The Better Water Project: How SunRiver will Ensure Water Security for the American Southwest

There are currently two large-scale water projects proposed with the goal of securing water supply in times of drought and changing climate in the American Southwest. The first aims to redistribute existing water resources by building two massive tunnels underneath the Delta. The second project actually creates a brand new water resource by combining renewable energy with existing infrastructure and cutting-edge technology. Chances are, you haven’t heard about this second project – the project that will deliver more water to more people with less environmental impact at a lower cost.


Diamond Valley Lake, which acts as the storage and distribution point for the Metropolitan Water District (MWD)

California Water Fix and Eco Restore (the project you know about)

In the 1960’s, politicians wanted to build a canal to carry water from the Sacramento River, around the delta to the intake pumps feeding the State Water project, and from there south to irrigate the San Joaquin Valley, and on to Southern California cities. The objective was to allow more pumping from the delta without sucking salt water into California’s fresh water plumbing – and incidentally killing a bunch of endangered fish. California voters buried this canal project in a June 1982 referendum that lost by 63% to 37%.

The California Water Fix and Eco Restore (formerly known as the Bay Delta Conservation Plan) is the last of these “old water projects”. It’s a rather controversial plan proposed by Governor Jerry Brown to build two large, four-story tall tunnels to move fresh water from the Sacramento River, underneath the Sacramento-San Joaquin Delta, to intake stations for the State Water Project. Essentially, this project moves water from where nature put it to where monied interests want it.

Huge tunnels will create a “peripheral canal” running beneath the Delta – out of sight and out of mind for voters who want such a thing. If the California Water Fix project survives environmental challenges, it will likely be the last big project for moving water from where nature put it to other parts of the Southwest.

Drought has worsened in California, population has grown, and dependence on water from the Delta has increased. Saltwater intrusion and destruction of endangered fish now restrict pumping from the delta, and if drought conditions persist Central Valley farms and Southern California cities will suffer.

Additionally, the Delta Tunnels, costing tens of billions of dollars, produce no additional water. Even if the project gets built, the existing aqueducts heading south will deliver no more water than they could before. This project acts as a Band-Aid to keep the old system working in the face of drought and changing climate.


SunRiver (the project you’ve probably never heard of)

If the Delta Tunnels are the last of the old water mega-projects, Sun River is the first of the new. Instead of gathering up water nature provides, SunRiver uses solar generated electricity to desalinate seawater at regional scale. SunRiver technology isn’t new, but making such huge volumes of new water is revolutionary.

Sun River uses the existing seawater inlet and discharge pipes and high power grid connection at the decommissioned San Onofre Nuclear Generating Station (SONGS) on the Southern California coast. This existing infrastructure saves huge expense and avoids the environmental impact of new construction. But there is a still greater savings.

SunRiver includes construction of a 35-mile long water transport tunnel (roughly the size of one of the proposed Delta Tunnels). This tunnel would deliver water from the SunRiver desalination plant directly to Diamond Valley Lake, which acts as the storage and distribution point for the Metropolitan Water District (MWD). This new desalinated water can then be swapped for water MWD would otherwise draw from the Colorado River or the Central Valley.


SunRiver is the first of the new Southwest US water mega-projects. It delivers 1.1 billion gallons a day of new, drought-proof water for use in the region. Sun River incorporates seawater intake / discharge and high power grid infrastructure built to serve SONGS, saving enormous cost and reducing environmental impact. None of the old SONGS plant is used.


Water Swaps

At first look, the SunRiver project might only look like a local water solution with its short 35-mile connection to MWD. However, this project provides ‘water swaps’ which work to supply distant needs.

Currently, water is being taken from both California’s Central Valley system and from the Colorado River to feed MWD and their customers in Southern California. When Sun River delivers a gallon of water to MWD, a gallon less water needs to flow from the Central Valley or the Colorado River. That means there is another gallon of water for some Central Valley farmer, or Northern California city, for a Las Vegas casino, or a Denver homeowner. SunRiver can even offset Colorado River water that the US, by treaty, is obligated to supply to Mexico.

Notice that no aqueducts from the Colorado River or Central Valley need to run backwards, we just turn down the flow going to MWD, and that water becomes available for other users of those systems. By replacing water currently taken by MWD through the short SunRiver water tunnel, water needs hundreds of miles away are satisfied without additional infrastructure.



Swapping MWD’s replaced water to other Colorado River and Central Valley users allows Sun River to supply water to the California Bay Area, Las Vegas, Mexico, or even Denver. Using existing infrastructure is the key to making Sun River affordable to build. Incorporating solar power plants and grid storage connected through existing transmission lines controls energy costs making SunRiver economical to operate.

Cost of solar power is falling while the efficiency of desalination is getting better. We have reached the point where renewably powered, environmentally friendly desalination works. Carefully using key existing infrastructure, allows large-scale desalination to compete with old- school water mega-projects. And, desalination is proof against drought and climate change. Sun River is insurance for our future water needs.

SunRiver Cost Estimate

Solar Plants (3.3GW, Tracking)

Water Tunnel (25’Dia, 35mi.)

Grid Storage (12GWh, 6GW)

RO Plant (1.5 billion gpd)


$ Billions






SunRiver Desalination and the Ocean

There are two big environmental problems with seawater desalination: sea life can get sucked in and lots of extra salty water comes out. Impingement and entrainment of fish and other organisms can endanger marine ecosystems. Un-diluted brine from desalination can kill sensitive creatures. It is irresponsible to do large-scale desalination projects without addressing these environmental issues.

The seawater inlet and discharge system serving SONGS addressed both of these issues. A fish separation and return system minimized impingement and entrainment of larger fish and wetland restoration was done to offset loss of smaller organisms sucked through the plant’s condensers. Arrays of mixing nozzles – a mile long on each discharge pipe – mixed the hot cooling water into the ocean greatly lowering discharge temperature.

Using these facilities for a large desalination plant raises additional and different concerns. The discharge pipes with their existing mixing nozzle arrays will dilute brine from the plant by 10 to 20 times, raising local salinity only a few percent and is environmentally responsible. But the open-inlet intakes present a challenge.

We all know open intakes that suck up fish eggs, larva and immature fish do serious ecological damage. At the same time, a desalination plant must remove all small particles, including eggs, larva and little fish or these will clog the desalination membranes. Because SunRiver is a very large desalination plant, it necessarily requires a very large intake filter. There is limited land area available at the Sun River desalination plant. What’s to be done?

The most straightforward, and we believe the best solution by far is to put the plant’s inlet filter on the seabed ahead of the existing intakes – that is “seabed filtration”.


SunRiver Energy and Related Environmental Impact

Seawater desalination takes about 15 kilowatt-hours of electricity for every thousand gallons of fresh water. This is about the same as pumping the water up a mile high mountain. SunRiver produces an average of 1.1 billion gallons of water a day and uses as much electricity as a large coal power plant produces.

Instead of a fossil fueled power plant, which would dump millions of tons of CO2 into the atmosphere, SunRiver gets its power from a combination of solar panels and grid storage batteries. Altogether 25,000 acres of solar power plants and 12 Gigawatt-hours of storage are used. The storage is distributed strategically at the solar plants, transmission substations and the desalination plant so energy for Sun River moves through the grid at times of low demand when the wires are under-utilized.

SunRiver’s renewable solar power and grid storage does more than make it a low carbon footprint water project. These generating and grid storage resources also provide backup energy for the Southwest grid. This backup energy will become increasingly important as more industries shift towards alternative energy.

During unusual events that stress the grid, SunRiver desalination can be throttled back, and power diverted to stabilize the grid. SunRiver solar power generation and storage are available to the grid during times of unusual stress at far lower cost than having stand-by generation that is rarely used. Not only does this diminish SunRiver’s carbon footprint, it lowers the carbon footprint of the entire Southwest grid.


Critical Steps to Secure Reliable Southwest Water

Implementing SunRiver and obtaining the large amounts of new, clean, affordable water we need requires action now. SONGS is being decommissioned right now. State regulators, the California Lands Commission, other agencies and the utilities who own SONGS need to preserve infrastructure that SunRiver will need. This includes the grid connection assets and the cooling system seawater inlet and discharge system. Abandoning and/or demolishing these assets would be irresponsible because it will increase the cost and delay implementation of Sun River.

For community safety reasons, and to support early and SunRiver implementation, spent fuel at SONGS must be removed from overloaded pool storage to dry casks, and those safely isolated. Delay is not only dangerous for the community, it makes implementing Sun River more costly and time consuming.

Prompt, thoughtful, resolute action to preserve useful assets and speed the safe decommissioning of SONGS will speed Sun River and help deliver the new clean reliable water that our region needs. It is the right path forward for all concerned.


Why SunRiver Is Worth It

SunRiver is a regional-scale solution to drought and climate change. There have been desalination projects before along the California coast. These projects meet a localized need here and there, but don’t pretend to address drought in the whole Southwest. SunRiver is much, much bigger. Sun River replaces 100% of the water DWP takes from the Colorado River – 1.3 million acre feet a year, 1.1 billion gallons per day, 50 metric tons of fresh water per second.

Bigger is better. SunRiver produces enough water to realize economies of scale, and enough water to meet needs of multiple, large, high value uses. Sun River’s scale makes it worthwhile for distant cities, states and even the federal government to have a stake in the project. This in turn brings enough diverse and powerful stakeholders to the table to make the necessary water swaps achievable.

SunRiver isn’t just bigger – it is different. Unlike every previous Southwest water mega- project, SunRiver isn’t about stealing someone else’s water. Sun River delivers new water, created from the ocean using our abundant sunshine. It’s drought-proof water. For the first time, large Southwest regional water needs can be met without steeling other people’s water. And come to think if it, that’s pretty big, too.