California's Drought: Where has the Water Gone this year?
Posted May 11, 2014
Although a few storms in March and April improved hydrology and water supply for some water districts, 2014 is still going to be a very tough year for most farmers, some cities, and our fish and wildlife. While this year is no longer on track to be the worst drought on record, it is still likely to be one of the worst droughts in recent history. However, those storms did allow the Bureau of Reclamation and California Department of Water Resources to increase water supply allocations by in recent weeks, particularly for senior contractors on the Sacramento River and Feather River. However, under California’s water rights system, some water contractors will get no water from the state and federal water projects, while other contractors will get 75% or 100% of maximum contract amounts.
Three years of drought have resulted in low water allocations for farms, cities, and the environment. Under existing environmental regulations, in dry years far less water is required to remain in our rivers and the Bay-Delta, as this graphic of average Delta outflows submitted by Sacramento Valley water users to the SWRCB in 2010 shows.
(In addition, here is a link to additional examples of how environmental protections are weaker in dry years). There have been no reductions in water pumping from the Delta this year due to Endangered Species Act protections for delta smelt, and minimal reductions in pumping due to protections for endangered salmon and steelhead. State water quality standards in the Bay Delta have been controlling operations for much of the spring – standards that protect water quality to benefit fish and wildlife, Delta farmers, water exports by the CVP and SWP, and other municipal and industrial users in the Delta like the Contra Costa Water District. Those standards were last substantively updated in the 1990s, and the State Water Resources Control Board is currently reviewing and updating that water quality control plan.
Yet even as the fishery agencies and State Water Resources Control Board have approved multiple waivers of water quality standards and environmental regulations in the Bay-Delta, there’s continued debate over how much water is actually going to environmental protections versus water diversions. Over the period of February 1 to April 15, 2014, nearly two-thirds of the approximately 4.9 million acre feet of unimpaired (full natural flow) in the watershed was captured in upstream storage or exported by the CVP and SWP. That means that only one third was allowed to flow through the Delta to Suisun Marsh and San Francisco Bay during this period – and nearly one third of that delta outflow was needed just to prevent salinity intrusion in order to protect water quality for the export pumps and other water users.
During this period, upstream reservoirs significantly increased in storage as a result of capturing a sizeable proportion of the runoff, particularly in Shasta Dam (over 700TAF), Oroville (over 550TAF), Folsom (nearly 350TAF), and New Bullards Bar on the Yuba River (nearly 250TAF). In addition, approximately 538,000 acre feet of water was exported by the CVP and SWP in the Delta.
Of course, in many cases it’s not so simple to delineate what water is used for water supply versus environmental protection. As noted above, more than one third of the Delta outflow during this period was needed simply to maintain minimal water quality for the export pumps and other agricultural and urban water users in the Delta, thus providing benefits to both the environment and water users (and higher outflow during the storms significantly improved water quality for exporters and Delta water users as well as fisheries). The more than 2.5 million acre feet of water that was stored in upstream reservoirs over these months will not only be used for water supply, but at many reservoirs will also be used to provide some limited cold water for spawning salmon (historically, salmon would migrate to cold water in the upstream river reaches, but the dams block access to this habitat and must provide cold water to mitigate impacts on salmon). And flows down the San Joaquin River into the Delta not only protect migrating salmon and steelhead, but also allow for increased water exports by the CVP and SWP (inexplicably, the SWRCB recently approved reducing San Joaquin River inflow to the Delta below the minimum required in critically dry years, even though that decision not only hurts migrating salmon and steelhead, but also reduces CVP and SWP exports by nearly 42,000 acre feet. NRDC and some water users are requesting the SWRCB to review and reverse that decision.).
Obviously, California needs more of these win-win solutions that benefit both water supply and the environment (whether that is changing the timing of diversions to better align with fishery needs, or inundating floodplains at lower flows through modifications of weirs and flood control systems). But we also need to provide sufficient Delta outflow, which is considered by most scientists to be one of the most important factors affecting the health of the Bay-Delta estuary and its native fisheries. Over the past decades, as this table from the Delta Stewardship Council shows, delta outflow has declined substantially as we have used, diverted and exported more and more water out of the watershed, particularly in drier years, leading to the collapse of native fisheries and the successful introduction of invasive species in the Delta.
Source: Delta Stewardship Council 2012
This spring, approximately 33% of the unimpaired flow made it through the Delta to Suisun Marsh and San Francisco Bay. Significantly reducing Delta outflow and weakening other environmental protections for the Bay-Delta may result in higher water deliveries for some contractors in the near term, but in the long run it’s likely to harm native fisheries, and ultimately may reduce water supply in the future. The choices we make during droughts have consequences that can last decades.
Drought years are bad for farmers, cities, and the environment, and as the Legislature has recognized, reducing our reliance on the Bay-Delta is an important way to minimize the impacts of the drought on all stakeholders. Investing in water recycling, water use efficiency, groundwater cleanup, and other local water supplies is critically important to help prepare for the next drought – not only for water supply, but also to help protect our native fisheries and the thousands of jobs and communities that depend on their health.
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