Question: The state is advancing funding for Flood MAR; why is the Water Bank project not actively considering this stormwater management/supply source.

Flood Managed Aquifer Recharge (Flood MAR) and the Sacramento Regional Water Bank (Water Bank) share a common goal: to recharge groundwater supplies using excess surface water when available. However, the Water Bank is not a Flood MAR project, and each takes a different approach to recharging the aquifers. While Flood MAR is more focused on utilizing spreading basins or ponds to recharge surface water, the Water Bank primarily utilizes in-lieu recharge and Aquifer Storage and Recovery, or direct injection through wells.

There are some similarities between the Water Bank and Watershed FIRO MAR, which combines the practices of Forecast Informed Reservoir Operation (FIRO) and Managed Aquifer Recharge. This approach creates a network of upstream reservoirs that are strategically optimized for both drought and flood scenarios.

By implementing Watershed FIRO MAR, reservoir operators at Hell Hole, French Meadows, and Union Valley can better coordinate with Folsom operators to enhance flood protection. This coordination also improves aquifer recharge by conserving excess winter floodwater, which can then be used to replenish groundwater through the Water Bank or support the Lower American River environment.

In the future, integrating Flood MAR into the Water Bank could further boost recharge capacity and address challenges such as the lack of recognition for water providers participating in Flood MAR initiatives.

For example, spreading grounds and high-capacity recharge channels in agricultural land between Rancho Cordova and Elk Grove could be used to refill groundwater. This recharge would be monitored as part of the Water Bank’s accounting framework. Participating water providers could receive incentives, recognition, or credits for their contributions to groundwater replenishment through Flood MAR, incentivizing the adoption of this technique.

Altogether, these strategies underscore the remarkable opportunity for developing a cutting-edge 21st-century water system for the Sacramento region. With the Water Bank playing a pivotal role in this integrated approach, we can create a resilient and sustainable water system adapted to the extremes of climate change.

To learn more about Watershed FIRO MAR, visit the WaterFuture section of the Water Bank website.

HELPFUL TERMS

What is Flood MAR?

Flood Managed Aquifer Recharge (Flood MAR) is a water management technique aimed at replenishing groundwater supplies by intentionally allowing floodwaters to infiltrate into underground aquifers. It involves directing excess surface water from rivers, streams, or rainfall onto designated areas where it can percolate down into the groundwater system.

Flood MAR systems typically involve the construction of structures such as recharge basins, infiltration ponds, or spreading grounds where floodwaters can be temporarily stored and allowed to seep into the ground. This process helps to recharge aquifers, providing a water supply for future use.

Flood MAR can be a sustainable approach to water management, particularly in areas prone to seasonal flooding or where there is excess surface water that can be utilized for groundwater recharge. It can also provide additional benefits such as flood control, habitat restoration, and water quality improvement.

What is in-lieu recharge and Aquifer Storage and Recovery (ASR)?

In-lieu recharge works by using both natural and managed methods. Water agencies facilitate in-lieu recharge by directing excess surface water from lakes and rivers to customers who typically receive groundwater. This reduces the demand for groundwater, which lets the aquifer recover naturally as water from rain, storms, and rivers seeps into the ground. Every gallon of surface water served to customers in lieu of groundwater results in water saved in the groundwater aquifer. Some water providers are also equipped to store water through ASR, which allows them to deposit treated water into the Water Bank during wet times using specially designed wells that can both recharge (inject) and recover (extract) water.

What is Watershed FIRO MAR?

FIRO MAR—Forecast Informed Reservoir Operation (FIRO) combined with Managed Aquifer Recharge (MAR)—a water resources management approach that integrates two techniques to optimize water supply and storage.

FIRO is an innovative approach that utilizes advanced weather forecasting and real-time data to optimize reservoir operations. This enables better decision-making regarding water releases and storage, taking into account forecasted precipitation and moisture content of the snowpack, to manage flood risk more effectively. MAR involves the intentional recharge of aquifers with excess surface water, which is what local water providers practice through the Water Bank or other recharge methods.