Groundwater Usage is Unsustainable
Supplemental Water Supply such as
Desalination Can Help Prevent Seawater Intrusion
For many years,
groundwater levels in the Soquel Creek Water District (SqCWD) have
been dropping and remain too low to protect against seawater
intrusion. Despite extensive conservation efforts by customers, the
Soquel-Aptos groundwater basin is in a state of overdraft because
more water is being pumped out annually than is naturally recharged
through rainfall. The groundwater basin is the SqCWD’s only source
the groundwater basin is not sustainable and early signs of seawater
intrusion are present in the
La Selva Beach area and low groundwater levels are affecting SqCWD
wells in the Aptos/Seacliff
area. Seawater intrusion occurs when groundwater levels drop so low
that wells become contaminated with seawater. This condition can be
irreversible and can result in either abandoning wells or requiring
costly treatment. In order to manage its groundwater basin, SqCWD
needs a supplemental water supply to meet customers’ needs and raise
groundwater levels to prevent seawater intrusion.
What is Seawater Intrusion?
As mentioned above, seawater intrusion is a
condition whereby groundwater is withdrawn at a faster rate than it
can be replenished by rainfall and seawater or ocean water moves
into the freshwater aquifers.
SqCWD's Integrated Resources Plan
desalination plant is consistent with the SqCWD’s Integrated
Resources Plan (IRP), a flexible, phased approach for providing a
reliable supply of water, preserving
coastal aquifers from seawater intrusion, and protecting public
health and safety. The IRP’s preferred alternative identified
maximizing conservation and further evaluation of a regional
seawater desalination project with the City of
Santa Cruz that
can be used in conjunction with groundwater resources. The IRP
includes the following components:
and Curtailment — Continue conservation and drought management
programs to reduce water demand and increase water-use efficiency.
Supply — Develop a regional desalination plant with the City of
to meet additional water needs.
Water — Develop site-specific recycled water supplies for
non-potable irrigation use.
Management — Continued monitoring and assessment of coastal
groundwater quality and levels; redistribute groundwater pumping to
the potential for seawater intrusion; and support aquifer recharge
protection and enhancement.
Soquel Creek Water District's Two-fold
Approach to a Sufficient Supplemental Supply
In order to assure a reliable water supply,
SqCWD’s two-fold approach includes developing a sufficient
supplemental supply to:
Restore protective groundwater levels by
limiting groundwater pumping. This could be as much as 45% (675
million gallons/year) less than current pumping and may take 10
years or more before the basin recovers. Protective groundwater
levels are the minimum needed to prevent seawater contamination
as identified by the District’s hydrologist.
Maintain protective groundwater levels for
the long-term. Hydrologists predict that after the basin has
recovered, groundwater pumping must be restricted by at least a
quarter million gallons per year less than current use.
Conservation alone will likely not save enough, and there will
be an ongoing need to supplement our groundwater sources.
if We Do Nothing?
Creek Water District (SqCWD) were to take no action to develop a
supplemental water supply, these consequences could occur:
continued overdraft of the groundwater basin would lower groundwater
levels and increase the risk of seawater contamination of SqCWD’s
pumping to the level needed to recover the groundwater basin would
result in water restrictions for customers that could create
hardships for residents and local businesses.
- Restrictions on year-round water use for existing customers
and a moratorium on new or expanded services could be imposed.
- Reduced water sales due to restrictions would cause rates to
increase in order to meet the fixed costs of delivery and
maintenance of the water system