GIS Data Catalog

Catchment boundaries derived from terrain data - King County only

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Summary

Drainage area delineations are drainage areas at the smallest scale derived from terrain data.

Description

These are drainage area delineations that generally define drainage areas at scale similar to neighborhoods.

However, the size of drainage areas is highly variable for this layer.

The variability in size of defined areas is usually driven by stormwater needs for a given municipality, capital improvement project, etc. They can be defined based on complex stormwater conveyances as well.

This is the finest scale of drainage areas that KC currently has for county wide.

The County has been undergoing updated mapping of drainage basins taking into account conveyances that may not be fully topographically driven.

For example underground stormwater water pipes may direct flows counter to surface topography.

This is an ongoing effort conducted by King County and various collaborating partners.

Layer information

Layer Name	topo_catchment_kc_area
Subject Category	Hydrography
Title	Catchment boundaries derived from terrain data - King County only
Feature Count	1224
Feature Type	Polygon
Next Update	As needed
Spatial reference	EPSG:2926
Control ID	343
Place Keywords	Pacific NW, Washington State, King County, WA
Theme Keywords	Hydro, Hydrology, None
Supplemental Information	Topo_Catchment is the master layer and is dissolved to produce Topo_Basin, Topo_Watershed, and Topo_WRIA by attributes.

Table Preview

Attribute information

FEATURE_ID From OBJECTID	Description Unique Identification Number Domain 1 to 1512 by 1
SHAPE From ESRI	Description Feature geometry. Domain Coordinates defining the features.
SUB_BASIN No Source Noted	Description Not Found Domain Not Found
CATCHMENT No Source Noted	Description Not Found Domain Not Found
OBJECTID From ESRI	Description Internal feature number. Domain Sequential unique whole numbers that are automatically generated.
BASIN_NAME No Source Noted	Description Not Found Domain Not Found
WTRSHD_NAME No Source Noted	Description Not Found Domain Not Found
WRIA_NO No Source Noted	Description Not Found Domain Not Found
WRIA_NAME No Source Noted	Description Not Found Domain Not Found
Shape.STArea() From SQL Server	Description Returns the area of a geometry instance in square units, based on the spatial reference identifier (SRID) of the geometry. Domain Double
Shape.STLength() From SQL Server	Description Returns the total length of the elements in a geometry instance. Domain Double

Contact information

Maintained by	DNRP - Water and Land Resources
Primary	Harkeerat Kang Harkeerat.Kang@kingcounty.gov

Terms of Use

License	Terms of use and copyright

Use this Data

Links How to use in ArcGIS Pro
Sharing Status	Public

Summary

Drainage area delineations are drainage areas at the smallest scale derived from terrain data.

Description

These are drainage area delineations that generally define drainage areas at scale similar to neighborhoods.

However, the size of drainage areas is highly variable for this layer.

The variability in size of defined areas is usually driven by stormwater needs for a given municipality, capital improvement project, etc. They can be defined based on complex stormwater conveyances as well.

This is the finest scale of drainage areas that KC currently has for county wide.

The County has been undergoing updated mapping of drainage basins taking into account conveyances that may not be fully topographically driven.

For example underground stormwater water pipes may direct flows counter to surface topography.

This is an ongoing effort conducted by King County and various collaborating partners.

Contact information

Maintained by	DNRP - Water and Land Resources
Primary	Harkeerat Kang Harkeerat.Kang@kingcounty.gov

Terms of use and copyright

License	Terms of use and copyright

Change history

10/1/2008	Each time TOPO_CATCHMENT is updated this feature class is updated by a dissolve and then clipped to the King County boundary.
10/17/2006	Quality control was done by comparing the original DRNBASIN catchments IDs to the new Topo_Catchment catchment IDs. Any missing catchments were added by using the command UPDATE and then MERGING of the sliver polygons generated from the UPDATE around the polygon. Multi part polygons caused by the original MERGING and UPDATE corrections were EXPLODED then MERGED using DRNBASIN as a guide.
10/4/2006	All King County WSC shapefile basins are fitted together using ArcGIS ArcToolBox command Integrate at 15 feet tolerance. Basins are merged together using the ArcToolBox Merge command into a GeoDataBase called DRNBASIN_NEW. Topology is created using "No Gaps" and "No Overlaps" rules. All topology errors are fixed in DRNBASIN_NEW.
10/4/2006	A copy of bigwater is edited to delete the rivers. An existing old copy of DRNBASIN was updated with the modified bigwater layer using the command UPDATE. The updated DRNBASIN is cleaned up to eliminate slivers between bigwater and dnrbasin. The conflated DRNBASIN to Bigwater is UPDATED with DRNBASIN_NEW, dissolved using the attribute catchment to produce the new drnbasin TOPO_CATCHMENT. TOPO_CATCHMENT is cleaned of slivers, then the 3 child products (Basin, Watershed, and WRIA) are dissolved from topo_catchment. All four levels of topo_catchment are clipped with the King County boundary to produce TOPO_CATCHMENT_KC, TOPO_BASIN_KC, TOPO_WATERSHED_KC, and TOPO_WRIA_KC.
10/4/2006	Create Arcmap project per basin and add basin data. Correct WTRCRS geometry using KC and USGS 2002 orthophotos, Lidar products elevation, slope, hillshade, and contours for referance in Arcmap. Place shapefile PRPT Pour Points per existing DRNBASIN catchments. Calc catchment ID to PRPT attribute "CATCHMENT". Add "DEMFIX" polygons as needed to facilitated water flow over obstacles i.e. roads crossing streams and calculate a depth. Export geodatabase WTRCRS to shapefile WTRCRS After the basin WTRCRS is corrected and Pour Points added for each catchment, the AML mk_ws.aml (Make Watershed) is used to produce the catchments for each basin. The mk_ws.aml converts shapefiles WTRCRS, DEMFIX, and PRPT to coverages. The lines of WTRCRS and polygons of DEMFIX are converted to grids. The grids "burn" or subtract cell values for a stream course into the DEM using the DEPTH value to facilitate the correct flow path though the DEM. Fills the DEM for sinkholes, Finds Flow Direction of the DEM, and the Flow Accumulation of cells. The cells with greater than 40,000 cells flowing into them are extracted to grid STRM40KG, then converted to coverage STRM40KG. PRPT coverage is converted to grid, then snaped using Grid command snappour to the STRM40KG grid. The Grid command WATERSHED deliniates the catchement watershed boundaries to grid WSG (Watershed Grid). Grid WSG is converted to coverage WS (Watershed). In ArcEdit, the existing label points in WS are replaced with the PRPT point labels that have the catchment attribute. The WS is polygon rebuilt, then blank attribute polygons are deleted, and duplicate catchments are dissolved by the same catchment ID. The WS coverage is converted to the shapefile: WSC.
10/4/2006	For each HYDROBASIN or TOPO_BASIN, a project area is built in Arc/Info 9.1 using the AML build_dem.aml. This AML builds a 2000 foot buffered Digital Elevation Model, Accumulation, and Slope grids for the basin area using the Bare Earth or Digital Ground Model Lidar grids. Clip existing WTRCRS per DRNBASIN's attribute BASIN_NAME or HYDROBASIN area. Import WTRCRS to a personal geodatabase. For WTRCRS, add field attributes DEPTH (Short, 4) for DEM "Stream Burning" of water courses, RATE (Short, 4) for geometry accuracy rating, and NOTES (Text, 254) for additional information for each line. Create polygon Shapefiles "DEMFIX" and point "PRPT" for each basin. Add field attribute DEPTH (Short, 4) to shapefile "DEMFIX" for DEM "Stream Burning" of water courses. Add attribute "CATCHMENT" (Text, 40) to "PRPT" for joining to existing DRNBASIN Polygon Attribute Table.
Update 7	Split Upper White River basin into 4 basins: Lower White 100304, Greenwater 10036, Westfork 100305, Upper White stays 100303. Spit Skykomish basin into 6 basins: North Fork 70110, South Fork 70111, Beckler 70113, Miller 70112, Foss 70114, Tye 70115. Corrected Thorton & North Fork Tolt basin boundaries.