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 has been allocated 28,800 acre-feet of imported water in 2023 to deliver and use for replenishment of groundwater 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 1,388 acre-feet (AF) of water to cyclic storage and 148 AF to CIC on behalf of Three Valleys Municipal Water District. 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.

Water supply conditions in the state and the San Gabriel Valley remain much improved as the year winds down thanks to last winter’s storms and Hurricane Hilary in the summer. Statewide rainfall was 141% of average in the 12 months ended September 30, representing the 10th wettest year since recordkeeping began 128 years ago. And imported water allocations from the State Water Project are at 100% for the first time since 2006, meaning there is more imported water flowing to our area to help replenish groundwater levels. 

Scientists with NOAA (National Oceanic Atmospheric Administration) indicate global ocean and surface temperatures have surged to record levels in the past few months, strengthening an El Niño condition which may lead to heavy rain in some coastal areas of California. In El Niño years, warmer waters in the eastern Pacific create an active jet stream over the southern U.S. in the winter, leading to higher chances of cool and wet weather in the southwest and warmer and drier weather in the northwest.

The graphics above show the marked improvement from January through December 2023 in state and local reservoir, snowpack and groundwater conditions, including significant lessening of drought conditions statewide. Local groundwater, which improves more slowly due to the time it takes stormwater runoff to percolate down to groundwater levels, has risen more than 50 feet year-to-date!

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 December 1, 2023, the level stood at 226.4 feet above mean sea level.

Prior to the storms earlier this year, 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. As presented earlier in the newsletter, 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.

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 of December 1, the State is reporting snowpack levels at 3% of the historical April 1 “peak,” which is 30% of normal to date. 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 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, with only three of the 17 largest reservoirs beneath their historical average. As of December 1, storage levels at Shasta Lake, the state’s largest reservoir, were 68% of capacity and 126% of the historical average for this date, and storage levels at Lake Oroville, the state’s second largest reservoir, were 66% of capacity and 133% of the historical average. San Luis Reservoir was at 57% of capacity and 110% of average.

Locally, both San Gabriel Reservoir and Cogswell Reservoir were concluding sediment removal. San Gabriel Reservoir is at 8% of capacity and 59% of average, and Cogswell Reservoir is at 8% of capacity and 84% 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 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.

Upcoming:

Monterey Park's 10th Annual Holiday Snow Village

Join us at the City of Monterey Park's 10th Annual Holiday Snow Village event on Thursday, December 7, 2023. This year's event will take place at Barnes Park (350 S. McPherrin Ave., Monterey Park, CA) from 4:00pm to 8:00pm.

There will be a range of free activities, from snow sled runs, snow play area, a trackless train, and much more. The event is running in conjunction with the city's weekly Farmer's Market.

More info: www.montereypark.ca.gov/HolidaySnowVillage