King County GIS Center
King Street Center
201 S. Jackson St.
Suite 706
Seattle, WA 98104

+ 47.59909 N
- 122.33136 W

+ 47°  35' 56.72"
- 122° 19' 52.90"


Floodways in King County

Description | Contacts | Attribute Information | Constraints

Data layer thumbnail image


Layer name: FLOODWAY
Subject category: hydro
Title: Floodways in King County
Feature Count: 76
Feature Type: Polygon
Abstract: A compilation of best available floodway boundaries. A floodway is the channel of a stream plus any adjacent floodplain area that must be kept free of encroachment so that the 1 percent annual chance flood can be carried without substantial increases in flood heights.
Purpose: This dataset provides the location of the regulatory floodways. This information is intended for informational purposes only, and should not be used for parcel level determinations.
Status: Complete
Updated: As needed
Time period of content: (single date,as YYYYMMDD):: 20180316
Time period of content: (date range, as YYYYMMDD):: -
Spatial reference: WA State Plane North
FGDC Documentation: Classic or FAQ
Open Data Availability: Yes
Place Keywords: King County, WA, Pacific NW, Washington state,
Theme Keywords: rivers, floodway, hydro, FEMA, flood, inlandWaters,
Lineage: Available
Supplemental Information: None


Maintained by:
King County Dept. of Natural Resources and Parks, Water and Lands Resources Division
Primary: Ken Zweig, Rivers and Floodplain Section Program Manager, 206-477-4732
(How to e-mail a County contact)
Secondary: KCGIS Center; This mailbox is monitored during business hours.

Attribute Information

_FLOODPLAIN_Areas designated as floodways.
FloodwayThe area regulated by Federal, state, or local requirements to provide for the discharge of the base flood so the cumulative increase in water surface elevation is no more than a designated amount (not to exceed one foot as set by the National Flood Insurance Program) within the 100-year floodplain.


Access: None

Use: King County data are made available with the understanding that they shall be used exclusively by the obtainer or his/her authorized agents. Digital products may not be reproduced or redistributed in any form or by any means without the express written authorization of King County. This coverage is intended to represent the best available floodway boundaries. It does not include features found on the officially published paper FEMA Flood Insurance Rate Maps such as cross section locations, elevations, and flood zones outside the floodway.