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FAQsThe City of Santa Cruz Water Department (SCWD) and the Soquel Creek Water District (SqCWD) formed the scwd2 Task Force to oversee the Pilot Test Plant Program, the Watershed Sanitary Survey, Intake Study, permitting, environmental review and design of the proposed 2.5 MGD plant, and to provide a forum for public input on the project and formulate an agreement and governance structure should the decision be made to proceed with the proposed desalination project. The scwd2 Task Force is comprised of two Santa Cruz City Council Members and two Soquel Creek Water District Board Members. 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.
What is reverse osmosis desalination? 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
What
are the benefits and challenges of desalination?
The benefits include: * Provides needed water supply during droughts * Protects underground water aquifers from seawater intrusion * Provides reliable and flexible source of water * Protects public health, safety and the economy The challenges
include: * Ensuring safe disposal of concentrated salty water * Preventing trapping of marine life in seawater intake pipes * Offsetting greenhouse gas emissions * Limiting economic costs to produce water * Preventing population growth-inducing impacts
Why does the City of The City of 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.
Why does Soquel Creek Water District need a supplemental supply of
water? 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: * Depressed coastal groundwater levels in the Purisima Formation aquifer suggest the potential for seawater intrusion. * Some landward movement of seawater in the Aromas aquifer in the vicinity of Seascape. 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: * Provide direction on the investigative stage of project (including the Pilot Test Plant Program, the Watershed Sanitary Survey, the Intake Study, Permitting and Environmental Review); * Oversee public outreach activities; * Develop an operational plan; and * Formulate a governance structure should the decision be made to proceed with a full-scale desalination plant.
scwd2
is comprised of two City of
What is the
Integrated Water Plan? 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. 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:
Curtailment: Plan on an additional 15% temporary rationing during droughts Recycled Water: Use recycled water for irrigation where feasible Develop Supplemental Supply: Investigate a cooperative desalination facility to protect against drought and preserve groundwater resources
Why did the City and District partner to jointly evaluate the
proposed project?
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.
Has the City and/or District ever looked at other projects instead
of desalination?
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).
Below is a partial list of supply projects that have been considered over the years:
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.
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 130 gallons
per person per day in
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; however, conservation alone cannot solve our water supply shortage. A supplemental supply is still needed in drought conditions and to prevent overdraft of the groundwater basin.
What about recycled
water?
(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 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 For Soquel Creek Water District, use of
recycled water from the 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
How
much water will the desalination facility treat? The proposed facility will produce up to 2.5 million gallons of freshwater a day.
Where will it be located?
Are there enough acres available for the
proposed project?
The exact
location of the facility has not been determined, but it proposed
project will likely be located somewhere within the industrial area
of
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 will be looking at potential sites (which may be comprised of
separate and/or contiguous properties in 2010 to see if there is an
area in this vicinity that will accommodate the proposed facility.
Location Size Intake Brine Disposal: Through current wastewater outfall
How
will water be shared between the City of
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
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:
How much ocean water does it take to make potable water? 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%. What is the proposed schedule for the project?
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 SWRO Desalination Facility-Design: 2009-2012 Environmental Review and Permitting: 2009-2012 SWRO Desalination Facility -Construction: 2012-2015
What is the
price tag for 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. A detailed cost estimate has not been completed since the findings of these studies will determine the scope of work and corresponding costs.
How much money has been spent so far on this project? Approximately $6 million has been spent over
the last 5 years to evaluate a supplemental water supply for the
City and the District. Of
that, approximately $2.6 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.
Will all costs related to the desalination project be recognized in
the total costs? 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. What does it cost to produce desalinated drinking water? 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.
How is the City and District evaluating the energy and green house
gas emissions for the project? Energy use at the proposed desalination
facility will be one of the most important issues to address for
both environmental review and permitting purposes. The proposed 2.5
MGD facility would incorporate as much advanced technology as
practical to improve SCWD and SqCWD are committed to thoroughly
evaluating the energy issues This study will:
How much
energy is required to desalinate water?
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.
What is the total energy that would be required for the proposed project? The conceptual total energy required for the
proposed facility will be calculated as part of the scwd2
Energy Minimization Plan and Greenhouse Gas Reduction Study.
This study is currently underway and includes the conceptual
operational use of the facility by the City of
What is included in the total energy associated with the proposed
project? The total energy that is being calculated includes the following: *
Bringing ocean water from the Bay to
the desalination facility. *
Treatment (including pretreatment,
reverse osmosis, and post-treatment). *
Discharge of the salty water
concentrate. *
Storage and conveyance needed for
distribution associated with the desalinated water.
Could the size of the project’s CO2 footprint prevent it from being constructed? The City of We are too early in the evaluation of the CO2
footprint of the proposed project to determine if this could be a
factor in preventing it from being constructed.
However, much larger projects are under construction in
How does forestry management offset greenhouse gases? There are a number of
standard and acceptable practices to offset greenhouse gases and
mitigate carbon emissions that will be considered by the City and
District. One approach is carbon
sequestration through forest management. By increasing inventories
of forests (or wetlands), and applying proper management techniques,
the amount of carbon removed from the atmosphere can be increased
and sustained. This increase may help buffer the effects of carbon
emissions elsewhere (e.g., carbon dioxide emissions from the
proposed desalination facility).
The proposed 2.5 million gallon per day
desalination facility would be used by the City of As provided for in the City’s Integrated Water
Plan, there is the possibility that the plant could provide the
means by which the City could accommodate modest future growth in
water demand, should that occur, by expanding the plant in two small
increments of one million gallons per day of production. 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 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 new water service connections. If the City Council, through a public process, were to decide to expand the proposed desalination facility in the future, and completed the additional permitting and environmental review, the expansion would be financed solely with System Development Charges (SDC), which are required for all developers, including UCSC, to cover the expansion costs. 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.
What environmental impacts will be evaluated for the proposed plant? Project level environmental review is scheduled to begin in Spring 2010. Impacts evaluated in the Environmental Impact Report (EIR) will include, but are not limited to:
Several studies are currently underway to evaluate these components for a full-scale plant. scwd2 has not completed a detailed cost estimate since the findings of these studies will determine the scope of work and the corresponding costs.
Where can I get more information? To learn more about the desalination program, the public may:
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