[mlyle]

The Central Valley aquifer does not extend to the coast and is poorly connected to the coastal aquifier: https://www.usgs.gov/mission-areas/water-resources/science/c...

There is not enough flat, cultivatable land closer to the coasts to move much agriculture out of the central valley towards the coast, even if desal'd water was free.

[simfree]

Desalination allows the now unused surface water to be collected and diverted further upstream, slowing the decline of upstream aquifers.

For the upstream cities that use the Colorado River this could be quite beneficial.

[seanmcdirmid]

But now we are talking about building a tunnel rather than an aqueduct. It isn’t weird to drill water tunnels for a hundred or so miles.

[mlyle]

Other than the fact that this is even more capex and opex that will exceed any economic use of water in agriculture.