Thurston County, Wash., has been using Greyline flowmeters since 2008. The county uses Stingray portable flowmeters and the permanent Area Velocity Flow Meter (AVFM II) to measure storm water flows in multiple applications.
The meters help the county’s design engineers determine flow capacity of storm water projects and aid the facilities in gauging the effectiveness of these designs and construction methods.
“Our engineers accomplish this by deploying the Greyline systems a minimum of one year before construction (during the design phase) and one year after construction to evaluate the pre- and post-construction periods,” said Mark Biever, the county’s environmental monitoring program supervisor. “When the job has been completed, we move the Stingrays to another location and begin again. We also use the robust, permanent installation of the AVFM II for long-term deployment in one of our permitted discharge sites.”
The AVFM II monitors and records flows directly related to the discharge fees the county pays to the local wastewater treatment utility. When discharge quantity is measured accurately, the facility saves money; it is billed by the gallon and by the rate of discharge into the municipal system. Previously, the plant overpaid thousands of dollars per year by using an interpolated chart.
“We were able to inform them that they had been grossly overestimating their summer discharge volume based on the results from AVFM II data that [are] continuously collected,” Biever said. “They now pay submitting exact volume measurements that they can verify.”