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> Water & Wastewater | The various supply sources are described below. The descriptions are intended as a brief summary and should not be construed as exhaustive or as a waiver of any right or interest in water. Water is measured in "acre feet" (AF). One acre foot equals 326,000 gallons. Annual amounts are measured in "acre feet per year" (AFY). | | Top l Gibraltar Reservoir l Devil’s Canyon l Cachuma Project l Mission Tunnel l Ground Water l Recycled Water l State Water Project l Desalination l Top
Gibraltar Reservoir
Description
Gibraltar Dam and reservoir are located on the Santa Ynez River in Santa Barbara County, about 9 miles north of the City and upstream from Lake Cachuma . The City owns and operates the dam and reservoir pursuant to a Notice of Appropriation posted on October 11, 1904. Stored water is diverted through Mission Tunnel to the Cater Water Treatment Plant. The dam is a constant radius, concrete arch dam constructed in 1920 with an original capacity of 14,500 AF; it was raised to current elevation in 1949 and strengthened in 1991.
Gibraltar Reservoir is the source of about one-third of the City of Santa Barbara’s water supply. Loss of storage capacity due to siltation has been an issue since the dam was constructed. To monitor changes in capacity, and pursuant to the requirements of the Upper Santa Ynez River Operations Agreement, the City commissions a bathymetric survey of Gibraltar Reservoir at approximately three year intervals. Watershed Drainage Area: 216 square miles
Water Surface Elevation at Normal Spill: 1,400 ft above sea level
Annual Yield: Average of approximately 4,600 acre feet per year
Current Capacity: 5,251 acre feet at 1,400 ft elevation (per 2010 bathymetric survey) Operating Criteria
Diversions are limited by the 1930 Gin Chow legal judgment and the 1989 Upper Santa Ynez River Operations Agreement (USYROA, also known as the "Pass Through Agreement"). The USYROA was developed to resolve concerns that the City’s planned raising of Gibraltar Dam would impact the feasibility of a potential Cachuma enlargement project. The City agreed to defer the planned raising of Gibraltar Dam in exchange for the right to “pass through” some of its Gibraltar water to Lake Cachuma for delivery to the City through Tecolote Tunnel. The amount of Pass Through water is based on the difference in Gibraltar spills under actual conditions as compared to a hypothetical “Base Reservoir.” The Base Reservoir is equal in size to the 1988 reservoir and “operated” (by computer model) according to a compromise interpretation of the Gin Chow judgment agreed to as a part of the USYROA. A basic goal of the agreement is to allow the City to stabilize the yield from Gibraltar at approximately 1988 levels while minimizing impacts on the Cachuma Project and other downstream interests. Cost Information
Costs for this source of supply are primarily "sunk" or fixed costs, including the original cost of construction, plus a cost of $9 million for strengthening in 1990-91, plus the cost of Mission Tunnel. Variable costs for Gibraltar water consist of the marginal cost of treatment at Cater Treatment Plant which is approximately $100/AF.
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Devil's Canyon Creek
 Description
The City maintains a small diversion structure on Devil’s Canyon Creek about a half a mile downstream of Gibraltar Dam which diverts water into Mission Tunnel. The diversion has been a source of supply for the City since the early 1900s. The primary use for the diversion is to supplement Gibraltar water during periods of turbidity, such as soon after a storm. The water from Devil’s Canyon clears up significantly faster than the reservoir water. Annual Yield
Average: 118 AFY
Range: 0 AFY - 557 AFY Operating Criteria
Water is diverted as available to help improve the quality of water going into Mission Tunnel. Water is diverted when a V-notch weir is lowered into a concrete channel causing the water flowing in the creek to back up and form a pool. An opening in the wall just upstream of the weir allows the water to enter a pipe which carries water to Mission Tunnel and into the City. This water is counted as a part of allowable diversions under the Pass Through Agreement. Cost Information
Variable costs are the same as Gibraltar water, or approximately $100/AF.
| | Top l Gibraltar Reservoir l Devil’s Canyon l Cachuma Project l Mission Tunnel l Ground Water l Recycled Water l State Water Project l Desalination l Top
Cachuma Reservoir
Description
Lake Cachuma and Bradbury Dam are located on the Santa Ynez River about 25 miles northwest of Santa Barbara. Bradbury Dam is owned and operated by the U.S. Bureau of Reclamation and was completed in 1953. Water is diverted from the reservoir through the 6.4 mile Tecolote Tunnel through the Santa Ynez mountains to the South Coast region. From the tunnel outlet, the water is carried through the 24 mile South Coast Conduit. About midway down the conduit, water is treated at the City’s Cater Water Treatment Plant and distributed to residents within the City’s service area, as well as put back into the conduit for delivery to residents in Montecito, Summerland and Carpinteria.
Cachuma Project Member Units
City of Santa Barbara
Goleta Water District
Montecito Water District
Carpinteria Valley Water District
Santa Ynez River Water Conservation District, Improvement Dist. No. 1
Drainage Area: 417 square miles (including Gibraltar drainage area)
Water Surface Elevation at Original Maximum Storage: 750 ft above sea level
Water Surface Elevation at Maximum Surcharge: 753 ft above sea level
Annual Yield: The Cachuma Project has a current yield of 25,714 acre feet per year and the City is entitled to 32.19% of the water available, which at the current yield is 8,277 AFY during normal years. Deliveries are typically decreased when the reservoir drops below 100,000 AF of storage.
Current Capacity: 186,636 AF at 750’ elevation, 195,578 AF at 753’ elevation
Operating Criteria
The project operates under a permit granted by the State Water Resources Control Board. Project water is accumulated to the extent that inflow is not needed to satisfy the release requirements. It is delivered to the member units in accordance with a Master Contract between U.S. Bureau of Reclamation, the Santa Barbara County Water Agency, and the Cachuma Project Authority. The contract was renewed in 1996 for a twenty five-year term.
Cost Information
The water supply contract with the U.S. Bureau of Reclamation sets the unit cost of the City's share of project yield at approximately $100 per acre foot for a total annual cost of approximately $993,000. Since this cost is treated as a payback of capital cost and fixed operating costs, it is not considered a variable cost. Variable costs are the same as for Gibraltar ($100/AF) since the water is treated at Cater Treatment Plant. | | Top l Gibraltar Reservoir l Devil’s Canyon l Cachuma Project l Mission Tunnel l Ground Water l Recycled Water l State Water Project l Desalination l Top
Mission Tunnel
Description
Mission Tunnel is used to convey water from Gibraltar Reservoir (and sometimes Devil’s Canyon Creek) to the Cater Water Treatment Plant. The tunnel itself is also a source of water for the City- water seeps from the walls, ceiling and floor into the tunnel. This 3.7 mile tunnel goes through the Santa Ynez Mountains and was constructed in 1904-1911; at the time it was the longest water tunnel in the world. Annual Infiltration
This infiltration of groundwater into Mission Tunnel has averaged approximately 1,000 AF annually, although this has fluctuated considerably over the years due to varying seasonal and yearly rainfall rates. Operating Criteria
Tunnel infiltration augments water conveyed from Gibraltar Reservoir- flowing to Cater Treatment Plant via gravity. A portion of this combined flow is sometimes diverted to Mission Creek for groundwater recharge purposes. Rehabilitation work was completed in December 1994 and the tunnel is inspected annually by City Water Resources and Engineering staff. Cost Information
Variable costs are the same as Gibraltar water or approximately $100/AF. The 1994 Mission Tunnel rehabilitation project was completed at a cost of $761,000.
| | Top l Gibraltar Reservoir l Devil’s Canyon l Cachuma Project l Mission Tunnel l Ground Water l Recycled Water l State Water Project l Desalination l Top
Groundwater
Description
Groundwater is produced primarily from two groundwater basins: Storage Unit 1 (in the general vicinity of downtown), and the Foothill Basin (upper State Street area). Storage Unit 3 (located generally in the Westside area) has the potential for limited production, though water quality is relatively poor. The United States Geological Survey currently estimates the usable storage volume to be approximately 16,000 acre feet. Groundwater recharge can be augmented through releases to Mission Creek and through injection capability at various production wells.
Perennial Yield
Perennial yield is the amount of water that can be pumped from the basins on a continual basis without causing overdraft. The portion of the perennial yield used by the City from all Storage Unit 1 and the Foothill Basis is approximately 1,300 acre feet per year. Storage Unit 3 is not normally used. Long-term average annual pumping has been estimated at 1,083 acre feet per year under the Long Term Water Supply Plan.
Operating Criteria
Groundwater is pumped to replace surface supplies lost to drought. During periods of ample surface supplies, groundwater is allowed to recharge naturally and by means of artificial recharge. Artificial recharge takes place only when space is available in the basin and as long as it is not precluded by pumping associated with the clean-up of groundwater contamination. Maximum pumping capacity is approximately 5,500 acre feet per year, but poor water quality and threat of seawater intrusion significantly reduces this capacity. Replacement wells are planned and a pumping capacity of at least 4,125 acre feet per year is the target for meeting long-term supply requirements. Cost Information
Variable costs for groundwater production range from $120 - $610 per acre foot. The rehabilitation of Ortega Groundwater Treatment Plant is expected to be completed in July 2013 at a cost of $8.8 million. The Corporation Yard replacement well is planned for construction beginning in February 2013 at a total estimated cost of $1.7 million.
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Recycled Water
Description
The City uses recycled water for irrigation of sites with large amounts of high water using plants, such as turf grass. Every gallon of recycled water used for irrigation saves a gallon of potable water that can be used in homes and businesses. At El Estero Wastewater Treatment Plant, treated wastewater (secondary effluent) is sent through filters to produce tertiary treated recycled water. The recycled water system is entirely separate from the drinking water system, typically using purple colored pipes, meter boxes, and sprinklers, and posted signage at all sites. Recycled water is mainly used for irrigating landscaping at parks, schools, the zoo, golf courses, and homeowners associations. Additionally, some of the recycled water is used for toilet flushing and dust control. The recycled water project was completed in 1991; the City continues to expand the use of recycled water at existing sites, as well as identifying new sites. For more information, visit our Recycled Water Homepage. Annual Capacity
The system in its current configuration has the capacity to treat and deliver 1,400 acre feet per year; current demand is approximately 800 AFY, plus about 300 AFY of process water used at EEWTP. Operating Criteria
Recycled water is a non-variable supply in that it can only be supplied to those customers that are connected to the recycled water system. Potable water is sometimes blended with recycled water as a means of maintaining acceptable recycled water quality. Cost Information
The capital cost for construction was approximately $15.2 million. Variable costs (operation and maintenance) range from $158/AF to $247/AF depending on pressure zone. Recycled water is provided to customers at a lower rate than potable water as an incentive for users.
WateReuse Association
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State Water Project
Description
The City is a participant in the State Water Project and receives State Water via the 102 mile Coastal Branch of the State Aqueduct and the 42 mile Santa Ynez Extension that was completed in July 1997 and ends at Lake Cachuma. When needed, South Coast participants receive State Water through the Tecolote Tunnel, intermingled with Cachuma water, but accounted for separately. Annual Yield
The City's entitlement is 3,300 acre feet per year, subject to availability. Average deliveries to the City are estimated at 1,151 acre feet per year under the LTWSP, with annual deliveries projected to range from 363 AF per year to 1,650 AF per year. The amount of water that can be delivered throughout California from the State Water Project varies year to year based on rainfall and riparian flow rates. Operating Criteria
The City typically takes State Water deliveries of approximately 600 to 700 AF pursuant to its obligation under the Exchange Agreement with the Santa Ynez River Water Conservation District, Improvement District No. 1. Aside from this, water is ordered annually on an as-needed basis to replace local surface supplies lost to drought or as a result of other shortages. In recent years, delivery requests have been mostly limited to the amount required by the Exchange Agreement.
Cost Information
The variable costs for State Water are approximately $160/AF for Exchange Water and about $300/AF for deliveries of Table A water into Lake Cachuma. The total Project capital costs include costs for the State portion and the local Central Coast Water Authority (CCWA) portion of the Project. Fixed costs are the major portion of total costs and are about $1,400/AF.
California Department of Water Resources, State Water Project
Central Coast Water Authority
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Desalination
Description
The Charles Meyer Desalination Plant is in long-term storage mode and is not currently producing drinking water for the City. The City constructed the reverse osmosis seawater desalination facility as an emergency water supply in response to the severe drought from 1986 to 1991. Two neighboring water purveyors, Goleta and Montecito water districts, participated in the project but have since opted out of the permanent facility. Due to sufficient freshwater supplies since 1991, the facility remains in long-term storage mode for reactivation within two years in the case of prolonged and severe drought. Annual Capacity
With the departure of the co-participants and sale of a portion of the capacity, the desalination facility now has a production capacity of 3,125 acre feet per year. Operating Criteria
Relatively high variable costs for desalination make this supply the last to be utilized during periods of shortage. The facility is normally in long-term storage mode and is expected to be recommissioned only when the demand cannot be met using all other available supplies. Cost Information
The original capital cost for construction in 1991 was $34 million. The capital cost to reactivate the plant at a capacity of 3,125 AF per year was estimated at $17.7 million, not including about $2.5 million dollars in distribution system improvements that would be required, if not already completed by the time of reactivation. Operating costs were estimated at approximately $1,500/AF.
American Membrane Technology Association
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Water Conservation
Water conservation by customers is an important part of the City’s water supply. In its most recent long-term supply plan, the City targeted 1,500 acre feet per year of water savings from improved efficiency. There are many cost-effective ways to save water, including high efficiency plumbing fixtures, water wise landscaping, and efficient irrigation systems. Go to the Water Conservation homepage for more information. | |
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