Moving from Assessment to Protection… The Delaware River Watershed Source Water Protection Plan Prepared by: Philadelphia Water Department (PWSID #1510001) Baxter Water Treatment Plant Surface Water Intake Philadelphia, Pennsylvania June 2007 Delaware River Watershed Source Water Protection Plan (PWD Baxter Intake – PWSID# 1510001) The Delaware River Watershed Source Water Protection Plan is on file and available for public review at the following location: Pennsylvania Department of Environmental Protection Southeast Regional Office 2 East Main Street Norristown, PA 19401 Any questions regarding the information contained within the protection plan should be directed to: Christopher S. Crockett, Ph.D., P.E. Manager – Watershed Protection Philadelphia Water Department Office of Watersheds 1101 Market Street, 4th Floor Philadelphia, PA 19107 phone: (215) 685-6234 fax: (215) 685-6034 email: [email protected] Delaware River Source Water Protection Plan i Philadelphia Water Department Delaware River Watershed Purpose The purpose of the Delaware River Protection Plan is to design a source water protection strategy to counter current and future water supply concerns of the Philadelphia Water Department and drinking water utilities that share the Delaware River as a resource. The Baxter Water Treatment Plant, one of three drinking water facilities in Philadelphia, is supplied by the Delaware River. The Delaware River watershed extends 8,000 square miles through Pennsylvania, New Jersey, and New York. The Delaware River Source Water Protection Plan uses critical water quality, land cover, and population analyses as well as point and non-point source pollution modeling to characterize the water supply. The source water quality and quantity characterization, incorporated with the results from the 2002 Source Water Assessment, provide the technical foundation for a Delaware River source water protection strategy. The Baxter Water Treatment Plant provides over 190 million gallons of safe and high quality drinking water per day to the citizens of Philadelphia and surrounding communities. The plant uses dual media filtration and chlorine disinfection technologies to provide high quality drinking water year round. The Baxter Water Treatment Plant has an exceptional performance record and has never violated Safe Drinking Water Act regulations. The Baxter Water Treatment Plant owes its exceptional record to the hard work of dedicated Philadelphia Water Department staff and the quality source water supplied from the Delaware River. The Philadelphia Water Department uses source water assessment and protection planning to maintain the integrity of the Delaware River as a drinking water supply. WATER QUALITY ANALYSIS PUBLIC COMMENT SOURCE WATER PROTECTION STRATEGY LAND COVER SOURCE WATER ANALYSIS ASSESSMENT FINDINGS Delaware River Source Water Protection Plan ii Philadelphia Water Department Delaware River Watershed Delaware River Water Quality The Delaware River is an excellent drinking water supply. The Delaware River was once plagued by pollution from sewage and heavy industry, but now again provides a welcoming environment to native fish and wildlife species not seen in decades. However, this does not mean our work is finished, as newer challenges to source water quality need to be addressed. The graph at the bottom of the page depicts the long term trends of water quality parameters measured at the Baxter Water Treatment Plant in Philadelphia. The features in the graph and the major water quality categories that are of interest to the Baxter Water Treatment Plant are described below. Metals Salts The metals iron and manganese are water Sodium and chloride are water supply supply concerns because they give drinking concerns because they are not removed in water odors, colors, and tastes as well as the drinking water treatment process and slowing filters and treatment processes. can pose a health threat to customers on low These metals have decreased from high sodium diets. Both sodium and chloride concentrations early in the twentieth have been steadily increasing in the century and are no longer a major concern. Delaware River over time. Nutrients Pathogens Nitrate and nitrite are water supply Cryptosporidium, absent from the graph concerns because they are not removed below, is the primary pathogen water during the drinking water treatment process supply concern because it is very difficult to and can cause health conditions in small remove and can cause intestinal discomfort. children and babies. These nutrients were This pathogen is fortunately present at very once increasing in the Delaware River, but low concentrations in the water supply at now the concentrations are stable and Philadelphia, but requires constant beginning to slowly decline. vigilance. Delaware River Water Quality at Philadelphia Nitrate mg/L Nitrite mg/L Sodium mg/L Chloride mg/L Iron mg/L Manganese mg/L 100.00 10.00 1.00 0.10 0.01 0.00 1913 1928 1943 1958 1973 1988 2003 (Jaworski 1996 and Baxter data) Delaware River Source Water Protection Plan iii Philadelphia Water Department Delaware River Watershed Water Contaminant Sources The Baxter Water Treatment Plant is located in the tidal zone of the Delaware River and can therefore be affected by contaminants moving north to south with the river flow and south to north with the tidal waters. The contaminants within the waters that reach the intake come from four potential sources: natural, point, non-point, and accidental. Natural Sources The most significant natural contaminant of the Delaware River is salt water. A distinct boundary, or salt line, is formed where the salt water from the Delaware Bay meets the fresh water from the Delaware River in the tidal zone. If the salt line were to reach the Baxter location, the plant would have to stop operation until the salt line retreated south of the intake. There are detailed Delaware River Basin Commission resolutions dictating minimum flow requirements and reservoir releases to keep the salt line south of the Baxter intake during drought conditions. There is a need to model the behavior of the salt line under climate change and higher sea level conditions. The minimum flow requirements will likely need to be adjusted to changing hydrologic conditions. Point Sources Point sources can introduce both industrial and municipal waste to water ways. Municipal point sources discharging effluent from wastewater treatment plants are a source of water quality contaminants in the form of pathogens. Wastewater treatment plants are responsible for the water quality improvement experienced by the Delaware River in the past 50 years. However, concerns remain about pathogens contained in the effluent, mainly Cryptosporidium. Year round disinfection of wastewater effluent is the desired means to reduce the threat to source water from Cryptosporidium. Non-Point Sources Non-point source pollution, stormwater runoff from urban and suburban areas, is a source of metals, nutrients, suspended solids, and chemicals such as pesticides, herbicides, fertilizers, gasoline, and motor oil. Stormwater is likely to increase in volume as the watershed becomes more populated and developed. The water quality threat from stormwater creates a need for low impact development, sustainable design, and stormwater best management practices. Accidental Sources Accidental sources of contamination are spills or leaks from cars, trains, shipping vessels, underground pipeline bursts, and industrial accidents. The most recent example is the oil spill from the Athos I shipping vessel in 2004. One protection against these activities is the Delaware Valley Early Warning System, which provides advance notice of accidental contamination events. The advance notice from the Early Warning System allows utilities to execute emergency response protocols and prepare the treatment plants for changes in source water quality. Delaware River Source Water Protection Plan iv Philadelphia Water Department Delaware River Watershed Key Water Quality Findings Sodium, Chloride, and Conductivity Sodium, chloride, and conductivity levels across the Delaware River watershed were found to be increasing since 1975. Sodium and chloride are not removed during the drinking water treatment process. Sodium, chloride, and conductivity were examined at four locations on the main stem Delaware River ranging north to south from Montague, NJ to Trenton, NJ. The chloride concentrations are increasing very slowly and do not raise concern. However, sodium is expected to surpass the American Heart Association’s recommended drinking water concentration, 20 mg/L, in under 100 years at the Baxter intake location. Total Organic Carbon (TOC) Total Organic Carbon (TOC) is at the lowest concentration in the Delaware River in decades. During the middle of the twentieth century, severe pollution on the Delaware River caused TOC concentrations to rise over 4 mg/L. The average concentration from 2006 is 2.43 mg/L. The reduction of TOC in the Delaware River is critical to reducing the formation of undesirable disinfection byproducts (DBPs) at Baxter. DBPs are formed when natural organic matter, accounted for in the TOC measurement, reacts with chlorine. In order to reduce the concentration of DBPs, the precursors that lead to their formation must be reduced in the source water. Bromide No trend was identified for bromide. Bromide is naturally occurring in the Delaware River at very low concentrations, < 0.03 mg/L average. Bromide concentrations rise when streamflow