The questions and answers included in the Frequently Asked Questions (FAQs) Section of this website are continually updated. If you have a question that is not addressed, please feel free to contact us.
The City of Santa Cruz, which serves a population of about 90,000 through 24,000 service connections, currently relies on surface water from rainfall captured in local reservoirs and streams (95%) and groundwater (5%).
The primary concern for the City regarding their water supply is inadequate supply during drought conditions. If a drought similar to the one 1976-1977 were to occur today, the City could experience a 45% water shortage. Even with a mandatory 15% mandatory water curtailment, an additional water supply for the City is needed to meet water demands.
For more information, click here.
The District, which serves a population of about 49,000 through roughly 15,000 service connections, currently relies solely on groundwater and to meet customer demands. The District does not take water from surface water or regional water supplies.
There are two primary concerns for the District regarding their water supply:
In order to supply adequate water supplies to District customers while maintaining sustainable groundwater levels, the District must reduce current groundwater pumping and secure supplemental water supplies.
For more information, click here.
The scwd2 Task Force is a Joint Task Force formed by the SCWD and SqCWD to:
The scwd2 Task Force is comprised of two City of Santa Cruz Council Members and two Soquel Creek Water District Board Members. The Task Force meets on the third Wednesday of the month. For information on the meetings, click here.
The Santa Cruz City Council conducted an exhaustive process beginning in 1997 to evaluate several new water source options to protect customers in drought years. From these background evaluations on water demand, conservation, curtailment, and alternative water supplies, the City of Santa Cruz Integrated Water Plan (IWP) was developed and adopted in 2005. The purpose of the IWP is to provide a reliable water supply to meet long-term needs while ensuring protection of public health and safety.
Similarly, beginning in the late 1990s, SqCWD began evaluating depressed groundwater levels and saltwater intrusion, long-term water demand, conservation opportunities, the adequacy of water supplies and the preferred options for supplemental water supplies. In early 2006, SqCWD adopted the Integrated Resources Plan (IRP) which recommends a flexible plan to address changing demand and water supply conditions. In 2012, the District updated their Integreated Resouces Plan (2012 IRP) which re-affirmed desalination as the preferred supply alternative to further evaluate.
The components of the City’s IWP and the District’s IRP are very similar. Together as scwd2, their Integrated Water Plan includes the following four components:
The City and the District both have different water supply needs that compliment each other such that a joint project could be feasible and successful.
Since the City needs a supplemental supply only during drought conditions (approximately one in every six years), the District could use the desalination facility during non-drought conditions to help supplement water demand needs while reducing groundwater pumping (approximately five out of six years).
This partnership allows for agency’s to share the costs associated to evaluate, study, and potentially build the project.
A joint desalination plant is not a “quick solution” or “silver bullet project” to solve our existing water shortages, but rather it was identified as the best apparent supplemental supply project after extensive consideration of over thirty (30) different projects. Both agencies have been investigating a new supplemental supply for over 20 years.
The City and District both conducted exhaustive evaluations of water supply options and potential new water sources through the City’s Integrated Water Plan (IWP, 2005) and the District’s Integrated Resources Plan (IRP, 2006 and 2012).
Below is a partial list of supply projects that have been considered over the years:
|Project||Agency||Reason(s) no longer considered|
|Construct New Dam (Zayante, Bald Mtn. School, Baldwin Creek)||SCWD||Insufficient supply, geologically poor site, or council unwilling|
|Import Water (with Pajaro Valley Water Management Agency (PVWMA))||SqCWD||SqCWD would purchase water from PVWMA. Proposed PVWMA project has not progressed since 2006.|
|Recycled Water for Irrigation||SCWD and SqCWD||Current permit does not allow and in times of drought, agencies need potable water, not irrigated water|
|Brackish Groundwater (from San Lorenzo River)||SCWD||Water rights conflict.|
|Diversion (Soquel Creek)||SqCWD||Issues related to fish passage flows, injection wells, and permitting.|
The IRP and IWP both concluded that a desalination facility would ensure that the City and District could provide providing a reliable water supply that meets long-term needs while ensuring protection of public health and safety.
**UPDATED, June 6, 2012**
On June 5, 2012, Soquel Creek Water District Board of Directors conducted a workshop to evaluate conceptual conservation scenarios to reduce demand by 37-40% to 2,900 acre-feet per year for a 20 year period, which is the limited amount of groundwater available to restore protective groundwater levels and prevent seawater intrusion. The workshop included the various methods, costs, customer/District impacts, and risks associated with two conceptual conservation approaches. Staff also presented comparisons related to the desalination project with respect to unit cost of water ($/acre-ft) and rate impacts. To view the board memo, click here. To view the PowerPoint presentation, click here.
Conservation continues to be the cornerstone of reducing water demands for both the City and the District. This chart shows the average water usage is about 192 gallons per person per day in California and the City/District’s use is less than 75 gallons per person per day. Santa Cruz area residents are already 60% lower than California's average use and are already below the 2020 water goal of 154 gallons per person per day.
Both the City and the District have on-going aggressive conservation programs that include a free water survey audit (a conservation specialist will visit make house calls to evaluate water use (indoor and outdoor) and make site specific recommendations to be as water efficient as possible) and suite of other programs that include toilet rebates, clothes washer rebates, etc. For more information on the City’s Conservation Programs, click here. For the District’s conservation programs, click here.
We will continue to encourage and provide incentives for customers to conserve water. A supplemental supply is still preferred by both agencies to further pursue to provide needed water in drought conditions and to prevent overdraft of the groundwater basin.
What about recycled water? Have you looked at or evaluated indirect potable reuse as an alternative?
(Indirect potable reuse refers to projects that discharge recycled water to a water body before reuse.)
The City and the District would like to diversify their water portfolios to ensure water system reliability and sustainability. In addition to their existing water supplies, conservation, curtailment, and desalination- both agencies have either implemented and/or are investigating recycled water opportunities.
Under current California regulations, highly-treated wastewater (recycled water) is not permitted for discharge into a potable water distribution system (otherwise known as direct potable use). It may be used to provide irrigation water for parks, sports fields, and/or golf courses, but would require a new dedicated distribution system that would be prohibitively expensive compared with the relatively small volumes of water delivered. In addition, during drought conditions, water restrictions are established for outdoor irrigation and therefore recycled water would not meet City’s potable water needs during these times.
Groundwater recharge is another possibility for indirect potable reuse; however, it is not practical for the City or the District because of current requirements that 1) recycled water be blended with at least 50% potable water before recharge and 2) extraction by any public or private drinking water well occur at significant distances from the point of recharge.
The City of Santa Cruz evaluated indirect potable use as an alternative in the Alternative Water Supply Study (Carollo, 2000) which evaluated a number of water supply augmentation options including additional groundwater supplies from groundwater recharge with reclaimed wastewater. The project had very limited viability as a drought supply due to a number of factors including the limited size of the aquifer, treatment and blending requirements, water rights constraints, and required detention time. The available water supply for this alternative was estimated to be approximately 200 MG/yr (compare to needed supply of approximately 500 MG/yr).
For Soquel Creek Water District, use of recycled water from the Santa Cruz wastewater treatment plant is limited by the long conveyance requirements (approximately 5 miles) from the treatment plant to the District’s service boundary as well as a small irrigation market within the District’s service area. SqCWD does not currently treat or reclaim any wastewater. The cost/benefit ratio to produce recycled water at the Santa Cruz wastewater treatment plant and deliver it to irrigation users within SqCWD’s service area in a new recycled water distribution pipeline is very high compared to other supplemental supply alternatives that could use the existing potable water distribution piping system to deliver water.
However, new technology using satellite reclamation plants (SRPs) to treat wastewater may have limited applications within the District and was recently evaluated (Black and Veach, 2009). This report is available online at www.soquelcreekwater.org under “District Reports Online”. The concept is to divert wastewater from the sewer system for local treatment to provide recycled water for large-scale irrigation.
scwd2 has prepared a white paper on opportunities and limitations for recycled water use for the City of Santa Cruz and Soquel Creek Water District. To access it, click here.
Increasing the capacity of the Loch Lomond reservoir has been studied in the past, though it cannot provide much more water without completely tearing down the existing dam and reconstructing it to make it more structurally sound and high enough to make a difference in terms of water supply availability. From an operational perspective, this would be impossible as the City cannot take Loch Lomond out of service for the length of time such construction would require. Further, a plan to modify the dam in this fashion could take decades to implement, which would not provide drought protection under current demand conditions for the City or reduce groundwater pumping by the District in the near term.
The City is likely to have less water from the San Lorenzo River and the North Coast sources once the HCP is complete as the California Department of Fish and Game has requested the City reduce stream diversions to protect threatened species. The City has agreed to study what must be done to minimize these impacts.
Regarding UCSC, the water shortages the City is facing are due to drought conditions and not University growth. During a drought, whether UCSC grows or does not grow - the City still needs a supplemental water supply. The City is pursuing evaluating desalination to provide drought protection and should not be viewed as a new supply source because of UCSC’s proposed expansion.
The City is not presently able to transfer surface water to Soquel, but interregional exchange of water is currently being actively investigated by the water agencies as a long term measure to improve water management. It is already clear that there are a number of challenges that would need to be met in order to accomplish this. The City’s water rights would need to be amended by the State to expand the allowed geographic area of use and to increase the allowed diversion rate. Or, the District could apply for its own water rights. Such a water right amendment or application for new water rights typically takes about 20 years. Any increase in surface water diversion could only be done between the months of December and April, and would require the approval of state and federal resource agencies. They are looking for solid documentation that the project would not adversely affect salmon and steelhead populations, but that it would go further and provide measurable benefits to the fish populations. While it is expected that fish should benefit on a long term basis from recovery of groundwater levels in the Soquel groundwater basin, the timing and extent of this benefit cannot be predicted until groundwater pumping rates are substantially reduced and the basin starts to recover.
It has also been suggested that fish could benefit if the City reduced its stream diversions during summer time or drought periods, and substituted groundwater pumped from the Soquel basin. Again, it cannot be predicted if and when that could ever occur until substantial recovery of the basin is observed. Measures to accelerate groundwater recharge of the Soquel Basin are being investigated, but the fine-grained and multi-layered characteristics of the underlying Purisima formation do not lend themselves to accelerated recharge techniques.
The County and the water agencies believe that exchanges of water between Santa Cruz and Soquel provide good potential for long term benefits for county residents and the environment, and we will continue to actively pursue those opportunities. However, many of these benefits will take many years to materialize, and would probably never offset the need for a supplemental water supply during dry years to meet both water supply needs and fish needs. In summary, while best practices of water resource management include maximizing the beneficial use of existing sources, the possibility of a water exchange is not a near-term solution to the water supply shortage faced by the City and Soquel Creek Water District and is not considered an alternative to developing a new reliable and flexible supplemental supply.
"This water transfer scheme would not eliminate the need for the proposed desalination plant or some other significant source of supplemental water in combination with continued conservation efforts," John Ricker, Water Resource Division Director Santa Cruz County Environmental Health Services.
A project-level Environmental Impact Report (EIR) is currently under way for the proposed 2.5 mgd facility that will be shared by the City of Santa Cruz and Soquel Creek Water District. The City’s 2005 Integrated Water Plan identified 3.5 mgd and 4.5 mgd as potential expansions of the proposed facility and these expansions may be addressed at a cumulative or programmatic level in the forthcoming EIR. However, the City is currently re-evaluating whether these expansions are still appropriate with lowered water demand projections and to the extent the City still foresees a potential need to expand it in the future, the current EIR would address that possibility. However, if built and the City was ever interested in expanding it, a new project-level EIR and new permitting would be required assuring that keeping the possibility of expansion open today most certainly does not assure its approval in the future.
The exact location of the facility has not been determined, but it proposed project will likely be located somewhere within the industrial area of Santa Cruz (due to the central location near the ocean for the intake system and the wastewater treatment plant for the disposal of the salty water concentrate).
The design of the facility has yet to begin, so any projections are conceptual and primarily based on the results of the pilot plant study that we conducted from March 2008-April 2009. The footprint, or land required for the facility may range from 3 to 12 acres, depending on the different components for the desalination process. We are looking at potential sites (which may be comprised of separate and/or contiguous properties to see if there is an area in this vicinity that will accommodate the proposed facility.
The conceptual design, at this time, includes:
Location: Facility would be located in Santa Cruz
Size: 2.5 million gallons per day (MGD)
Intake: Open Ocean Intake (using abandoned Wastewater Treatment Plant outfall) or subsurface intake (slant wells or infiltration gallery)
Brine Disposal: Through current wastewater outfall
We are currently evaluating several of the components and the findings, when completed, will help us refine the design. For more information on our current studies, click here.
The scwd2 Task Force is currently working on an Operational Plan which will include the operational use for the City and the District.
It is anticipated that the operations of the desalination facility will be based on a priority of use schedule. Conceptually, the City of Santa Cruz would use the facility during drought conditions (primarily between the months of May-October) at 2.5 million gallons per day and Soquel Creek Water District would operate the facility at a smaller capacity (average use of 1.5 million gallons per day) at all other times.
There are several studies that are currently being conducted that will be used in support of the environmental review and the engineering design of the desalination facility. These studies include:
Evaluating pretreatment and RO desalination treatment can meet water quality standards
Study Complete. Click here for more info.
Desalinated water proved to meet all local, state, and federal water quality reports.
Energy Minimization and Greenhouse Gas Reduction Study
Impacts due to Energy and Greenhouse Gases. Evaluation of carbon offsets required to achieve carbon neutrality.
Currently being studied. Click here for more info.
Evaluating an open ocean intake and the impacts to marine life in terms of impingement and entrainment.
Study Complete. Click here for more info.
Evaluating the feasibility and/or potential for a subsurface intake structure (such as slant wells or infiltration gallery)
Study Complete. Click here for more info.
Evaluating the blend/dilution of the brine (from the desal. facility) with the existing wastewater treatment plant effluent via the existing wastewater outfall.
Study Complete. Click here for more info.
It takes approximately 2 gallons of ocean water to produce one gallon of potable water using reverse osmosis; this is known as 50% product recovery. Depending on how a desalination facility is operated, the product recovery range can range normally range from 40-55%.
Construction of the scwd2 desalination facility is dependent on the completion of various engineering/environmental studies (pilot test program, intake, energy/greenhouse gas emissions, brine discharge dilution), environmental approval and permitting. The preliminary project schedule is:
Pilot Plant Testing: 2008-2009
Preliminary Design and Environmental Review: 2009-2014
Public Vote on Project: 2014
Permitting and Design: 2014-2016
Construction and Begin Operations: 2016-2018
A public vote will be placed to City of Santa Cruz residents after the environmental review process and following certification of the final Enviromental Impact Report (EIR).
Officials are also discussing options on how Soquel Creek Water District may weigh-in on the proposed project.
The capital and operating costs for the proposed project depends on several components including: intake structure, land acquisition, SWRO (seawater reverse osmosis) treatment, concentrate disposal, storage and delivery, and alternative energy. Several studies are currently underway to evaluate these components.
Current estimates, used for planning purposes, of the total project cost is approximately $115 million, which includes a 30% contingency and an expected range of accuracy of -15% to +30%.
A detailed cost estimate has not been completed since the findings of these studies and the environmental review will determine the actual scope of work and corresponding costs.
Approximately $12 million has been spent to evaluate desalination as a supplemental water supply for the City and the District. Of that, approximately $2.5 million was grant money received from the Department of Water Resources and the State Water Resources Control Board. The grant funds were used to help fund the seawater reverse osmosis pilot plant project and the intake studies. Expenditures for the evaluation phase are shared 50/50 by the City and the District.
Yes, all project components of the proposed desalination facility including, but not limited to, intake, treatment, land, pumping/conveyance, and brine disposal will be evaluated and estimated as information becomes available.
Based on industry estimates, the cost to turn ocean water into potable drinking water ranges from $2,000 - $3,000 per acre foot of water, depending on salt content, necessary pretreatment, and finished water quality goals/standards.
Energy consumption and GHG emissions from the proposed desalination project are of major importance for both the City of Santa Cruz and Soquel Creek Water District. We are committed to evaluating ways to reduce the project’s energy requirements, how to reduce the carbon footprint and how to make the project net carbon neutral.
The City of Santa Cruz and Soquel Creek Water District both have committed to making the proposed desalination project at least net-carbon neutral.
The agencies are currently conducting an Energy Minimization and GHG Reduction Study (Energy Study) which will:
A Technical Working Group was formed in 2011 to help oversee the Energy Study and is evaluating potential projects that could reduce energy and carbon emissions for the project.
Projects being discussed include converting food waste to energy at the wastewater treatment plant, various types of solar projects, wind/wave/tidal/hydro projects, renewable purchases, GHG offsets, and additional water conservation programs, to name a few.
For more information specific to the Energy Study, visit: http://www.scwd2desal.org/Page-Energy.php.
For informational material from our December 8 Community Meeting on Energy, visit: http://www.scwd2desal.org/Page-Project-phases_Informational_Meeting_December_2011.php
The industry range to desalinate water using reverse osmosis technology is 15-23 kWh per 1,000 gallons (normal standard efficiency). If ‘high efficiency’ components are incorporated, the industry range is 12.5-16 kWh per 1,000 gallons.
scwd2 is currently looking at the baseline energy requirements for the proposed 2.5MGD desalination facility.
The conceptual total energy required for the proposed facility is approximately 6,800 MWh/year based on the anticipated use of the desalination facility by the the City of Santa Cruz and Soquel Creek Water District. Below is a comparison of the energy needs for desalination compared with other energy demands within our community.
The total energy that is being calculated includes the following:
The desalination process does not directly emit greenhouse gases (GHGs) in the way that a power plant does. The emissions are attributed to the power that is purchased — similar to the way emissions are attributed to electricity used in a home or business. Based on the amount of energy used by the proposed project, the GHGs are calculated using PG&E’s Emissions Factor. Electricity on the California power grid comes from many different sources, including both fossil-fuel based and renewable energy sources. PG&E supplies electricity for the power grid in the Santa Cruz area. This energy emits a varying amount of greenhouse gases for every kilowatt-hour produced, depending on the mix of renewable and non-renewable (fossil-fuel) energy sources. scwd2 calculated the proposed project’s GHG footprint using PG&E’s most recent emission factors. Based on state regulations, it is anticipated that the emission factor will decrease over time as PG&E’s energy portfolio shifts toward increased alternative and renewable energy sources that produce less carbon emissions to meet AB32.
Both the City of Santa Cruz and Soquel Creek Water District have declared that the proposed project will be at least net-carbon neutral.
The estimated annual indirect GHG emissions for the assumed operation of the scwd2 Desalination Facility are:
To put this in perspective, approximately 2,000 metric tons CO2e is equivalent to the emissions from approximately 400 typical automobiles travelling 12,000 miles a year.
The Energy Study is evaluating potential offset projects to reduce the carbon footprint of the project.
The proposed 2.5 million gallon per day desalination facility would be used by the City of Santa Cruz to meet water demands during drought conditions. Implementation of the desalination facility does not have an impact in terms of causing or aiding planned growth at the University.
Additional environmental review would be required for any such expansion of the desalination facility or change in operation to ensure that development of additional water supply for Santa Cruz is responsive to planned growth. That possibility was considered too speculative to be included in the Water Supply Assessment that looked at whether or not water was available for University Expansion.
In the summer of 2008, an agreement was forged between the City and UCSC. It included provision 3.2b, which states that UCSC would be treated as any other developer and subject to all costs and provisions related to any new water service connections. In addition, should the City declare a water shortage emergency moratorium on new connections to the system, the university agrees to cap its water use as long as the moratorium exists.
The water shortages the City is facing are due to drought conditions and not University growth. During a drought, whether UCSC grows or does not grow the City still needs a supplemental water supply. The City is pursuing evaluating desalination to provide drought protection and should not be viewed as a new supply source because of UCSC’s proposed expansion.
Desalination is any process that separates saline water (water containing salts) into two parts - one that has a low concentration of salt (treated product water or fresh water), and the other with a much higher concentration than the original source water, sometimes referred to as salty water concentrate or salty water.
The reverse osmosis process is one type of desalination technology that occurs by forcing a solvent (liquid salt solution) from a region of high salty concentration through a semi-permeable membrane to a region of low salty concentration by applying a pressure to the water.
Desalination processes may be used in municipal, industrial, or commercial applications. Available technologies can desalinate water from a variety of sources including: seawater, brackish, river, waste water, pure, and brine.
For more information on the technology of desalination, click here.
This varies slightly from ocean to ocean, but the range is 32,000 mg/L - 45,000 mg/L. For inland seas like the Red Sea, the salinity (salt content) is about 45,000 mg/L. For the contiguous oceans like the Pacific Ocean, Atlantic Ocean, Indian Ocean, the salinity is about 32,500 mg/L.
The benefits include:
The challenges include:
To learn more about the desalination program, the public may: