There are just two technologies used for depth measurement and around seven technologies used for velocity measurement. Many meter manufacturers use off-the-shelf technologies and the result is a restricted performance envelope of pipe size and depth of flow. Consequently, in a large collection system with a wide range of pipe sizes and hydraulic conditions, a manager will own meters from several manufacturers just to acquire the metering technology that works best in both shallow and deep flows. The manager ends up with different data collection techniques, different software and different data formats.