Continuous measurement or drainage discharge

The west side of the San Joaquin Valley of California has had drainage disp osal problems since irrigation was introduced in the early 1900s. Selenium toxicity problems associated with the Kesterson Reservoir caused closure of the existing agricultural drainage system in 16 194 Ha (40,000 acres) in 1 986. The continuing need for drainage of irrigated agricultural lands has p rompted several welter management studies by the Water Management Research Laboratory of the USDA. One of the essential data requirements in these stu dies is the quantification of drain flows. A measurement station was constr ucted for this purpose employing a manhole with a 90 degrees V-notch weir a nd datalogging electronics to provide hourly waterflow data. Power was supp lied by solar and conventional sources. Construction details, costs (for a solar powered station), and resulting data are shown. As configured, the me asurement station has provided seasonal data streams for analysis during th ree years of operation.