California can effectively use no more than a 15 percent increase - 6 million acre-feet - in surface water storage capacity. Exceeding this expansion runs into limits of available precipitation and the ability to transport water. The study determined the maximum additional storage space that could be used, both with and without coordination with other parts of California\textquoterights water system. It does not include an economic or environmental analysis to determine whether additional storage is justified. The report advocates a more integrated approach to surface and groundwater water storage where projects are planned, designed and operated as components of a statewide water system. An integrated, multi-benefit analysis would include a wide variety of water sources and delivery alternatives, and address managing California\textquoterights multiple water demands \textendash flood management, energy production, water quality, recreation and ecosystem support. Such an approach would be a departure from most project analyses and policy discussions that examine water storage proposals as independent, isolated projects. The report said integrated water projects are likely to \textquotedblleftsignificantly outperform\textquotedblright individual projects in achieving multiple water management objectives.