In the Field and In the Stream: California Reasonable Use Law Applied to Water for Agriculture

When it comes to fresh water consumption in California, going forward we will need to learn to do more with less. There are at least two main reasons why California will need to learn to do more with less water. First, there is a growing population in the state, a population that is increasingly urban which means there will be greater demand for urban
municipal domestic water supplies.

Second, there are now increasing demands to leave additional amounts of
surface fresh water instream. The demands for additional instream flow relate in part to the declining condition of California’s native fisheries (such as salmon, steelhead and smelt). The demands for additional instream flow also relate to  water quality and salinity concerns. With reduced fresh water flows in our coastal rivers, seawater is pushing further upriver, and increasingly saline water cannot be used for drinking or irrigating.6 With seawater intrusion, excessive upstream diversion of fresh water threatens the very supply of fresh water.

The long-standing debate over water exports from the Sacramento-San Joaquin Delta, and the impact of such Delta exports on salinity, water quality and native fisheries, is perhaps the most prominent illustration of such demands for additional instream flow.