National Fish Habitat Action Plan (NFHAP) 2010 HCI Scores - by HUC12

This shapefile contains summaries of habitat condition indices (HCI scores) from the National Fish Habitat Action Plan (NFHAP) 2010 National Assessments for 12 digit Hydrological Unit Codes (HUC12s) of the United States. Initial HCI scores were developed in three separate assessments (Conterminous U.S., Hawaii, and Alaska) due to differences in data availability across these regions. In the NFHAP 2010 Alaska assesment HCI values were already attributed to HUC12s. For this reason values for Alaska in this shapefile are identical to those represented in the Alaska assessment. To summarize data into HUC12s for the Conterminous United States and Hawaii a length-weighted average was used (i.e. the cumulative HCI score assigned to each river reach within a HUC was weighted by reach length using the formula (H1*L1+H2*L2...+HX*LX)/(L1+L2...+LX) where H = reach HCI score and L = reach length). Although data from all three assessments are summarized to HUC12s in this shapefile, it is important that values are not compared across assessment regions. More information on the three assessments can be found at the following links: Conterminous United States (http://dx.doi.org/doi:10.5066/F7B56GN1) ; Alaska (http://dx.doi.org/doi:10.5066/F7KD1VWD); Hawaii (http://dx.doi.org/doi:10.5066/F7V9863B).