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Final Report Potomac River Source Water ~s.ejgitllm~tsjjK.,..~IW1I~ for Marylan . Prepared by: Becker and O'Melia, LLC in association with Straughan Environmental Services, Inc. Becker and O'Melia, LLC WATER PROCESS RESEARCHERS AND CONSULTANTS POTOMAC SOURCE WATER ASSESSMENTS Introduction The 1996 Safe Drinking Water Act Amendments required states to develop and implement source water assessment prograIlli to evaluate the safety of all public drinking water systems. A Source Water Assessment (SWA) is a process for evaluating the vulnerability to contamination ofthe source of a public drinking water supply. The assessment does not address the treatment processes, or the storage and distribution aspects of the water system, which are covered under separate provisions of the Safe Drinking Water Act. The Maryland Department of the Environment (MDE) is the lead state agency in this source water assessment effort. There are three main steps in the assessment process: (1) delineating the watershed drainage area that is likely to contribute to the drinking water supply, (2) identijYing potential contaminants within that area and (3) assessing the vulnerability, or susceptibility, of the system to those contaminants. Public notification is the final component of the source water assessment report process. The goal of the source water assessment program is to provide a framework for local stakeholders and governments in developing a Source Water Protection Plan. The source water assessments for Maryland water systems utilizing the Potomac River was undertaken as a joint effort by MDE, the Washington Suburban Sanitary Conunission (WSSC), and several consultants, including The Center for Watershep Ptotection, and Becker & O'Melia, the lead consultant. The consulting team looked at many factors to determine the vulnerability of each water system utilizing the Potomac River, including the size and type of water system and watershed, available water quality data, the characteristics ofthe potential contaminants, and the capacity of the natural environment to attenuate any risk. Water quality modeling was perfonned by the consultants to analyze the threats posed by potential pollution sources and the likelihood of the delivery of contaminants to each water supply. Future management scenarios were also modeled to determine the benefits ofimplementing agricultural and urban best management practices. General Findings ... The source water assessment report for each of the seven water systems that use the Potomac River as a drinking water source have been completed. These water systems include (upstream to downstream): Luke-Westvaco, Hagerstown, Sharpsburg, Brunswick, New Design (Frederick County), WSSC, and Rockville. Below are some general findings from the assessment reports: • Drinking water contaminants of concern were identified and include natural organic matter (NOM) and disinfection byproduct precursors (DBPs), Cryptospridium oocyts and Giardia cysts, taste and odor causing compounds, ammonia, sediment/turbidity, algae, fecal coliforms, and dieldrin. .. • Even as far downstream as Rockville's intake, the watershed for the Potomac Basin is mostly forested. The percentage of agricultural land within the watershed of the main stem of the Potomac increases significantly with the inclusion of the basins draining the Great Valley. Some urban and upstream .. agricultural land uses appear to be the most significant sources of contaminants impacting the source water quality for water systems. • Modeling was used to predict the overall impact of management practices on source water quality; future conditions are expected to show a small deterioration in water quality without implementation of increased management practices. Also, the amount of contaminants reaching the river and its tributaries can be reduced noticeably by implementing aggressive management practices. However, for some .. contaminants, such as sediment, the benefits will not appear for many years because of existing hydrologic conditions within the mainstem river. • Potential sources of contaminants were complied using a variety of data sources and were organized according to contaminants source type and shown on GIS maps. These maps included land uses, point and nonpoint source locations, as well as potential spill sources. - .' Water Systems LukelWestvaco's intake is located just downstream ofthe confluence of the Savage River and the North Branch ., ofthe Potomac. The upstream watershed is about 406 square miles and is 82% forested. The Jennings-Randolph dam and lime dosers maintained by MDE provide significant protection from upstream mining activities. •• Hagerstown's intake watershed is 4,940 square miles, and is mostly forested (73%) with some agricultural land use (24 %). The North and South Branches of the Potomac as well as Town Creek and Cacapon are the major upstream watersheds. Cumberland, Frostburg, Moorefield and Petersburg are the major cities and towns upstream ofthis intake. Upstream combined sewer overflows (CSOs) are a potential problem for Hagerstown's intake. Town of Sharpsburg watershed is 5,950 square miles. Land use is similar to Hagerstown, but a significant amount ofnew agricultural and urban lands are included with the addition of the Conococheague and Opequon tributaries. Hagerstown, Martinsburg, Winchester and Chambersburg are the additional urban centers. - The City ofBrunswick withdraws from the Potomac about 5 miles downstream from its confluence with the .. Shenandoah River. Antietam Creek enters the Potomac upstream of the intake. Forested land accounts for 65% of the 9,410 total square miles, with agricultural land use accounting for approximately 30%. Additional urban areas upstream are Front Royal, Harrisonburg, Staunton and Waynesboro. Automobile and railroad bridges are just .. upstream ofthis intake, making it susceptible to hazardous spills. , Frederick County (New Design Plant) withdraws from the Potomac River upstream of its confluence with the .. Monocacy River. The watershed is 9,660 square miles. Watershed characteristics are similar to Brunswick. New tributaries include Catoctin Creeks from Maryland and Virginia. Developed land is about 2.9% oftotal upstream area. - The WSSC intake is just downstream with the confluence ofWatt's Branch. The watershed is about 11,400 square miles. Forested land use is 60% of the total, agricultural 35% and urban 4%. Other tributaries entering the Potomac downstream from its confluence with the Monocacy include Goose Creek, Seneca Creek, Muddy Branch and Watts Branch, with Watts having the most significant negative water quality impacts. The assessment - recommended that WSSr should consider a new submerged channel intake to quickly negate the effects of Watts Branch during storm events. The Cities ofFrederick, Leesburg and Gaithersburg are also upstream ofthis intake. Rockville's intake is the furthest downstream MD intake, although just downstream from the WSSc. No significant streams or rivers enter the Potomac between the WSSC and Rockville. Watershed characteristics and water quality are essentially the same for these two plants. Recommendations - Each assessment report includes recommended strategies to protect drinking water sources in the future, which are specific to each water system. However, there are several recommendations that apply to all seven Potomac River water systems: - • Formation of watershed protection groups. These groups are necessary to set reachable goals and monitor the success of source water protection strategies. A multi-jurisdictional group, with local stakeholders and interstate commission members would be needed to bring together parties from each state, county, .. and local jurisdiction in the Potomac watershed. • Control the contamination of fecal coliform, Cryptosporidium, and Giardia in the watershed. This can be accomplished by increased implementation ofbest management practices that reduce erosion and .. sediment discharge into tributaries from agricultural and urban land, and minimizing the impact from pastures and concentrated agricultural operations (CAFOs). Reducing the load ofthese contaminants by wastewater treatment plant discharge is also important. .. • A basin-wide hazardous spill response plan is needed. A plan would help mitigate the potential damage of a spill into the Potomac or its tributaries. Advanced notice to water treatment plants will avert the threat of dangerous materials entering the public water supply. .. .. -;.. ~..............•..•... - MARYLAND DEPARTMENT OF THE ENVIRONMENT 2500 Broening Highway • Baltimore, Maryland 21224 (410) 631·3000 • 1-800-633-6101 • http://www.rnde.state.rnd.us Ipl..rris N. Glendening MerryJin Zaw-Mon Governor Acting Secretary August 2, 2002 I J.. Mr. Mike Marschner Frederick Co. Water & Sewer 7303 Marcies Choice Lane Frederick, MD 21701 RE: Source Water Assessment for the New Design Water Treatment Plant /'7i.e.c. DearMr.~ , The 1996 Safe Drinking Water Amendments requires each State to complete source water assessments for all public water supplies. The Maryland Department of the Environment's Water Supply Program (WSP) is responsible for the completion ofthese assessments for Maryland's water systems. The Potomac River Protection Act passed in the 2000 General Assembly required that assessments for water systems using the Potomac River be completed and submitted to the General Assembly by July 1,2002. In response to the Potomac River Protection Act, .. the WSP enter~d into an agreement with the Washington