King County Surface Water Design Manual
Hydrologic/Hydraulic Software Programs and Data

This page contains the software programs referenced in the Surface Water Design Manual, as well as other supporting files related to stormwater analysis and facility design.

(08/29/07) Updated versions of WKCRTS and WKCBW are now available.

Updated versions of the WKCRTS Program and the WKCBW Program are available to download for users having problems on machines with Windows XP Service Pack 2 software. In addition, other users may want to download the updated versions of the programs because the new programs offers some additional user friendly features.

Latest Software Updates

WKCRTS Software Patch: WKCRTS Version 6.0. Updated: 08/29/07

WKCBW Software Patch: WKCBW Version 6.0. Updated: 10/24/06

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2005 Surface Water Design Manual Application Maps:

Application of the Design Manual's targeted protection levels is determined from the following three application maps of King County. The maps are available here to view or download. To view the Adobe Acrobat maps you need Acrobat Reader, Version 3.0 or later, which is FREE. This format was chosen to allow the user to zoom in and out, pan the map in any direction, and print the map at the best resolution possible. Click the icon below if you need the Adobe Reader.

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2005 Flow Control Applications Map, PDF file

2005 Water Quality Applications Map, PDF file

2005 Landslide Hazard Drainage Areas Map, PDF file

1998 Surface Water Design Manual Application Maps:

Application of the Design Manual's targeted protection levels is determined from the following three application maps of King County. The maps are available here to view or download. To view the Adobe Acrobat maps you need Acrobat Reader, Version 3.0 or later, which is FREE. This format was chosen to allow the user to zoom in and out, pan the map in any direction, and print the map at the best resolution possible. Click the icon below if you need the Adobe Reader.

Get Acrobat Reader

1998 Flow Control Applications Map, PDF file

1998 Water Quality Applications Map, PDF file

1998 Landslide Hazard Drainage Areas Map, PDF file

KCRTS Hydrologic Model Program:

King County Runoff Time Series (KCRTS) Model Program

The KCRTS model is a required methodology under the 1998 and 2005 King County Surface Water Design Manual for sizing detention and infiltration flow control facilities. The program and software reference manual may be purchased for $50. For KCRTS software reference manuals purchased prior to 1999, an upgrade package is available for $25. The software package includes the King County Backwater (KCBW) program. Tax and shipping charges will be applied as applicable. For information on purchasing software of documents, [Document List], or contact Document Sales at (206) 296-6519.

King County Runoff Time Series Model Program; Version 6.0

Before you download this file, view the Read Me file.
WKCRTS.EXE (519k)

Self-extracting file containing an upgrade to the KCRTS program. Requires version 4.40g, or later, currently installed. This upgrade fixes the items indicated in the 10/24/06 Bug Report .

King County Runoff Time Series Model - Online Documentation

Links to downloadable reference documents

Pond Volume Calculation Spreadsheet

This Excel spreadsheet can be used to estimate pond volumes for typical land cover conversions on till soils.
PONDVOL.XLS (25k)
(King County provides no warranty of any kind as to the accuracy of this spreadsheet on specific projects. All facility volumes should be verified using the KCRTS software.)

KCRTS FAQ

Please review the frequently asked questions and responses before contacting the Water and Land Resources Division for technical support.

For help with the KCRTS program, contact Technical Support.

KCRTS/HSPF Data Files:

Sea-Tac Full Historical Runoff Files

For more information, view the Sea-Tac Read me file before downloading.

1ST-HIST.EXE (2,432k)
Self-extracting file containing the Sea-Tac full historical runoff files. The period of record is water-years 1949 through 1998. Requires KCRTS Version 3.04 or later (see above), and 3 MB of available RAM.

Landsburg Full Historical Runoff Files

For more information, view the Landsburg Read me file before downloading.

1LA-HIST.EXE (3,322k)
Self-extracting file containing the Landsburg full historical runoff files. The period of record is water-years 1949 through 1998. Requires KCRTS Version 3.04 or later (see above), and 3MBs of available RAM.

Sea-Tac Historical Precipitation

For more information, view the Sea-Tac Precipitation Read me file before downloading.

1ST-PPT.EXE (209k)
Self-extracting file containing the Sea-Tac historical precipitation record in WDM format. The period of record is water-years 1949 through 1998. Also includes Puyallup pan evaporation for the same period. This file requires HSPF Release 9 or later and/or ANNIE (see above).

Landsburg Historical Precipitation

For more information, view the Landsburg Precipitation Read me file before downloading.

1LA-PPT.EXE
Self-extracting file containing the Landsburg historical precipitation record in WDM format. The period of record is water-years 1949 through 1998. Also includes Puyallup pan evaporation for the same period. This file requires HSPF Release 9 or later and/or ANNIE (see above).

KCBW Backwater Software:

King County Backwater program; Version 6.0

The KCBW program is bundled with KCRTS on the blue and now a light green CD-ROM. The program may also be downloaded separately below. The KCBW program documentation is included with the KCRTS software reference manual and online. People with KCRTS software reference manuals dated prior to 1/1/99 may purchase an upgrade package for $25-. Tax and shipping charges will be applied as applicable. For information on purchasing, contact Document Sales at (206) 296-6519.

King County Backwater program; Version 6.0

For more information, view the Backwater Read me file before downloading.

WKCBW.EXE (355k)
This self-extracting EXE file contains an updated version of the King County Backwater (WKCBW) model. This is a standard step backwater analysis program for pipe networks, culverts, and simple open channels. KCBW or other approved backwater analysis techniques are required to verify capacity of existing and new conveyance systems under the 1998/2005 Design Manual. For information on the changes made from the CD-ROM version 5.30d, view the Bug Report (10/23/06).

King County Backwater Program Documentation

These are the program documents.