§ 18.108.027. Sensitive domestic water supply drainages.

A.

Applicability. The provisions of this section shall apply in sensitive domestic water supply drainages.

B.

Vegetation Clearing. A minimum of seventy percent of the tree canopy cover on the parcel existing on June 16, 1993 along with any vegetation understory, or when vegetation consists of shrub and brush without tree canopy, a minimum of forty percent of the shrub, brush and associated annual and perennial herbaceous vegetation shall be maintained as part of any use involving earth-disturbing activity. Two or more contiguous parcels held and maintained under common ownership or legal control at the time the plan is submitted may be considered combined and treated as one holding for purposes of compliance with the vegetation retention requirements in this section; provided that: (1) the total vegetation proposed for clearing would not be greater than what could be cleared if each contiguous parcel was treated as an individual unit; (2) a report prepared by a qualified professional biologist is submitted to the director which concludes that the proposed vegetation clearing would not result in greater impacts to biological resources than what would occur if the combined parcels were treated as individual units; and (3) a perpetual protective easement or perpetual deed restriction is recorded for each parcel describing the amount of vegetation to be retained on each of the parcels.

C.

Winter Shut-Down. All earth-disturbing activities on any slopes (pursuant to subsection (L) of Section 18.108.070) shall be limited to the period of April 1st through September 1st of each year except earth-disturbing activities that are in compliance with the NPDES program administered by the planning department shall be limited to the period of April 1st through October 1st of each year. No earth-disturbing activities other than installation of winterization measures shall take place during other times of the year. All winterization measures shall be in place by September 15th of any given year or by October 15th for earth-disturbing activities that are in compliance with the NPDES program. However, earth-disturbing activities may be authorized by the director during the winter shut-down period, using the procedures specified for other watersheds in subsection (L) of Section 18.108.070. The applicable water purveyor shall be notified in writing at least seven calendar days prior to the director's decision to grant or deny a grading extension to allow the purveyor to comment on the request.

D.

Drainage Facilities. Concentration of runoff shall, wherever feasible, be avoided. Runoff shall instead be spread in small incremental doses into relatively flat buffer areas. Those drainage facilities and outfalls that unavoidably have to be installed shall be sized and designed to handle the runoff from a one hundred-year storm event without failure or unintentional bypassing. Outlets shall be protected against erosion in the one hundred-year storm event.

E.

Notice Required. The director shall provide notice to the owner/operator(s) of a public-serving water supply system(s) located in a sensitive domestic water supply drainage of each erosion control plan filed in their drainage. Said notice shall include a copy of the plan submitted and shall provide twenty-one days for a response. If the owner/operator(s) submits credible evidence within this time period that the delivery of sediment or other pollutants into their reservoir(s) from the drainage will be increased by more than one percent on an individual project basis or by more than ten percent on a cumulative basis, the subject erosion control plan shall not be approved until a public hearing on the matter has been held before the commission and a use permit has been issued.

F.

Geotechnical Report Required. A report prepared by a qualified professional specifying the depth and nature of the soils and bedrock present and the stability, both current and projected, of the area potentially effected shall be submitted by the property owner at the time of application for any project located in a sensitive domestic water supply drainage.

G.

Setbacks. No earthmoving activities shall take place within 500 feet of the Kimball Reservoir and Bell Canyon Reservoir, or within 200 feet of any other sensitive domestic water supply. The setback shall be measured from the top of bank of the municipal reservoir.

(Ord. 1300 § 2, 2007: Ord. 1269 § 1, 2005: Ord. 1259 § 3, 2005: Ord. 1219 § 2, 2003: Ord. 1062 § 4, 1994; Ord. 991 § 1 (part), 1991: prior code § 12452.2)

(Ord. No. 1438, § 5, 4-9-2019)