water Article Use of the Hydraulic Model for the Operational Analysis of the Water Supply Network: A Case Study Urszula Kepa   Citation: Kepa, U. Use of the Hydraulic Model for the Operational Analysis of the Water Supply Network: A Case Study. Water 2021, 13, 326. https://doi.org/10.3390/w13030326 Academic Editor: Inmaculada Pulido-Calvo Received: 5 November 2020 Accepted: 24 January 2021 Published: 28 January 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the author. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). Faculty of Infrastructure and Environment, Czestochowa University of Technology, 42-200 Cz˛ estochowa, Poland; urszula.kepa@pcz.pl Abstract: This paper presents an analysis of the operation of the water supply system. The analysed network provides water to six small towns. The water supply network covers rural areas of approx- imately 50 square kilometres with a total of 6130 inhabitants (2020). The area is characterised by relatively large differences in elevation. The water-pipe network supplies water mostly to family housing, public utility buildings, recreational buildings, service and craft entities, religious buildings, and commercial facilities and farms, including breeding farms. The network is supplied from one deep water well and a centrally located water supply tank. A hydraulic model was used for the analysis. The model was developed using the Epanet program, based on numerical and operational data. After validation, selected measurement points were used to calibrate the model. Furthermore, a series of simulations were performed to illustrate the network operation for variable water supply and demand conditions. Single-period analysis was used for modelling due to the type of data obtained. The model allowed for the determination of the head of pressure in the network points and flows in particular sections for the operation parameters studied. The analysis showed that at present, the network is not operating stably. In the case of average demand, water is supplied to all users, but there are areas in the network characterised by high pressure. On the other hand, during maximum water demand, due to the limited water supply to the water reservoir, from which most of the network is supplied, there are water deficiencies that cannot be compensated for by the operating pumping system. Keywords: water supply network; hydraulic model; operational analysis 1. Introduction The water supply network is an essential and very expensive part of the entire water supply system. It is designed to supply water of the appropriate quality, at the quantity, pressure, and time required by consumers. For the network to operate properly, it must be well designed and constructed, and used effectively. Furthermore, the operation and control of a water supply system have a key effect on the costs associated with water distribution, and thus on its final price. A hydraulic model is a versatile tool that can be used both at the stage of designing a new network and during the operation of an already existing network. The use of information technology and available software offers virtually unlimited possibilities to solve problems related to water distribution that would not be possible with conventional methods (e.g., the possibility to simulate the quality of water supplied in the network). The computer simulation of network operation facilitates the making of important decisions concerning current operations in a water supply company [1–4]. The numerical analysis of the network helps to evaluate the network from an op- erational perspective. It is particularly useful for the optimisation of the operation of already existing networks. Modelling is helpful, for example, when planning the flush- ing of individual sections of the water supply system, or shutting them down for repair and maintenance purposes. Furthermore, an analysis of the behaviour of the network Water 2021, 13, 326. https://doi.org/10.3390/w13030326 https://www.mdpi.com/journal/water