wo years to end (although some effects will last for decades). Floods move faster and more violently, seen when Oroville’s spillways tore themselves apart in mere hours.
- Groundwater is key to sustainability and prosperity for California’s human water uses. Increased groundwater pumping replaced about 70 percent of the drought’s agricultural water shortage. Groundwater provides by far the most water storage in California, and is the predominant storage for longer droughts. The 2014 Sustainable Groundwater Management Act shows that this lesson was learned, but implementation remains a challenge.
- The southern Central Valley will see large reductions in net water use. This uncomfortable truth is now widely accepted following the drought. About 15 percent of the southern Central Valley’s agricultural land depends on groundwater overdraft. Problems in the Delta and increased outflows of the San Joaquin River threaten perhaps another 15 percent of supplies. Soil salinization, urbanization of agricultural land, technology and climate change will also mostly push to reduce irrigated acreage.
- Preparation is key to managing extremes – for both droughts and floods. Most cities and farmers did well in the recent drought and floods. A roughly 30 percent loss of water supply reduced statewide agricultural revenue by about 2-3 percent, and urban losses were financially inconvenient but economically negligible. Local impacts were sometimes much worse, especially for some rural communities. The biggest losses were in the areas least prepared. Ecosystems were unprepared for this drought, with often devastating effects. This wet year saw widespread minor flooding, but little major flooding, and identified some areas as needing more attention and funding.
- Future droughts and floods will be a bit different. This drought was worsened by higher temperatures, hit an agricultural economy with many more permanent (and more profitable) crops and hit a system with more effective water supply agency cooperation, and a different composition of species in the Delta ecosystem. We need to prepare for future droughts (and floods).
- We need to do better. The extreme drought and wet year served to identify weaknesses in California’s water management. We must learn from these tests and improve local, regional and statewide water management. Learning from past droughts and floods has made California’s water management as successful as it has been, and remains vital for sustaining a major dynamic civilization in such a dry and increasingly variable climate.
The past few years have shown some major problems:
- Groundwater. Implementing the Sustainable Groundwater Management Act remains one of California’s greatest water challenges.
- The Sacramento-San Joaquin Delta is a second key to sustainability and prosperity for California’s water system. We are still struggling with this one.
- Rural water supplies. Some 1-2 percent of California’s population still have drinking water of substandard quality. The drought highlighted the problems of these mostly small rural water systems. Some progress is occurring, but it will require stronger county responsibility, oversight and capability, aided by others.
- Ecosystem management. The drought showed the weakness of the remaining native ecosystems and the agencies’ pretty dreadful drought capability and preparation for their environmental responsibilities. State and federal agencies are neither organized nor funded to succeed here.
- Investments in flood infrastructure. While most of California’s flood infrastructure did pretty well, the floods showed a need to invest in the maintenance and updating of major flood infrastructure – and Californians will need to pay for this.
- California lacks a coherent state water technical and scientific program, integrated across agencies. Lack of a common effective water balance, inadequately organized, transparent and expeditious data and modeling, fragmented science, and incoherent fragmentation of technical efforts add confusion, delays, costs and hassles. The state’s majo