Reliability of Harvested Rainfall as an Auxiliary Source of Non-potable Water

AbstractRainwater harvesting is an ancient practice that involves collecting, storing, and using precipitationto meeton-site water needs. This paper develops and demonstrates guidelines for sizing the capacity of storage tanks to provide areliable continuous supply of harvested rainwater for residential households. Operation of the rainwater harvesting system is simulated with a stochastic mass balance performed on an Excel spreadsheet. The daily volume of rainwater in an unbounded tank is tracked to determine the maximum accumulated deficit on a monthly basis. Results are summarized in dimensionless charts showing the minimum size of a rainwater storage tankneeded to meet water demands at specified levels of reliability

Correlation or not correlation? This is the question in modeling residential water demand pulses

Published© 2013 The Authors. Published by Elsevier Ltd. This paper presents a comparison of two different modelling approaches for the generation of residential water demand pulses as Poisson processes. Both approaches are able to preserve the mean value of daily water demand. The main difference lies in the fact that the first considers the correlation between pulse durations and intensities whereas the second neglects it. Overall, the results of the applications aimed at reproducing the measured pulses in two households show that the increase in parameterization burden associated with taking correlation into account delivers a considerable improvement in the quality of model predictions

Multiple Satellites Remote Sensing Images For The Derivation Of A Water Availability Index

Recent drought events in the U.S. have threatened drinking water supplies for communities in Maryland and Chesapeake Bay in 2001 through September 2002, Lake Mead in Las Vegas in 2000 through 2004, the Peace River and Lake Okeechobee in South Florida in 2006, and Lake Lanier in Atlanta, Georgia in 2007. In the environmental science community, there is a renewed interest to develop a new Water Availability Index (WAI) that serves for short-term water resources planning and water infrastructure management in dry periods. Such a development may be geared toward presenting a near real-time, risk informed and forward-looking instrumental message in terms of both the quantity and quality of available fresh water in major metropolitan regions. The success of this effort could incorporate the use of integrated remote sensing technologies in concert with intermediate- and long-term climate change forecasts. It is the aim of this paper to present a state-of-the-art review about: 1) How the multi-scale and multi-dimensional databases are collected by optical and microwave satellite images, such as the NASA GOES, MODIS Terra and Aqua etc., and ground-based radar stations, such as the NOAA NEXRAD system, and 2) How these databases can be applied to support the development of a new WAI and help reduce the managerial risks of water infrastructure across the continental U.S. These discussions lead to the derivation of a new WAI with the aid of remote sensing technology. © 2008 ASCE

Source Location Inversion and the Effect of Stochastically Varying Demand

In recent years, significant advances have been made in the development of gradientbased optimization algorithms and their application to inverse problems in water distribution systems. We apply a gradient-based optimization procedure to the problem of identifying the location of a contaminant injected into a distribution system based on data collected at a finite number of sensors. The solution of this problem is complicated by uncertainty in the instantaneous water demands occurring at nodes throughout the distribution system. We characterize the effect of this demand uncertainty on the ability of the inversion algorithm to accurately and precisely identify the correct source location by varying the time step at which the variable demands are aggregated from 30 minutes to 24 hours. These calculations determine the effect of demand aggregation on the inversion results by comparing the results across time step sizes to the results achieved at the smallest time scale (30 minutes). In a distribution system the true water demands at any time step are unknown and represent irreducible uncertainty. We show how large of an effect this irreducible uncertainty has on our ability to locate the source location of contaminants within a distribution system. The calculations are done on a moderately sized distribution system network and the stochastic demands are generated using a recently developed Poisson Rectangular Pulse (PRP) demand generator. The contaminant is simulated with tracer transport using EPANET. Results for the example problem examined herein using 100 sensors show that the inverse approach is capable of identifying the correct source node at all time step aggregations

Investigating the characteristics of residential end uses of water: A worldwide review

A detailed characterization of residential water consumption is essential for ensuring urban water systems' capability to cope with changing water resources availability and water demands induced by growing population, urbanization, and climate change. Several studies have been conducted in the last decades to investigate the characteristics of residential water consumption with data at a sufficiently fine temporal resolution for grasping individual end uses of water. In this paper, we systematically review 114 studies to provide a comprehensive overview of the state-of-the-art research about water consumption at the end-use level. Specifically, we contribute with: (1) an in-depth discussion of the most relevant findings of each study, highlighting which water end-use characteristics were so far prioritized for investigation in different case studies and water demand modelling and management studies from around the world; and (2) a multi-level analysis to qualitatively and quantitatively compare the most common results available in the literature, i.e. daily per capita end-use water consumption, end-use parameter average values and statistical distributions, end-use daily profiles, end-use determinants, and considerations about efficiency and diffusion of water-saving end uses. Our findings can support water utilities, consumers, and researchers (1) in understanding which key aspects of water end uses were primarily investigated in the last decades; and (2) in exploring their main features considering different geographical, cultural, and socio-economic regions of the world.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Sanitary Engineerin