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Water: Nonpoint Source Success Stories

New Hampshire (Section 319I - 1994)

New Hampshire's Nonpoint Source Management Plan lists unlined landfills--prevalent throughout the state and affecting groundwater, which is an important supply of drinking water--as the state's highest priority problem. New Hampshire used section 319 funds for needed hydrogeological analysis and permitting to close landfills.

Unlined Landfill Closure Protects Groundwater Groundwater protection has been a concern in New Hampshire for many years. And for at least 10 years, the state has attempted to close its unlined landfills. Therefore, when New Hampshire received its first 319 grant, it was finally able to establish a database and provide a quicker and more consistent regulatory review to expedite closure. A statewide database, listing 2,300 contaminated sites, pinpointed 200 unlined landfills that potentially threaten groundwater. Although state groundwater protection rules require that landfills obtain a groundwater permit, most of these unlined landfills have not applied. In addition, many unlined landfills that no longer received solid waste had not yet been closed to mitigate impacts to surface and groundwater. The permitting process provides the state a vehicle for tracking landfill closures. In order to obtain a permit, the landfill operator must complete a three-phase hydrologic study, including geological studies and groundwater samples. Once the permit has been issued, the operator can proceed with the engineering work necessary to design an appropriate closure system.

The $60,000 section 319 grant, received in February 1992, enabled New Hampshire for the first time to provide a dedicated technical staff person. This person's duties are to review hydrologic studies and closure designs submitted by landfill owners, develop a database to track the closure process, prioritize landfills according to environmental risks, and enforce state groundwater protection rules. This oversight is performed in cooperation with the Department of Environmental Services Groundwater Protection Bureau, which regulates groundwater and potential surface water impacts through groundwater permits, and the Waste Management Division, which regulates closure designs and post-closure maintenance through solid waste permits. From February 1992 to June 1993, the state issued 30 groundwater permits.

The database lists landfills by risk level according to their potential to affect water supplies. For example, a landfill adjacent to a municipal well might be rated 1-- the highest level-- because it presents a major risk. A landfill in a rural area where groundwater is not currently used as a source of water supply may be rated lower because it presents less risk. In addition, the database provides a way to monitor the status of each landfill in the closure process. State officials report that closing landfills has contributed to a significant reduction in concentrations of volatile organic compounds (VOCs)--a broad class of chemicals that contributes to air and water pollution--in groundwater at unlined landfills. Prior to closing landfills, the VOC concentrations were often well above drinking water standards. However, in many cases VOC levels have decreased significantly after landfill closure and now meet drinking water quality standards.

For example, Figure 1-1 shows the concentration of total VOCs in groundwater at a monitor well downgrade from a municipal solid waste landfill in the Town of Hudson. A clear improvement in groundwater quality can be seen following closure of the landfill in September 1991. Closure involved placing an impermeable synthetic cap over the landfill and constructing a groundwater interception trench to divert shallow groundwater flow away from the landfill. As the figure indicates, beginning around January 1993 the water met drinking water quality standards.

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