Most open channel flow measurement methods require flow to transition from subcritical to supercritical. In some cases, the flow transition is difficult or impossible to achieve due to conflicts with existing utilities, existing interceptor hydraulics, or downstream connections. In those cases, alternate methods of flow measurement are needed. The Trinity River Authority of Texas recently installed an area-velocity meter to measure flow in an interceptor that was not suitable for other types of metering. Using Doppler radar and an ultrasonic level indicator, the open water surface area and the velocity of the water can be measured. These two values are used to calculate the flow rate in the interceptor. This meter station started operation in 2015.