The Centennial Founders have gone to great lengths to ensure that Centennial will have diverse and secure water sources over the long term.
Building the Future: Centennial's Water Needs
Centennial is envisioned as a self-contained, master-planned community that will provide 23,000 homes for young families, single adults and senior citizens over the next 25 years. Located 45 miles south of Bakersfield on the Kern County/Los Angeles County border, Centennial is an important step toward providing quality housing opportunities as well as much needed services and amenities.
It is an understatement, especially in Southern California, to say that water is one of the most important issues facing community builders today. In fact, water is vital to every step of the development process, from land acquisition and initial planning, through environmental reviews and irrigation decisions.
“Learning how to cope with dry years and store the water from plentiful rainfall years is the key to a stable Southern California economy.”
- Russell Fuller, general manager of the
Antelope Valley East Kern Water Agency
Centennial Founders has gone to great lengths to ensure that Centennial will have diverse and secure water sources over the long term. Working in coordination with entities like the Antelope Valley East Kern Water Agency (AVEK), Centennial will execute an aggressive recycled water program and a water conservation program, as well as pursue the combined use of water from the groundwater basin and the State Water Project.
This paper reviews the current water situation in California today; what is being done by the building industry to address the critical water needs of the state's growing population; and how Centennial's multiple water source approach will maintain an adequate supply under virtually any circumstances.
Water Supply Issues and Building Industry Perspective According to the California Department of Water Resources, urban water demands in average water years will increase from 8.8 million acre-feet (1995 numbers) to 12 million acre-feet in 2020. An acre-foot of water - which equals 325,851 gallons, or enough to cover a football field to a depth of one foot - is enough to meet the water needs of two families for one year.
Addressing this need is the crux of state water policy. The state's two most important water sources are the Colorado River and the runoff from the Sierra Nevada. Countless books and articles have been published on how best to manage these essential resources, and through cooperative efforts among federal and state agencies, much progress has been achieved.
For example, CALFED - a federal/state coalition - is working to resolve issues such as those affecting the Sacramento-San Joaquin River Delta, the central nervous system of the state and federal water projects. California is also working with federal authorities to, over time, reduce its dependence on water from the Colorado River.
The California Building Industry Association supports a number of water policies and initiatives aimed at meeting the state's water supply needs. Centennial Founders not only supports many of these policies, too, but it also has incorporated these beliefs into the planning for Centennial. The building industry and Centennial support:
The Centennial Solution
Centennial’s water plan encompasses conservation and recycling, as well as multiple sources of water including groundwater, State Water Project (SWP), and banked water. This multi-source approach guarantees that no single source of water will be used exclusively, and that the quantities from each source may vary from year to year depending on availability.
Centennial’s water strategy provides for more available water than will be needed at buildout of the new town, even during single or multiple dry year periods. With this multi-phased approach to water supply and demand, Centennial can provide a flexible, reliable water supply without adversely affecting other local groundwater or SWP users in the region.
Centennial recognizes the need to efficiently manage its water resources. As such, it has proposed an aggressive water conservation program that features the use of water conserving appliances, ultra-low flow water fixtures, water-wise landscaping and managed irrigation systems using drip and climate-based irrigation controllers.
Water demands for Centennial are estimated to be approximately 47 percent less than those projected by the Antelope Valley-East Kern Water Agency (AVEK) in the 2005 Urban Water Management Plan (UWMP) based on per capita projection methods, illustrating the extent of conservation planned for the project.
A primary goal of Centennial is to recycle all wastewater generated by project land users for beneficial landscape irrigation uses. This will be accomplished through extensive greenbelts, parkways, golf courses, school yards, slopes, homeowners’ association common areas, and park that are planned throughout Centennial.
Two wastewater reclamation plants are proposed to provide additional treatment. Seasonal storage ponds will be constructed to provide the necessary volume to balance winter (lower) and summer (higher) irrigation demands by either storing or supplementing the constant wastewater generated from the plants. The use of recycled water reduces the need for water from other potable sources by 36 percent.
The Antelope Valley Groundwater Basin occupies an area of approximately 920 square miles in the western Mojave Desert. The Basin consists of seven sub-basins, including the Buttes, Finger Buttes, Lancaster, Neenach, North Muroc, Pearland, and the West Antelope sub-basins. While these sub-basins are within the overall Antelope Valley Groundwater Basin area, local conditions, including ground faulting, keep these sub-basins from being hydrologically connected to other sub-basins.
Based on the existing and past pumping levels, a water balance analysis determined that the existing uses in the project area are within the safe yield of the sub-basin. The project could, therefore, convert a portion of existing agricultural use to proposed urban uses without affecting this balance. The project proposes an average use of 2,500 acre feet per year (AFY) of water converted from existing agricultural uses.
Return flow – the portion of the irrigation water applied to the land that is not actually utilized by the plant material and eventually migrates into the underlying groundwater basin – is expected to add an additional 1,035 AFY to the total groundwater basin supply.
State Water Project (SWP)
AVEK is one of the wholesale water agencies that contracts with the Department of Water Resources (DWR) for imported potable water from the SWP. AVEK currently provides water to a population of approximately 285,000 through 17 retail water agencies and water companies. The west branch of the California Aqueduct delivers SWP water to southern California and traverses the Centennial property from north to south before its outfall into Quail Lake. The east branch is just north of the project. AVEK could provide SWP water to Centennial through turnouts in the west and east branches of the California Aqueduct.
AVEK’s annual entitlement to SWP water supplies is 141,000 acre feet per year (AFY) and can expect to receive 77 percent (108,878) acre feet in an average year. Centennial will require 3,866 AFY, which accounts for approximately 3.6 percent of AVEK’s likely annual delivery.
A water banking program is proposed for Centennial to optimize the use and ensure the availability of imported SWP water. Water banking programs typically operate by taking deliveries of imported supplies in years when water supplies are plentiful and storing it in groundwater basins for withdrawal in periods of drought.
The U.S. Bureau of Reclamation, AVEK and Centennial has recently completed a water bank feasibility study – including percolation testing and test ponds – which concluded that a 100-acre site could recharge a maximum of 7,200 AFY of SWP water. This would allow adequate time for drying and bottom maintenance between rain cycles.
Based on this pilot study and the site’s location immediately adjacent to the Aqueduct, Centennial – which has proposed a bank of 13,500 acre feet at buildout – would serve as an ideal location to operate a water bank.
Centennial’s Water Supply will Exceed Demand
The implementation of project design features at Centennial such as community-wide commitment to water conservation techniques, use of recycled water for non-potable uses, and groundwater banking during years of surplus water supplies will result in a community whose water supply will far exceed demand.
At buildout, demand for water at Centennial will be approximately 11,600 AFY. Approximately 4,200 AFY of this demand is projected to be from centralized landscape irrigation systems, all of which can be met through recycled water. The remaining potable water demand would be 7,400 AFY, far less than the available water supply from all sources (potable water and recycled water supply).
“Centennial has proven itself as a good neighbor by designing the new town with an eye towards wise water use. Their plans to employ state-of-the-art water conservation, water banking and reclamation will minimize the impact on the region's water”
-Frank Sanchez, Resident in Pine Mountain Club