Flow Measurement for Small Quarry Stream

MantaRay provides flow measurement for quarry discharge

At a quarry in the UK, there was a requirement to measure the environmental impacts of a proposed site expansion. Discharges from quarries vary in type, but in any case, it is illegal for a quarry to discharge into local environments with contaminated water. In recent court cases, some quarries have been fined up to £35,000 for discharging in controlled waters.

In this expansion case, a larger site will generate greater volumes of water runoff into the surrounding environment, and so the impacts needed to be explored further to obtain the permit for the expansion. The quarry needed an open channel flow meter that was compact, with logging capability, and could be operated in a remote location with no mains power.

The MantaRay is a portable area-velocity flow meter that measures flow using a submersible ultrasonic sensor. The unit is designed for flow surveys in open channels, partially full sewer pipes, and surcharged pipes - making the portable open channel flow meter suitable for sewer monitoring, industrial flow monitoring, irrigation flow, and natural streams.

By using the 'Sleep Mode' function to extend battery life while logging flow, the digital display, outputs, and non-essential functions are suspended. Based on the logging interval, the MantaRay activated the sensor for 12 seconds to obtain flow readings and then resumes low power mode until the next logger sample interval.

The battery operation has proved to be a success for the quarry, due to the remote location of the measurement point, allowing the unit to be able to collect the flow data required for the expansion permit. The compact size of the unit has also meant it could be installed discreetly in a cabinet on the side of a small bridge. Accurate flow data is now being recorded and logged; 3 years of data is required for the expansion permit to be granted.