David E. Rosenberg

Modeling integrated water user decisions in intermittent supply systems

[1]xa0We apply systems analysis to estimate household water use in an intermittent supply system considering numerous interdependent water user behaviors. Some 39 household actions include conservation; improving local storage or water quality; and accessing sources having variable costs, availabilities, reliabilities, and qualities. A stochastic optimization program with recourse decisions identifies the infrastructure investments and short-term coping actions a customer can adopt to cost-effectively respond to a probability distribution of piped water availability. Monte Carlo simulations show effects for a population of customers. Model calibration reproduces the distribution of billed residential water use in Amman, Jordan. Parametric analyses suggest economic and demand responses to increased availability and alternative pricing. It also suggests potential market penetration for conservation actions, associated water savings, and subsidies to entice further adoption. We discuss new insights to size, target, and finance conservation.

Heterogeneous Residential Water and Energy Linkages and Implications for Conservation and Management

AbstractThis paper develops an integrated approach to model heterogeneous household water and energy use and their linkages. The approach considers variations in behavioral and technological water and energy use factors that affect U.S. indoor residential water and energy use for toilets, showers, faucets, clothes washers, and dishwashers. The study uses a recent, large, national, disaggregated household water use data set collected from 11 cities, as well as national energy data on water heater efficiency and setpoint/intake temperatures. First, probability distributions of water and energy use factors are identified and correlated. Then, Monte Carlo simulations are used to calculate probability distributions for estimated household water and energy use. Finally, linear regressions are used to find the relative effects of water and energy factors on household energy use. Results show that water and energy distributions among households are skewed, with the largest 12% of the users consuming 21% and 24% o...

Intermittent water supplies: challenges and opportunities for residential water users in Jordan

Intermittent access to improved urban water supplies is a large and expanding global problem. This paper describes 16 supply enhancement and 23 demand management actions available to urban residential water users in Jordan to cope with intermittent supplies. We characterize actions by implementation, costs, and water quantities and qualities acquired or conserved. This effort systematically identifies potential options prior to detailed study and shows that water users have significant capacity to affect demand. We suggest several methods to evaluate options and highlight the need to include local water management decisions in integrated water resources management and planning at utility and regional scales.

Water management with water conservation, infrastructure expansions, and source variability in Jordan

[1]xa0A regional hydroeconomic model is developed to include demand shifts from nonprice water conservation programs as input parameters and decision variables. Stochastic nonlinear programming then jointly identifies the benefit-maximizing portfolio of conservation and leak reduction programs, infrastructure expansions, and operational allocations under variable water availability. We present a detailed application for 12 governorates in the Hashemite Kingdom of Jordan. It considers targeted installations of water-efficient appliances, leak reduction in the distribution system, surface and groundwater development, seawater desalination, conveyance, and wastewater treatment projects. Results show that (1) water conservation by urban users generates substantial regional benefits and can delay infrastructure expansions; (2) some rationing and conjunctive use operations smooth operations during droughts; (3) a broad mix of source developments, conveyance expansions, and leak reduction programs can forestall the need for desalination; (4) the Disi carrier to Amman should include a large branch to Karak; and (5) increasing conveyance from Maan, Irbid, and Mafraq can avert impending crises in the neighboring districts of Tafelah, Ajloun, and Zarqa.

Residential water demand under alternative rate structures: simulation approach.

Econometricians have long studied the effect of price on residential water demand and the impact on water use of the rate (tariff) structure in which price signals are embedded. This paper applies an existing deductive model of residential water use for the intermittent supply system in Amman, Jordan and simulates demand responses across a cross section of households over many uniform, increasing block, and linear price (quadratic charge) rate structures at historically low and significantly higher prices. Results show inelastic piped water demand responses for all rate structures at historically low prices similar to findings from a prior econometric study for Amman. However, piped water demand turns more elastic when prices rise above

iSAW: Integrating Structure, Actors, and Water to Study Socio-Hydro-Ecological Systems

0.50/ m3 with uniform rates showing the most elastic response. But results also highlight several complications to determine and interpret price elasticity of demand under different rate structures. They also illustrate trade-offs among rate structures and rate structure ...

Water Resources Systems Analysis: A Bright Past and a Challenging but Promising Future

Urbanization, climate, and ecosystem change represent major challenges for managing water resources. Although water systems are complex, a need exists for a generalized representation of these systems to identify important components and linkages to guide scientific inquiry and aid water management. We developed an integrated Structure-Actor-Water framework (iSAW) to facilitate the understanding of and transitions to sustainable water systems. Our goal was to produce an interdisciplinary framework for water resources research that could address management challenges across scales (e.g., plot to region) and domains (e.g., water supply and quality, transitioning, and urban landscapes). The framework was designed to be generalizable across all human–environment systems, yet with sufficient detail and flexibility to be customized to specific cases. iSAW includes three major components: structure (natural, built, and social), actors (individual and organizational), and water (quality and quantity). Key linkages among these components include: (1) ecological/hydrologic processes, (2) ecosystem/geomorphic feedbacks, (3) planning, design, and policy, (4) perceptions, information, and experience, (5) resource access and risk, and (6) operational water use and management. We illustrate the flexibility and utility of the iSAW framework by applying it to two research and management problems: understanding urban water supply and demand in a changing climate and expanding use of green storm water infrastructure in a semi-arid environment. The applications demonstrate that a generalized conceptual model can identify important components and linkages in complex and diverse water systems and facilitate communication about those systems among researchers from diverse disciplines.

Shades of grey: A critical review of grey-number optimization

The field of water resources systems analysis is now experiencing one of its most exciting eras where scientists, decision makers, and funding agencies want to apply systems approaches to solve varied, complex, uncertain, and interdisciplinary resource management problems. Solving these problems presents great opportunities for us to engage in complex, real-world decision-making and make positive changes. However, to capitalize on these opportunities, we as a field must also overcome several large challenges related to problem identification, integration, blind use of systems tools, a focus on optimality, and harnessing big data. To overcome, we must look back to find what we have accomplished, why we have sometimes failed, and how we can improve upon past work. In May 2013, we had the privilege to organize and facilitate a thought-provoking panel discussion at the Environmental Water Resources Institute (EWRI) Congress in Cincinnati, Ohio, where different researcher and practitioner panelists spanning multiple generations plus esteemed audience members discussed the past and future of water resources systems analysis. Here, we distill some of the key points that emerged during the discussion that we think should guide our systems analysis work and research in the years and decades ahead.

Estimating and Verifying United States Households' Potential to Conserve Water

A grey number is an uncertain number with fixed lower and upper bounds but unknown distribution. Grey numbers find use in optimization to systematically and proactively incorporate uncertainties expressed as intervals plus communicate resulting stable, feasible ranges for the objective function and decision variables. This article critically reviews their use in linear and stochastic programs with recourse. It summarizes grey model formulation and solution algorithms. It advances multiple counter-examples that yield risk-prone grey solutions that perform worse than a worst-case analysis and do not span the stable feasible range of the decision space. The article suggests reasons for the poor performance and identifies conditions for which it typically occurs. It also identifies a fundamental shortcoming of grey stochastic programming with recourse and suggests new solution algorithms that give more risk-adverse solutions. The review also helps clarify the important advantages, disadvantages, and distinctions between risk-prone and risk-adverse grey-programming and best/worst case analysis.

Land-use system modeling and analysis of shaded cacao production in Belize

AbstractBehavior and technological impacts on residential indoor water use and conservation efforts in the United States are identified. Preexisting detailed end-use data was collected before and after toilets, faucets, showerheads, and clothes washers were retrofitted in 96 owner-occupied, single-family households in Oakland, California; Seattle, Washington; and Tampa, Florida, between 2000 and 2003. Water volume, duration of use, and time of use were recorded and disaggregated by appliance for two weeks before and four weeks after appliances were retrofitted. For each appliance, observed differences in water use before and after retrofits are compared to water savings predicted by simple analytical, regression, and hybrid models. Comparisons identify prediction precision among models. Results show that observed and predicted distributions of water savings are skewed with a small number of households showing potential to save more water. Regression and hybrid model results also show the relative and sign...