On March 25, 2025, the University of Southern California’s (USC’s) Public Exchange and independent advisor Solar Aquagrid announced the California Solar Canal Initiative, a seven-university project to assess the technological, social, and legal capacities to install solar panels over the many water canals and aqueducts flowing through California. The project builds from a 2021 study conducted at UC Merced, one of the project’s partner universities, that estimated that covering all 4,000 miles of California’s canals with solar panels could generate enough electricity to power 10 million homes and reduce solar energy’s land footprint by placing solar arrays on already developed land.
But renewable energy is not the only predicted benefit. Solar panels should also significantly reduce evaporation from the canals, conserving water while generating electricity. For example, the UC Merced study calculated that if all 4,000 miles of California’s water canals and aqueducts are covered with solar panels—which won’t happen, but the estimate still gives some idea of scale—California would conserve enough water to supply up to 2 million homes each year. The Gila River Indian Community near Phoenix, Arizona, is validating these predictions. It completed the nation’s (and perhaps western hemisphere’s) first solar canal project in October 2024. The Tribe covered over 2700 linear feet of the Casa Blanca Canal on its reservation with solar panels, using $5.6 million from President Biden’s Investing in America Agenda and the Inflation Reduction Act. This project reduced evaporation from the canal by 50% and generated 1.3 megawatts of renewable electricity, supplying the Tribe with both more water and more energy, as well as helping to take some pressure off the Colorado River and Central Arizona Project as water supplies.
Because the water canals are unlikely to be habitat for species, installing solar panels over them instead of open land also should avoid Endangered Species Act issues and other wildlife conflicts. And some of the electricity generated can replace water pumps that run on diesel, significantly improving local air quality in the rural communities along the canals.
These benefits, however, depend on resolving the many legal issues that these projects face—legal issues whose resolution will change from canal to canal, depending on who owns the canal, who owns the underlying land, who owns the water right(s), who controls the electricity generated, and what transmission and storage already exist or can be economically constructed. Every project developer, therefore, must answer a number of questions: who owns the saved water under California’s complex water law; who owns the electricity generated, and where it can be sent (or stored); whether the real property owner also own the canal and consents to the installation of solar panels, or, alternatively, if the canal’s presence is based on an easement, whether the easement’s scope plausibly extends to the installation of solar panels or needs to be renegotiated; and, for state- or federally-owned canals and aqueducts, whether the relevant legislation (e.g., Reclamation Act) allows solar panels to be installed.
Small wonder, then, that the first solar canal projects are being pursued on canals and aqueducts where a single entity owns and controls everything, like the Gila River Indian Community. The California Solar Canal Initiative benefits from UC Merced’s and Solar Aquagrid’s involvement in the Project Nexus pilot project at the Turlock Irrigation District (TID), which takes advantage TID’s ownership of and control over everything, including access to the electric grid. Construction began in July 2024 and is expected to be completed by the end of 2025.
