How much water storage capacity can we gain with $2.7 billion?

California gets to vote tomorrow on whether or not they support Proposition 1 - also known as the Water Quality, Supply, and Infrastructure Improvement Act of 2014. Irregardless of whether Proposition 1 is passed, local water managers will still be faced with resolving water storage issues. Although there is no single solution to increase drought resiliency, finding ways to store water during water during wet years, so that it is available during dry periods is important. Acquiring adequate storage space in the right locations and having an opportunity to diversify water supply (i.e. stormwater and wastewater) while doing so in a cost-effective manner are important elements for securing water resources in California.

Last Friday, Deb Perrone and I, released a new research brief [download PDF] titled “Storing Water in California: What Can $2.7 Billion Buy Us?” that compares the benefits and economic costs of surface water and groundwater storage. Our work uses data from past California bond initiatives to look at groundwater recharge in terms of their costs and water management benefits as part of a diversified water supply. Our key findings are:

Groundwater recharge and storage is six times more cost-effective than surface water storage
Groundwater recharge and storage can serve as part of an integrated strategy to take advantage of new sources of water like recycled wastewater and stormwater. This enables local water managers to employ groundwater recharge and storage as a versatile water management tool and promote a diversified water portfolio.
Past bond funding is concentrated in areas with higher basin prioritizations, and only 40% of applications were awarded. As a result, demand in groundwater recharge and storage projects remains unmet through state bond funds.

This analysis is particularly relevant for the state today, given that the proposed water bond (Proposition 1 on the California ballot) includes $2.7 billion for water storage, which can include groundwater storage and surface storage. For a more information on the contents of Proposition 1, use Stanford's Water in the West interactive graphic.

Historically, state bond funds represent a very small percentage (only 3%) of total water expenditures. Although these funds are small they represent an important source of funding for many water agencies. Our findings suggest that groundwater recharge and storage can play an important role in managing California's water resources in the future.

The findings in our research brief are an extension of our "Understanding California's Groundwater" work published on the Water in the West website.