Development and evaluation of a device to control time varying flows

摘要

Testing of flow measurement and sampling devices is usually done using static flow rates, but natural flows-and especially runoff from small watersheds-can vary greatly with time. Static testing does not provide an adequate picture of the devices'performance, as inherent flow storage and time lags in dynamic settings will distort the measured hydrograph or alter contaminant concentration values.This report describes the development and testing of a device to produce accurate and repeatable time-varying flows use in such testing. The device was constructed from readily-available materials for approximately US