- Why was the assessment done?
Under the 1996 Amendments to the federal Safe Drinking Water Act, the NH Department of Environmental Services (DES) is required by the US EPA to assess each of the 3,000 sources of public drinking water in NH for their susceptibility to contaminants regulated by the Act. This assessment is based on the results of the most recent sanitary survey performed at this system and a land use inventory of each source's protection area. It describes susceptibility in terms of multiple land use and water quality susceptibility factors. Factors that are ranked medium or high generally increase the risk of drinking water contamination.
- How were land uses identified?
Land uses shown on the map from Part 3 are characterized as potential or known contamination sources. Known contamination sources are sites where contaminants are known to have been released onto or into the ground (currently there are no known ongoing releases of contaminants to surface water in source water protection areas). Potential contamination sources are facilities that typically use large quantities of regulated substances. Many of the land uses are regulated by DES and were already in a DES database and the DES Geographic Information System. Others were identified by driving through source water protection areas. Although the most current land use information was used to rank the susceptibility factors in Part 1, it should be noted that the ranking and maps could contain errors and should be reviewed carefully by the user of this information.
- What area was evaluated for this assessment?
The source water protection area is the critical area surrounding a public water supply well or an intake on a surface source. For a public water supply well, this is the wellhead protection area (WHPA), which is the estimated area from which groundwater and surface water will flow to the well under severe pumping conditions. For most bedrock wells, this area is a volume dependent circle. For wells in sand and gravel there is generally enough site specific information to delineate the area of flow. If not, a 4000 foot circle was used. For a public water supply intake or a surface source, the source protection area is the watershed area, or a portion of that area from which surface and groundwater flow to the intake.
- Will the potential contamination sources shown on the attached map contaminate my source?
Potential contamination sources are facilities that typically use, produce, handle, or store contaminants of concern, which, if improperly managed, could find their way to a source of public drinking water. It is important to understand that a release may never occur from a potential contamination source provided it is using good management practices. Many potential contamination sources are regulated at the federal level, the state level, or both to reduce the risk of a release. There are a number of methods that water systems can use to work cooperatively with potential contamination sources. These often involve educational visits and inspections of stored materials. Minimizing the risk from potential contamination sources is discussed in our fact sheet .
- How should this assessment be used?
This assessment should be used to plan for improved protection of public drinking water sources. Additional information may also be useful. For instance, a community may wish to add additional features to the map from Part 3 such as 100-year flood plain, tax map information, soils information or high-density development, etc. The assessment is a good starting place for planning protection programs.
This system may or may not be currently implementing source protection measures. Regardless of the current level of protection activity, or current land use scenario, DES encourages water suppliers and municipalities to use this information and available resources to improve water supply protection.
Whether the source currently has a pristine protection area or numerous industrial land uses which require education and surveillance, the way to ensure good water quality in the future is to act now to protect valuable water supply resources. Once contamination occurs, clean up is costly and sometimes technically infeasible. Additionally, unprotected watersheds and wellheads can lead to deterioration of water quality that may eventually lead to higher treatment costs.
An effective local source water protection program is tailored to the particular source water protection area. DES and others are available to assist municipalities or water suppliers in designing a program to address the most significant concerns in a pragmatic and cost effective manner. Our fact sheet shows a list of options that could be considered at the local level for inclusion in a source water protection plan. These options are explained in detail in The DES Guide to Groundwater Protection and NEIWPCC's Source Protection, A Guidance Manual for Small Surface Water Supplies in New England, which are available by calling DES at 271-7017.
- If I have questions or want help protect drinking water whom should I contact?
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