Description: Catchment boundaries of National Hydrography Dataset Plus Version 1 used for the National Fish Habitat Partnership's 2015 Conterminous US Assessment of Fish Habitat Condition. Original data were accessed at ftp://ftp.horizon-systems.com/NHDplus/NHDPlusV1/.
Name: NFHP 2015 Conterminous US Assessment of Fish Habitat Degradation
Display Field: hci_lc_hcitxt
Type: Feature Layer
Geometry Type: esriGeometryPolygon
Description: These data contain cumulative fish habitat condition index (HCI) scores generated for river reaches of the conterminous United States as well as indices generated specifically for four spatial units including local and network catchments and 90 m local and network buffers of river reaches. Note that the cumulative HCI score is determined from limiting index scores generated for the four spatial units listed above. Detailed methods for calculating cumulative fish habitat condition index scores as well as the indices for each spatial extent can be found on the following website: https://assessment.fishhabitat.org/: The variables used to create indices in catchments vs. buffers differ due to differences in resolution of datasets. The following anthropogenic disturbance variables were used to create local and network catchment indices: Percent of urban land use, percent of impervious surface, human population density, road density, percent of pasture/hay, percent of cultivated crops, density of point source pollution sites (National Pollution Discharge Elimination, Toxic Inventory Release and National Superfund), nutrient and sediment loading to watersheds, habitat fragmentation metrics (density of dams and road crossings), density of mines and water withdrawals. The following anthropogenic disturbance variables were analyzed to create the local and network buffer indices: percent of urban land use, percent of agriculture, percent of pasture/hay and percent of impervious surface. The source datasets that were compiled and attributed to catchments were identified as being: (1) meaningful for assessing fish habitat; (2) consistent across the entire study area in the way that they were assembled; (3) representative of conditions in the past 10 years, and (4) of sufficient spatial resolution that they could be used to make valid comparisons among local catchment and buffer units. Also included in these data are the most limiting and severe disturbances to stream reaches operating within each of the four spatial extents. Limiting disturbances are defined as those disturbances that result in a stream reach not being in the best available condition determined for the region. Severe disturbances are a subset of limiting disturbances that are associated with stream reaches in a given region that were scored as having high or very high risk of habitat degradation (red and orange color groups). In this dataset, indices as well as limiting and severe disturbances are linked to the stream reaches, catchments and buffers created for the National Hydrography Dataset Plus Version 1 (NHDPlusV1) using the COMID identifier. It is important to recognize that these broadly-defined disturbance variables often act together with other measured or unmeasured threats to degrade habitat. Thus, while we may identify “urbanization” as a major threat to fish habitat in some regions, “urbanization” represents an umbrella term that describes many facets of urban development that could cause degradation to habitats. Fields in this dataset that begin with the "L_" prefix represent the local catchment whereas network catchments (defined by all upstream contributing catchments to the reach's outlet, including the reach's own local catchment; attributes begin with "N_" prefix. Like the catchment variables the buffer variables are labeled using a "LB_" and "NB_" prefix for local buffer and network buffer variables, respectively. More information about the processes used to create scores can be found in the processes section. Version 2.0 includes the addition of severe disturbances for each spatial scale and fixes errors documented in the change log. These data are part of the NFHP 2015 National Assessment.
Data Citation: Daniel, W.M, Infante, D.M, Herreman, K., Cooper, A., and Ross, J., 2019, National Fish Habitat Partnership (NFHP) 2015 Cumulative Habitat Condition Indices and Limiting Disturbances for the Conterminous United States linked to NHDPlusV1, (ver. 2.0, March 2019): U.S. Geological Survey data release, https://doi.org/10.5066/P94C5B06.
Copyright Text: Michigan State University, National Fish Habitat Partnership