Groundwater is a vital resource for landowners in the McMullin Area Groundwater Sustainability Agency (MAGSA) and across the state of California. In this blog post, we’ll return to the basics, answering questions about the Sustainable Groundwater Management Act that led to the creation of agencies like MAGSA, the dangers of over pumping groundwater, and strategies for replenishing the reserve of water beneath our feet.

What is groundwater? Why is it so important in California?

Groundwater is the water found underground in the cracks and spaces in soil, sand, and rock. It’s stored in and moves slowly through geological formations called aquifers. According to the California Department of Water Resources, as of 2023, nearly 85 percent of Californians depend on groundwater for some portion of their water supply. This makes it essential for agriculture, drinking water, and sustaining natural ecosystems.

What is the problem with over pumping groundwater?

Over-pumping groundwater means extracting more water than is naturally replenished. This can lead to several issues according to State law, including:

• Declining Water Tables: The water level in aquifers drops, making it harder and more expensive to pump water.
• Land Subsidence: The ground can sink or collapse, damaging infrastructure like roads and buildings.
• Degraded Water Quality: Lower water levels can lead to contamination by drawing in pollutants.
• Surface Water Depletion: Over-pumping can decrease the water available in rivers and streams, harming wildlife and ecosystems.
• Reduction of Groundwater Storage 
• Significant Seawater Intrusion (This does not apply to the MAGSA area).

The California Department of Water Resources defines these as “sustainability indicators.” By measuring these six factors, we can determine efforts toward groundwater sustainability are effective.

What is the Sustainable Groundwater Management Act (SGMA)?

The Sustainable Groundwater Management Act (SGMA) is a law passed in 2014 to regulate the use of groundwater in California. It was enacted to address the severe over-pumping issues and to ensure the long-term availability of groundwater. SGMA requires local agencies to form Groundwater Sustainability Agencies (GSAs) and develop and implement Groundwater Sustainability Plans (GSPs) to manage and use groundwater sustainably.

What is a Groundwater Sustainability Agency (GSA)? What is the role of a GSA?

A Groundwater Sustainability Agency (GSA) is a local agency created under SGMA to manage groundwater resources. The role of a GSA includes:

• Developing a Groundwater Sustainability Plan (GSP) tailored to the local basin or subbasin.
• Implementing the GSP to ensure sustainable groundwater management.
• Monitoring and reporting on groundwater conditions.
• Enforcing regulations and managing groundwater use to prevent over-pumping.

What is a Groundwater Sustainability Plan (GSP)?

A Groundwater Sustainability Plan (GSP) is a detailed roadmap created by a GSA to achieve sustainable groundwater management. It outlines the current state of the groundwater basin, identifies problems like over-pumping, and sets goals for sustainability. The GSP also includes specific projects and management actions to meet these goals, along with a monitoring plan to track progress

What is the Kings Subbasin?

The Kings Subbasin is a groundwater subbasin located in California’s Central Valley. It’s part of the larger San Joaquin Valley Groundwater Basin. The subbasin includes portions of Fresno, Kings, and Tulare counties and is a critical water source for agriculture, cities, and communities in the region.

View map of Kings Subbasin

What is the McMullin Area Groundwater Sustainability Agency (MAGSA)?

The McMullin Area Groundwater Agency, also known as MAGSA, is a GSA that was formed on January 31, 2017 when Fresno County, Raisin City Water District, and Mid-Valley Water District executed the McMullin Area Groundwater Sustainability Agency Joint Powers Agreement which officially formed MAGSA as a GSA. MAGSA is one of over 250 agencies in the State of California created and tasked with implementing SGMA, and one of seven GSAs within the Kings Subbasin.

What is MAGSA’s approach to sustainability?

MAGSA is committed to securing a sustainable groundwater supply through collaboration with landowners and the implementation of innovative groundwater projects. Some of the innovative projects MAGSA is working on to achieve groundwater sustainability include:

Aquaterra Water Bank
The Aquaterra Water Bank is designed to enhance water supply resilience and support groundwater sustainability in the McMullin Area. Strategically located between the Kings and San Joaquin rivers, it has the capacity to store up to 1.8 million acre-feet of water. The project will utilize highly porous soils for efficient water infiltration and recovery, enabling the storage and later extraction of water during dry periods. The bank involves the construction of canals, basins, and agricultural recharge sites over an 80,000-acre area​.
Learn more about the Aquaterra Water Bank here.

McMullin On-Farm Flood Capture Expansion Project 
The McMullin Expansion Project builds on a previously completed flood capture and recharge initiative. This second phase involves increasing the conveyance capacity at the James Bypass from 150 cubic feet per second (cfs) to 450 cfs, and expanding groundwater recharge potential by up to 40,400 acres of farmland. The project will include the construction of a new canal and installation of pump stations to facilitate the movement of water for recharge, enhancing the region’s capacity to manage floodwaters and improve groundwater levels​.
Learn more about the McMullin Expansion Project here.

Meters and Telemetry
MAGSA is implementing a meters and telemetry program to enhance water use monitoring and management. This involves installing meters on wells and utilizing telemetry systems to collect real-time data on groundwater extraction. Accurately measuring groundwater use with meters and telemetry provides the best defense against current estimations of groundwater overdraft in MAGSA. In addition, meters and telemetry are crucial to improving irrigation efficiency and the supply-side solutions MAGSA is moving forward to bring water into the region including the Aquaterra Water Bank, McMullin Expansion Project, and the future Groundwater Marketing Program. MAGSA has also secured grant funding to create a Meter and Telemetry Rebate Program providing approximately a 40% rebate for the cost of a landowner’s to support widespread adoption among landowners.
Learn more about the Meter and Telemetry Rebate Program here.

Do you have questions about these projects or MAGSA’s approach to sustainability? Contact MAGSA directly by calling (559) 515-3339 or emailing info@mcmullinarea.org.