PRLAC Co-occurence Mapping


New Hampshire is currently the fastest growing state in New England. From 1980 to 2006, the population grew by 43 percent - more than twice the regional average of 20 percent. The growing population is putting pressure on the region’s forests, rivers, and lakes as land is converted from its natural state to developed areas. Our natural resources are also facing threats from increasing recreational use, invasive species, and pollution.

Amidst these mounting land use pressures are several programs designed to address resource protection. In 2008 the Comprehensive Shoreland Protection Act (CSPA) was modified to increase protection for our irreplaceable shorelines*. New Hampshire also signed an agreement with the U.S. Army Corps of Engineers to enact the In-Lieu Fee Program. This program will allow developers impacting wetlands to pay a ‘fee’ to the state that will in turn be used to purchase and/or restore wetland and upland habitat within the watershed. *Note: In 2011 the CSPA was renamed the Shoreland Water Quality Protection Act (SWQPA) and many of the protections were greatly modified.

This report is designed to provide assistance to the Pemigewasset River Local Advisory Committee (PRLAC), municipalities, and other planning entities for identifying conservation planning opportunities in the Pemigewasset watershed, and in four identified subwatersheds, through the development of co-occurrence maps

The four subwatersheds evaluated in this report encompass part of the Pemigewasset River corridor, where 1,000 feet on each side of the river fall within PRLAC’s jurisdiction. The subwatersheds include:

1. Beebe River
2. Campton Tributaries
3. Plymouth/Ashland Tributaries
4. Bristol/New Hampton Tributaries


Pemigewasset Watershed Products

Bristol-New Hampton Tributaries Watershed Products

Why Conduct Co-occurrence Mapping?
Co-occurrence mapping is created by layering a series of individual maps (i.e. datasets) on top of one another to create a graduated snapshot of the region. For the Pemigewasset watershed, water quality datasets were used to create a snapshot of current conditions. The end-product is a map that uses graduated colors to illustrate where the areas of highest quality waters, wetlands, and uplands are located within the watershed. This map can become the foundation for conservation planning efforts in the watershed.

The purpose of this report is to provide a systematic, science-based approach to identify areas of high quality waters (surface and ground water), wetlands, and uplands for the larger Pemigewasset watershed and the Study Area. The co-occurrence results will enable PRLAC and the municipalities to make informed land use planning decisions to preserve or conserve these identified areas.