TMDL was completed and approved by USEPA for Muddy Run in 2001. Several unnamed tribu- taries to Mill Creek also have a TMDL completed and approved (2005) by USEPA. The land use in the Mill Creek Watershed is distributed between agriculture, forested land, and developed areas. Agriculture covers more than 75 percent of the watershed. Forested areas comprise more than 11 percent of the watershed, and developed land makes up almost 10 percent of Figure 2. Land Cover in the Conestoga River Watershed 2 20296.qxp 6/23/08 10:12 AM Page 3 the watershed. The Mill Creek PADEP uses the Unassessed Waters Watershed is dominated by traditional Protocol, a modification of the USEPA farming practices, with the majority Rapid Bioassessment Protocol II (RPB-II), of the stream channel bordered with as the primary mechanism to assess open farm fields. The watershed has Pennsylvania’s waters. All the biological one of the highest dairy cow densities surveys include kick-screen sampling in Pennsylvania (WRAS, 2001). of benthic macroinvertebrates, habitat Intense agriculture also characterizes surveys, and measurements of field the upper portion of the Little chemistry. After the survey is completed, Conestoga Creek Watershed. Overall, the status of the stream segment is deter- more than 56 percent of the Little mined. If the stream is determined to be Conestoga Creek Watershed is used impaired, the source and cause of the for agricultural purposes. The middle impairment are documented on the section of the watershed is densely state’s Section 303(d) List. populated, with only a little more than Each of the subwatersheds and eight percent of the watershed forested. the mainstem Conestoga River contain In 1997, the U.S. Geological Survey stream segments listed on the Clean (USGS) and the Alliance for the Water Act Section 303(d) List. Within Point-source discharge on the Conestoga River. Chesapeake Bay conducted a stream the Conestoga River Watershed, quality snapshot and found that the approximately 330 stream miles have The surficial geology in the most stressed areas of stream in the been listed as impaired, and the main Conestoga River Watershed allows Little Conestoga Creek Watershed were sources of impairment include siltation groundwater to influence surface water directly correlated to the agricultural and nutrients. quality conditions quickly in a significant dominated land uses (WRAS, 2001). portion of the watershed. Almost 60 percent Sources of Impairment of the watershed is underlain with Based on the varied land uses in carbonate rock. Carbonate rock is primarily the watershed, sources of siltation and composed of limestone and dolomite, nutrients include point-source discharges, which can be dissolved over time by urban runoff, agricultural runoff, small water to form surface depressions, residential runoff, and groundwater. In fractures, and subsurface conduits. the Conestoga River Watershed, there These areas are generally susceptible to are more than 50 point-source nutrient sinkhole formation under certain dischargers permitted to discharge conditions. Within this type of terrain, more than 48 million gallons per day. pollutants on the surface of the ground Also, nutrients are provided by nonpoint can be introduced more easily sources, primarily during storm events. into groundwater. During base flow Stormwater flows across all types of land conditions, groundwater contributes a carrying sediment, fertilizers, metals, significant amount of the streamflow, Little Conestoga Creek. and other pollutants into waterways. potentially carrying pollutants back to the surface water. Background on In 2005, SRBC completed a ground- TMDL Development water study in the northern