Also, DWR’s Paul Marshall updates Commission on the effectiveness drought barrier
Attending a Delta Protection Commission meeting is, among other things, a chance to step inside some of the Delta’s beautiful and historic buildings, and the March meeting was no exception. Held at the historic Ryde Hotel near Walnut Grove, the meeting featured a report by Delta Watermaster Michael George on last year’s voluntary diversion reduction program among Delta users and an update on the Delta consumptive use study, and a briefing by DWR’s Paul Marshall on the effectiveness of the drought barrier.
MICHAEL GEORGE, Delta Watermaster
Created as part of the 2009 Delta Reform Act, the Office of the Delta Watermaster is responsible for overseeing the day-to-day administration of water rights, enforcement activities, and reports on water right activities regarding diversions within the Delta. Michael George is the second Delta watermaster, having started his four-year service in 2014.
As part of the duties of the position, the Delta Watermaster gives periodic reports to the Delta Protection Commission, as well as the Delta Stewardship Council. The following week, Mr. George gave a lengthier update to the Delta Stewardship Council; a report on that presentation will be posted tomorrow.
Delta consumptive use study
Delta Watermaster Michael George updated the Commission on an agricultural consumptive use study which is a comparative study of different methods for measuring consumptive use in the Delta. The study builds on a proof of concept study to develop better methodologies and to compare methodologies for determining consumptive use in the Delta, he said.
“It’s important to get a better handle on that primarily so that we have less dissonance in the system about what consumptive use actually is; we ought to be able to agree on what the consumptive use is and then use that to inform policy decisions,” he said. “There has been controversy in the past about how and what the quantification of consumptive use is and there are multiple methods that are used for different purposes by different organizations. The purpose of this study is not to figure out which one is best, but to compare them all, because those methods will probably have good applications for different purposes, but we need to know how they compare and how they operate.”
Technology in this area is developing rapidly, Mr. George pointed out. “We believe it will be possible to correlate some of the old physical mechanisms for determining what consumptive use is at the field level by using new technology including computer analysis of satellite imagery, so that we would hope to be able to know with a high degree of certainty what the consumptive use it, what the land use is, and what the crop in the field is, so that we can get a better handle on all of that to better manage agriculture , water rights and the water in the system, whether it’s for salinity management, export control, or what have you.”
Consumptive use is only one leg of the stool, he said. “We also have to look at diversion within the Delta as that’s how we manage water rights,” he said. “Water rights are determined and administered by diversion, but how the water is consumptively used after it’s diverted, and then the third leg of the stool, how much of it is returned to the system. There are places in the Delta that actually return more water to the system than they divert because they are farming below the water table and they are having to drain more than they are actually using, so we’re trying to get a handle on that. This is one leg of the stool; it’s the one we’re starting on first, so that we get better operational data.”
The UC Davis Center for Watershed Sciences is the lead for the two-year study. It is now fully funded, with many agencies helping to provide funding, including the State Water Resources Control Board, the Department of Water Resources, the Delta Protection Commission, the Delta Stewardship Council, Delta water agencies, and others.
With the support of the Delta water agencies, 5 new CIMIS stations have been deployed in the Delta. The stations with help with better spatial differentiation so that they can have a better sense for weather and the effects of winds in open channels on consumptive use, he said.
The Department of Water Resources has funded a land use survey by satellite survey through a third party contractor, Land IQ. “It has given us a great deal of very granular information that can be updated regularly so that we have a much better handle on land use and crop use as well as natural uses in the Delta outside of the cropland, so for instance, a better sense for how much freshwater is taken out of the system by water hyacinth, or by riparian habitat, and by evaporation from open channels. It’s a big improvement.”
The data that is being developed is being subjected to significant QA/QC processes. “We’re trying to raise the level of confidence in all the data that we’re looking at so we can have greater confidence in the decisions that we make based on that data,” Mr. George said. “The final report of this study will be a peer-reviewed report that will be published in a scientific journal and should be available in about a year from now. We’re hopeful that because of the large number of people involved in the study, and because it will be a quality study, that it will have a lot of credibility so that we can get beyond arguing about what the facts are and use the facts to inform policy.”
Delta voluntary diversion reduction program
The Delta Watermaster recently issued a report on last year’s diversion reduction program. “This was a voluntary program that bubbled up from the farmers in the Delta, particularly the south and central Delta, who don’t have the advantage that the north Delta has of the water supply contract,” he said. “The concern as we went into the fourth year of a drought at the beginning of 2015, was that there would be insufficient water to provide the water to finish crops, and so farmers came forward and suggested a voluntary program which they would reduce their diversions from the surface water supply by 25% over the course of four months of the growing season, June, July, August, and September. In exchange for that, if there were to be a basis for more severe curtailments of riparian rights later during the season, we would exercise our enforcement discretion to not enforce against anybody who participated in the program.”
A total of 217 plans were submitted, covering 180,000 acres or roughly two-thirds of the Central and South Delta. Participation was not 100% as the program was only available to riparians so not everyone could qualify, and others decided to take their chances, he said. “Overall, the program was a success and the plan participants collectively saved about 32%, or reduced their diversion by about 32% versus base year 2013, so there is some success. We reduced a little bit the pressure on the overall water system, but I think even more important than that, there was a demonstration here of the Delta coming together, without litigation, without regulation, to figure out a way to solve a common problem, and we did it flexibly so that at the field level, farmers could decide how they were going to hit the target, and not only did they hit it, but they overachieved.”
Note: The following week, Delta Watermaster Michael George gave a lengthier report on the diversion reduction program to the Delta Stewardship Council. See tomorrow’s coverage for more details.
In May of 2015, due to the exceptionally dry hydrology and low storage in upstream reservoirs, a barrier was installed on West False River between Jersey and Bradford islands to block salt water from intruding into the Central and South Delta. The barrier was intended to preserve Delta water quality and conserve water in upstream reservoirs that otherwise would have been released to help block incoming tides of salty water from San Francisco Bay. Paul Marshall, chief of DWR’s Bay Delta Office gave a brief presentation on how the barrier at West False River performed.
Mr. Marshall began by presenting a slide with four quadrants, noting that the top half is showing a flood tide with water coming in from the Bay and the bottom half is during an ebb tide; he also noted the left side is without the barrier at West False River in the Frank’s Tract area, and the right side is with the barrier. “What happens is that with the no barrier in place in False River, salinity freely goes into the Franks Tract area, rather like dye going into a cup,” he said. “Once it gets in there, it starts dispersing right away. With the barrier installed as shown on the right side, the salinity is forced into the San Joaquin River and has to stay in a more or less in the San Joaquin River. And as it stays in that channel, it kind of acts like plug flow where when it goes in, all the salinity stays together, and when it goes out, it all stays together. Therefore, on the right hand side, Franks Tract is not getting as saline during the flood tide … this barrier basically just prevents salinity from getting into Franks Tract.”
That’s the theory, so how did the barrier perform? Mr. Marshall first presented a map showing the locations of four monitoring stations: One at Jersey Point in front of the barrier, one at West False River just behind the barrier, one at Bethel Island, and one further beyond at Holland Tract.
He then presented a graph showing salinity intrusion in 2014, a year in which flows were low, noting that Jersey Point and False River follow each other very closely throughout the entire time period shown on the graph, which is September 2013 through April 2014.
In 2015, they continue to follow each other until the installation of the barrier. “As we installed the barrier, you can see that they are separated, so this illustration basically shows that by placing that barrier there, we get that separation,” he said. “On the west side of the barrier, it continues to vary along with the tides, and on the right side, it’s a much more muted variation.”
He then presented a slide of 2014 prior to the installation of the barrier, showing the monitoring stations at Bethel Island and Holland Tract in purple and pink lines, and noting that they are varying together, although perhaps not quite as tightly as the Jersey Point and False River locations.
“As we go into 2015, you can see how even those signatures become more muted as we installed the barrier, so we have evidence that the barrier is working as designed and we actually needed it quite a bit this past year,” he said. “In 2015, one of the things we did run into is higher than astronomical tides, meaning the tides were actually higher than predicted. We usually get those kinds of situations when we get a lot of weather coming in such as onshore breezes or low pressure systems. Without this barrier, we would have had a lot more salinity going into the Central and South Delta than we experienced, so it was money well spent for the Delta farmers as well as the Contra Costa Water District and so forth.”
In terms of how 2016 shaping up, the good news is that there will not be the need to build any barriers this year; there is enough water, Mr. Marshall said. But the hydrology is really pretty average, he said.
He presented a graph of the Northern California 8-station index, noting that it’s right at average, and pointing out that the other lines indicate other El Nino years. “It looks like it’s kind of a flip of a coin as to whether or not El Nino is a good predictor of strong weather systems.”