Desalination & Reuse Handbook - Flipbook - Page 19
THE YEAR IN SCARCITY
California Water Withdrawals
Total water withdrawals in California dropped
by 24% between 2010 and the height of the
most recent drought in 2015. Plant closures,
a shift from coal to natural gas and more
efficient water use in new power plants meant
that withdrawals in power generation fell
by more than 50%, compared to a national
average of 18%. Surface water available to
agriculture plummeted during the drought,
and the sector made savings of 17.7%. Both
groundwater extraction and trading of water
between farmers also increased substantially
during the drought.
Irrigation
Thermoelectric
Power Generation
Public Supply
Industrial
2010
2015
Other
0
20
40
60
80
100
Water withdrawals (million m3/d)
Source: US Geological Survey
outstanding approvals, California WaterFix will be capable of transporting 255 m3/s (22 million m3/d) of water from the
Sacramento River to the State Water Project aqueducts in the south through two vast tunnels, bypassing the old system
completely. Whilst not increasing supply, the project will make the region’s water conveyance system more dependable and
able to take advantage of temporary surges without damaging the Delta’s delicate ecosystem further.
Alongside increasing the reliability of surface water supplies, MWD is exploring the use of mass-scale, local wastewater
reuse. Since 1990, MWD has invested $1.4 billion in conservation, water recycling, and groundwater replenishment,
and now aims to establish the largest such system in the US. At full buildout, the Regional Recycled Water Program will
produce 567,759 m3/d of treated effluent to recharge local groundwater sources. Even before the programme’s pilot comes
online in early 2019, the region’s recycling and replenishment capacities are significant. From July 2016–June 2017,
MWD-supported projects yielded a collected average of 608,000 m3 recycled water per day, putting more than 597,000
m3/d into groundwater recharge.
Besides securing increased and long-term supplies, steps have been taken to reduce Californian water demands. For
the past decade, through residential and commercial ‘SoCal Water$mart’ programmes, MWD has offered community
outreach, including rebates for high-efficiency appliance installation, irrigation controllers, rain butts, and turf removal.
The utility offered rebates of $1 for every square foot of turf grass converted to California native flora (up to a maximum
$1,500 rebate), and surveys suggest 70% of target properties had carried out full turf removal from their front gardens,
with 11% carrying partial removal, between 2015 and 2017.
The public has responded positively to MWD and State conservation initiatives alike. During the 2011–17 drought, the
California State Water Resources Control Board (SWRCB) adopted emergency water use regulations for the first time.
From July 2014, outdoor potable water use was restricted and urban suppliers serving more than 3,000 connections were
required to submit usage reports. In the year following the regulations, per capita water usage fell by almost 26%, from 0.5
m3/d to 0.37 m3/d. Although usage rose following the regulations being lifted in November 2017, state-wide water savings
for the five years to June 2018 were approximately 15% – an average of 70,000 m3/d.
In May 2018, water conservation became subject to permanent legislation in California as two bills were signed into law.
Together, the new laws require cities and water districts to set strict annual water budgets by 2022, including mandatory
usage targets based on a standardised indoor water allowance of 55 US gal/d (0.2 m3/d) per user, regionally defined
outdoor usage allowances, and uniform assumptions of losses due to leaks. Punitive action for failing to meet these targets
will begin in 2027, with fines for non-compliance of $1,000/d in normal conditions and $10,000/d in drought conditions.
The per capita indoor water allowance is set to fall to 50 US gal/d (0.19 m3/d) by 2030.
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