Josh Weimer, External Affairs Manager of Turlock Irrigation District, in support
Good morning, Chair and members. My name is Josh Weimer with the Turlock Irrigation District. And I appreciate the opportunity to be here today to highlight TID’s industry leading water operations. TID is the first irrigation district in the state of California, formed 135 years ago. We’re not part of the State or Federal Water Project. Rather, the Don Pedro Reservoir is locally owned and operated on the Tuolumne River. We also have sole flood control responsibility for the Tuolumne River.
Over the last 135 years, one principle has held firm. Necessity drives innovation, and that has clearly been the case in our watershed management. Wet years are getting wetter and drivers are getting drier. That comes as no surprise to anybody in this room. We’ve had to learn how to operate Don Pedro, with these changing conditions. 1997 changed everything for us. The wettest period on record for the time. Abnormal temperatures and a Pineapple Express as it was turned back then came through and we had no idea what was in the snowpack or when it was coming off. 1997 revealed a need and TID invested right away in a state of the art model that we have spent the last 25 years building on and fine tuning.
TID’S HFAM model is one of the few, if not the only hourly and physically based hydrological models used for water operations and planning in the state of California. HFAM was built specifically for our watershed and breaks down the nearly 1800 square mile watershed into 5000 land segments. Each land segment factors in the unique soil and vegetation type and then uses over 100 different variables to calibrate each land segment. HFAM also allows us to input the 16 day forecast as well as bring in 90 years of meteorological data into that model. HFAM is game changing.
But the drought ten years ago showcased another need, and that need was to better understand what was in the snowpack today to partner with NASA ten years ago to re-imagine snowpack measurement by using LIDAR mounted to airplanes, which has reduced the error rate from 30% to less than 3%. We now know exactly how much snow is in the snowpack around that same time to start to incorporate incorporate the new atmospheric river research coming from Scripps Institute into our HFAM model to improve our forecasting. This information is what recently has been popularized by the concept of Forecast Informed Reservoir Operations, which TID has been doing for decades. These models and new technologies have provided significant results that have benefited our region. In 2017, we were able to use all of these inputs to know that the runoff was going to exceed our maximum storage capacity and started making flood control releases 15 feet before the top of the dam. It cannot be overstated that at that time this was unheard of. In 2018, we use the same technology and received a deviation from the Army Corps of Engineers that allowed us to capture 150,000 acre feet that would normally have been forced to be released due to a flood control manual from 1950. Last year we were able to predict the April to June runoff in March, and it was only 10,000 acre feet off or less than 2%.
We do not have a static climate. Necessity continues to drive innovation. We need to stretch our facilities capabilities to try to reduce the uncertainty moving forward. And we are embracing and embarking on new technologies and modeling to provide even greater analysis and operational intelligence. Thank you.
Julie Rentner, President of River Partners, in support
My name is Julie Rentner and I’m the President of River Partners, which is a not for profit organization with a mission to create wildlife habitat for the benefit of people in the environment. Our organization has the largest footprint of river restoration across the American West. We’ve restored more than 20,000 acres of rivers and floodplain habitat types, as well as 200 river miles focused almost wholly in the Central Valley of California… River Partners works closely with the Department of Water Resources, and we know that they’re very hard working people at the state who are trying desperately to predict water and runoff as accurately as they can. I stand here in support of this audit not to highlight shortcomings or assign blame about water management decisions that are made, but instead to support improvements that are needed in managing this most precious of public resources. We all know that ecosystems need water. We’ve known this for decades as habitat managers along river corridors. We have learned to be as precise as possible with the use of every single drop of water that’s available. We rely heavily on forecast river forecast models and information about historic weather patterns to design and manage the critical habitats that support the biodiversity of the state. When we don’t have access to good, reliable information, we can’t do our job. What’s different in 2022 than in any years past is that climate change is driving an unprecedented change in the hydrology in the Sierra Nevada, and we don’t have time to litigate and fight and study further. What we need to do is make dramatic improvements to the way we manage our water resources so that we can stem this crisis of looming extinction and the edification of our great Central Valley. So I believe audit is a powerful tool that can drive institutions towards improvement. I am encouraged by the technology that I’ve seen developed by our partners in the local water management agency at Turlock Irrigation District, as well as the NOAA forecasting models that have been so accurate. And I encourage the committee to consider this audit today to improve the way the state manages its precious water resources.
Karla Nemeth, Director of Department of Water Resources, in opposition
Good morning, Mr. Chair and Mr. Vice Chair. My name is Karla Nemeth. I am the Director of the California Department of Water Resources, and I am here today to share with you my opposition to this audit request. First, the item before the Committee requests an audit of the Department of Water Resources and the State Water Resources Control Board as a result of the discrepancy between DWR’s initial snowpack runoff forecast in 2021 and the runoff realized in the Sacramento River Valley watershed. This forecasting work is undertaken exclusively by the Department of Water Resources. The State Water Board is not responsible for this action and as such should not be a party to the audit.
The audit also appears to be based on an inaccurate assumption that 700,000 acre feet of water was released because of the forecast. As I mentioned, this is not accurate. There was no release of water made due to the forecast. The reservoir levels were not at an elevation that would have warranted a release of water to ensure space in the reservoirs to capture runoff as as a matter of important flood protection. The initial forecast was made in December of 2020 and was updated in April based on what was what became one of the driest and warmest March-April 2021 period. During this period, there were no flood releases made to allow for the additional capture of runoff, so our reservoirs were not full and had sufficient space to capture any spring runoff.
However, the initial forecast was overestimated and the question is why the data upon which the forecast was made did not accurately account for exceptionally dry and hot conditions in the spring of 21, but equally as important in the previous summer and August of 2020. These conditions resulted in a significant percent of our state snowpack disappearing into dry soil or evaporating. Northern California, as you recall, was exceptionally dry and the spring was exceptionally hot. Historic forecasting and the data upon which it has been based did not reflect these conditions. As soon as the effects of these conditions were observed, DWR took numerous actions, including a requesting a change in Delta outflow standards from the State Water Resources Control Board, installing emergency salinity drought barriers and reducing water supply allocations.
The audit request does note that improved model accuracy is needed, and I could not agree more. In point of fact, the Department of Water Resources was the initial funder of the work that our colleagues have been doing at the local water agency level, including Turlock Irrigation District. The Department, together with NASA, has been funding their aerial snow observatory forecasting techniques. That’s a lot of important updating information. We were able to take that information to scale based on funding provided by the Legislature last year, which has resulted in specific and important changes this year, watershed wide. I agree wholeheartedly that work needs to be accelerated and the Department is so doing. So with those comments, I believe I’ll turn it over to my colleague Eileen Sobeck.
Eileen Sobek, Executive Director of the State Water Resources Control Board, in opposition
Thank you, Chair and members, and I do concur with the remarks of my colleague. I am Eileen Sobek, the Executive Director of the State Water Resources Control Board. As his name has noted, the Water State Water Board does not engage in independent forecasting. We rely on the forecasts put out by others.
As soon as we all realized how bad 2021 was, we worked very hard to coordinate best practices. I can’t tell you how many hours on on Zoom we spent with our colleagues at DWR and other agencies throughout the state to ensure that the necessary measures were taken. We had many, many public proceedings before the board involving the Temporary Urgency Change Petitions that were necessary and also curtailments that were necessary in order to deal with the surface water shortages throughout the systems. I will say that those those measures that we took to address shortcomings were all very public and they were very. They enabled us to make water available when it was available and to make sure that it was equitably distributed according to our water rights legal system when it was not.
We couldn’t agree more that better data is a key component for all of these efforts and recognize the need for a more efficient data management system. Last year, the legislature did allocate $30 million as part of last year’s budget to update the state’s water rights data management system. And we really look forward to implementing that as soon as possible. Thank you.