DRAINAGE DESIGN CASE STUDY:

In response to severe erosion and wall failure during a series of heavy storms in early 2023, the Alameda County Flood Control and Water Conservation District undertook emergency and permanent repairs along the Estudillo Canal (Line A) in San Leandro, CA.

To ensure long-term wall stability and effective flow management in this trapezoidal concrete channel, 32 JET Filter maintainable weep hole assemblies were installed as part of a reinforced concrete wall reconstruction along a 300-foot section of the canal

Originally constructed in the 1960s, the Estudillo Canal channel features inclined and vertical concrete walls designed to convey stormwater through residential neighborhoods in Zone 2 of Alameda County.

During heavy rains on December 31, 2022 and January 1, 2023, over 300 feet of the west channel wall collapsed, threatening nearby homes along Crosby Street. Emergency actions included:

• Temporary plastic sheeting and sandbags

• Installation of steel support brackets and struts

• Debris clearing to maintain water flow

Permanent repairs required a full wall reconstruction, proper drainage installation, and backfill stabilization.

To restore the wall and prevent future failures, the district implemented a drainage retrofit with JET Filter’s closed-end stainless steel weep hole system embedded within the reconstructed concrete channel wall.

✅ System Specs:

• 32 units of JF4SSCVLV

• 4” Closed-End ASTM 316/316L Stainless Steel Housing

• Mirafi® Filter-Weave FW 300 Geotextile Filter Media

• Installed through reinforced concrete and aligned to engineered flow locations

This system relieves hydrostatic pressure, filters sediment, and allows for maintenance access—critical in flood control structures like open channels.

Concrete-lined flood control channels can suffer from:

• Wall leaning or collapse due to trapped water

• Backfill erosion from poor drainage

• Costly emergency repairs without long-term drainage solutions

Maintainable weep holes provide hydrostatic pressure relief, debris control, and long-term serviceability—ensuring the stability of reconstructed channels like Estudillo Canal.