Water Use Intensity Research Articles

Impact of climate forcing uncertainty and human water use on global and continental water balance components

Abstract. The assessment of water balance components using global hydrological models is subject to climate forcing uncertainty as well as to an increasing intensity of human water use within the 20th century. The uncertainty of five state-of-the-art climate forcings and the resulting range of cell runoff that is simulated by the global hydrological model WaterGAP is presented. On the global land surface, about 62 % of precipitation evapotranspires, whereas 38 % discharges into oceans and inland sinks. During 1971–2000, evapotranspiration due to human water use amounted to almost 1 % of precipitation, while this anthropogenic water flow increased by a factor of approximately 5 between 1901 and 2010. Deviation of estimated global discharge from the ensemble mean due to climate forcing uncertainty is approximately 4 %. Precipitation uncertainty is the most important reason for the uncertainty of discharge and evapotranspiration, followed by shortwave downward radiation. At continental levels, deviations of water balance components due to uncertain climate forcing are higher, with the highest discharge deviations occurring for river discharge in Africa (−6 to 11 % from the ensemble mean). Uncertain climate forcings also affect the estimation of irrigation water use and thus the estimated human impact of river discharge. The uncertainty range of global irrigation water consumption amounts to approximately 50 % of the global sum of water consumption in the other water use sector.

Regional variability in water use intensity in China by clustering analysis

Water use intensity (WUI) reveals water withdrawals with respect to economic output. Decomposing WUI into factors provides inner-system information affecting the indicator. The present study investigates variability in WUI among provinces in China by clustering the principal components of the decomposed factors. Motivated by the index decomposition method, the authors decomposed WUI into seven factors: water use in agricultural, industrial, household and ecological sectors, exploitation rate of water resources, per capita water resources and population intensity. Those seven factors condense into four principal components under application of principal component analysis. Comprehensive WUI is calculated by these four components. Then the cluster analysis is applied to get different patterns in WUI. The principal components and the comprehensive intensity are taken as cluster variables. The number of clusters is determined to be three by applying the k-means clustering method and the F-statistic value. Variability in WUI is detected by implementing three clustering algorithms, namely k-means, fuzzy c-means and the Gaussian mixture model. WUI in China is clustered into three clusters by the k-means clustering method. Characteristics of each cluster are analyzed.

Modeling water use in schools: A disaggregation approach

Modeling urban water use plays a key role in water resource planning and management. From the literature it was found that a vast amount of research has been conducted on modeling residential water use and limited attention has been given to modeling non-residential urban water use. However, it has significant importance for effective water resources management in any urban area. This study aims to model urban water use in schools in the eastern part of Melbourne. A total number of 375 schools were considered in this study. These schools were first grouped into different categories based on the annual volume of water use. Multiple Linear Regression models were then developed for each of these groups. Model performance was measured using the Nash-Sutcliffe efficiency (E). It was found that the developed models have the capacity to estimate water use in schools satisfactorily, achieving E values greater than 0.5 in most cases.

Modeling the determinants of large-scale building water use: Implications for data-driven urban sustainability policy

As the world's population continues to urbanize, cities are struggling to meet the demand for key resources such as clean water. In urban areas, enhancing the sustainability and water efficiency of buildings is crucial to meeting the resource needs of a growing population. Nevertheless, the understanding of the determinants of urban water consumption – and specifically of multi-family residential buildings that constitute the bulk of the urban building stock – is limited. Using an extensive database of actual water use from New York City's Local Law 84, coupled with land use and demographic data from the NYC Primary Land Use Tax Lot Output (PLUTO) database and Census data, we apply weighted robust regression and geographically weighted regression (GWR) models to analyze the determinants and spatial patterns of water consumption in over 2300 multi-family buildings located in New York City. Our results indicate that occupancy, building size, building age, ownership structure, neighborhood demographic and socioeconomic characteristics, and the energy use intensity (EUI) of a building all have statistically significant effects on the water use intensity (WUI) of multi-family housing. Results of the GWR spatial analysis demonstrate large spatial variability across building characteristics, demographic variables and household income. The analysis and findings presented here give further support to the potential of targeted measures and incentives, segmented and classified by building characteristics and neighborhoods, to be effective tools for policymakers seeking to increase water efficiency in urban buildings and to accelerate reductions in resource use at the city scale.

The Upper Orange River Water Resources Affected by Human Interventions and Climate Change

The major problem in the study area is the unlawful water abstractions for irrigation use. In South Africa, indications show that about 240 million m3/a of illegal water use is due to unauthorised withdrawals or violations of water use licenses. The status of water use for irrigation in the Orange-Senqu Basin also shows that insufficient information exists such that work needs to be done to understand the potential for increased efficiency of water use, taking into account issues pertaining to crop type, soil type and technological options. Studies like this one could also shed light on the potential impact of climate change on water use in the basin as this area may well experience significant impacts from rising temperatures and changing rainfall patterns. The processes of validation and verification will determine the extent of existing lawful water use. The use of remote sensing techniques (satellite, aerial photographs, etc.) could be employed to determine if the volume of water use registered by irrigators is accurate, i.e. valid and that the volume of water use registered is lawful (verification). Currently, ecological requirements for the river mouth are met through releases from Vanderkloof Dam and amount to just 290 million m3/a. However several recent studies including the Gesellschaft fur International Zusammenarbeit - Integrated Water Resources Management (GIZ – IWRM) study highlight that this is based on a fairly outdated methodology. The more recent Lower Orange Management study found a high level estimate of ecological requirements to be in order of 1 062 million m3/a.

Multiple metrics for quantifying the intensity of water consumption of energy production

Discussion of the environmental implications of worldwide energy demand is currently dominated by the effects of carbon dioxide (CO2) emissions on global climate. At the regional scale, however, water resource challenges associated with energy systems are a growing concern. This paper, based on an inventory of national energy portfolios, posits an indicator-based framework for characterizing regional energy portfolios’ relative water intensity. These calculations extend upon a previous paper that established a method for calculating the national water consumption of energy production (WCEP) at the global level. Intensity indicators are based on normalizing the WCEP results with a set of additional indicators (including population, gross domestic product, total energy production, and regional water availability). The results show great variability in water consumption across nations, as well as across the various water intensity measures that were applied. Therefore, it is best to apply this full suite of indicators to each country to develop an integrated understanding of the intensity of water use for energy across countries.

Source and Fate of Hydraulic Fracturing Water in the Barnett Shale: A Historical Perspective

Considerable controversy continues about water availability for and potential impacts of hydraulic fracturing (HF) of hydrocarbon assets on water resources. Our objective was to quantify HF water volume in terms of source, reuse, and disposal, using the Barnett Shale in Texas as a case study. Data were obtained from commercial and state databases, river authorities, groundwater conservation districts, and operators. Cumulative water use from ∼ 18,000 (mostly horizontal) wells since 1981 through 2012 totaled ∼ 170,000 AF (210 Mm(3)); ∼ 26 000 AF (32 Mm(3)) in 2011, representing 32% of Texas HF water use and ∼ 0.2% of 2011 state water consumption. Increase in water use per well by 60% (from 3 to 5 Mgal/well; 0.011-0.019 Mm(3)) since the mid-2000s reflects the near-doubling of horizontal-well lengths (2000-3800 ft), offset by a reduction in water-use intensity by 40% (2000-1200 gal/ft; 2.5-1.5 m(3)/m). Water sources include fresh surface water and groundwater in approximately equal amounts. Produced water amount is inversely related to gas production, exceeds HF water volume, and is mostly disposed in injection wells. Understanding the historical evolution of water use in the longest-producing shale play is invaluable for assessing its water footprint for energy production.

Water Conservation—Whole Effluent Toxicity Paradox

Total dissolved solids (TDS) management in water has become an increasingly important topic as competition for water supply sources and the intensity of use both increase. Regulatory failure of National Pollutant Discharge Elimination System (NPDES) whole effluent toxicity (WET) tests is one of several potential factors in managing TDS concentrations in effluent. Consequently, WET tests have become a de facto concentration standard that sets the limit for the intensity of water use and the amount of water conservation feasibly obtained for a facility. Conflicting regulations dealing with the application of mixing zones and antidegradation policies can prevent water conservation and actually result in the unintended consequence of causing more water use. The impact of TDS on NPDES-required WET tests, conflicting regulations dealing with the application of mixing zones that are counter-productive to water conservation, alternative practices currently being used, and other means of rectifying this paradox are discussed.

Water management complex of Russia: Concept, state of the art, and problems

The structure of the water management complex of the Russian Federation is discussed. The main features showing the degree of meeting the demands for water in different spheres of economic activities are presented. The tendencies for variations in volumes of water use are revealed in housing facilities and public utilities, manufacturing and extractive branches of industry, electric power engineering, and agriculture. The article shows the present condition of fishery in inland water bodies, river craft and the infrastructure of inland water and aquatic water transport, and recreation.

Vulnerability of farm water supply systems to volcanic ash fall

Agriculture is critically dependent on continuity of water quality and quantity. It is well-established that even small quantities of volcanic ash can disrupt municipal water supplies, with known impacts to quality including: acidification, increases in turbidity and ionic concentrations. In addition, delivery systems may be blocked or damaged by hard and abrasive suspended ash and related ash-cleanup operations place extra stress on water reserves. The aim of this study was to characterise the key areas of vulnerability of farm water supplies to volcanic ashfall, and to identify management recommendations to reduce these. From literature review and case studies of farms impacted by the 1991 Pinatubo (Philippines) and 1991 Hudson (Chile) eruptions, key issues were: sedimentation of irrigation ditches and drinking water ponds, turbidity induced abrasion of sprinkler nozzles and water pumps, and damage to electric pumps (by ash on air-intakes). Building on this, we characterised the water-use regimes and water supply system vulnerability of eight case-study farms from across the North Island, New Zealand. From this, we propose an index system to evaluate the vulnerability of farm water supply systems. The key contributors to the vulnerability index include: water source, storage capacity, reliance on electricity, independence/interconnectedness of system elements, volume of water use and other load factors. These allow identification of key strategies for mitigating water supply vulnerability during prevention, preparation, response and recovery phases of a volcanic eruption.

Groundwater Demand Management in the Great Lakes Basin—Directions for New Policies

Demand-side management should be used to maximize the efficiency of groundwater use. Implementation of conservation measures would decrease the volume of water use and also exert less pressure on the water distribution system as well as the wastewater treatment system. Allocation of ground water in the Great Lakes basin must conform to priorities established at the community level. Groundwater pricing should reflect the full costs arising from ground water use. A differential pricing structure would help conserve water in the residential and industrial sectors. A user-friendly database on ground water use, quality and quantity for the entire Great Lakes basin is also essential. New policies for sustainable groundwater allocation, regulating water prices for water conservation, conservation education, pollution prevention, recycling and reuse of water as well as effective information management provide new directions for managing the groundwater demand in the Great Lakes basin.

Introduction to Water Use From Arctic Lakes: Identification, Impacts, and Decision Support1

Introduction to Water Use From Arctic Lakes: Identification, Impacts, and Decision Support¹

Simulating Exposures to Deliberate Intrusions into Water Distribution Systems

A well-known network solver (EPANET) and a novel water-use generator (PRPsym) were linked in Monte Carlo computer experiments to simulate a deliberate biochemical assault on a municipal drinking-water distribution system. The attack was modeled as a steady 6-hour injection delivering 3,600 g of a soluble conservative contaminant to a single node on the main line in a small town. Migration of the contaminant plume was tracked for 55 hours throughout the pipe network, and the cumulative mass loading was computed at four target nodes strategically located on looping links and dead-end branches. This exercise was repeated for 1,000 independent trials to establish a baseline distribution of consumer dose exposures at the target nodes. A battery of simulation experiments was then performed to examine the sensitivity of the nodal load distributions to various system characteristics and water-use patterns. Results show that variability in the total mass load received at a node can be apportioned between the variability in the water-use volume and variability in the mean delivered concentration. Overall, however, the operation of the network storage tank had the greatest influence on the nodal mass loadings. This study demonstrates that Monte Carlo techniques are a useful tool for simulating the dynamic performance of a municipal drinking-water supply system, provided that a calibrated model of realistic network operations is available.

Influência da irrigação e do cultivo nas propriedades de um latossolo e um argissolo da região do submédio São Francisco: atributos morfológicos e físicos

Foram estudados os efeitos da irrigação e do cultivo nas propriedades morfológicas e físicas de dois solos da região do Submédio São Francisco. Foram selecionadas seis áreas: três num Latossolo Amarelo, no município de Casa Nova (BA), e três num Argissolo Amarelo fragipânico, no município de Juazeiro, BA, ambos nas condições não irrigada e irrigada por diferentes períodos e métodos. Os solos foram morfologicamente caracterizados e, nas amostras de cada horizonte, foram determinadas a granulometria, umidade nas tensões de -0,034 e -1,52 Mpa, densidade do solo, densidade das partículas, macroporosidade, porosidade total, condutividade hidráulica saturada e microporosidade. Os resultados mostraram que o uso do solo com irrigação provocou mudanças na morfologia do horizonte superficial, com o desenvolvimento do horizonte Ap, com consistência muito dura e transição abrupta, afetando também o BA, no caso de utilização mais intensiva. Observou-se aumento significativo no gradiente textural superficial do Argissolo, proporcional à intensidade da movimentação do solo e do uso da água. Nos dois tipos de solos estudados, o uso agrícola com irrigação promoveu aumento na densidade do solo e redução da macroporosidade, porosidade total e condutividade hidráulica do horizonte subsuperficial.

FORECASTING URBAN WATER USE: THE IWR‐MAIN MODEL1

ABSTRACT: In the current forecasting practice, future water requirements of a growing urban area are often represented as the product of the number of people to be served by the water system and an assumed quantity of gross per capita water use. This paper describes a forecasting approach that differs from the per capita method in two important aspects. First, it disaggregates urban water use into a large number of categories, each consisting of a relatively homogeneous group of water users. Second, it links water use in each category to factors that determine both the need for water as well as the intensity of water use. This approach is incorporated into a computerized forecasting system referred to as IWR‐MAIN. The advantages of the IWR.MAIN model over the traditional per capita method are illustrated in a case study of Anaheim, California.