Delta Conveyance Project Receives Environmental Approvals Needed to Move Potential Modernization of State Water Project/Imported Water Infrastructure to Engineering, Design and Permitting Phase

Operations Update

State Water Project (SWP) allocations to state water contractors for 2023, such as SGVMWD, were increased to 100% of plan for the first time since 2006, helping stabilize water supplies statewide and in the San Gabriel Valley. The District was allocated 28,800 acre-feet of imported water in 2023 to deliver and use for replenishment of groundwater in the Main San Gabriel Basin. Some of the District’s allocation will be carried over into 2024 as capacity to deliver and store water in the Basin was limited late in 2023 due to high volumes of water in the system.

The state has forecasted allocations at 10% of requested supplies for 2024 as current conditions are dry and the hoped-for wet El Niño weather conditions have yet to materialize. Imported water is used to supplement local groundwater supplies in the Main San Gabriel Basin.

We are working closely with state and county water agencies to utilize available capacity in reservoirs, pipelines and spreading grounds to deliver the imported water. With water delivery capacity at times challenged by the abundance of stormwater runoff and snow melt throughout the state, scheduling deliveries is complicated and requires smart water management. Some of the 2023 water deliveries will likely need to carry over into the next calendar year.

Imported water supplements local groundwater supplies in the Main San Gabriel Basin and Raymond Basin, the primary sources of water for the District’s member cities of Alhambra, Azusa, Monterey Park, and Sierra Madre.

In November, the District delivered 646 acre-feet (AF) of water to cyclic storage and 148 AF. Power generation in November was 485 MWh and 225 MWh in December.  Three important facility maintenance projects remain in progress: the Hydro 24-inch Butterfly Valve Replacement Project; the San Gabriel Flow Control Structure 30-inch Ball Valve Replacement Project and Schedule I Pipeline Continuity Bonding and Corrosion Assessment Validation Project.

With the start of 2024, California’s and the San Gabriel Valley’s water supply conditions remain much improved. The graphs above show what a difference a year makes! However, the forecasted wet “El Niño” weather condition has yet to materialize and we are experiencing a dry start to the “water year” compared to last year’s record rain and snowfall. In fact, local rainfall is only 13.2% of average and the statewide snow pack is at its lowest level in ten years, at only 9% of the April 1 average and 25% of normal. 

Our improved water supply conditions result from Statewide rainfall being 141% of average in the 12 months ended September 30, the 10th wettest year since recordkeeping began 128 years ago. And imported water allocations from the State Water Project were at 100% in 2023 for the first time since 2006, meaning there was more imported water flowing to our area to help replenish groundwater levels. 

One of the most important indicators for the San Gabriel Valley is local groundwater which improves more slowly due to the time it takes stormwater runoff to percolate down to groundwater levels. Our local groundwater levels have risen more than 40 feet since January 2023.

The Main San Gabriel Basin captured more than 95% of stormwater to supplement local groundwater supplies in the storm surge earlier this year, which is much different than other watersheds that convey the majority of their stormwater to the Pacific Ocean as a flood control measure. Data from Watermaster reveal that of the more than 500,000 acre-feet of stormwater captured this year, about 300,000 AF came from the San Gabriel River watershed.

We must remember we live in a region where most years are dry, we use more water than Mother Nature provides, infrastructure is aging, drought will return, and climate change makes the work of water planning and delivery challenging. We need to sustain our focus on investments in long-term water infrastructure and developing a long-term water conservation ethic. 

Groundwater – in the Main San Gabriel Basin, the “Baldwin Park Key Well” is the indicator of local groundwater levels (see graph below – blue line includes cyclic storage; black line does not). As of January 1, 2024, the level stood at 224.1 feet above mean sea level, more than 40 feet higher than a year ago.

Prior to the storms in early 2023, the Basin had experienced a steady decline in groundwater levels from a high of 212.5 feet above mean sea level in December 2019 and was trending downward toward the historic low of 169.4 recorded on November 21, 2018. One vertical foot is equivalent to about 8,000 acre-feet of groundwater in the Main Basin. Watermaster’s operating guidelines for replacement water or “safe yield” is between 200 and 250 feet above mean sea level. 

Note: About 80 percent of the Valley’s water supply is furnished by local groundwater, and the Valley imports about 20 percent of the water we use from northern California and the Colorado River. A 60 percent allocation is needed to meet the demand of our member cities for replacement water. Thus, in years where the allocation dips below that amount, we see the important role that water storage and water conservation play. Groundwater use accounts for 41% of California’s total water supply (80% in the San Gabriel Valley) on an average, annual basis, and as much as 58% in a critically dry year. About 85% of public water systems rely on groundwater as their primary supply. Of water diverted and pumped in California, about 80% is used by agriculture and 20% is used by cities and towns.

Imported Water – In April 2023, the California Department of Water Resources increased State Water Project allocations to State Water Contractors such as SGVMWD for 2023 to 100% for the first time since 2006. Those deliveries have been maximized as much as the delivery and storage “system” can handle, and some of the District’s allocation is being carried over into 2024. 

As presented earlier, the state has forecasted allocations at 10% of requested supplies for 2024 as current conditions are dry and the hoped-for wet El Niño weather conditions have yet to materialize. A final allocation plan is usually determined in May or June. Imported water is used to supplement local groundwater supplies in the Main San Gabriel Basin.

Note: Two-thirds of California’s water originates in the Sierra Nevada Mountains and flows through the Delta, a large inland river delta and estuary in northern California.

Statewide Snow Pack – as the first snow survey of the season in early January, the State is reporting about 8 inches of snow depth and a snow water equivalent of 2.4 inches, which is 9% of the historical April 1 “peak,” and 25% of normal. This is the lowest snow reading in 10 years. By comparison, the January 2023 snow survey showed a water content of 177% of average…and several major storms followed in February and March. Snowpack is measured from April 1 to March 31, a 12-month period. April 1 is usually 

the “high point” for snow accumulation each year.

Given above average reservoir levels, forecasted El Niño conditions, and a dry start to the water year, California needs to be prepared for both dry and flood conditions in the months ahead. 

Note: On average, the Sierra Nevada Mountains snowpack, which is a key source of water banked in reservoirs, supplies about 30% of California’s water needs as it melts in the spring and early summer, feeding reservoirs and the water table, resulting in groundwater. The snowpack is often referred to as California’s “frozen reservoir.”

Statewide Reservoir Levels – statewide, as of October 31, 2023, (the latest statewide data available to us), reservoir levels were 125% of average and 66% of capacity. Most reservoirs in the state are above average. As of January 1, storage levels at Shasta Lake, the state’s largest reservoir, were 68% of capacity and 116% of the historical average for this date, and storage levels at Lake Oroville, the state’s second largest reservoir, were 68% of capacity and 130% of the historical average.

Locally, both San Gabriel Reservoir and Cogswell Reservoir were concluding sediment removal. San Gabriel Reservoir is at 128% of average, and Cogswell Reservoir is at 73% of average. Lake Silverwood, which rests above San Bernardino and is adjacent to the start of the District’s Devil Canyon-Azusa Pipeline, is filled to about 90% of capacity and 101% of average. 

Note: Every winter, most areas need about 12 inches of rainfall before the ground is saturated enough to get large amounts of runoff into streams and reservoirs. California’s reservoirs generally hold enough water to go one dry year without impacts but begin to empty if a wet year does not follow.