Description: Significant StreamsThis and it's dependent and encompassing datasets is to represent the spatially accurate and historically rectified surface flow of water courses within Napa County, and the authoritative GIS layer for all known or derived streams. For associated and streams or flowline layers see the following:Significant StreamsSignificant Streams 1500' BufferIntermittent and Ephemeral StreamsBlueline Streams Archived LayerNHD FlowlinesThe Streams_NapaCounty_master (Napa County Streams Layer) is an alternative layer to the county’s blueline streams layer. Historically, the county bluelines layer utilized flowline geometry directly from the USGS topographic map (TM) series and the National Hydrography Dataset (NHD). With the USGS pivoting away from future TM releases as we have known them, this additional county streams layer serves to prime county hydrological data to be incorporated into the new national standard as well as creating a more accurate and useful resource for the county, its partners, and the public.Flowlines for this layer were produced with a combination of lines generated from running spatial analysis tools against the 2018 Digital Elevation Model layer by drainage boundaries, heads-up adjustment of generated lines, and fully hand drafted lines using the 2018 DEM, ESRI’s World Hillshade, and aerial imagery dating from 1940 to 2022 as reference. Segments of the lower Napa River Watershed also used line geometry from the 2015 RCD layer.Attribution of fish presence was compiled from the previous county bluelines layer, RCD 2015 stream layer, fish habitat and stream inventory reports from RCD, Historical fish presence research done by Robert A. Leidy, and assorted State and National Fish and Game data. Full details can be found within a companion document at request from PBES GIS staff.Each stream segment has two different Strahler order values. The field labeled “StrahlerOrder_Full” should be displayed when the layer is displaying all line segments. The field labeled “StrahlerOrder_LatestOnly” should be displayed when the layer is filtered to show only line placement referenced in the latest large-scale USGS topographical map release. By default, refer to “StrahlerOrder_Full”.Future updates plan to add additional flowline geometry that falls within the county’s definition of stream, along with further attribution to keep Napa County data in line with national standards. The current layer displays flowlines that meet at least one of these qualifications: Placement matches latest USGS largest scale topographic map release blue lines, placement matches flowlines on previous county bluelines layer, flowlines with current or historical fish presence, flowlines that fall under county ordinance 1307, and flowlines listed in county resolution 94-19.
Service Item Id: cb19c4e2454e4d8994d203707dda3009
Copyright Text: Napa County PBES Dept. GIS Division
Spatial analysis, aerial interpretation, and hand digitization of line geometry as well as attribution collection and application completed by Logan Laudano, PBES GIS Technician I.
2018 DEM layer prepared by Matt Lamborn, PBES GIS Dept Coordinator using the 2018 LiDAR USGS flew over Napa County and surrounding areas after the 2017 fires in part of the 3DEP program. Napa County Resource Conservation District (RCD) Stream layer covering the Napa River Watershed 2015 and 2019 versions. Geographic Names Information System (GNIS).
Leidy, R.A. 2007. Historical references for native stream fishes for the period 1854-1981. SFEI. Contribution No. 530 Appendix II.
California Fish and Biogeographic Information and Observation System (BIOS) ds69, ds2673, ds340, ds122.
Leidy, R.A., G.S. Becker, B.N. Harvey. 2005. Historical distribution and current status of steelhead/rainbow trout (Oncorhynchus mykiss) in streams of the San Francisco Estuary, California. Center for Ecosystem Management and Restoration, Oakland, CA.
EcoTrust 2001 Snorkel Count for Steelhead Trout in the Napa Watershed, California.
NCRCD and PCI. 2012. Northern Napa River Tributary Stream Surveys Report – May 2012.
Suisun Creek Watershed Assessment and Enhancement Plan Prepared by Laurel Marcus and Associates.