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23.16.020 Required improvements.
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A. General. All improvements as may be required as conditions of approval of the tentative parcel or subdivision map, or by county ordinance or resolution, together with, but not limited to, the mandatory improvements set forth below, shall be required of all subdivisions.

B. Remainder. Except as required pursuant to an agreement between the county and subdivider, improvements will not be required for a designated remainder until a permit or grant of approval is issued, or earlier upon a finding that 1) the construction is necessary for the public health and safety, or 2) the construction is a necessary prerequisite to the orderly development of the surrounding area.

C. Frontage Improvements. The frontage of each lot shall be improved to its ultimate adopted geometric section, including street structural section, curbs, sidewalks, driveway approaches, and transitions as specified by the Commission after consultation with any applicable resolutions of the Board of Supervisors.

D. Flooding and Drainage.

1. The subdivider shall design the subdivision so that it shall be protected from inundation, flood hazard, sheet overflow, and ponding of local storm water, springs, and other surface waters. Improvements shall be designed so that water occurring within the subdivision will be carried off such subdivision without injury to any improvements, building sites, buildings, structures, or adjoining areas and will not cause erosion or siltation that would be detrimental to the environment of the area. Waters occurring within the subdivision shall be carried to a storm drainage facility or to a natural watercourse by such improvements as may be required by the Planning Commission to meet the design standards set forth in this title and by Board of Supervisors’ resolution. Drainage design within the subdivision shall accommodate reasonable anticipated future development within the drainage area. Any off-tract outlet drainage facility required to carry storm water from the proposed subdivision to a defined channel or conduit shall be made adequate for the ultimate state of development in the drainage area.

2. In any case when a watercourse traverses or serves a subdivision, adequate on-site and off-site easements for storm drainage purposes shall be provided.

3. A storm drainage maintenance district or acceptable alternative which includes the entire subdivision shall be established for the maintenance of storm drainage facilities within the subdivision and any off-site drainage easements. If a storm drainage maintenance district has previously been established within a particular drainage area, where said subdivision is being proposed, the proposed subdivision shall be annexed to the existing district.

4. If the county has adopted a drainage plan for all or part of the proposed subdivision, the subdivision shall be required to pay a fee consisting of a pro-rata share of the cost of contracting or estimated cost of constructing drainage facilities within the drainage area.

E. Sewage Disposal. Every tentative subdivision map and tentative parcel map approved pursuant to this title shall be conditioned upon compliance with the requirements of the California Regional Water Quality Control Board – Central Valley Region, and the Sierra County Code.

1. The Planning Commission may require that the subdivider connect to a sewer and drain system having plant capacity to handle his subdivision; that the subdivider construct an adequate sewage treatment plant and lines if there is no district having adequate capacity serving the proposed subdivision; or that the subdivider construct such other means of sewage disposal as shall be approved by the County Health Department.

2. Lots not served by sewers shall require the filing by the subdivider of a report indicating the feasibility of the proposed method of sewage disposal and the approval of the County Health Department for private sewage disposal.

3. In a subdivision served by a sewer system under county jurisdiction, all sewer lines, sewage treatment facilities, and appurtenances shall be constructed in accordance with the requirements of the County Engineer and the County Health Department.

4. Approval of improvement plans by the serving utility district for sewer improvements shall be required. The sewage capacity shall be calculated and submitted to the county identifying that the district has reserved sewage disposal capacity to serve this development and that this capacity will not be used for any other purpose.

F. Water Supply.

1. The Planning Commission may require that the subdivider connect to a water treatment and distribution system having adequate plant capacity to handle the subdivision; that the subdivider construct an adequate water treatment and distribution system if there is no district or water company having adequate capacity serving the proposed subdivision; or that the subdivider construct such other means of water treatment and distribution as shall provide adequate water to meet domestic and fire use. Fire use shall be no less than 500 gallons per minute for duration of four hours. Water mains supplying water to fire hydrants shall conform to the specifications set by Board of Supervisors resolution.

2. In those areas within a subdivision served by a water furnishing district or water company under county jurisdiction, all lines and facilities shall be constructed in accordance with the requirements established by state law and this title.

3. If the water system is not retained in private ownership, a district, county service area, or other public entity shall be formed to provide for maintenance and operation of the water system.

4. Mutual water companies and homeowners’ associations shall be permitted to be the water suppliers only with the approval of the county. Individual water treatment systems on the lots for water serving the lots in a subdivision shall not be permitted.

5. Domestic water shall meet all the local and state standards for quality and quantity. Any treatment plant, storage facilities and appurtenances used to render water safe for domestic use must be approved by the County Health Department.

6. Approval of improvement plans by the utility district for water service supply and maintenance is required. The water capacity shall be calculated and submitted to the county, stating that the district has the capacity to serve and meet the flows and volumes required for domestic use and fire protection for this development, over and above previously approved and existing users.

7. The following criteria shall apply to lots or parcels located or proposed to be located within 1,000 feet of a body of water or within 800 feet of a watercourse used, or likely to be used, for domestic water within five miles upstream or downstream from said lots or parcels:

a. Lots or parcels shall have a minimum lot area of five acres if both individual water and individual sewage disposal have to be installed on the lot.

b. In the event that other than individual sewerage disposal or treatment is proposed, the minimum lot areas shall be governed by water supply and applicable zoning.

c. In any event, effluent from a sewer collection system in a watershed area must be treated as required by the County Health Department and Regional Water Quality Control Board, state of California.

8. Water supply provided by wells shall be subject to approval by the County Engineer and the County Health Department. Prior to any approval the adequacy of such supply shall be demonstrated by the subdivider in any of the following ways:

a. Providing a test well or wells on five percent to 10 percent of the proposed parcels which are proposed to use individual wells (not less than one test well) as required by the County Sanitarian, accompanied by a water supply evaluation report from a hydrogeologist registered in the state of California.

b. In subdivisions where domestic water is proposed by individual wells and under the written advisement of an experienced hydrologist, supported by approval of the County Sanitarian and County Engineer, a report can be substituted for the required test well. This report shall minimally contain the location of and log data from active wells on adjoining property and an analysis of subsurface geology indicating the reliability of transferring data from the control wells to the proposed parcels.

c. In subdivision where community wells are proposed, all proposed wells shall be pump tested. The pump tests shall be provided by the subdivider and shall be performed under the direction of the County Engineer. The tests shall be performed by a groundwater geologist or hydrologist licensed in the state of California and a water supply and evaluation report containing the results of the pump tests shall be submitted to the County Engineer.

9. All groundwater sources shall be capable of delivering a sustained flow of five gallons per minute for each parcel served and shall meet the approval of the County Health Department. A test, provided by the subdivider and under the direction of a hydrogeologist or hydrologist, licensed in the state of California shall be conducted for at least 24 to 72 hours for an individual well and 24 hours to 15 days for a community well after the source is developed to determine the yield and maximum drawdown. The results of these tests shall be reviewed by and meet the approval of the County Engineer.

10. Treated or untreated distribution systems may be considered by the Planning Commission and may be determined to be adequate as sources of domestic water supply when the subdivider submits a letter from the serving entity which agrees to supply water to the proposed parcels and states the following:

a. The source and location of the distribution facility (name of canal, ditch, pipeline, etc., and its distance from the proposed parcels) and whether the water to be delivered is treated or untreated.

b. Water will be available on a year-round basis to all proposed parcels.

c. Minimum quantity of water available to each proposed parcel.

d. Any restrictions, reservations, conditions or controls set by the serving entities upon the delivery, sale, or use of the supplied water.

e. Approval has been secured from the County Health Officer and state of California, Regional Water Quality Control Board.

11. A pump test and/or water supply evaluation report shall include, but not be limited to, the following:

a. The total groundwater supply available for the project.

b. The long-term yield of proposed project wells.

c. The impact of groundwater withdrawal on stream flow, springs, vegetation, water levels, and any water sources in the area.

d. The relation between groundwater development at the project and adjacent present and future water supply development.

e. The impacts of waste disposal facilities on groundwater quality.

G. Each unit or lot within the subdivision shall be served by electric, telephone and cablevision facilities where reasonably available.

H. Underground Utilities. At the time a tentative parcel map or tentative map is approved, the Planning Commission may impose, as a condition of such approval, the requirements to install underground utilities as hereinafter provided.

1. The installation of underground utilities shall comply with not less than the minimum requirements for the placement of electrical and communications facilities in compliance with State Public Utilities Commission regulations. Equipment appurtenant to underground facilities, such as surface-mounted transformers, pedestal terminal boxes, and meter cabinets and concealed ducts may be installed above the ground; provided, that such facilities shall be located and designed so as to harmonize with the area and shall be appropriately screened and landscaped.

2. The responsibility of the coordination and obtaining approval from each utility concerned for the placement of underground utilities shall rest solely with the subdivider.

3. The number of working days and the sequence of installation for each utility shall be listed separately on the submitted improvement plans. The location of each utility facility and the common trench detail shall be shown by plan and cross section on the improvement plan and shall be approved by the County Engineer.

4. The subdivider shall be responsible for complying with the requirements of this section and shall make the necessary arrangements with the utility companies involved for the installation of said facilities. An agreement shall be entered into between the subdivider and the utility companies listing who performs and finances each segment of work relating to electrical and telephone installations. A letter from the serving utility company will be required before the improvement plans are signed by the County Engineer and the County Planning Director. The letter shall state that said company has approved the design, utility location and scheduling and has entered into the above agreement.

5. Any high voltage or major communication facility should be identified in accordance with public utility company requirements by a buried cable marker or acceptable alternate on each side of the roadway.

I. Fire Protection. The County Planning Commission, after consultation with the appropriate fire protection district, shall require fire protection improvements for all subdivisions.

J. Other Improvements. Other improvements including, but not limited to, grading, street lights, fire hydrants, signs, street lines and markings, street trees and shrubs, landscaping, monuments, bicycle facilities, fences, noise barriers, fire fighting improvements or fees in lieu of any of the foregoing shall also be required as determined by the Planning Commission in accordance with this title, the general plan, county standards and specifications.

K. Off-site Improvements. If the subdivider is required to construct off-site improvements on land in which neither the subdivider nor the county has sufficient title or interest to allow construction, the county shall, within 120 days of recording the final map, acquire by negotiation or commence condemnation of the land. If the county fails to meet the 120-day time limit, the condition for the construction shall be waived. Prior to approval of the final map, the county may require the subdivider to enter into an agreement to complete the off-site improvements at the time the county acquires title or an interest in the land.

The subdivider shall pay the cost of acquiring off-site land or an interest in the land required to construct the off-site improvements. (Formerly 23.16.002)