Review of Water Network Analysis and Validation of SCALER Hydraulic Simulator

The article intends to present the validation stage of a software to model and simulate hydraulic networks for water distribution, the SCALER, through its application to a real system, with many branches, with a model previously developed and verified using the EPANET software. SCALER was developed in 2020 and 2021 and, until then, had only been applied to networks with a relatively small number of branches. After discussing topics related to hydraulic modeling of distribution networks, techniques and applications, a brief review of the fundamentals of SCALER is carried out, passing on to its application to the case at hand, which is the Vila Joaniza community, in the municipality of Rio de Janeiro. Data from image, scheme and table are used to assist in the description of the local situation and respective distribution network, with the objective of assessing whether the nodal pressures obtained by SCALER are sufficiently similar to those obtained by EPANET, in order to ensure the proper functioning of the software. After this step, and the calculations have been made by the program, an operation screen, the generated graph of the local situation and a table with the comparison of absolute and percentage deviations between the nodal pressures resulting from the SCALER and those obtained with the EPANET are inserted, confirming that the deviation values are quite small, which validates SCALER as a software also applicable to networks with many branches.

Hortonian Surface Runoff, Hillslope Form and Energy Dynamics, can we read the fingerprints?

<p>Since Horton’s famous reinterpretation of Playfair’s law hydrologists have marvelled over the organization of drainage networks in catchments and on hillslopes. We start at the cross junction of hillslope hydraulics and geomorphology, trying to interpret the formation of hydraulic networks and erosion alike and wondering why movement of fluid creates structure at all.</p><p>In its most basic form structure and form has been explained as the result of optimization, either of certain types of energy such as free energy or its thermodynamic counterpart entropy. Research has shown that river networks and river junctions tend to minimize dissipation of kinetic energy and it has been suggested that simultaneously other forms of free energy, such as sediment transport tend to increase along the flow path. Studies have focused on hydraulic networks on the hillslope scale as well as on the catchment scale. Surprisingly little attention has been given to the question why these networks exists in the first place and why discharge confluences towards the catchment outlet.</p><p>In the first part of our study we put Hortonian surface runoff into a thermodynamic framework and derive the energy balance for steady state runoff. We derive the equations on the hillslope scale, where we observe the transition from evenly distributed potential energy (the rainfall) to spatially organized discharge in micro rills to larger rills and gullies. In hydraulic terms we distinguish between sheet- and rill flow. We then apply Manning-Strickler’s equation to estimate the distribution of hydraulic variables and compare energy conversion rates on typical 1D hillslope profiles for sheet- and rill flow. Interestingly, we find that only certain hillslope forms lead to spatial maxima of stream power.</p><p>In the second part of the study we extend the energy balance to transient flow and analyse power maxima during typical rainfall-runoff events. Finally, we relate our findings to observable, measurable hydraulic structures such as rill systems and estimate past work on sediments. We believe that current energy dynamics of surface runoff reflects past optimization and therefore holds potential for the understanding of landscape evolution and surface runoff contributions alike.</p>

A Computer Program to Support the Selection of Turbines to Recover Unused Energy at Hydraulic Networks

For this paper, a computer program was designed and developed to calculate which turbines could be placed in a water distribution system considering the hydraulic constraints. The aforementioned turbines are placed in locations where we have unused hydraulic energy, i.e., when this energy is dissipated by a regulating valve. In our case, what we do is place a turbine to make use of that excess energy. Once the data has been entered into the program, it provides the type or types of turbines that can be placed in each location, what power these turbines would be, and how much they would generate annually. The program offers us two calculation options. In the first, and simpler, one, it would be done using the net head at the location where the turbine is to be placed. For this option, it would only be necessary to introduce the flow rate, the net head, and the hours that the turbine will be in operation to perform the calculation. The second option would be in the case where we did not have the net head, and, instead, we had the gross head. In this case, we have to calculate the head losses. Normally, this would be the most used option because there are usually no pressure drops. To perform the calculation, in this case, it is necessary to know, apart from what is mentioned in the first option, the characteristics of the pipe (diameter, length, and material).

BEHAVIOR OF WATER-FLOWED PIPES AT DIFFERENT TEMPERATURES

The implementation of water piping systems shows significant technological advances in the specialty of hydraulics. The pipes have great advantages, namely, in the reduction of fluid losses, as well as in the mitigation of problems resulting from water interruption and its preservation in relation to external harmful agents. In this numerical study will be tested pipes of various materials such as cast iron, stainless steel, galvanized steel, pex and fiberglass. The fluid that will circulate inside is water at different temperatures. Subsequently, several parameters will be evaluated, such as the friction factor, the head losses, the linear thermal expansion and the stress in the piping. Knowledge of these factors is paramount for the correct sizing of hydraulic networks, as well as for the correct choice of pumping systems.

A method of analysis of complex hydraulic networks

A simple and reliable iterative solution method of classical hydraulic network flow rate distribution problem is described. The method is based on chord linearization of inverse branch loss function which keeps basic branch properties. It has good speed of convergency which is practically independent of initial values.

EPANET in QGIS framework: the QEPANET plugin

In the current era, the digitization of geographical data is a transverse need of several engineering sectors, including the hydraulic networks management. Thus, water supply systems' modelling requires adequate tools in both the digitization and the simulation phases. This paper presents the QEPANET plugin, which aims at merging the flexibility of QGIS and the robustness of EPANET hydraulic simulations software. Several editing and graphical tools available with QEPANET are introduced to model new and existing water distribution systems, to read and modify existing text-based EPANET files, to run simulations and visualize results in a geo-referenced framework. In addition, an application is illustrated to underline the novelty and the practical functionality of the presented tool, such as 3D pipe lengths' automatic calculation and the supporting functionalities for the network drawing. The plugin is available via the official QGIS Python Plugins Repository and on the world-wide-web at https://gitlab.com/albertodeluca/qepanet.