Tule River Spillway Raise Enlargement Project

Don’t let vibration monitoring burst your project momentum, GeoSonics/Vibra-Tech can help you develop a site-specific monitoring plan complete with inspections, monitoring and reporting to keep your project flowing.

To raise the gross pool elevation of Success Lake, reducing the downstream risk of flooding while also increasing the water supply capability of the reservoir, phase one of the two-phase project included realigning Avenue 146 on the southwest side of the lake. The road currently passes through the spillway and becomes inundated during high-water encroachment. The realignment will reduce road closures due to flooding in the future and will also provide improved access for phase two project work, which includes widening the 200-foot-wide spillway to 360 feet wide and constructing a 10-foot-high concrete Ogee Weir across the spillway.

GeoSonics/Vibra-Tech was retained by the U.S. Army Corps of Engineers to conduct an onsite refraction study to help determine if there was overblasting of the rock near the dam. GeoSonics/Vibra-Tech also provided a blast vibration monitoring plan to address vibration and soil sedimentation concerns. The blasting would take place near the dam structure and 10ft from its concrete sill. The plan included pre-blast inspections of the existing dam and spillway, appurtenant structures and other improvements and facilities in the vicinity of the project site. Vibration monitors were installed four weeks prior to the start of construction to determine background vibration levels. During construction activity, vibration monitors collected data and a regression analysis was conducted after each blast to provide valuable information to the client. High velocity portable seismographs, measuring 100 in/sec were used to collect data close to each shot in addition to the remote units. Data from two other portable units close to each shot was also collected. This allowed GeoSonics/Vibra-Tech to create a regression analysis graph to provide extra information to the client for use on where to place the portable units on future blasts.