Description

Siphon 21 is located on the SJRA Main Canal near Barrett Station, where it conveys water beneath a Harris County Flood Control District drainage channel. Originally constructed in 1943 with dual 48-inch reinforced concrete pipes and later supplemented with a 60-inch bypass siphon in 1979, the structure exhibits cracking, spalling, and other concrete deterioration that increases the risk and likelihood of failure. Replacement of Siphon 21 is critical due to its location on the Highlands canal system, age, and current structural condition.

Improvements will include removal or abandonment of the existing siphon pipes and removal of the existing concrete, and replacement with new dual siphons, headwalls, wingwalls, staff gauges, stop logs, and manual control gates. Additional enhancements that will be considered include improving site access and evaluating measures to reduce debris accumulation. These improvements will enhance structural reliability, operational flexibility, and the continued delivery of water to downstream customers.