Estimation of unregulated, natural monthly and annual streamflows on Forest City Stream, and unregulated lake levels on East Grand Lake
The East Grand Lake Basin in eastern Maine and southwestern New Brunswick drains an area of 132 mi2. The impoundment provides storage for hydropower operations and the maintenance of minimum streamflows on Forest City Stream for environmental compliance. Estimates of unregulated hydrology for the basin are sought in the interest of understanding streamflow and impoundment level conditions in the basin in the event the gates at the dam are removed or otherwise not operated for regulation. The goals of the project are to estimate unregulated, natural monthly and annual streamflows on Forest City Stream at the outlet of East Grand Lake by use of statistical methods, and to use hydraulic modeling and bathymetric data to estimate lake levels that correspond to these monthly and annual streamflows. The USGS will build a HECRAS (Hydrologic Engineering Center – River Analysis System) hydraulic model for the outlet of East Grand Lake that will be available for future scenario testing. In addition, USGS will publish data, methods, resulting streamflows and lake level estimates in a USGS Scientific Investigations Report. These estimates will provide insight to the hydrologic component of the natural state of East Grand Lake Basin under unregulated conditions. This information can be used to guide future decision-making as it relates to the ecological health of the watershed.