Androscoggin Regional Risk Assessment

Androscoggin River Watershed Risk Assessment A regional scale ecological risk assessment was conducted for the Androscoggin River watershed (ARW) in Maine and New Hampshire, using the Relative Risk Model of Landis

and Weigers (2005).  This risk assessment marks the first timethat the Androscoggin River has been studied using a watershed perspective. This large watershed supports industry, agriculture, forestry, recreation, residential communities and much wildlife, including many threatened/ endangered species. Historically, the river was one of the nation’s most polluted and helped inspire the Clean Water Act of 1972. Two risk assessments were conducted. The first was for the Androscoggin from the Lake Umbagog outlet, the official beginning of the Androscoggin River, to the end of Gulf Island Pond. The second risk assessment covers the region south of Gulf Island Pond to Merrymeeting Bay.

Summary Upper Androscoggin River Risk Assessment

Assessment endpoints were determined after meeting with stakeholders.  These stakeholders represent large and small businesses, industry, governments, nongovernmental organizations and citizens.  Sources of stressors to endpoints include, but are not limited to, three pulp and paper mills, 15 dams, logging, agricultural runoff, stormwater, historically contaminated sediments, and atmospheric mercury deposition from industry in the Midwestern United States.  The watershed was divided into six sub-regions to spatially characterize risk.  Results showed the most risk to occur in sub-regions one and five (the most upstream sub-region and Androscoggin Lake, respectively).  Reproductive output of all fish species showed the highest risk.  Sources such as agriculture, atmospheric deposition, tributaries and sediments were shown to contribute the most risk through stressors such as pesticides, mercury, sedimentation, TSS, PCBs, and 2,3,7,8-TCDD. 

Monte Carlo techniques were used for the assessment of uncertainty and sensitivity.  In many cases, the highest risk scores were accompanied by the most uncertainty, highlighting the need for data collection for specific attributes.  Monte Carlo analyses produced quantitative estimates of uncertainty and identified critical data gaps, providing guidance for future studies. 

The five most pressing data needs for the ARW were found to be: 1) Data for atmospheric deposition of mercury within the watershed, 2) Sediment quantity in each sub-region and chemical concentrations in those sediments, 3) Contribution of stressors to the river from agricultural runoff, 4) Contribution of stressors to the river from tributaries, 5) Fate and transport characteristics for pulp and paper mill effluents, particularly for stressors influencing DO.

The project report ANDROSCOGGIN RIVER WATERSHED ECOLOGICAL RISK ASSESSMENT can be downloaded as a .pdf file here

Summary Lower Androscoggin River Risk Assessment

The lower Androscoggin river watershed extends from New Hampshire to Maine and contains the Androscoggin, Little Androscoggin and Sabattus River as well as other smaller tributaries. In the risk assessment, a broad range of sources, habitats and endpoints were identified within the watershed. Some sources include agriculture, atmospheric deposition, impounds, forestry, permit compliance facilities, sediment and urban development. Chosen endpoints include water quality, brook trout, bald eagle, fallfish and common loon. The study area extends from the Gulf Island dam to the Merrymeeting Bay. The purpose of the preliminary ecological risk assessment was to compile and catalogue current information and to identify data gaps on the effects of sources and stressors on the endpoints in various habitats for the watershed using the framework of the relative risk model and to calculate risks and uncertainty so that hypotheses of the risks to the various components are generated where possible. Results indicated that non-point sources such as agriculture, forestry and urban development had the highest contribution to overall risks and the endpoints of water quality and bald eagle are most at risks. The largest sources of uncertainties based on Monte Carlo analysis include uncertainty in the river profiles, stressors released by the various sources, atmospheric deposition and fallfish and brook trout distribution.

This project was the Masters Thesis of Ms. Valerie Chen entitled "LOWER ANDROSCOGGIN RIVER WATERSHED INITIAL ECOLOGICAL RISK ASSESSMENT . The document can be downloaded here

This research was supported by the National Council for Air and Stream Improvement