§ 700-120. WATER TABLE EVALUATION

(a)

Applications for the evaluation and/or installation of an OSS shall be subject to winter water table evaluations when a determination of the maximum groundwater level cannot be made.

(b)

Applications for the evaluation and/or installation of an OSS may be subject to a water table evaluation period not to exceed 30 days during summer (June—August) irrigation periods if it is suspected that the groundwater levels are influenced by such agricultural activities.

(c)

The LA's decision to hold a site for winter water table evaluation shall be based on the following conditions:

(1)

Historic high water table information documented in county development files;

(2)

Alterations of landscape, or filling and grading practices, which in the opinion of the Health Officer could alter the flow of surface/ground water at the site;

(3)

Redoximorphic soil features within the effective soil depth;

(4)

Restrictive layer at a depth that may create high seasonal groundwater levels;

(5)

Observations of wetland vegetation;

(6)

Proximity to water bodies, including but not limited to canals, marshes, and wetlands;

(7)

Areas or parcels located in drainage and flooding problem areas; and/or

(8)

High water table measurements recorded at the time of initial site evaluation.

(d)

Winter water table evaluations shall be conducted by an authorized professional and shall include at a minimum, monitoring of the groundwater levels every two weeks during the months of January, February, March, and April immediately following the initial site evaluation.

(e)

Any application submitted after the beginning of the winter water table evaluation period may require evaluation during the following winter water table evaluation season.

(f)

Results of a winter water table evaluation shall be submitted to the Department within one month after the conclusion of the evaluation period for review. The LA's decision shall be based on an evaluation of:

(1)

The site conditions recorded during the evaluation period; and

(2)

The amount of rainfall that equals or exceeds 80% of the seasonal mean rainfall for the period of November through April. This number shall be calculated using data from the Sacramento reporting station of the Department of Water Resources, Division of Flood Management.

(g)

All winter water table evaluation seasons (November through April) with recorded rainfall greater than or equal to the established comparison listed in Section 700-120-F(2) shall allow for the installation of systems complying with the regulations herein.

(h)

The LA may increase the vertical separation and/or level of sewage treatment for those parcels evaluated during an evaluation season with less rainfall than 80% of the mean seasonal rainfall as established under Section 700-120-F(2). Such increases in vertical separation and/or treatment requirements shall be determined via analysis of the site conditions in Section 700-120-C and the manual.

(i)

Sites shall be denied if the water table is measured within 24 inches of grade on any two consecutive readings or if surface water setbacks cannot be maintained. If a substandard reading of less than 24 inches is recorded, another reading shall be recorded within seven days of the first substandard reading.

(j)

All applicants shall have the opportunity to submit results from an additional winter water table evaluation period. This evaluation shall be compared to the results obtained during the previous evaluation period and its associated rainfall.

(Ord. No. 1632, § 1, 3-28-2017)