§ 17.15.535. Aquifer recharge areas—Special reports requirements.

The following describes the requirements of each special report:

A.

Drainage and Erosion Control Plan.

1.

This plan shall address methods to minimize erosion and contain soil within the project boundaries during construction and to provide for stormwater management from the site and its surroundings during and after construction.

2.

The design standards for this plan are contained in the Drainage Design and Erosion Control Manual for Thurston County (1994), as amended.

B.

Hydrogeological Report.

1.

This report shall identify the proposed development plan and the risks associated with on-site septic systems and other on-site activities which may degrade the groundwater beneath or down gradient from the site.

2.

This report shall be prepared by a licensed professional engineer, licensed in the state of Washington, qualified to analyze geological and hydrological information and groundwater systems, or prepared by a geologist schooled and trained in geology and groundwater systems.

3.

A hydrogeological report shall contain:

a.

A description of the soil, geological and hydrological characteristics of the area under permit application consideration, and including the relationships between groundwater and surface water and stream flows;

b.

A discussion of how the characteristics described in subsection B3a above will influence drainage and the movement of water and contaminants in the groundwater, and a discussion of how the proposed project will influence surface water including instream flows;

c.

A description of conditions prior to project development;

d.

A description of conditions as they are likely to exist after complete development of the proposed project, and their impact on groundwater quantity and quality;

e.

A list of those recommendations to be used to mitigate any of these potential groundwater impacts. This shall include the effects of sewage disposal, lawn and yard activities, agricultural and animal husbandry, household chemical use, stormwater impacts and any other impacts reasonably associated with the project type described;

f.

This post development description shall include the effects of the activities likely to occur as a result of the complete development and use of the project at final equilibrium.

4.

Review and evaluation of the report may be delegated to other county departments and to qualified private consultants under the direction of the health officer.

C.

Foundations. The applicant shall submit the following information, certified by a qualified engineer, for foundations subject to review in accordance with Section 17.15.520(E)(2).

1.

The proposed depth of the foundation below the ground's surface;

2.

The depth to the aquifer that the well(s) within two-hundred feet of the proposed foundation draws upon. If the aquifer drawn upon is less than fifty feet below the bottom of the hole proposed to be excavated to accommodate the foundation, then the applicant shall submit the information called for in subsections (C)(3) through (C)(5) of this section;

3.

The distance from the proposed foundation to the subject well(s);

4.

The foundation design and materials, including the concrete mix and the specific components of any additives, and the composition of any sealer/slurry proposed to be employed in construction of the foundation;

5.

Proposed construction techniques, such as use of a casing, to mitigate potential groundwater contamination.

(Ord. 12908 § 10, 2003; Ord. 11200 § 21, 1996: Ord. 10528 § 1 (part), 1994)