New Guidance Available to Protect Surface Sources of Drinking Water
New guidance is now available to help revise local zoning to better protect critical riparian buffer areas adjacent to surface water used as a source of drinking water. Preserving vegetated buffer areas can significantly limit non-point source (NPS) pollutants, like phosphorous and nitrogen, from entering lakes, reservoirs and rivers. Non-point source pollution in stormwater runoff is the leading cause of surface water quality problems in the United States. Maintaining vegetated buffers is important to filter and reduce NPS pollution and protects source water by limiting contaminants that tend to increase the cost and complexity of drinking water treatment for public water systems.
Riparian buffer – An area adjacent to streams, lakes and wetlands that protect water quality and provide conservation benefits. They contain trees, shrubs and perennials, which absorb and mitigate erosion, stormwater runoff, excess nutrients and other types of pollutants from reaching surface waters.
The New Hampshire Drinking Water Quality Buffer Model Ordinance (2021) recommends a minimum 100-foot natural buffer measured from the reference line of the surface water source. The guidance also recommends the same buffer protection for wetlands that are contiguous and discharge into a drinking water source. An analysis of New Hampshire’s water supply watersheds done by the Source Water Protection Program found many municipalities have not adopted zoning ordinances with riparian buffers wide enough to effectively filter out certain NPS pollutants. Adopting a minimum 100-foot vegetated buffer that applies to the shoreline of lakes and rivers used as sources of drinking water would be a big step forward to protecting these important drinking water resources.
The new guidance was supported through a grant from the Local Source Water Protection Grant Program. For more information and additional resources from NHDES or the Rockingham Planning Commission, please contact Pierce Rigrod at pierce.rigrod@des.nh.gov or (603) 271-0688 or Jennifer Rowden at jrowden@therpc.org or (603) 658-0521.