- Water Quality
Resource Use -- Healthy Natural Environment -- |
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What are the Most Important Goals?• Informed populace What Can We Do?Individuals:
Communities: Decision-makers: |
What is this Indicator?The Drinking Water Quality Indicator tracks the level of nitrate-nitrogen (nitrate) - measured in parts per million (ppm) - in our public drinking water supply. Nitrate is a dissolved form of nitrogen that is commonly found in lawn fertilizers and wastewater effluent. Excessive nitrogen is unhealthy for humans, especially babies, and can cause extensive ecosystem damage in coastal surface waters because it stimulates the growth of algae, which consumes oxygen that aquatic organisms need to survive. Nitrate-nitrogen is also the primary contaminant coming from septic systems, which are the predominant form of wastewater disposal on the Cape. It is important to note that the indicator focuses on the data collected by public water suppliers and small-volume wells, but does not include any data from private wells that are prevalent on the Outer Cape. The Drinking Water Quantity Indicator measures the total amount of water that is being pumped by Cape public water suppliers. This indicator does not include water pumped by private wells, small-volume wells or water used for golf course or cranberry irrigation. As available land decreases and the cost increases, developing future water supplies and protecting existing supplies becomes more difficult. In addition to financial issues associated with land purchases, towns and water suppliers also have to be concerned with costs associated with treatment and infrastructure issues. Why are these Indicators Important?Groundwater is Cape Cod's only source of water. In recognition of this, the Cape Cod aquifer was designated a sole-source aquifer by the U.S. Environmental Protection Agency in 1982. This means that the aquifer is recharged solely by rainfall and is the only source of drinking water for Cape Cod. As such, it is connected to and supplies all of the water for the Cape's thousands of lakes and ponds, and ultimately flows to the sea. Anything we spill or put in the ground-septic waste, motor oil, lawn chemicals, etc. - infiltrates into the groundwater system, including lakes, ponds and coastal embayments. This same groundwater also supplies the 145 public wells and thousands of private wells for drinking water. Drinking water quality is an indicator of what is being discharged to our bays and ponds. Because approximately 85% of the 153,000 Cape Cod homes use on-site septic systems, an enormous amount of nitrate is introduced through these systems into the same groundwater that is used for drinking. Although the Title 5 septic systems approved by the state for wastewater disposal can treat effluent for pathogens, these systems do not treat for nutrients such as nitrogen. Wastewater treatment plants can reduce nitrogen and phosphorus significantly, but very few areas of the Cape are sewered. There are also alternative on-site systems, such as composting toilets and nitrogen-reducing septic systems, that can treat wastewater for nutrients. Without careful monitoring, management of contaminants, and the expanded use of sewers and alternative septic technologies, the Cape could jeopardize its only source of drinking water, and adversely affect the quality of its fresh and coastal surface waters. Drinking Water Quality Drinking Water Quantity |
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We are living beyond our means. As a people, we have developed a lifestyle that is draining the earth of its priceless and irreplaceable resources without regard for the future of our children and people all around the world.
Water is synonymous with Cape Cod. Virtually every aspect of Cape life - economic, social, recreational - is tied to the water.
It had long since come to my attention that people of accomplishment rarely sat back and let things happen to them. They went out and happened to things. |
Analysis of DataDrinking Water Quality Cape Cod's drinking water quality is generally very good, but there is a trend towards water quality degradation during the past decade. Between 1993 and 2002, the percentage of public water supply wells tested at or below 0.5 ppm (considered very clean) decreased from 57% to 41%. During the same period, the percentage of wells that were between 0.5 and 5-ppm (the nitrogen-loading standard) increased from 43% to 58%. Between 1993 and 2002, between 1% and 3% of these tested wells reached a level above 5-ppm of nitrate. Although the trend indicates higher nitrate concentrations from development, the proportion of "clean" wells is a general reflection of the large amounts of protected undeveloped lands surrounding the public supply wells, and larger residential lots that predominate in wellhead protection areas. Analysis of drinking water from small-volume non-community supply wells indicate, overall, higher levels of nitrate-nitrogen as compared to public supply wells. Of the 166 small-volume wells tested in 2000, 85% were below 5 ppm and 15% were greater than 5 ppm. Of the 205 small-volume wells tested in 2002, 89% were below 5 ppm and 11% were greater than 5 ppm. Based on this, the overall percentage of contaminated small-volume wells is much greater than that for public water supply wells (3%). These higher levels are indicative of smaller volumes of water pumped, shallower well depths and the close proximity of septic systems to the wellhead. Water quality data available from coastal embayments, whose ecosystems are more adversely affected by nitrogen than human health is, indicate that many of these systems are severely impacted by nitrogen. Eelgrass has nearly disappeared from most of the embayments along Vineyard and Nantucket Sounds, and some waters are experiencing regular low dissolved oxygen conditions. Drinking Water Quantity What Connections Do These Indicators Have?The demand for clean water will continue to increase as Cape Cod becomes more developed. As more land is developed, nitrate levels and associated pollutants in our public water supplies increase, affecting the health of our residents, our ecosystem, and our economy. Changes in land consumption, or in the technologies that treat wastewater, are needed to prevent further degradation. Increases in water use means that existing water supply systems will use more of their capacity, ultimately requiring austere conservation measures, especially in periods of drought or low water table conditions. These conditions may impose limitations on growth and require large public expenditure for additional supplies. Less predictable but no less important are the impacts that sustained pumping regimes can have on ponds, wetlands and other surface waters and the wildlife that depend on them. Increased water use may further stress these systems during low water level conditions. Economic Environmental Furthermore, the concentration of nitrogen that can adversely affect coastal embayments is far smaller than that which adversely affects drinking water. Therefore, even relatively small increases in nitrate in public drinking water supply wells may reflect substantial degradation in coastal water quality and aquatic habitat, which includes fish spawning marshes, shellfish beds, and anadromous fish runs. Using centralized wastewater treatment such as sewer systems can not only reduce nitrogen loads but also can allow much more compact development than is possible with on-site septic systems. This in turn reduces the amount of impervious surface and habitat disruption associated with suburban sprawl. Ample water for ponds and wetlands is essential to sustain wildlife and wetland plants. Under low-water conditions, sustained pumping regimes may further stress pond, wetland and other surface water ecosystems, and the wildlife that depend on them.
Water is synonymous with Cape Cod. Virtually every aspect of Cape life - economic, social and recreational - is tied to the water, from the fish we eat to the enjoyment we get beachcombing or boating. Without clean and abundant water, the Cape loses the very essence of its being. When centralized wastewater systems are available, development can be built much more densely within serviced areas, allowing for more housing and a more diverse and affordable housing stock, with fewer impacts to water quality. |


