SCH Number 2025041172

Project Info

Title

Mathews Recharge Basin

Description

The MDC is proposing a recharge project located in Tulare County adjacent to the St. John’s River on the north side of the City of Visalia. The Project includes construction of a multi cell recharge basin facility on an approximately 100-acre site with delivery from the St. John’s River. The Project would assist the MDC in expanding its groundwater recharge efforts in response to the 2014 Sustainable Groundwater Management Act (SGMA). The Project would include a turnout and pump structure with a capacity for approximately 50 cubic feet per second. The proposed turnout facility would allow MDC to divert surface water from the St. John’s River into the proposed basin area to increase groundwater storage. The proposed facility would consist of cast-in-place concrete structure, control gate(s), trash rack, and related appurtenances from the north bank of the St. John’s River to divert to the proposed basin cells. The turnout structure would connect to an inlet structure approximately 300 linear feet (LF) from the St. John’s River in a proposed distribution channel through reinforced concrete piping, equipped with a metered connection. The diversion structure excavation depth would be up to 15 feet below ground surface. Approximately six (6) inter-basin connection structures would also be constructed to connect the distribution channel to the proposed basin cells. Each connection would be equipped with two structures (delivery channel and basin cell), rip rap, and approximately 90 LF of piping. The Project would also include conservation space area that would be pedestrian accessible. Conservation space would be in the form of terraced grading within the basin cells with flatter side slopes (i.e. 6:1 or flatter) to facilitate plantings for native habitats and provide varying water depths such as areas with 3 feet of water depth, areas with 1.5 feet, and areas with 6-9 inches of water depth. Native habitat plantings would be in accordance with the recommended species outlined in the Kaweah MLRP Vegetation Outline document. There would also be graded dirt walking paths around and between the basin cells. The proposed facilities would be owned and operated by MDC. Construction would include equipment mobilization, excavation of earthwork for the recharge basin cells, construction of basin perimeter berms and grading on the outer portion of the berms for the purpose of providing pedestrian-accessible habitat conservation space. The Project site would contain temporary staging areas for construction equipment and material storage during the construction effort. Basin components could include constructing ponds/cells within the basin, as well as performance testing and demobilization. Excavation material would be used on site for berm construction along the perimeter of the basin and between each proposed cell. Any excess material would be exported off site. It is anticipated that contractors would take the export material to their construction projects as needed. New berm construction would not exceed six feet in height, measured from the exterior toe to the top of new berm. The maximum depth of ground disturbance for the basin would be as much as nine (9) feet. Through the improvements of this proposed multi-cell recharge basin, it is anticipated to recharge approximately 1,900 acre-feet (AF) in years when water is available. This is derived by an estimated recharge rate of 0.5 AF per acre across approximately 75 acres of wetted area. Assuming surplus water is available for approximately 50 days equates to the approximate 1,900 AF recharged. 50 days is the average annual amount of surplus surface water availability on the Kaweah and St. John’s River system.

2 documents in project