On November 22 the City Council has a chance to choose a direction in how it plans to cope with a mandate to reduce diversion of water from area streams in order to allow more ample stream flows needed for coho and steelhead salmon. On that day the Council will conduct a hearing on the City’s 5-year Urban Water Management Plan.
The Water Department says that building a desal plant is the only way to provide better habitat for endangered fish. SC Desal Alternatives has another view. We point out that setting a goal to freeze water consumption at 2010 levels would allow stream flows in normal years that meet “Tier 3″ standards, defined by the City as “flows that most closely approximate fisheries agency goals”.
The Water Department’s response to our advocacy of freezing demand at 2010 levels is that we are “overly optimistic”. The Water Department expects demand to immediately rebound by 10% from 2010 levels, and grow another 14% by 2030. These assumptions make it look like a desal plant is necessary to ward off unacceptable levels of drought-year curtailment.
Our message to the City Council is that our level of demand is a matter of policy, not a factor outside of our control. If Soquel Creek can set a policy to reduce water demand by 8% between 2015 and 2030, then surely Santa Cruz can set a policy to freeze demand at 2010 levels.
Freezing demand at 2010 levels would require two things: a campaign to achieve this goal among existing water users, and a program to offset growth in demand from new development, such as is in effect in Soquel Creek Water District. In allowing growth in water demand to erode our drought security, the Water Department is out of step with our County Local Agency Formation Commission (LAFCO) that set a policy that water demand must not be allowed to grow in areas of overdrafted aquifers and streams.
For a more detailed discussion of the how Santa Cruz citizens can out-perform desalination in providing fish habitat as well as drought security, continue reading.
The Water Department makes two assumptions in their argument for desalination: rebound and further growth. Rebound, they say, is inevitable after every period of dry years in which people change their water use behavior. After the dry years of 2007, 2008, 2009, people are going to go back to their old water-carefree ways, goes the logic.
We don’t disagree that this is what has happened in the past. We just think we can’t afford to repeat the past. And so far we’re not. Since 2009, Santa Cruz water users are proving that they aren’t getting careless. In 2010 water demand has dropped even from 2009 levels in which there were mild restrictions on landscape watering.
The second assumption is growth in water demand of 500 million gallons between now and 2030, above and beyond the 10% rebound level. Ironically, this amount of growth wipes out any gain from desalination, which in drought years is expected to provide 450 million gallons. So unless the desal plant is expanded by 2030, the fish will be worse off in drought years than they are today under this unrestrained growth policy.
In normal years freezing demand outperforms desal hands down in terms of benefit for fish. The desal plant offers negligible benefit in normal rainfall years, since the plant will only be producing water for Santa Cruz in drought years. The following table shows what water production is available in normal rainfall years, with Tier 3 flows. It shows that there is enough water to support 2010 levels of water consumption.
Note: The Table comes from data on Tier 3 flows supplied by the Water Department. I have reduced the amount of water available from Loch Lomond by 450 million gallons, in order to assume a prudent reserve of water in the lake in case of following year drought.