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Land Development

Development of land changes both the quality and amount of stormwater that runs off into downstream streams, lakes and ponds.

Construction on a subdivisionStormwater runoff from a forest, meadow or other natural environment is filtered by natural processes as it flows along the ground and over native vegetation, and filtered further when it passes through the soil before reaching groundwater. Stormwater pollution from developed land (and from construction activities) is one of the leading causes of water pollution nationally, and the largest source of water pollution in New Hampshire. Stormwater can become polluted when it runs off of streets, lawns, farms and construction and industrial sites if there are fertilizers, sediment (small soil particles), pesticides, oil and grease, or other pollutants in its path. When stormwater is left untreated, it enters our surface and coastal waters and can introduce pollutants that can impact drinking water supplies, stream health, and aquatic and land-based wildlife. In addition to introducing pollutants into surface and groundwater, development can increase the amount and rate of stormwater runoff which, if unchecked, can contribute to flooding in other areas.

The Alteration of Terrain (AoT) permitting program requires the control and treatment of stormwater from large developments. The program applies to earth moving operations, such as gravel pits, as well as industrial, commercial and residential developments. Treatment usually occurs through biological or physical means, and can take the form of rain gardens, infiltration ponds, gravel wetlands or other best management practices. Controls implemented to satisfy the requirement of no increase in runoff from the developed property include detention ponds and underground storage facilities. The same structures that provide treatment can also be used to store and control the rate of stormwater runoff.

To help protect surface water and groundwater, the Alteration of Terrain (AoT) regulations require a permit whenever a project proposes to disturb more than 100,000 square feet of contiguous terrain (50,000 square feet, if any portion of the project is within the protected shoreland). In addition to these larger disturbances, disturbances of greater than 2,500 square feet over terrain having grades of greater than 25%, may also require an AoT permit. In addition, an AoT General Permit by Rule applies to smaller sites and does not require an application or notification to the department.

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Did you know?

Did you know?

The progress of an application can be tracked by conducting a NHDES OneStop Alteration of Terrain Permitting Query.  

Stormwater Manual

The New Hampshire Stormwater Manual is suggested as guidance when an AoT permit is NOT required. If there are conflicts in the manual and AoT rules, the rule requirements take precedence.

Subdivisions

Subdivision approval is required for lots under or being reduced to under 5 acres. Subdivision applications require a permitted septic designer and a licensed land surveyor, and can be submitted on OneStop.

Waterfront Development

The subdivision, use and development of shorelands adjacent to the state's public waters is regulated under the Shoreland Water Quality Protection Act (RSA 483-B).

Land-Resources-Management
Part-time – Civil Engineer
gloria.andrews@des.nh.gov
Land-Resources-Management
Civil Engineer
Land-Resources-Management
AOT Supervisor, Civil Engineer
ridgely.mauck@des.nh.gov
Land-Resources-Management
Civil Engineer
Land-Resources-Management
Civil Engineer