Section 246-272B-03200. Environmental review—Site risk survey.

At a minimum, the SRS must include the following information:

(1) Design flow and waste strength.

(2) A description of the physical characteristics of the primary and reserve drainfield site including:

(a) Predominant soil type;

(b) Vertical separation; and

(c) Water table.

(3) Identification of sensitive or critical areas designated by a local, state, or federal agency if the primary or reserve drainfield is located within the boundaries of the area including, but not limited to:

(a) Critical aquifer recharge area;

(b) Sole source aquifer;

(c) Designated wellhead protection area;

(d) Marine recovery area; and

(e) One hundred-year flood plain.

(4) Identification of sensitive lands or resources within one-half mile of the primary or reserve drainfield perimeter including, but not limited to:

(a) Fish hatcheries;

(b) Shellfish growing areas; and

(c) Water recreation areas.

(5) Basic hydrogeology information for the primary and reserve drainfield including, but not limited to:

(a) Well logs for all wells within one thousand feet;

(b) Depth to groundwater including perched groundwater and deeper aquifers;

(c) Vadose zone characteristics, including the presence of impermeable layers or aquitards;

(d) Direction of groundwater flow;

(e) Groundwater quality information, including nitrate and fecal coliform;

(f) Nitrate screening balance; and

(g) Potential hydraulic continuity to surface water.

(6) Topographic map that clearly shows site features including:

(a) Map scale and north arrow;

(b) Section, township, and range where project is located;

(c) Project or property boundaries;

(d) Location of proposed primary and reserve drainfields;

(e) Location of areas prone to flooding including any designated one hundred-year flood plain boundaries;

(f) Unstable areas prone to significant surface or mass erosion;

(g) Direction of groundwater flow;

(h) Other contaminant sources including other OSS;

(i) Critical area boundaries or other sensitive areas listed in subsections (3) and (4) of this section;

(j) Surface water and wetlands within one thousand feet of the proposed drainfield perimeter; and

(k) Active and abandoned wells within one thousand feet of the proposed drainfield perimeter.

(7) Other information the department may request to determine public health and environmental impacts from the LOSS.

[Statutory Authority: RCW 70.118B.020. WSR 11-12-035, § 246-272B-03200, filed 5/25/11, effective 7/1/11.]

RCW 70.118B.020. WSR 11-12-035, § 246-272B-03200, filed 5/25/11, effective 7/1/11.