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HomeMy WebLinkAbout04-27-16 PC Correspondence - Item 2 (Lucas)RECEIVED Meeting. CITY OF SAN LUIS OBISPO Lomeli, Monique Item: AP? 2 6 2016 COMMUNITY DEVELOPMENT To: Davidson, Doug Subject: RE: 2015 Urban Water Management Plan Item 2, April 27 meeting From: Bob [ Sent: Monday, April 25, 2016 2:39 PM To: Davidson, Doug Cc: Subject: 2015 Urban Water Management Plan Item 2, April 27 meeting Please forward this email to the Planning Commission for its April 27 meeting. On Wednesday the City will be looking to you for guidance with its development of a revision to its Urban Water Management Plan and Water Shortage Contingency Plan. At its Water Forum last Thursday, City staff did an excellent job disseminating information about water conservation techniques, policies, and plans. People who attended found much good information, which is also now available at their website. Its Frequently Asked Questions section has been vastly improved and expanded. This will continue to serve the city and its residents as an important tool. Those changes were called for. Much in the 2010 Urban Water Management Plan concerning conservation and rationing was done at a much more relaxed time, and the extent to which earlier policies should have been scrutinized is exemplified in how drastically the stages of water rationing have been changed in your agenda report. Only six years ago, three stages for rationing seemed sufficient; now these have been expanded into six stages, and made much more specific. Unfortunately at the same forum, answers to questions about long range water availability and reliability were less convincing and informative. The Urban Water Management Plan is in dire need of a much closer look at long range water projections. It was weak in the area of the impact of climate change. The 2010 Urban Water Management Plan cited the 2002 report by Boyle Engineering Corporation to verify Naci's reliability in providing 17,500 AF per year into the distant future. But that report, in its sparse three and a half page, makes at least four major mistakes or omissions as follows: 1. It only mentions climate change to say that it did not consider it. 2. It only speaks to wet years and normal years of rainfall. It had no dry year projections. 3. It underestimates the maximum impact of SLO County's increased draw by 140%. 4. It "annual" outflow of water from Nacimiento is based on only 10 years' data. So many serious errors in so few pages indicates a report that ought to be discounted and replaced by a more careful model. On this topic, input from the Planning Commission will be crucial, and the City has acted wisely to bring it to the Commission before it proposes a full draft to the City Council in June. This is critically important because reservoir water is the source of 98% of our potable water. Lake Nacimieto, which came on line after the last report was filed, was heralded as a secure source of reliable water well into the future, buttressing stressed Whale Rock and Salinas reservoirs. But things have taken a turn for the worse since it went on line. The drought in the intervening years has been the worst the city has experienced since it started taking reliable records. The negative impact of climate change appears to be accelerating, as evidenced from the "failure" of el nino this year. Information from the 2002 analysis plan about long range reliability of Naci seems, on second look, badly flawed. Salinas Reservoir, which was supposed to have no surprises, is now off line and has been rendered effectively useless by algae. And in the intervening five years, our County has decided to max out its entitlement to Nacimiento, while the reservoir itself appears stressed by the drought, leaving us not place to look easily for more water in the future. Future Update should use an appropriate model that accounts for climate change. So far, none of the documents the Utilities Department has offered at its website includes any date on the impact of climate change. The Water Forum was unfortunately no better at answering this vexing question. The 2015 Urban Water Management Plan should incorporate clear models and projected data for water sources as part of its plan that can be relied on until such time as reclamation and recycling of water becomes viable and widespread for all our needs. Even had the city offered a revised model that does a better job of predicting the impact of climate change (which I contend it does not), that model cannot incorporate the stresses that are outside the reach of science, which are just as likely to create havoc for our projections. The city at its Forum and on its website addressed only a few of these issues, and those that it did were among its weaker and more vague answers. Since Lake Nacimiento plays a key role in our near term secure water future, I want to review some facts and concerns about Lake Nacimiento as a reliable source over the next twenty or thirty years. First, SLO County users are entitled to 17,500 acre feet (AF) of water a year from Nacimiento. Its capacity is 378,000 acre feet. SLO City's share of that is about 5500 AF a year. Each year over the past 56 years, there would have been enough water to meet our needs. But in the future, we can expect things to be different. How different depends on a number of factors. Some of these are physical, some are legal, others are sociological and political. A few are in our control but most are not. One cause of concern is our entitlement. It is not ironclad. It dates from a contract written in 1959 that has never been tested in court, partly because we began drawing our share of its waters in earnest only five years ago. Now that we are taking our full allotment, and the drought is here, and global warming seems more than a vague threat, it is time to look at these factors more closely. At some critical points, the language of our County's contract guaranteeing 17,500 acre feet a year is not as strong as we would like. Once the reservoir's levels gets low and in danger of remaining low, once we dip into our protected waters in the last acre feet of the minimum pool, we can expect others who rely on the reservoir to a much greater extent, like the farmers of Monterey County, to want into our supply. So what are some of these pressures, over which we have little or no control? Over the past five years, our draw on Naci has gone from about 1750 acre feet per year to next year when it will likely be ten times that, that is, 17,500 AF a year (5500 for us and the rest for Atascadero, Templeton and Paso Robles who are also part of our contract with Monterey County.) That annual draw will increase the impact on Nacimiento. These steps were completely under our control. Now that they have been taken, they are unlikely to be reversed. The lake has overlapping jurisdictions, with varying degrees of authority over what happens in Nacimiento. The big one is the Monterey County Water Resources Agency (MCWRA), which owns the dam and governs how much water comes out on any given day and where it goes. Behind, next to, or above them is an array of regulatory agencies such as the Army Corps of Engineers, the CA Department of Dams and Reservoirs, the Federal Energy Regulatory Commission, and the CA Department of Fish and Game. They all have something to say, and it is difficult predicting when or how their voices will be heard or how far their legal arms will reach toward the spillway's spigot. Evaporation is a concern. Naci already loses as much as 20,000 acre feet a year to evaporation. Global warming will increase evaporation amounts because of higher temperatures year round and greater winds. How much more is unknown, but it could double the evaporation rate both in summer and in winter as well. Unknown impact—some estimate twice as much loss, or 40,000 AFY. Out of our control. Global warming may reduce our rainfall by 2 to 4 inches annually. That will reduce the recharge to the reservoir by 20,000 to 40,000 AF per year (a very conservative estimate). So the inflow to the reservoir will be less each year. A continuation of rainfall of 2-4 inches less would inevitably create periods when there is no run-off into Naci. Unknown impact. Out of our control. Climatologists agree that whatever happens in the future, we can expect greater extremes in weather. So our droughts will be deeper and longer, and our storms will be greater. If the droughts are deeper, it will take longer for rainfall to saturate our watersheds before runoff appears in our reservoirs. If the storms are more severe, we may not be able to capture all the water usefully without stressing our reservoir system. This reduces the amount of water we will have by an indeterminate amount. One calculation shows the likelihood of a zero run-off year by mid to late century, and two back to back would make us totally reliant on Whale Rock Reservoir. Unknown, but possibly severe impact. Out of our control. When the reservoir does fill to overflowing, which has happened five times since it was built in 1959, much of that water—as much as 100,000 acre feet --is released to reduce pressure on the earthen dam and to flush silt buildup out of the Salinas River. The flushing of the Salinas has to be done periodically. Otherwise the river will turn into a floodplain and become useless. Such rapid reduction of water in Nacimiento reduces its effective working capacity to much less than its calculated capacity. Timing and impact out of our control. The steelhead trout/salmon also need a strong stream flow to spawn. This calls for releases at other times in the year. Timing and impact out of our control. The farmers in the Salinas River Valley need water to recharge their ground water to keep seawater from intruding and ruining it. The Nacimiento Dam contributes 62% of the water that flows into the river. The farmers depend hugely upon this water to keep seawater out of their groundwater. The Monterey County Water Resources Agency (MCWRA), a board composed of nine ag-knowledgeable Monterey County citizens, controls such releases. Unknown impact. Out of our control. The MCWRA is activating plans to build a ten foot in diameter tunnel from Nacimiento Reservoir to Lake San Antonio. That tunnel will channel water from Nacimiento to San Antonio for storage until needed to recharge the Salinas Valley water basin. SLO County has no rights to water in Lake San Antonio, even though it helped to build the dam. The new tunnel will be built over and through SLO County land, so that gives us some leverage. MCWRA already has $25M of the est. $56M needed. Unknown impact. The only one of the above factors completely within our control is how much water we as a City use. If Naci runs out, of course, we can't even use that water. That's why keeping our eye on this precious resource is critical to our continued safety as a community. Any increase in our water use must be undertaken only after the most stringent review and examination. That's when long term planning becomes short term planning. We can't wait until the last year before we run out of water to control our buildout plans; it should start well before then. Thank you, Bob Lucas 4594344