1. (1) These regulations are applicable to dams which can impound a volume of ten acre-feet or more of water as measured at the dam crest elevation. The ten acre-feet threshold applies to dams which can impound water on either an intermittent or permanent basis. Only water that can be stored above natural ground level or which could be released by a failure of the dam is considered in assessing the storage volume.

   The ten acre-feet threshold applies to any dam which can impound water of any quality, or which contains any substance in combination with sufficient water to exist in a liquid or slurry state at the time of initial containment.

2. (2) For a dam whose dam height is six feet or less and which meets the conditions of subsection (1) of this section, the department may elect to exempt the dam from these regulations.

   The decision by the department to exempt a dam will be made on a case-by-case basis for those dams whose failure is not judged to pose a risk to life and minimal property damage would be expected (downstream hazard class 3).

3. (3) These regulations do not apply to dams that are, or will be, owned, by an agency of the federal government which has oversight on operation and maintenance and has its own dam safety program for periodic inspection and repair of safety deficiencies of completed projects. The department will continue to be the state repository for pertinent plans, reports, and other documents related to the safety of federally owned dams.

4. (4) These regulations do not apply to transportation facilities such as roads, highways, or rail lines which cross watercourses and exist solely for transportation purposes and which are regulated by other governmental agencies.

   Those transportation facilities which cross watercourses and which have been, or will be, modified with the intention of impounding water on an intermittent or permanent basis and which meet the conditions of subsection (1) of this section shall be subject to these regulations.

5. (5) These regulations do not apply to dikes or levees constructed adjacent to or along a watercourse for protection from natural flooding or for purposes of flood plain management.
6. (6) These regulations do not apply to concrete or steel water storage tanks.
7. (7) These regulations do not apply to FERC licensed projects and to FERC exempted projects. The department will continue to maintain a repository for pertinent plans, reports, and other documents related to the safety of FERC licensed and FERC exempted projects.

[Statutory Authority: RCW 43.21A.064, 43.21A.080, 86.16.061, 90.03.350 and [90.03].470. WSR 04-16-122 (Order 03-08), § 173-175-020, filed 8/4/04, effective 9/4/04. Statutory Authority: 1995 c 8. WSR 95-22-030 (Order 94-15), § 173-175-020, filed 10/24/95, effective 11/24/95. Statutory Authority: RCW 43.21A.064, [43.21A].080 and 86.16.061. WSR 93-01-090 (Order 92-35), § 173-175-020, filed 12/16/92, effective 1/16/93; WSR 92-12-055 (Order 91-17), § 173-175-020, filed 6/1/92, effective 7/2/92.]