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NFHAP Inland Assessment - Fish Habitat Condition Index Scores by HUC8basin - Tiled Map Service


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This map service contains summaries of habitat condition indices (HCI scores) from the National Fish Habitat Action Plan (NFHAP) 2010 National Assessments for 8 digit Hydrological Unit Codes (HUC8s) 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 initial NFHAP 2010 Alaska assessment HCI values were attributed to HUC12s. For this reason, to summarize data into HUC8s for Alaska an area-weighted average was used (i.e. the cumulative HCI score assigned to each HUC12 within a HUC8 was weighted by reach area using the formula (H1*A1+H2*A2...+HX*AX)/(A1+A2...+AX) where H = HCI score of the HUC12 [...]



NFHAP assessment data were collected and developed for multiple purposes. First, data were gathered in support of conducting a condition assessment of fluvial waterbodies throughout the United States in support of the National Fish Habitat Action Plan (NFHAP). Second, these data were intended to be made available to NFHAP Partnerships as well as other users interested in acquiring consistently-organized information available characterizing river systems over larger regions. This work was supported by local, state, and federal partners of NFHAP, including the U.S. Fish and Wildlife Service and the U.S. Geological Survey. Because the condition assessment was conducted over such a large geographic region, we adopted a landscape approach for assessment which assumed that anthropogenic disturbances as well as natural characteristics in the watersheds affect a given unit of habitat which in turn would affect fishes. It was necessary to use a landscape approach because landscape data are available for every location in of the United States whereas local measures of habitat or biological indicators of habitat condition are only available at a very small percentage of locations around the country.

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