Quick Take:

Lookout political columnist Mike Rotkin explains why the atmospheric bomb cyclones that flooded parts of Santa Cruz County at the start of January do not signal an end to the drought we are currently in. He also offers a mini primer on the city’s water-solutions history, from storage to desalination efforts and more. He also explains why water bills might eventually go up.

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Mike Rotkin

Readers will not be surprised I focus this Lookout piece on water and storms. There is so much misinformation — or perhaps we should simply say “ bad assumptions” — flying around that I thought I would try to address some of them.

Let me start with why we are officially still in a drought after all of this rain. It’s simple: Santa Cruz County has no connection to the state water system. We are on our own. It does not matter to us how big the snowpack in the Sierra Nevada is.

After all of these storms, the Loch Lomond reservoir, which holds just under 3 billion gallons, is full, so we have about a year’s worth of storage. That is good news, but we might easily be in a new drought as early as next year, and it might last more than one year. Studies of rings in redwood trees show that we have had 80-year droughts in the past, and many droughts documented in written, historical records have lasted five and more years.

So a full reservoir is not the end of the drought.

The Santa Cruz Water Supply Advisory Committee, which met monthly in 2014-15, and on which I sat until it disbanded, looked at lots of other options for water supply — including an invitation to the public to bring us every idea citizens had to the Civic Auditorium. We got over a hundred ideas, including grids to capture fog as a supply, rain barrels at every home, reservoirs all over the place, and so on. When the city did the cost-benefit analysis, we realized none of these solutions worked at the scale we needed to address our water-shortage issues.

Clearly the problem in Santa Cruz County is storage.

We get enough rain on average, at least so far, that if we could store more of it for drought years, we would be OK. Of course, climate change could change that, but we’d all be a lot more confident of avoiding a disaster if we knew we had at least a bit more than one year of storage.

The Santa Cruz City Water Supply Advisory Committee studied various options for water supply in great detail, and for a variety of reasons too complex to go into here, we found that above-ground storage reservoirs not a good solution. They tend to destroy fish habitats on streams, particularly for threatened and endangered species like coho salmon and steelhead trout because they reduce stream flows so significantly. They also are expensive (causing water rates to rise dramatically) and they are subject to failure from earthquakes and leakage into the extensive limestone karsts that are the basic geology of our area. And, given all those reasons, they are difficult to get approved by regulatory agencies. Dams are being taken down all over the West and not encouraged as a solution for the most part.

When in 2012 the city raised the idea of increasing the height of the Loch Lomond reservoir on Newel Creek in order to store more water, the regulatory agencies told us they would require releases for fish, which would result in less, not more, water in storage for the City of Santa Cruz.

From the turn of the century until 2013, the city also worked on a desalination plant that would provide us and our neighboring Soquel Creek Water District enough water for drought years at a reasonable cost. But public opposition killed that plan.

Storage solutions do depend on at least some rain in our future, and climate change puts that at risk. Views on desalination in California are changing and we may yet see desalination in our future, but it is not our current Plan A for water supply.

Another question people ask is why all of this rain we have had won’t just soak into the ground and replenish our groundwater aquifers? The problem is that extensive clay layers near the surface of much of our county’s land do not support even moderately rapid recharging of our groundwater aquifers. If we want to store water in the ground for later use in droughts — which is a good idea and the city’s primary plan at this point — we need to inject it through wells into the aquifers.

Just as a well can be drilled to draw water out of the ground, one can be drilled to pump water into the aquifers below. And just as wells drilled to collect water can miss major aquifers, even with modern scientific ground mapping, it is possible to drill an injection well that misses a major aquifer and is not very useful. So this process takes a while.

Injecting the excess water from storms like the ones we have been having requires building a great many more injection wells, which is part of the city’s current plan — in conjunction with our neighbors in the Soquel Creek Water District. (Despite the name, the district takes no water from Soquel Creek. It depends entirely on groundwater.)

But more significant and more expensive is the requirement that before injecting the excess water flowing down the San Lorenzo River during these storms into groundwater aquifers (excess because it is more than we or the fish can use in the short term), it needs to be cleaned up at the city’s treatment plant at Graham Hill. The plant there is already antiquated and in need of major upgrades, but upgrading it to treat the often-muddy water from storm runoff in the San Lorenzo, along with other needed upgrades, will cost about $100 million.

The Santa Cruz Water Department has already saved some money for this project, but it will need to raise rates over time, and it will not happen overnight.

So here we are, still in a drought.

We have a solution in the city’s groundwater storage strategy, but it won’t be in place for a while yet. As they say: “Water, water everywhere, and not a drop to drink!”

Mike Rotkin is a former five-time Santa Cruz mayor and six-term councilmember. He teaches in Merrill College at UCSC and served on the city’s Water Supply Advisory Committee. His previous piece for Lookout, on the midterm elections, ran in December.

Mike Rotkin is a member of the Santa Cruz Metro board of directors and the Regional Transportation Commission. He is a former five-time mayor of the City of Santa Cruz and a lecturer at UCSC.