§ 17.20.200. Hydrogeological report.

If a hydrogeological report is required by Chapter 17.15 TCC, the approval authority may require the report to include any of the following additional elements:

A.

Groundwater elevation of uppermost saturated zone based on at least one year of conservation water level data, including seasonal variations. Other reliable data may be employed upon approval by the health officer;

B.

Locations on existing wells within one thousand feet of the excavation boundary. Well information including well logs, static water level, well depth, well elevation, estimated withdrawal rate and other relevant information shall be included as it may be available;

C.

Description of effects including water quality and water level changes expected to occur in any of these existing wells as a result of mining activity;

D.

Proposed final depth of excavation;

E.

If proposed mining will intercept an aquifer, background water quality for iron (Fe), manganese (Mn), turbidity, nitrate (NO ₃ expressed as N), total petroleum hydrocarbons, and water chemistry parameters related to the ability of silts and clays to settle from water shall be determined as part of the report. Additional water quality parameters may be required on recommendation by the health officer if local conditions merit such inclusion. When adequate and reliable water quality background data exists it may be used by approval of the health officer. If background water quality data does not exist, water quality background shall be based on methods acceptable to the department of ecology or be based on at least six sampling events of data generally collected once per month. The health officer may accept other methods of determining background parameters if performed according to methods approved by the Environmental Protection Agency or the United States Geological Survey;

F.

An analysis of turbidity (for mineral extraction) and water chemistry (for mineral extraction and asphalt production) as related to the proposal. This includes a professional estimate of how far turbidity might be expected to be transported, based on overlying soil type, earth materials lateral to the mining activity, particle composition, pore sizes within the aquifer, the groundwater flow velocity, and the chemistry of the groundwater;

G.

Estimated effects of stormwater and process water.

(Ord. 10368 § 3 (part), 1993)

(Ord. No. 14782, § 4(Att. C), 8-14-2012)