The LADWP says it has long asserted its rights on Mammoth Creek, historically with the State Water Resources Control Board, and now in lawsuits to be heard in court.
Telling who owns the water in California, say in a creek, isn't always easy. The horrors of California water law came flooding back to me in reporting on LADWP's legal disputes with Mammoth Lakes over water in Mammoth creek. (Listen to the story!)
As you'd expect (or perhaps hope), we left out a lot of terms of art regarding water in California, so I'll offer a brief and incomplete explainer here as a nerd addendum.
Generally, the most senior water rights in California are "riparian," held by property owners whose land adjoins a river or a creek. Riparian rights let you use the water flowing by, for example, on the land, but not to store the water long-term. In the Mammoth-DWP dispute story, I refer to LADWP's claims that it has what are called "pre-1914 appropriative" water rights. What's not in the story, but is in court documents, is that DWP also claims it has riparian rights, stemming from its ownership of a property that has them, Chance Ranch.
After riparian rights come appropriative rights, the power to divert or store water. Nineteen fourteen is the big year separating old from new appropriative rights, because that's when California established its first comprehensive water permitting system. Anytime someone wanted to divert or store water after 1914, they went to the State Water Resources Control Board to seek a permit.
Detail of a map to accompany a state engineer's report about water in California, circa 1888.
(David Rumsey Cartography Collection)
You can find older pre-1914 rights records in a lot of places, because we didn't have just one authority for water then. For example, county recorders also had some authority. Pre-1914 rights holders have to have used their water continuously and for beneficial use, and they usually offer proof to back that up.
The last category is prescriptive rights: when someone uses water openly, continuously and adversely, for a period of 5 years, it's possible they obtain a limited right on that water. But that's rare and tricky to do.
California's hierarchy of water rights is complex, rather than linear, thanks in part to the state's constitution, which in Article 10, section 2 requires that all of the state's uses be reasonable and beneficial. So all of these rights, in addition to meeting the definitions above, have to meet that additional test. That's pretty squishy language that's given plenty of lawyers plenty long careers helping to shape that concept in court and at the State Water Resources Control Board.
Another thing that makes this a messy battlefield is the fact that water rights holders have two places to go when they have a dispute. Both courts and the state's water regulators have authority over California's water. With Mammoth, DWP's filing lawsuits in the courts. But it also has the right to protest at the State Water Resources Control Board, at least when there's an application for use before the state. There presently is such an application, regarding flows at Mammoth Creek.
Finally, water rights aren't guarantees of supplies. They're more like a percentage of the total water pie; if you've got superior claims, you can get your slice first.
What does all of this mean? Well, if you're trying to solve a water dispute, you're destined for a ton of fact finding. And leave your computer at home. You'd have to search through some of the millions of pieces of paper, some on parchment, in the Sacramento archive of the State Water Resources Control Board's water rights division. Parchment! No wonder much of water use is negotiated, rather than adjudicated. Fact finding costs money, in Los Angeles and in Mammoth Lakes both.