A complete system for flow measurements of open channels can be composed by Venturi, by ultrasonic level sensors (PTU5_ or METER), and associated a calculation, indication and volume totalization unit such as the model VLW90M, or directly using the compact flow transmitter FLOWMETER. SGM-LEKTRA has developed its own flumes family called BS… in co-operation with the Pavia University Hydraulic Division. The BS… flume is a special Venturi with flat bottom and ready to be lodged in a pre-existing rectangoular channel.. The BS… flumes are suitable for use in irrigation systems, industrial waste water treatment, sewage, and in general for turbid waters; the flat bottom without protrusions has a self-cleaning effect, does not favor the debris deposit and can be easily inserted in rectangular ducts existing. The submerged flow (ratio from downstream head and upperstream head) can be well tollerated. The practical limit of submergence for all sizes is about 90%