Solving the Santa Cruz Water Crisis
It took 18 months of meetings. 18 months of studying, touring facilities, evaluating citizen submitted proposals, hearing from organizations, engineers, scientists, and pollsters, yet last Friday the Santa Cruz Water Supply Advisory Committee voted unanimously, as per their consensus based charter, to pass on a portfolio recommendation to the Santa Cruz City Council for addressing the water department’s billion gallon annual gap.
The feat is nothing short of astounding in the landscape of Santa Cruz politics where it’s difficult to agree on anything. Add in the fact that this committee was formed in the wake of the public fallout surrounding the proposed desalination facility, and it’s near impossible to believe that a 14 person appointed committee that was purposefully chosen along all sides of the political spectrum could come to a consensus based decision, on water no less. But in politics you get what you pay for, and with a consensus based committee you get a little something for everyone, and a large price tag. But hey, that’s definitely something, and after putting in over 200 hours each these public servants deserve some credit. So what did they come up with?
The WSAC recommendation is a 4 pronged approach with 2 preferred options, a back up plan if those fail to work, and even greater emphasis paid to conservation. Conservation measures alone are expected to save the department close to 200 million gallons a year (for reference the City’s main reservoir Loch Lomond holds about a billion gallons, but is rarely drawn below 50 percent as an insurance policy). Beyond this conservation becomes too costly per unit of water saved when compared to building new infrastructure.
The primary approach in called in-lieu recharge, and it involves upgrading the Graham Hill Treatment facility to the tune of 50 million dollars to expand its total capacity while also building what are called Ranney Collectors, which collect water from the San Lorenzo River that would otherwise be considered too turbid (dirty and fast moving). Together these new pieces of infrastructure will allow the City to draw more water from the river during the winter rainy season, which they will in turn sell to both Scotts Valley and Soquel Creek Water districts so that they can both avoid pumping their groundwater supplies.
The second preferred option is referred to as Aquifer Storage and Recovery (ASR), which is an extension of the first option, but with a more active component. Instead of just resting their groundwater supplies this option calls upon both Scotts Valley and Soquel Creek to actively inject water back into their aquifers. This would again be performed primarily in the winter months. Both districts, with the help of Santa Cruz, would have to buy a large number of well sites throughout their services areas to build injection wells, which is no easy feat, and then quite literally force water back into the hopefully permeable water table. The bet, and it is nothing short of a bet, is that enough water can be stored in the aquifers so that both districts can sell water back to Santa Cruz in drought years, which is really the only time Santa Cruz actually needs additional water.
The problem: no one can say with any confidence that this will actually work, and not a single technical expert working to support the WSAC would say otherwise. The water might drain out somewhere, or simply not hold given the varying levels of permeability. We just don’t know. And we won’t know until we try it out, to the tune of at least another 50 million. If it proves to be successful the total cost of ASR could break 200 million in total. Land isn’t cheap, siting and permitting something like 20+ large scale injections wells is a nightmare, and building out the pumping capacity to send water back and forth between districts is just inherently expensive.
There is a backup plan however, and it’s called recycled water. In the event that ASR doesn’t work, or proves too costly, the WSAC recommends building a recycled water facility that would be built on site at the Bay Street Treatment facility. There are 2 types of recycled water that could be utilized, indirect potable reuse and direct potable reuse. Both involve extensive treatment of the existing effluent (tertiary treated human waste) that we are currently pumping into the bay to a level of being on par with distilled water. Indirect reuse would require that this treated water be pumped up into the back of Loch Lomond where it could be blended with the water in the reservoir, which actually does very little other than perhaps nullify some psychological concerns. Direct reuse does add an additional level of treatment (UV radiation), but would pump the water directly to Graham Hill where it could be added directly into the existing water supply. Direct potable reuse is technically not legal in California, but legislation is currently being prepared with most reasonable timetables estimating it to be approved within 1-5 years. A Direct to Potable plant costs roughly 90 million, while an Indirect plant would cost substantially more because of the additional pumping required. Both are proven technologies with many contemporary case studies to draw from (Santa Clara later this month in fact), and the health effects have been thoroughly tested.
So what causes the backup plan to go into effect? 2 things: if ASR doesn’t show progress within 5 years of creating a pilot program, and/or if the per unit cost of water over the expected lifetime of the project exceeds 130 percent of what it would cost through a recycled water facility. The reason why in-lieu and ASR are the preferred option despite very likely costing more is the concern over energy use. A direct to potable reuse facility would use roughly 30 percent more energy than both of the preferred options, which is why the per unit cost trigger is set at 130 percent. Simply put, the WSAC is willing to pay more for using less energy and contributing fewer green house gas emissions.
Should the City Council accept the WSAC recommendation? Could the recommendation be improved? Should the City go with the preferred options? Vote and comment below.
|Adopt the WSAC Portfolio Recommendation
This portfolio recommendation contains 200 million gallons of additional conservation measures, the preferred options of in-lieu recharge and Aquifer Storage and Recovery, and the back up plan of building a recycled water facility if these options prove ineffective or too costly. Under the agreement the decision to switch to the backup option will be considered in 5 years time, or if the per unit water cost exceeds 130 percent of the per unit cost of the preferred options. The total portfolio cost depends on the effectiveness of the preferred options, but is likely to be close to 200 million dollars.