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HomeMy WebLinkAboutBOCC Staff Report 2.10.03REQUEST: BOCC 2/10/03 TP PROJECT INFORMATION AND STAFF COMMENTS Application for Site Approval for Construction of a new Domestic Wastewater Treatment Facility at the Bair Ranch Rest Area APPLICANT: Colorado Department of Transportation (CDOT) ENGINEERS: Church & Associates, Inc. LOCATION: Bair Ranch Rest Area is located along Interstate 70, approximately 8 miles east of the City of Glenwood Springs, in the NE1/4, SW1/4, Section 15, T5S, R87W of the 6th P.M. I. SUMMARY OR REQUEST CDOT is proposing the construction of a wastewater treatment facility ("WTF") at the Bair Ranch Rest Area. II. DESCRIPTION OF THE PROPOSAL The Bair Ranch Rest Area ("Rest Area") is currently served by on-site water wells and by an individual sewage disposal system ("ISDS") consisting of septic tanks and a drain field. The request is to abandon the existing ISDS drain field and convert the composting toilets to flush toilets. The wastewater will be treated by the proposed WTF. The proposal is to discard the treated wastewater to the Colorado River. The "service area" will consist only of the Rest Area. PROJECTED POPULATION According to the engineering report, the projected population for the proposed WTF is based on daily people counts provided by CDOT for the year 2001 and a portion of year 2002, and on the projected increase in usage of the Rest Area to the year 2015. 1. One thousand (1,000) to 1,200 people have consistently used the Rest Area over weekend and holiday periods during the busiest months, July and August. 2. Approximately 500 to 900 people use the rest area during mid -week periods of those months. 3. Peak people counts ranged from 1,300 to 1,400 people per day and were observed only occasionally. 4. Considering the weekend and holiday, people counts are significantly greater than the Bair Rest Area Site Application Board: February 10, 2003 Page 2 midweek counts and occur consistently. The average daily usage should be based on the weekend counts. 5. An average daily people count of 1,100 for the year 2002 is proposed. 6. Per CDOT projection, the usage of the Rest Area will increase approximately 50 percent by the year 2015. An average daily usage of 1,650 people per day is proposed. WASTEWATER FLOW Average daily wastewater flows have been estimated by monitoring the daily water usage at the No Name Rest Area, and the people count data at the Bair Ranch Rest Area, and taking into account the type of fixtures planned for restrooms. An average flow of 2 gallons per person per usage is proposed. An average daily flow (q 015) of 3,300 gallons per day ("GPD") is proposed. Proposed Average Daily Flow (g201) = (1,650 people/day) X (2 gallons/person) = 3,300 GPD WATER AND SANITATION DISTRICTS The Two Rivers Water and Sanitation District ("District") is the only District located within a 5 - mile radius of the proposed WTF. There are 15 commercial, industrial, and/or municipal permitted wells located within a 5 mile radius of the WTF. These include: 1. Ten wells near Dotsero. 2. One well for irrigation/commercial use at the Rest Area and owned by CDOT. 3. Four wells for industrial, commercial, irrigation and/or domestic uses located at the Hanging Lake Rest Area and owned by CDOT. No water supply intakes are located within a 5 -mile radius of the proposed WTF. There are four wells registered with the Division of Water Resources of the Colorado State Engineers Office located within 1 -mile of the proposed WTF. The wells, include one irrigation/commercial well owned by CDOT, mentioned above, and three domestic and/or livestock wells. One of the three domestic wells is located at the Rest Area and owned by CDOT, and two of the domestic/livestock wells are owned by Mr. James Bair. HAZARDS According to the engineering report, there are no geologic hazards that would prevent the development as proposed. The proposed facility is located higher than the identified 100 -year floodplain. Bair Rest Area Site Application Board: February 10, 2003 Page 3 DESCRIPTION OF SELECTED ALTERNATIVE A Packed -Bed Filter (PBF) treatment system consisting of a septic tank, recirculation tank, geotextile packed filters, and disinfection system with surface discharge is proposed for the Rest Area. The treatment system will be located east of the rest area and north of the access road. The following description of the PBF system was taken from the Engineering Report. The PBF system includes a standard, two-compartment septic tank for solids retention and digestion. Effluent from the septic tank will flow to a recirculation tank where an effluent pumping system will dose effluent to the surface of geotextile filters. The geotextile filter media develops aerobic bacteria, which bio -chemically treat the effluent, and convert ammonia nitrogen to nitrate nitrogen. The treated effluent flows back to the recirculation tank where it mixes with the anaerobic septic tank effluent. Additional bio- chemical reactions occur which convert the nitrate nitrogen into a harmless and odorless nitrogen gas, which is ventedfrom the system. Total nitrogen reductions of 40% and 50% can be anticipated. After 3-5 passes through the geotextile filters, the effluent is ready for discharge to the proposed ultra -violet light disinfection system. Once disinfected, the effluent will discharge to Colorado River. The bio -chemical oxygen demand (BOD) and total suspended solids (TSS) concentrations should consistently be less than 10 mg/1. According to the engineering report, numerous PBF systems have been installed in the United States since the early 1990s. Audits and routine monitoring by county, state, and federal agencies have shown generally excellent results, even with a wide variation in incoming flows. The average daily wastewater loading to the proposed WTF is 3,330 GPD. The system will be operated and maintained by either a certified wastewater system operator, or by CDOT personnel, or through a contract with a wastewater system management company. TREATMENT ALTERNATIVES The Applicant indicated that several wastewater system alternatives were considered. These alternatives include the following: 1. Connect to an existing Treatment Facility: The closest WTF is located in Dotsero, for the Two Rivers Water and Sanitation District, approximately 5 miles from the rest area. Due to the distance, difficult terrain, and costs in general, this option is not feasible for the anticipated flows. Bair Rest Area Site Application Board: February 10, 2003 Page 4 2. Consolidation of Treatment Facilities: The Colorado Department of Public Health and Environment ("CDPHE") requested an evaluation be conducted for the consolidation of treatment facilities for Bair Ranch, Hanging Lake, and Grizzly Creek Rest Areas. Due to fill including significant large boulders and the installation of as much as 5 miles of connection sewer line making consolidation of the three treatment plants impractical and prohibitively expensive. 3. Install New Subsurface Drain Fields: There is adequate area for installing new drain fields for the anticipated wastewater flows. However, an anticipated 10 mg/1 nitrate limit required for drain fields would require treatment that is cost prohibited. 4. Package Treatment Plant: This option evaluated extended aeration and sequential batch reactor technologies. The primary consideration is the relatively small, highly variable flows encountered from a single source used with seasonal peaks. The PBF system was chosen due to its filter media treatment capabilities, its recirculation characteristics, and its ability to be designed in modular form minimizes the concerns for highly variable flows. A similar PBF system was approved by CDPHE for use at the Grizzly Creek Rest Area. IMPLEMENTATION PLAN AND SCHEDULE The following is the anticipated WTF permitting, construction and operation schedule. 1. Permitting: a. By December 2002 — submittal of the application for site approval to the CDPHE with signatures from the associated government agencies b. By June 2003 — submittal of the completed wastewater system design to Garfield County and CDPHE 2. Construction: a. By August 2003 — begin construction b. By November 2003 — complete construction 3. Operation: a. By July 2003 — submit application for a Discharge permit b. By November 2003 — place system into operation III. RELATIONSHIP TO THE COMPREHENSIVE PLAN The Garfield County Comprehensive Plan of 2000 identifies the area of the WTF as a Low Density Residential. The recommended density in the low-density residential category is 10 acres or more per dwelling unit. Bair Rest Area Site Application Board: February 10, 2003 Page 5 IV. ISSUES AND CONCERNS State Statutes: C.R.S. 25 -8 -702(2)(a -c), and the "Regulations for Site Applications for Domestic Wastewater Treatment Works, defines the parameters by which the Water Quality Control Division ("Division") shall review and approve or deny a site application for a wastewater treatment works. The Division is required to determine that each site location is 1) consistent with the long range, comprehensive planning for the area in which it is to be located; 2) that the plant on the proposed site will be managed to minimize the potential adverse impacts on water quality; and 3) must encourage the consolidation of wastewater treatment works whenever feasible. The Applicant is required to obtain a recommendation of approval, denial or no comment from the Garfield County Board of Health and County Board of County Commissioners and various other local and regional agencies. Garfield County's involvement in the process is to determine whether or not the proposed wastewater treatment work is consistent with "the long-range comprehensive plan for the area as it affects water quality and any approved regional wastewater management plan for the area". The Garfield County Comprehensive Plan ("Plan") identifies the site as Low Density Residential area. With respect to the "Septic System Constraints" map, this area has not been identified as an area consisting of a high water table, slow perc rate or solution evaporite minerals. The Plan provides very little guidance through the goals and objectives section of the plan with respect to the WTF. One of the applicable Water and Sewer Services goals is: "To ensure the provision of legal, adequate, dependable, cost effective and environmentally sound water and sewer services for new development." Objective 7.5 of the Plan, provides the most direct guidance to this issue. It states that: "Garfield County will strongly discourage the proliferation of private water and sewer systems." V. RECOMMENDATION 1. Staff recommends that the Garfield County Board of County Commissioners recommend APPROVAL of the site application for the Bair Ranch Rest Area Wastewater Treatment Facility and authorize the Chairman to sign the site application. Bair Rest Area Site Application Board: February 10, 2003 Page 6 2. Staff recommends that the Garfield County Board of Health recommend APPROVAL of the site application for the Bair Ranch Rest Area Wastewater Treatment Facility and authorize the Chairman to sign the site application.