(1) As authorized by RCW 43.21A.064, the department has the authority to conduct routine periodic inspections of all existing dams with high and significant downstream hazard classifications to reasonably secure safety to life and property.

• Dams with high downstream hazard classifications will be inspected every five years.

• Dams with significant downstream hazard classifications will be inspected every five years, or ten years if workload or staffing necessitates a longer cycle between inspections.

• Dams classified as low hazard are not included in the periodic inspection program.

(a) The department will give at least thirty days notice of the date of the periodic inspection and advise the owner of any requirements such as gates or valves that are to be operated during the inspection.

(b) Fees shall be charged for periodic inspections conducted by the department. The amount of the fee and owner requirements for the fee payment are described in WAC 173-175-755 through 173-175-775.

(2) The downstream hazard classification of existing dams shall be determined by the department in accordance with WAC 173-175-130, Table 3.

(3) The classification of each dam shall be reviewed during each periodic or other inspection and may be changed as the result of such inspection.

(4) Each periodic inspection shall consist of, but not be limited to, the following:

(a) Review and analysis of available data on the design, construction, operation, and maintenance of the dam and its appurtenances;

(b) Visual inspection of the dam and its appurtenances, the downstream area, and all other areas affected by the structure;

(c) Evaluation of the safety of the dam and its appurtenances, which may include assessment of the hydrologic and hydraulic capabilities, structural stabilities, seismic stabilities, and any other condition which could constitute a hazard to the integrity of the structure;

(d) Evaluation of the downstream hazard classification;

(e) Evaluation of the operation, maintenance, and inspection procedures employed by the owner and/or operator; and

(f) Review of the emergency action plan for the dam including review and/or update of dam breach inundation maps.

(5) The department shall prepare a written safety inspection report that describes the findings from the inspection and lists remedial actions that must be taken to ensure the continued safety of the dam.

(6) The department shall provide the dam owner with a copy of the written report of the periodic inspection. The dam owner must correct any identified safety deficiencies in a timely manner.