The Elsinore Valley Municipal Water District awarded Dudek the contract to conduct surveys and provide annual reports for the Lee Lake Dam and the Railroad Canyon Dam.
The state’s Division of Safety of Dams requires that both dams be surveyed each year to monitor deformation of each dam and also requires that monitoring data be submitted to the state agency each year along with the survey results. On May 13, EVMWD staff issued a request for proposals to complete the dam surveys and annual reports for the two dams.
Although Dudek submitted the only proposal, the company has conducted the surveys and provided the monitoring data for the two dams since 2016 and their work has been declared satisfactory by both the district and the state authority. In past monitoring reports, Dudek identified that the Lee Lake Dam spillway tunnel has been showing significant seepage through joints in the concrete panel, that the creek and channel downstream of the spillway are eroding and beginning to undermine the spillway and that a recent storm caused significant runoff from erosion near the toe of the dam.
Dudek’s Riverside office is 22 miles from the water district’s headquarters, and Dudek also has nearby offices in San Juan Capistrano, Encinitas and La Quinta. GSI Surveyors Inc., which is the sole subcontractor, is headquartered in Poway.
The scope of work includes Dudek preparing a trend analysis of coordinate geometry for each monument, which will identify any observable trends in the monument’s location or movement. Detected movement could indicate deformation of the monument if not the dam itself. The current year’s survey data will be compared to the complete historic record to characterize any trends or anomalies. Dudek will also provide and compare to past information, data on crack monitoring, water surface elevation and tendon load cell monitoring. A linear trend analysis will allow the data sets to be analyzed independently, and if trends are observed, the data will be compared collectively and overlaid on a timeline with the other data sets to determine potential cause and effect relationships. The findings may cause Dudek to develop recommended measures such as more frequent monitoring or observation of specific issues. A digital level which removes the human element from the observation will allow an accuracy of 160 millimeters.
Joe Naiman can be reached by email at email@example.com.