When it rains, it pours at Sundt’s San Pedro Creek job site in San Antonio. Good thing we have plans in place.
Our team knew going into the project that we would have to deal with rain on a regular basis since the west side of downtown San Antonio drains into San Pedro Creek. A small half-inch rain event causes 2 feet of water in the channel.
There’s virtually no flexibility in the schedule. Our work has to be complete in time for the city’s 300th anniversary celebration next May 5.
“We don’t have the ability to ask for more time,” said Senior Project Manager Chad Yount. “So we developed a plan. “When our employee-owners are given a challenge they come up with great solutions that keep our projects moving forward,” Chad said.
Dealing with excessive rainfall was addressed during preconstruction. The last block of Phase 1 Segment 1 is 8 feet below the existing channel, creating a dam at the end of the project. To solve the problem, the team over-excavated the area by 1 foot and placed filter fabric and drain rock which creates a working surface during minor rain events.
A 6-inch perforated pipe was installed down the middle of the channel below the drain rock which conveys the water to a 6-foot diameter casing that sits 6 feet below the surface. Within this casing, a 6-inch submersible pump is set to turn on and off by a float system reducing the labor costs. As water enters the channel, it drains through the rock to the perforated pipe and into the 6-foot diameter casing. The floats then automatically trigger the 6-inch pump to turn on, sending water over the “dam” and downstream.
The system was tested Aug. 8 when 4 inches of rain fell in four hours. Part of the site ended up under 11 feet of water. With the system in place, the water was pumped out by the next morning and crews were back at work a day later. Without the system in place, work would have been shut down for almost a week.