Changes In Water Use Research Articles

Index number analysis of Namibian water intensity

There has long been a great deal of interest in methods for analyzing energy use and energy use intensities. Many methods developed within energy studies are also applicable in other areas where materials use is of interest, but in several cases these methods have not been applied to other materials. Index number analysis is a method that is often used in energy economics to analyze changes in the aggregate energy intensity of an economy and to determine whether these changes are due to shifts in the composition of the economy, changes in the energy efficiencies of individual sectors, or both. In order to be useful, index number analysis requires detailed data on the materials usage in individual economic sectors over time. One reason why this method has not been used outside energy studies could be that other materials are rarely regarded as critical enough for this extensive data collection to seem meaningful. However, water is also a crucial resource for many economic sectors, and there are many developing countries where limited water availability is a major issue. In countries that place sufficient priority on water issues to keep track of water use by individual economic sectors, index number analysis provides a methodology which can readily be adapted to analyze changes in water use. This study uses index number analysis to study changes in Namibian aggregate water intensity between 1993 and 2001. The results show that despite considerable increases in water tariffs during this period, sectoral water efficiency has not improved at all. Sectoral water intensities have actually increased, and the only reason why overall water intensity has not increased more than it has is that there has also been a structural shift towards less water intensive economic sectors.

Consumptive water use to feed humanity - curing a blind spot

Abstract. Since in large parts of the world it is getting difficult to meet growing water demands by mobilising more water, the discourse has turned its focus to demand management, governance and the necessary concern for aquatic ecosystems by reserving an "environmental flow" in the river. The latter calls for attention to river depletion which may be expected in response to changes in consumptive water use by both natural and anthropogenic systems. Basically, consumptive use has three faces: runoff generation influenced by land cover changes; consumptive use of water withdrawn; and evaporation from water systems (reservoirs, canals, river based cooling). After demonstrating the vulnerability to changes in consumptive use under savanna region conditions - representative of many poverty and hunger prone developing countries subject to attention in the Millennium Development Goal activities - the paper exemplifies; 1) changes in runoff generation in response to regional scale land cover changes; 2) consumptive use in large scale irrigation systems. It goes on to analyse the implications of seeing food as a human right by estimating the additional consumptive use requirements to produce food for the next two generations. Attention is paid to remaining degrees of freedom in terms of uncommitted water beyond an environmental flow reserve and to potential food trade consequences (so-called virtual water). The paper concludes that a human-right-to-food principle will have major consequences in terms of altered consumptive water use. It will therefore be essential for humanity to address river depletion to avoid loss of resilience of the life support system. This will demand a deep-going cooperation between hydrology, ecology and water governance.

Evapotranspiration of a declining Quercus robur (L.) stand from 1999 to 2001. II. Daily actual evapotranspiration and soil water reserve

The components of actual evapotranspiration (ET) - interception (In%), tree transpiration (T) and forest floor ET - were measured from 1999 to 2001 in a mixed stand dominated by declining pedunculate oaks. Sap flux density measurements (oaks and maple) and forest floor ET [38] were extrapolated to season and stand scales by regressions with potential evapotranspiration (PET) and leaf area index (ET/ PET: 0.75 - 1.23). Oak transpiration (21 - 38% of stand transpiration) is lower than forest floor ET: forest floor can therefore not be neglected in this stand water balance. The soil water reserve dynamics deduced from those measurements reflects the inter- annual changes of water use. No water stress have been calculated on the 1999 - 2001 period, but it is suspected to have occurred previously; together with soil constraints and caterpillar defoliation, it could in part explain the severe oak decline symptoms.

Environmental Impact of Urban Heat Island Phenomena —Cause-effect chain and evaluation in Osaka City—

The impacts of urban heat island phenomenon on human activity and ecosystems have already been obvious in Japanese large cities. To discuss importance of urban heat island mitigation measures, it is necessary to identify and quantify urban heat island impacts such as change in energy use (cooling, heating and hot water supply), change in water use, heat stress, damage to urban ecosystem, air pollution, change in precipitation and floods, etc. In this paper, cause-effect chain of urban heat island impacts is proposed and some examples of heat island impacts in Osaka city are identified and evaluated. Change in energy consumption in residential and commercial sector is evaluated quantitatively by numerical simulation. The result shows the difference in total energy consumption by different air temperature is small since decrease in heating and hot water energy use compensate for increase in cooling energy use.

ENSO impacts on regional water management: case study of the Edwards Aquifer (Texas, USA)

CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials CR 28:175-182 (2005) - doi:10.3354/cr028175 ENSO impacts on regional water management: case study of the Edwards Aquifer (Texas, USA) Chi-Chung Chen1,**, Dhazn Gillig2,**, Bruce A. McCarl3,*,**, R. Lynn Williams4 1Department of Applied Economics, National Chung-Hsing University, Taichung 402, Taiwan2American Express, Phoenix, Arizona 85021, USA3Department of Agricultural Economics, Texas A&M University, College Station, Texas 77843, USA4Department of Agricultural Economics, California State University, Fresno, California 93740, USA *Corresponding author. Email: mccarl@tamu.edu **Seniority of authorship is shared by the first 3 authors ABSTRACT: This study investigates the water management actions required for, and regional benefits of, conditioning Edwards Aquifer water and agricultural management on the phases of El Niño–Southern Oscillation (ENSO), using data on ENSO frequency from 1970 to 1996. Water management adjustments would involve changes in agricultural crop mixes and urban water use to exploit seasonal climatic changes associated with ENSO. The value of ENSO-dependent management ranges from $1.1 to $3.5 million yr–1, depending on initial water level elevations in the aquifer. Exploitation of ENSO events has the potential to help offset the costs of diminishing regional pumping due to legislative mandates. KEY WORDS: ENSO · Water management · Edwards Aquifer Full article in pdf format PreviousExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in CR Vol. 28, No. 2. Online publication date: March 16, 2005 Print ISSN: 0936-577X; Online ISSN: 1616-1572 Copyright © 2005 Inter-Research.

Diurnal and seasonal changes in stem increment and water use by yellow poplar trees in response to environmental stress.

To evaluate indicators of whole-tree physiological responses to climate stress, we determined seasonal, daily and diurnal patterns of growth and water use in 10 yellow poplar (Liriodendron tulipifera L.) trees in a stand recently released from competition. Precise measurements of stem increment and sap flow made with automated electronic dendrometers and thermal dissipation probes, respectively, indicated close temporal linkages between water use and patterns of stem shrinkage and swelling during daily cycles of water depletion and recharge of extensible outer-stem tissues. These cycles also determined net daily basal area increment. Multivariate regression models based on a 123-day data series showed that daily diameter increments were related negatively to vapor pressure deficit (VPD), but positively to precipitation and temperature. The same model form with slight changes in coefficients yielded coefficients of determination of about 0.62 (0.57-0.66) across data subsets that included widely variable growth rates and VPDs. Model R2 was improved to 0.75 by using 3-day running mean daily growth data. Rapid recovery of stem diameter growth following short-term, diurnal reductions in VPD indicated that water stored in extensible stem tissues was part of a fast recharge system that limited hydration changes in the cambial zone during periods of water stress. There were substantial differences in the seasonal dynamics of growth among individual trees, and analyses indicated that faster-growing trees were more positively affected by precipitation, solar irradiance and temperature and more negatively affected by high VPD than slower-growing trees. There were no negative effects of ozone on daily growth rates in a year of low ozone concentrations.

African Enclosures: A Default Mode of Development

This paper draws on recent empirical studies of changing land and water use in semi-arid Africa to identify socioeconomic and political dynamics and discusses their implications for current policy which emphasizes decentralization and the strengthening of “local”––often customary––land rights. The paper presents cases where local initiative in response to market opportunities is driving investment and intensification of water use to increase production. This trend is associated with an increase in individualized control and market relationships in access to land, with increasing disadvantage to the poor. It is argued that this “default” pattern of development is occurring irrespective of the formal system of land tenure and may be promoted, rather than inhibited, by policies of decentralizing natural resource management.

Patterns of stomatal conductance among blue oak (Quercus douglasii) size classes and populations: implications for seedling establishment.

Quercus douglasii Hook. & Arn. (blue oak) is a deciduous white oak that is currently failing to regenerate throughout much of its range in California, USA. Patterns of water use were observed in adult trees, saplings and seedlings to determine if ontogenetic changes in water use occur, which might be important in the establishment of this long-lived perennial species in a Mediterranean-type system. Seasonal and diurnal stomatal conductance (g(s)), late-season predawn xylem water potentials (Psi(pre)), carbon isotopic ratio (delta(13)C) and soil water status were compared among the three size classes at three sites differing in mean precipitation and soil water characteristics. Comparisons were also made between microsites with and without regeneration (defined by the presence or absence of saplings). Overall patterns of water use were consistent among the three sites, except that, at the site with the highest rainfall, Q. douglasii plants had higher g(s) and more positive Psi(pre) values. Although no differences in water use patterns were found between regeneration and non-regeneration microsites, the observed ontogenetic differences in water use may have important implications for Q. douglasii establishment. Compared with adult trees and saplings, seedlings had higher gas exchange rates during periods of high soil water content (early in the season and in the morning). Seedling g(s) was correlated with percent extractable soil water (ESW) throughout the season; adult tree and sapling g(s) was correlated with ESW between June and September. Despite experiencing greater water stress (indicated by more negative Psi(pre) values) than older trees, seedlings had more negative delta(13)C values, implying lower water-use efficiencies.

Drawers of Water II: assessing change in domestic water use in East Africa

Despite abundant research on the relationship between water supply projects and health, relatively little is known about long-term trends in household water use. This article compares information from the original Drawers of Water study, which took place in East Africa in the late 1960s, and the Drawers of Water II study in the same region in 1997, and points to improvements as well as deterioration.

The use of stable isotopes to evaluate water mixing and water use by flood plain trees along the Garonne valley

Before the confluence of the Tarn, the Garonne valley was the driest area in the entire south-west of France, due to the relatively low rainfall and low summer discharge of the Garonne River and its tributaries. The natural abundance of the stable isotope of oxygen (18O) and ionic charge of surface and ground water were used to estimate the water source for the Garonne River and phreatic subsurface water. We also measured these constituents in the sap of trees at several flood plain sites to better understand the source of water used by these trees. 18O signatures and conductivity in the Garonne River indicated that the predominance of water was from high altitude surface runoff from the Pyrenees Mountains. Tributary inputs had little effect on isotopic identity, but had a small effect on the conductivity. The isotopic signature and ionic conductivity of river water (δ18O: −9.1‰ to −9.0‰, conductivity: 217–410 µS/cm) was distinctly different from groundwater (δ18O: −7.1‰ to −6.6‰, conductivity: 600–900 µS/cm). Isotopic signatures from the sap of trees on the flood plain showed that the water source was shallow subsurface water (<30 cm), whereas trees further from the river relied on deeper ground water (>1 m). Trees at both locations maintained sap with ionic charges much greater (2.3–3.7×) than that of source water. The combined use of 18O signatures and ionic conductivity appears to be a potent tool to determine water sources on geographic scales, and source and use patterns by trees at the local forest scale. These analyses also show promise for better understanding of the effects of anthropogenic land-use and water-use changes on flood plain forest dynamics.

Changes in Lot Scale Water Use and Management by Adopting Direct Seeding Culture in a Well-drained and Non-tilled Paddy Field

Changes in Lot Scale Water Use and Management by Adopting Direct Seeding Culture in a Well-drained and Non-tilled Paddy Field

Towards an integrated water resource management in Tanzania: the role of appropriate institutional framework in Rufiji Basin

Over the past 50 years, changes in the intersectoral water use in the Rufiji Basin have been enormous. A growing human population, migration and increasing demands in the basin have culminated this change. The basin, however, still lack an appropriate integrated management approach. This has resulted into inter-institutional conflicts, ineffectiveness, gaps in management imperatives and duplication of efforts. This paper reviews the existing institutional linkages identifies the gap and proposes an appropriate institutional framework which involve questions of institutional arrangements and the assignment of responsibilities among various levels of development, ensures stakeholders participation, accommodates adaptive change and remain self sustainable. The basic argument of this paper is that water management issue is both a question of developing stakeholders’ participation and transferring state’s competence to water user associations. Such an endeavour requires a complete and complex institutional framework, which would define clearly the role and rule of each stakeholder in water resource management. The paper further argues that; in Tanzania, the institutions that are involved in water management are loosely connected and lack basic coordination and are often at the periphery of the water management agenda––divorced from the water management programs; the predominance of isolated institutions locked up in narrowly defined activities with no interactive learning process will continue to hamper national aspirations to manage water; and that to change this situation will require innovative reforms in national institutions and institutional learning.

A System to Measure Evapotranspiration of In-ground Container Plants of Mexican Elder

Accurate measurement of evapotranspiration (ET) is difficult and expensive for large, in-ground container (pot-in-pot) plants. We engineered and used a simple and inexpensive system to determine evapotranspiration of in-ground container trees. The system was shop-assembled and used a block and tackle system attached to a collapsible tripod. A unique container harness system attached to the block and tackle system was used to lift containers that were sunken in the ground. Containers were weighed with a battery-operated balance that was accurate to 1 g (0.04 oz) at its maximum load capacity of 60 kg (132.3 lb). One person operated the system, and the weight of the system exclusive of the balance was 17.5 kg (38.50 lb). Gravimetric water use data obtained with the system werecombined with meteorological data to compute crop coefficients (Kc) of mexican elder (Sambucus mexicana). The system detected small changes in daily water use of mexican elder trees grown in 76-L (20-gal) in-ground containers. Crop coefficients ranged from 0.17 to 0.71. The acquisition of evapotranspiration data from relatively large, containerized landscape plants may be facilitated because the system is simple, inexpensive, and accurate.

Assessing a Policy Grab Bag: Federal Water Policy Reform

AbstractThis article examines the economic impacts of policy alternatives for addressing allocative inefficiencies among agricultural, urban, and environmental uses of federal water. The Central Valley Project Improvement Act, composed of multiple incentive‐based and command‐and‐control policies, forms the context for this analysis. Estimated multi‐output agricultural revenue functions and urban water demand functions are incorporated into a nonlinear programming model designed to predict changes in water use, returns to agriculture, and urban consumer surplus. Results suggest that analysis that does not explicitly model policy instruments implemented at sub‐optimal levels and, as part of a package of reforms, could over‐ or underestimate the costs, benefits, and effectiveness of each policy instrument.

Water use projections in DEVELOPING COUNTRIES

As developing countries are faced with maintaining water resources and building adequate delivery systems, it is important to analyze historical data to determine actual levels of use. In many developing countries, however, records with the necessary level of detail have not been maintained. Therefore, it is especially important to account for a variety of factors that may influence usage rates. This paper explores how water use trends are specific to local conditions and how making the assumption that per‐capita rates in the United States, for example, will also be achieved in developing nations can lead to overdeveloped systems. Evidence is given regarding how many times gross estimates are made of future water demand based on assumed increase factors and ways in which these assumptions can be incorrect. This article identifies actual changes in water use over time and provides actual water use data for a range of consumer sectors to assist in planning demand. The article also examines the impact of water cost on domestic use.

An Integrated Analysis of Changes in Water Stress in Europe

Future changes in water availability with climate change and changes in water use due to socio-economic development are to occur in parallel. In an integrated analysis we bring together these aspects of global change in a consistent manner, and analyse the water stress situation in Europe. We find that today high water stress exists in one-fifth of European river basin area. Under a scenario projection, increases in water use throughout Eastern Europe are accompanied by decreases in water availability in most of Southern Europe – combining these trends leads to a marked increase in water stress in Europe.

Positive biodiversity–production relationships: towards mechanisms

Several elegant experiments have demonstrated positive relationships between species diversity and biomass production. The underlying causes of this relationship have been hotly debated, with complementarity in resource use and facilitation suggested on the one hand, and sampling effect on the other, according to which species-richer communities work better because they are more likely to contain productive species. Based on careful experimental design and statistical analysis, sampling effect could be refuted for some experiments, including the one used in the new study by Caldeira et al. [1xMechanisms of positive biodiversity–production relationships: insights provided by δ13C analysis in experimental Mediterranean grassland plots. Caldeira, M.C. et al. Ecol. Lett. 2001; 4: 439–443CrossRef | Scopus (61)See all References][1]. They studied the role of water use for the positive diversity–production relationship observed in their experimental Mediterranean (i.e. frequently water-stressed) grasslands.Caldeira et al. looked at the ratios of stable carbon isotopes in leaves of five important species of this system, representing grasses, legumes and forbs. The ratios indicate differences between ambient and intercellular CO2 levels, which, in turn, are affected by stomatal behaviour and water use. For all species, water use was elevated at high diversities, significantly so for at least one species per group. Moreover, during an intermittent rainy period, soil moisture in the upper soil layer, where most of the roots were situated, was lowest in bare soil, intermediate in monocultures and higher in diverse plots. This indicates that stomatal behaviour was triggered by higher water availability in diverse communities. The higher biomass in more diverse plots, which, early in the season, could have been caused initially by complementary resource use, could have reduced subsequent evaporation or percolation, or increased dew capture, thus facilitating growth via reduced water loss. Plot biomass explained significant variation in the carbon isotope ratios; however, we are not told whether this explains all of the species-richness effect. Thus, the diversity effect on water use could be direct or indirect via increased biomass.This study clearly demonstrates mechanisms beyond the sampling effect that could affect the diversity–production relationship. Moreover, it suggests feedback between early- and late-season complementarity and facilitation, and implies that the biodiversity–production relationship also involves changes in soil moisture and water use, which in turn might affect organisms other than these primary producers. Regardless of whether the observed diversity effect on water use was ‘just’ a biomass effect initially started by earlier complementarity, the study suggests that the biodiversity–production question has left the pattern stage for the mechanism stage.

A fine balance: water wisdom from the KAWAD project, India

This article discusses the findings from a study undertaken by the Karnataka Watershed Development Project. The study examined the impact of changes in water use on rural livelihoods and highlighted the difficult choices that are made and how they impact differently upon everyone within the community.

Drawers of water: assessing domestic water use in Africa

This paper reviews the book of water: domestic water use in East by Gilbert White David Bradley and Anne White which is now considered a public health classic. It is noted that data reported in this book which was the first thorough study of water use in a developing country from the consumer’s point of view were acquired between 1966-68 through interviews and observations at study sites in Kenya Uganda and the United Republic of Tanzania. The researchers examined the use of water for basic consumption hygiene and amenities in domestic life and assessed the social cost of obtaining water. The following of the book’s findings influenced water policy and practice for years to come: 1) It presented a typology of water-related diseases based on their transmission routes; 2) It suggested that increasing the quantity of water used per capita could be more important for a households health and well-being; 3) It suggested that the addition of a closer but still distant water source would not necessarily increase household water use; and 4) it raised incisive questions about the desirable intermediate goals needed to meet demand for water in both rural and urban areas. Moreover information from the book has enabled Drawers of Water II Team to carry out a study on the changes of domestic water use in East Africa over the last three decades.

Water Right Reallocation in New Mexico's Rio Grande Basin, 1975‐1995

The results of a spatiotemporal investigation of water right transfer activity are presented. The data demonstrate a robust level of transfer activity over the period 1975-1995, and nearly unidirectional change in water use to higher-value uses. Whereas activity is locally focused and constrained in an upstream administrative area, it is more geographically and operationally diffuse in the administrative area containing the Albuquerque Metropolitan Area. A larger number of conservation district related transfers suggests that the forces of structural economic change are stronger there, and that it is more likely to experience third-party effects than other areas.