Assessing the Risk of 100-year Freshwater Floods in the Lamprey River Watershed of New Hampshire Resulting from Climate Change and Land Use
The Great Bay National Estuarine Research Reserve, the University of New Hampshire, and Antioch University New England are working to improve information regarding flood risk in the Lamprey River Watershed in New Hampshire. This project will develop a methodology for assessing flood risks and, based on future land use and climate change scenarios, will provide decision makers, planners, and the public with products to support land use decision-making.
The Great Bay Estuary is one of the largest on the Atlantic Coast and is located nearly 10 miles inland. One of the many rivers that drains into the estuary is the Lamprey River, which originates in the Saddleback Mountains and flows 47 miles to its mouth at the estuary. The Lamprey River Watershed drains approximately 212 square miles. The primary towns in the watershed are Candia, Deerfield, Durham, Epping, Lee, Northwood, Nottingham, Newmarket, and Raymond. Major flood events in October 2005, May 2006, and April 2007 caused infrastructure damage and habitat degradation. Other stressors to the system include development pressures and climate change impacts, such as sea level rise, precipitation changes, flooding, erosion, increased storms, and landslides. Development and land use change combined with climate change effects can affect flood events in both magnitude and frequency.
This project is designed to assess flood risks to the Lamprey River Watershed associated with land use and climate change scenarios. The main products from this project will be municipal scale maps of the 100-year flood risk boundaries and river discharge at specific locations in the watershed. The project also involves an education component; the public, local policy makers, and planners will get guided demonstrations of the process and products to support land use decision making in coastal communities.
This is a two year project funded by the Cooperative Institute for Coastal and Estuarine Environmental Technology (CICEET) and is led by an interdisciplinary team from the Great Bay NERR, University of New Hampshire, and Antioch University New England. Scientists are assessing flood risks under different urban growth/land use and climate change scenarios (greenhouse gas emissions, sea level rise, temperature fluctuations, precipitation levels). This information will be used to created maps at watershed and municipal scales of 100-year flood risk boundaries and river discharge. Project leads will educate the public and policy makers on flood risks and past and potential land use patterns and climate change at professional meetings and workshops in the Lamprey River Watershed and statewide in 2010 and 2011. In addition, information will be made available on the New Hampshire Geographically Referenced Analysis and Information Transfer System (GRANIT) website (http://www.granit.unh.edu).
Outcomes and Conclusions
Decision makers, planners, and the public will have access to new information on flood risks, past and future land use patterns, and climate change, and how these will affect the frequency, magnitude, and spatial extent of flooding in the Lamprey River Watershed. This project will serve as a model that can be used by other NERRs and watersheds.
Gregg, R. M. (2010). Assessing the Risk of 100-year Freshwater Floods in the Lamprey River Watershed of New Hampshire Resulting from Climate Change and Land Use [Case study on a project of the Great Bay National Estuarine Research Reserve, University of New Hampshire, and Antioch University New England]. Product of EcoAdapt's State of Adaptation Program. Retrieved from CAKE: http://www.cakex.org/case-studies/assessing-risk-100-year-freshwater-flo... (Last updated March 2010)