Satellite data is one monitoring tool regulators turn to in this very dry year.
The California Department of Water Resources constructed a rock barrier in the Sacramento-San Joaquin Delta at the beginning of the summer to prevent salt water from pushing too far inland. Photo taken June 15, 2021. Andrew Innerarity / California Department of Water Resources
By Brett Walton, Circle of Blue – September 9, 2021
Michael George is not a spy — but he does use some of the same equipment.
George, a gregarious talker, is a lawyer by trade, and in his current role as Delta watermaster he oversees the use of water in one of the country’s most contested waterways.
The Delta in this case is the Sacramento-San Joaquin, a jumble of fertile land, diked islands, tidal flows, and meandering sloughs that is the heart of California’s engineered water system. A habitat for endangered salmon and smelt, the delta is a hydrological switchyard, where water moves east and west with the daily tides. Water is also transferred north to south via massive state and federally operated pumps that supply farmers in Kern County as well as urbanites in Los Angeles, locations that are hundreds of miles distant.
Those movements of water have taken on new meaning in this extremely dry year, when there is not enough to go around. Regulators at the State Water Resources Control Board voted in August to cut off many farms and towns that withdraw water from the Sacramento-San Joaquin watershed, which drains about 40 percent of the state’s land. The Water Board said that the curtailment order, one of several it made this year for depleted rivers, was necessary to keep salt water out of the Delta, to protect fish species, and preserve scarce supplies. Though the current irrigation season is nearly over, the emergency regulation extends for one year. It is being challenged in court by cities and irrigators, who claim that the Water Board is exceeding its authority.
George is responsible for a small section of the watershed: about 750,000 acres, an area called the “legal Delta,” which extends from the I Street Bridge in Sacramento to the Stanislaus River, south of Stockton. He and other regulators have a variety of tools at their disposal to monitor and enforce the water rights system, from water use reports filed by diverters to satellite imagery.
But the effectiveness of those tools is limited by an antiquated system for tracking who is authorized to divert water and how much. The need for a thorough overhaul of the data management system was brought up in a Water Board review that was published earlier this year and in commentary from advocacy groups and academics.
Policing the use of water in California is all the more difficult because of the complexity of the water rights system and patchy data. The state’s water rights system is an unusual hybrid. It recognizes the rights of landowners who abut a river to withdraw water (riparian rights) and those who moved water away from the river via a ditch or canal (appropriative rights).
Appropriative rights are further divided into those claimed before and after 1914, the year in which the Legislature began issuing diversion permits. Riparian rights and pre-1914 rights don’t need permits, but courts have held that the state still has authority to regulate them under provisions of the state Constitution requiring that water use be beneficial and reasonable, categories that include irrigation, recreation, municipal supply, and hydropower generation.
Owing to the dynamic hydrological situation, the State Water Resources Control Board is reviewing its curtailment orders weekly in case storms suddenly make water available. Right now, most riparian rights holders are not cut off. Many post-1914 appropriative rights holders are. But only in certain sub-watersheds. Because of these complexities, people who divert water can sometimes be confused about their responsibilities, according to Diane Riddle of the Water Board.
So that people can’t claim ignorance, “the first step is to make sure everyone understands what their obligations are and how the curtailment process works,” Riddle told Circle of Blue.
Riddle said the Water Board cannot identify every illegal diversion among 17,000 water rights in the larger delta watershed. There isn’t enough staff and many of the rights are for tiny diversions like a livestock watering pond. But she said the Water Board does have the tools to identify the biggest scofflaws that would affect downstream water availability. Only a few hundred water rights are responsible for 90 percent of the water use in the watershed.
If the number of complaints the Water Board receives is an accurate indicator, then improper diversions do spike during droughts. Nearly 200 complaints were filed in the very dry 2014, three times as many as the previous year.
To make sure that farmers or landowners aren’t illegally diverting water, George has an array of tools. He can check pesticide permits, which are required for applying the poison to fields. There are pumping logs and metering data, but those can be inaccurate due to peculiarities in the delta’s ebb-and-flow movements. There are annual reports that diverters are obligated to file.
Then there are the higher tech tools such as satellite imagery. Google Earth is a digital sidekick, George said. So are the images provided by the federal government’s Landsat or commercial space companies.
“Everyone knows we have an eye in the sky,” George said. “If you’re going to irrigate that alfalfa you’re going to take the risk that not only I will know in real time but after the drought I’ve got all that data I can sift through and I can time stamp when you were irrigating that field.”
Those tracking systems, George said, have modified behavior in the legal Delta. The disputes are not about quantities of water. They are instead about which right a diverter has.
“That risk of an audit trail is such that in our experience we don’t get much cheating,” George explained. “What we do get is arguments about the nature of their water rights or whether the data in our methodology is sufficient to curtail them. But we don’t have much disagreement about whether the pump was turned on or off.”
A new tool will help George determine more accurately water use on irrigated lands. Based on satellite data, OpenET is a platform for estimating water consumed by crops. Delta agencies have been testing the platform since March and starting October 1 they will deploy it full time for the next water year. George said that water users in the Delta have concluded that the platform is “reliable and credible.”
Open ET is one of several technological advances that could bring California’s system for overseeing water rights into the 21st century. That system began with notices tacked to trees and continues today with paper records kept in filing cabinets. George says digital records are essential. The future begins with better information about who is using water and how much.
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