ABSTRACT

The Chico Urban Area Nitrate Compliance Plan (Plan) was prepared in response to the contamination of groundwater in the Chico Urban Area by nitrate, a form of nitrogen, and the subsequent issuance of Prohibition Order No. 90-126 adopted by the Central Valley Regional Water Quality Control Board on April 27, 1990. This prohibition order affects approximately 30,000 residents on 10,000 parcels, and represents nearly 12,000 dwelling units.

The source of nitrate contamination to the shallow aquifer beneath the Chico Urban Area is from the use by residents of on-site septic systems for wastewater disposal. Residential developments with a housing density equivalent of four or more dwelling units per acre contribute concentrations of wastewater nitrate loading that slightly exceed the nitrate maximum contaminant level to groundwater. Federal and State water quality standards indicate that nitrate concentration levels of 45 milligrams per liter or more are considered a threat to drinking water and public health. Approximately 65% of the 12,000 dwelling units affected by Prohibition Order No. 90-126 are located within high density areas and are recommended to be connected to the City of Chico's sewer system. This figure translates to approximately 7,800 dwelling units located in neighborhoods in north Chico (Lassen Avenue corridor), central Chico (the Avenues), and south Chico (Chapman-Mulberry area). These areas represent unincorporated portions of the Chico Urban Area and include single family dwelling units, apartment complexes, and mobile home parks.

The resulting installation of a sewer collection system for these target areas (7,800 dwelling units) is at an estimated capital cost of nearly $71 million dollars, with an average cost of about $9,000 per dwelling unit.

Program financing will be developed and managed by the County and involve combining a portfolio of low interest federal or state loans, local redevelopment agency funds, and available grants. It is proposed that loan re-payment mechanisms will include the formation of assessment districts for areas targeted to receive sewer installation and service. The County is also the lead agency for preparation of related environmental and construction documents in accord with the Plan.

It is proposed that construction of the sewer collection system and implementation of corrective action will occur within three to ten years from the date of adoption of the Plan by the Butte County Board of Supervisors (Board) and the Central Valley Regional Water Quality Control Board. Those parcels to remain unsewered may continue to use on-site waste water disposal systems, with additional monitoring, to ensure their safe and sanitary operation.

When adopted, this Plan will supersede the Nitrate Action Plan which was adopted by the Board and Chico City Council in 1985. It is imperative that the State, County, and City of Chico, maintain a cooperative and focused effort to mitigate and solve the public health threat to groundwater nitrate contamination beneath the Chico Urban Area.

(Abstract - Chico Urban Area Nitrate Compliance Plan)

k:\ad\e\quickref.tabQUICK REFERENCE GUIDE

to the

COUNTY OF BUTTE,

CHICO URBAN AREA NITRATE COMPLIANCE PLAN

This intent of this reference guide is to assist the reader in locating pertinent information in the Chico Urban Area Nitrate Compliance Plan (Plan).

DESCRIPTION OF PROJECT AREA & LOCAL GROUNDWATER BASIN

Table 1 provides a quick summary of the project area and important background information as it concerns the groundwater basin beneath the Chico Urban Area. All cited pages refer to the Plan.

Table 1. Description of Project Area & Aquifer (Groundwater Basin)

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PRIORITY AREAS FOR SEWERING

The priority areas for sewering include high density areas with more than 4 dwelling units per acre and locations where poor soil conditions may inhibit the performance of onsite systems. Figure 4-1 (page 4-4 of the Plan) shows a map of the Chico Urban Area and waste water nitrate loading as expressed in residential dwelling units per acre. Figure 4-2 (page 4-6) shows the locations of neighborhoods having an average density at or above approximately four dwelling units per acre. Figure 4-6 (page 4-11) shows the relative priority of sewering based upon the average residential density.

Table 5-1 on page 5-3 of the Plan shows a break down of the types and number of dwelling units north and south of Lindo Channel, and also the priority areas for sewering. Table 2 below provides summary information on the priority areas to be sewered north and south of Lindo Channel.

Table 2. Priority Areas for Sewering

Total units	Approximately 7,831 units.
# units north of Lindo Channel	Approximately 5,034 units
# units south of Lindo Channel	Approximately 2,797 units
Priority Area "I"	Lassen Avenue corridor between Cussick Avenue and to the Pleasant Valley ditch which is west of Cohasset Road. Includes high density neighborhoods north and south of Lassen Avenue. See also the map shown in Figure 4-2 (pp 4-6). Includes approximately 3,087 units.
Priority Area "II"	Located in the Avenues in neighborhoods west and east of the Esplanade, in general north of 3rd Avenue and as far east as State Highway 99. Refer also to the map shown in Figure 4-2 (pp 4-6). Approximately 930 units.
Priority Area "III"	Located in the Chapman-Mulberry area in neighborhoods south of E. Eighth Street, east of Mulberry and Cypress Streets, north of Silver Dollar Fairgrounds, and west of State Highway 99. Refer also to the map shown in Figure 4-2 (pp 4-6). Approximately 721 units.

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ESTIMATED PROGRAM COSTS

Table 3 addresses the total estimated costs to property owners who would connect to sewer in accordance with the Plan. Also refer to Table 5-2 (page 5-5) of the Plan for more explanation of onsite and offsite costs.

Table 3. Costs to Property Owners

(SOURCE: These cost figures were updated as part of the Phase 2 Sewer Feasibility study (December, 1998).

Estimated construction costs to abandon a septic tank, install the lateral sewer line from the living unit to the sewer main, to install the sewer main, and pay for City treatment plant capacity, sewer trunk line capacity, and sewer main fees, are approximately $9,000 per unit. The costs of applicable fees charged by the City of Chico need to be examined further. Public financing costs have not yet been determined and will depend upon the type of financing method that is selected.

These costs will be further refined as the financial program is developed.

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METHOD OF FINANCING

Table 4 summarizes Butte County's strategies to develop a financial program in accordance with the Plan. The financing of sewer improvements is addressed in Chapter 5, pages 5-8 through 5-13.

Table 4. Method of Financing

In reference to Chapter 6, the County is the lead agency that will create a financial program for the construction of onsite and offsite sewer facilities. Financing activities may include provisions for long term loans, imposing liens upon the sale of private property, and/or developing or pursuing grants to those needing financial assistance.

Butte County will pursue financing that will combine grants and low interest loans available through Federal, State and local programs. Methods for the re-payment of loans may include the establishment of assessment districts and also the use of redevelopment agency funds in priority sewer areas. The terms for loan re-payments may range from 10 to 20 years.

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