Section 096-587-3 - Calculation of seasonal aquatic base flow valuesA.Using flow records. Seasonal aquatic base flow is determined using flow records where adequate flow records are available for a specific waterbody. "Adequate flow records" means a minimum of 10 years of U.S. Geological Survey gauging records, or other equivalent flow records of good quality from unregulated waters, except as follows or as approved by the department. (1) Where the period of flow record is at least 1 year, the available flow records may be extended by means of flow data from a nearby watershed with similar hydrologic characteristics and a minimum of 10 years of U.S. Geological Survey gauging records or other equivalent flow records.(2) Where flow records are unavailable, flow records may be established by using a drainage area adjustment ratio for records from other gauged sites within the same drainage with at least a ten year period of record, and where the drainage areas of the gauged and ungauged sites differ by no more that 50%.B.Without using flow records. Estimates of seasonal aquatic base flow may be calculated using the most appropriate of the following publications, or by use of a regional flow study to establish seasonal median flows for rivers and streams within a region. An adequate regional flow study should be based on a minimum of 20 stations where at least 10 independent base flow measurements have been made for each site. Where conditions, such as watershed area, fall outside of the conditions by which these estimates were calculated, estimates of seasonal aquatic base flow are considered as interim estimates and may be refined as new site-specific data is obtained. "Estimating Monthly, Annual, and Low 7-Day, 10-Year Streamflows for Ungaged Rivers in Maine", USGS Scientific Investigations Report 2004-5026
"August Median Streamflow on Ungaged Streams in Eastern Aroostook County, Maine" USGS Water Resources Investigations Report 2003-4225
"August Median Streamflow on Ungaged Streams in Eastern Coastal Maine", USGS Scientific Investigations Report 2004-5157
06- 096 C.M.R. ch. 587, § 3