See also metadata file calwater.txt for a description of the California
Department of Forestry and Fire Protection (CDF) Planning Watersheds
(CALWATER), which are further subdivisions of the SWRCB basin delineations.
See also California Teale GIS Technology Center (Teale)
ARC/INFO coverages and metadata (hbasa.txt) and DFG refinements of
federal hydrologic unit codes (USGS HUCs, 1978) (hucdfg1.txt).
CALWATER, USGS, SWRCB, and DWR surface hydrologic basin delineations are being reviewed by the California Interagency Hydrologic Basin Map Committee, Chaired by the California Department of Water Resources. Basin names, codes, and boundary delineation reviews are expected to be completed within fiscal year 95/96. This coverage and the 1:500,000- scale SWRCB maps and the Teale GIS library "hbasa" coverages will be superceded by the CALWATER system, digitized on a 1:24,000-scale base (USGS 7.5'-series quadrangles), as modified by DWR and Teale."
"DATA QUALITY ASSESSMENT
The following comments regarding the data quality of coverage hbasa3
are a mixture of quantitative and subjective, qualitative statements.
Coverage hbasa3 attribute tables of watershed basin codes and names
are very accurate. Basin boundary delineations, however, are not precise
with respect to lines representing river networks, such as the 1:100,000
USGS Digital Line Graphs (DLG) of hydrography. This is due to the
small scale of digitizing of hbasa3 (1:500,000).
All SWRCB hydrologic names and codes were verified for consistency with 1:500,000-scale, SWRCB-published maps as of their August 1986 revision. Regional (RWQCB) and State (SWRCB) Boards have performed subsequent revisions. Expect updates of the coverage hbasa3 and the database swrcbhc.dbf and this metadata file (see also SWRCB MAP REVISION HISTORY section in the APPENDIX below). USGS Hydrologic Unit Codes and names were verified for all basins wholly or partially contained within California.
Several discrepencies among the above basin coding systems have been discovered to-date. For example, maps in Bulletin 130-85 do not contain some of the basin polygons contained in the map of 2-10-81 (coverage hbasa3 employs the DWR codes of 2-10-81). Other basin coding discrepencies are described in the APPENDIX below. Users are cautioned to examine the boundaries of basins in their areas of interest for consistency with CALWATER delineations (undocumented discrepencies may exist as CALWATER development progresses).
DFG eliminated two polygons from the SWRCB source coverages from Teale. In both cases, these polygons were artifacts, inadvertently formed by the connection of reservoir shorelines with the surrounding basin boundary (see Pine Flat Reservoir HSA 552.32 and Lake Kaweah HSA 553.44).
Humboldt, San Diego, and Mission Bays, unlike San Francisco, San Pablo, and Tomales Bays, are not formally coded by the WRCB/RWQCB system.
The relationship between the federal (USGS HUC) and state (DWR and SWRCB) basin delineations is not consistent statewide. In the North Coast, for example, several federal CUs may comprise a single state Hydrologic Unit (Klamath HU 105.00, Trinity HU 106.00), whereas in southern California, the converse is true: several state HUs comprise a single federal CU (San Diego CU 18070304). The majority of federal CUs can be assembled by mixtures of state HUs, HAs, and HSAs (conversely, most state basins 'nest' into the federal basins), "
Structure of table HBASA3.PAT
(standard ARC/INFO fields AREA, PERIMETER, HBASA3#, and HBASA3-ID
are
not described here; details on codes follow the table structure)
COL ITEM NAME WIDTH TYPE N.DEC DESCRIPTION
17 BASIN 5 I - integer form of SWRCB code (w/o decimal)
22 NHCODE 6 N 2 numeric representation of SWRCB HSA code
28 ADCODE 6 C - DWR Areal Designation code (Bulletin 130-85)
34 CHBPA 2 C - Hydrologic Basin Planning Area code
36 CHUNAME 50 C - SWRCB Hydrologic Unit (HU) name
86 CHANAME 50 C - SWRCB Hydrologic Area (HA) name
136 CHSANAME 50 C - SWRCB Hydrologic Sub-Area (HSA) name
186 CHUCODE 6 C - SWRCB HU code as character string
192 CHACODE 6 C - SWRCB HA code as character string
198 CHSACODE 6 C - SWRCB HSA code as character string
204 R 1 I - integer code for SWRCB Hydrologic Region
205 RU 3 I - integer combining Region and HU codes
208 RUA 4 I - combines Region, HU, and HA
212 RUAS 5 I - combines Region, HU, HA, and HSA
(same as BASIN, as present in original
Teale "hbasa" coverage)
217 SPLITCU 2 I - Flag indicating that 1, 2, or 3 CUs overlap
a given SWRCB HU, HA, or HSA
219 CU 8 I - USGS Cataloging Unit (aka Hydrologic Unit
Code, HUC) see below.
227 CUNAME 48 C - Descriptive basin name of USGS CU
275 CU2 8 I - Secondary CU overlapping a given SWRCB basin
283 CU3 8 I - Tertiary CU overlapping a given SWRCB basin"