Uncertainty evaluation of totalization of flow and volume measurements in drinking water supply networks.

Abstract

Clean water and sanitation are one of the 17 sustainable development goals (SDG) of the United Nations’ 2030 agenda for action, being directly related to several other objectives, namely, economic growth, sustainable cities’ communities, responsible consumption and production, and climate action. Since demand for this resource is constantly growing, problems of scarcity of water and transboundary issues are becoming critical to increase water supply efficiency and to improve water management in modern society. Water providers make use of large infrastructures – water supply networks – defined as engineering systems based on hydrological and hydraulic elements able to supply water to consumers, industries, facilities, services and other users. These infrastructures rely on the quality of measurement as a condition to management, having a relevant role in the process of decision-making and to deal with the common problem of water losses. Good measurement practices and uncertainty evaluation are needed to support robust analysis in urban water supply systems. For many water utilities the evaluation of uncertainty is still considered a difficult task, often in situations of missing data for the analysis, having to deal with large amounts of raw and processed data, and requiring support to apply the provisions of the Guide to the expression of uncertainty in measurement (GUM). However, the application of the GUM to the simple mathematical models used in this context makes it possible to obtain simplified equations that can be used in specific conditions of measurement, providing support to non-expert users with more straightforward approaches. Those include measurement of constant flow, totalization of volume at a single measurement point, sums and differences obtained by combining branches of a network.