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2025 URBAN WATER MANAGEMENT PLAN <br /> MAY 2026/FINAL DRAFT/CAROLLO <br /> and precipitation changes, researchers have identified several areas of concern for California water <br /> planners (CAMP4W, 2025).These areas include: <br /> ■ A reduction in Sierra Nevada Mountain snowpack. <br /> ■ Increased intensity and frequency of extreme weather events. <br /> ■ Prolonged drought periods. <br /> ■ Water quality issues associated with increase in wildfires. <br /> ■ Changes in runoff patterns and amounts. <br /> ■ Rising sea levels resulting in: <br /> >> Impacts to coastal groundwater basins due to seawater intrusion. <br /> Increased risk of damage from storms, high-tide events, and the erosion of levees. <br /> >> Potential pumping cutbacks to the SWP and Central Valley Project (CVP). <br /> Other important issues of concern due to global climate change include: <br /> ■ Effects on local supplies such as groundwater. <br /> ■ Changes in urban and agricultural demand levels and patterns. <br /> ■ Alterations to power generation and pumping regime. <br /> ■ Increases in ocean algal blooms affected seawater desalination supplies. <br /> Without additional surface storage, earlier and heavier runoff will flow to the ocean instead of being held <br /> as mountain snowpack, causing California to lose more water. California therefore needs to place a strong <br /> emphasis on expanding storage <br /> As described in Chapter 6, the Colorado River Basin supplies have been inconsistent since about the year <br /> 2000, with precipitation near normal while runoff has been less than average in two out of every three <br /> years. Climate models are predicting a continuation of this pattern whereby hotter and drier weather <br /> conditions will result in continuing lower runoff, pushing the system toward a drying trend that is often <br /> characterized as long-term drought. <br /> Dramatic swings in annual hydrologic conditions have affected water supplies available from the SWP <br /> over the last decade. The declining ecosystem in the Sacramento-San Joaquin Delta (Delta) has also led to <br /> a reduction in water supply deliveries, and operational constraints will likely continue until a long-term <br /> solution to these problems is identified and implemented (MET, 2025). <br /> Climate change is also projected to impact future water demands.The 2025 Orange County Water <br /> Demand Model TM developed a sensitivity for the water demand forecast based on using future climate <br /> variables from a subset of 15 downscaled global climate models (GCMs) from the World Climate Research <br /> Program (WCRP) Coupled Model Intercomparison Project (CMIP6). Future weather variables under two <br /> climate scenarios were substituted for baseline historical average weather, with the results indicating that <br /> projected water demands under one to five consecutive dry years could be 5 to 17 percent greater than <br /> baseline demands (MWDOC, 2025). <br /> CITY OF SANTA ANA <br />