16.18D.050 Critical area report – Additional requirements for critical aquifer recharge areas.
In addition to the general critical area report requirements of Section 16.18A.220, critical area reports for critical aquifer recharge areas must meet the requirements of this section. Critical area reports for two or more types of critical areas must meet the report requirements for each relevant type of critical area.
A. Preparation by a Qualified Professional. An aquifer recharge area critical area report shall be prepared by a qualified professional who is a hydrogeologist, geologist, or engineer, who is licensed in the state of Washington and has experience in preparing hydrogeologic assessments.
B. Hydrogeologic Assessment. For all proposed activities to be located in a critical aquifer recharge area, a critical area report shall contain a level one hydrogeological assessment. A level two hydrogeologic assessment shall be required for any of the following proposed activities:
1. Activities that result in five percent or more impervious site area;
2. Activities that divert, alter, or reduce the flow of surface or ground waters, or otherwise reduce the recharging of the aquifer;
3. The use of hazardous substances, other than household chemicals used according to the directions specified on the packaging for domestic applications;
4. The use of injection wells, including on-site septic systems, except those domestic septic systems releasing less than fourteen thousand five hundred gallons of effluent per day and that are limited to a maximum density of one system per one acre; or
5. Any other activity determined by the mayor or designee likely to have an adverse impact on ground water quality or quantity or on the recharge of the aquifer.
C. Level One Hydrogeologic Assessment. A level one hydrogeologic assessment shall include the following site- and proposal-related information at a minimum:
1. Available information regarding geologic and hydrogeologic characteristics of the site including the surface location of all critical aquifer recharge areas located on site or immediately adjacent to the site, and permeability of the unsaturated zone;
2. Ground water depth, flow direction, and gradient based on available information;
3. Currently available data on wells and springs within one thousand three hundred feet of the project area;
4. Location of other critical areas, including surface waters, within one thousand three hundred feet of the project area;
5. Available historic water quality data for the area to be affected by the proposed activity; and
6. Best management practices proposed to be utilized.
D. Level Two Hydrogeologic Assessment. A level two hydrogeologic assessment shall include the following site- and proposal-related information at a minimum, in addition to the requirements for a level one hydrogeological assessment:
1. Historic water quality data for the area to be affected by the proposed activity compiled for at least the previous five-year period;
2. Ground water monitoring plan provisions;
3. Discussion of the effects of the proposed project on the ground water quality and quantity, including:
a. Predictive evaluation of ground water withdrawal effects on nearby wells and surface water features; and
b. Predictive evaluation of contaminant transport based on potential releases to ground water; and
4. A spill plan that identifies equipment and/or structures that could fail, resulting in an impact. Spill plans shall include provisions for regular inspection, repair, and replacement of structures and equipment that could fail. (Ord. 1104-15 § 1 (Att. A)).