Operations Update

Imported Water Deliveries

In February, the District was not able to deliver water to cyclic storage due to the frequent storm activity and volume of rainwater, which did not allow for use of County spreading grounds. There was not an efficient window for the District to make its deliveries. Thus, there were no hydroelectric operations in February as well.

Joint Bonding/Condition Assessment Validation Project

Contractors continue to assist the District with the joint bonding project, and we expect joint bonding to be complete the first week of April. Pipe segment 940 will be excavated in early March to visually inspect the exterior of the pipe and take exterior ultrasonic and pit gauge measurements at one of the validation locations. In December, internal measurements detected wall loss, but no visual defect was observed.

SDH 24” Butterfly Valve Replacement Project

This project remains active while the District awaits delivery of the replacement valve actuator and its subsequent installation.

SGFCS 30” Ball Valve Project

This project awaits leak testing and re-torquing of the hardware when the pipeline is pressurized.

State Water Project Update

In February 2024, following significant rain and snow throughout California, the Department of Water Resources increased its allocation of imported water to State Water Contractors from 10% to 15% or requested supplies. The state may increase or decrease the allocation amount as the year proceeds based on hydrological conditions.

Last year, State Water Project (SWP) allocations to state water contractors 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. Thus, 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 for 2023 has been 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.

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 collaboration and smart water management with other water agencies in the Main San Gabriel Basin.

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.

As our March newsletter was being completed, the San Gabriel Valley had just received additional rain and northern California and the Eastern Sierra were experiencing blizzard conditions. These are very positive developments for our improving statewide and local water supply conditions. As the graphic above shows, drought conditions have nearly disappeared in the state, local groundwater supplies are slowly improving, statewide snowpack has more than doubled in the past month, and state and local reservoir levels are well above average. 

The combination of “atmospheric river” storm events and El Niño conditions have quickly and vastly changed our “water year” data. It will be interesting to see how the rest of the winter/early spring plays out and how 2024 compares to last year when we experienced the 10th wettest year since recordkeeping began 128 years ago.

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 March 1, 2024, the level stood at 222.6 feet above mean sea level, more than 40 feet higher than a year ago.

Prior to heavy precipitation and 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 – As presented earlier, the state has increased allocations of imported water to State Water Contractors to 15% of requested supplies for 2024. A final allocation plan is usually determined in May or June based on evolving hydrological conditions. Imported water is used to supplement local groundwater supplies in the Main San Gabriel Basin.

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 2023 allocation is being carried over into 2024. 

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 – We have benefitted from rapidly increasing snowpack amounts throughout the first two months of 2024, with blizzards ushering in the month of March. Snowpack has now risen to more than 75% of the April 1 “peak” and is poised to rise higher when upcoming snow surveys are completed. 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.

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 January 31, 2024, (the latest statewide data available to us), reservoir levels were 115% of average and 69% of capacity. Most reservoirs in the state are above average. As of March 1, storage levels at Shasta Lake, the state’s largest reservoir, were 84% of capacity and 118% of the historical average for this date, and storage levels at Lake Oroville, the state’s second largest reservoir, were 84% of capacity and 135% of the historical average.

Locally, San Gabriel Reservoir was at 78% of capacity and 186% of average, and Cogswell Reservoir was at 76% of capacity and 262% 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 107% 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.