ABSTRACT
Modern stormwater management often involves the development of numerical hydrologic/hydraulic models in order to provide decision making tools regarding placement of retention facilities, in-system storage, etc. A review of the metering systems indicates the possibilities of considerable differences between the independent discharge measurements; this is verified by a comparison for selected discharge events. Formal methodology is generally available for making estimates of measurement uncertainty, however the types of data available in many applications is insufficient to fully implement the specified procedures. Measurement errors can be categorized into three elemental sources namely calibration errors; data acquisition errors; and data reduction errors, each of which has a bias and a precision component. The Detroit sewer system consists of a combination of combined and separate sewer systems with the central, older portion of the system being primarily combined sewers. The two semi-independent methods of discharge metering involve measurements from a single metering installation.
