Significant Reductions In Water Use Research Articles

Adapting to water restrictions: Intensive versus extensive adaptation over time differentiated by water right seniority

AbstractThis study explores farmers' adjustments to their water use when faced with water restrictions, distinguishing between intensive and extensive adjustments and examining adaptation over time. Specifically, the study uses a difference‐in‐differences framework to explore the effect of a groundwater restriction on irrigation management strategies. In 1992, the Kansas Department of Agriculture created an Intensive Groundwater Use Control Area to improve streamflow in Walnut Creek, which feeds water to a highly important migration point on the mid‐continent flyway. The program allocates permission to extract groundwater in 5‐year allotments. The stringency of the program's restriction depends on the seniority of the water right. We find significant reductions in water use along the intensive margin for senior water rights and along both the intensive and extensive margins for junior water rights. The results indicate significant reductions in water use that imply negative welfare impacts on farmers. We also find evidence of dynamically optimal behavior within each 5‐year allotment period.

Improving water efficiency and productivity using a condensation irrigation technique

In arid to sub-humid region, water has always been the main factor limiting crop production. The need for water is increasing and water availability is a major factor in the development and sustainability of ecosystems. The call to improve the efficiency and productivity of water use, development of new technologies for improving water use efficiency and availability to ensure future food security, has never been more urgent. Condensation irrigation is a new method that has the potential of increasing water efficiency and productivity. In this method, the steam transfers directly to the root zone and sustains the moisture content of the soil. The purpose of this study was to investigate the performance of the CI1 system in increasing water productivity and evaluating potential of this technology to provide moisture in various soils improved with adding organic matters. After selecting the proper temperature and soil texture, lettuce was planted in selected soil and condensation irrigation applied during growing period. Then the water consumed was measured and compared with water use of lettuce planted in greenhouse and traditional practice. Selected medium texture soil (in combination with 35% organic matter) was designated for cultivating lettuce under controlled conditions, CI application, using coated conducting tube, GH2 and TP3. The results of this study showed that after harvesting and full growth of lettuce in all three conditions, production per 1 m3 water to grow lettuce in CI, GH and TP was 1250, 333 and 75.5 kg, respectively. Water use efficiency was investigated in all treatments and the results showed that with a probability of 99% there is a significant difference between different irrigation methods, and the highest water use efficiency resulted from CI. The consumed water during the growth period in the GH was about four times that of CI, and in TP it was 21 times that of CI, which indicates a significant reduction in water use and more productivity in CI. By examining the weight of dry lettuce in all three methods, the results showed that in all samples taken from all methods the biomass was 12.5%. Further research is needed to verify the feasibility and applicability of this method in large scale.

Water Stress Patterns of Xerophytic Plants in an Urban Landscape

Efficient water use in urban landscapes is a common objective throughout the western United States. Vegetative species promoted for their drought tolerance characteristics are often included in landscapes designed for resource conservation. However, water requirements of most common landscape species have not been quantified. This is especially true for xerophytic species. This lack of landscape plant water requirement data is a significant constraint on the design of efficient irrigation systems and management practices affecting urban landscape water use. Current irrigation practices often fail to consider the unique physiology of xerophytic species, and irrigation scheduling models may not be appropriate for xeric landscapes using xerophytic vegetation as the primary method of reducing water use. This work describes the seasonal patterns of growth and xylem water status for four regionally native xeric shrub species planted in an unirrigated urban landscape in the semi-arid environment of central Oregon. The four species (Artemisia tridentata, Holodiscus microphyllus, Ericameria nauseosa, and Ribes cereum) exhibited substantial growth over the course of 18 months without irrigation in a heavily modified urban soil profile. Water potential of the four species was strongly correlated with surface (10 cm) soil moisture (r ≥ 0.90), less so with reference monthly evapotranspiration (r ≤ 0.55), and only weakly with water vapor deficit (r ≤ 0.22). In A. tridentata and H. microphyllus, xylem water potential became more negative during the growing season and tracked the seasonal decline in soil moisture. In contrast, the xylem water potential of E. nauseosa and R. cereum tracked soil moisture early in the season but became less responsive to soil moisture in the driest months, suggesting different drought adaptation strategies in these species. Three of the four species showed no visual signs of drought stress and maintained acceptable aesthetics even as soil moisture decreased to less than 10%. However, R. cereum exhibited a drought dormancy strategy that made it less aesthetically desirable. These results suggest that extreme xerophytic shrubs provide an opportunity for significant reductions in water use in urban landscapes.

Saving Water with a Nudge (or Two): Evidence from Costa Rica on the Effectiveness and Limits of Low-Cost Behavioral Interventions on Water Use

Abstract The study uses a randomized controlled trial to test the impact of simple, inexpensive, and nonpersonalized behavioral interventions (or “nudges”) on water consumption in the context of a developing country. A descriptive social norm intervention using neighborhood comparisons reduces average water consumption in the first two postintervention months by 4.9 percent relative to the control group, while a planning postcard intervention reduces consumption by 4.8 percent. A descriptive social norm intervention using a town-level comparison also reduces water consumption by 3.2 percent, but this effect is not statistically significant. Finally, the study's one-time interventions continue to generate statistically significant reductions in water use for up to four months after they are implemented.

A Comparative Analysis for a Novel Irrigation Method: Partial Rootzone Drying

Partial Rootzone Drying (PRD) is an irrigation technique which offers a means of modifying the growth and development of crops through relatively simple changes to the method of water delivery. The technique causes the stimulation of physiological responses which are normally associated with water stress and this results in a significant reduction in water use through the production of chemical signals in drying roots. Partial drying of one half of the roots of plants grown with two root systems is rapidly translated into a reduction in transpiration and assimilation of all the crop leaves. The aim of this research is to examine and simulate the novel irrigation method (PRD), which would stimulate the endogenous stress response mechanisms of Conocarpus erectus trees in the pilot area of the Arabian Gulf University in Bahrain and wheat and maize crops in the Mashtul Pilot Area (MPA), Egypt using Saltmed model so that vigor is reduced and the efficiency of water use is enhanced. This is to be achieved by the manipulation of the hydration status of parts of a crop’s roots that could be used to control vegetative vigor without detrimental effects on canopy water relations. The PRD technique is researched for wheat as a winter crop and maize as a summer crop in Egypt. The technique causes the stimulation of physiological responses which are normally associated with water stress and this results in a significant reduction in water use through the production of chemical signals in drying roots. The results confirmed an increase in irrigation water use efficiency using PRD comparing with conventional flood irrigation. The research highly recommends applying the PRD method in the Gulf Cooperation Council (GCC) countries and in new reclaimed areas in Egypt to save water and improve crop quality.

Optimum irrigation regime to maximize the yield, water use efficiency and quality of potato [Solanum tuberosum (L.) cv. Spunta

This study investigated the effects of different irrigation regimes on the yield, water use efficiency and quality of potato [Solanum tuberosum (L.) cv. Spunta] grown at the experimental field of Deir Alla Agricultural Research Station, Jordan during 2012–13 and 2013–14 growing seasons. Five different drip irrigation regimes were compared: 50% (I50), 75% (I75), 100% (I100) and 125% (I125) of crop evapotranspiration assessed according to the class A pan equation (which equated to 184, 274, 366 and 458 mm, respectively), and farmer irrigation (506 mm). The results indicated that irrigation to 100% of evapotranspiration (I100) was the optimum regime for maximizing potato production. The specific gravity and water use efficiency, as well as most nutritional contents of potato decreased with increasing amounts of water, and the maximum ash content was achieved with I100. Thus, use of the I100 regime would improve water use efficiency in potato crops compared with farmer irrigation levels that are currently used, allowing significant reductions in water use while maintaining production levels.

The Effect of Huanglongbing on Young Citrus Tree Water Use

Understanding the role of Huanglongbing (HLB) caused by Candidatus Liberibacter asiaticus on citrus (Citrus sp.) water use is critical for determining if changes in water management of commercial citrus orchards affected by this disease is necessary. Reference evapotranspiration (ETo) is the most used methodology for irrigation scheduling, particularly in light of reports that indicate the lack of water for irrigation will become a major problem in many places around the world including Florida. The objectives of this study were to determine citrus tree water relationship [water use, sap flow, and stem water potential (Ψ)] as affected by ETo and HLB. The study was initiated on Jan. 2014 on two sweet orange (Citrus sinensis) cultivars included Hamlin and Valencia grown in a fine sandy soil texture (sandy, siliceous, and hyberthermic Arenic Alaquods) in a greenhouse. Twelve weighing lysimeters of each cultivar (six HLB-affected and six nonaffected trees) were used to determine selected water relation parameters. Results indicated a significant reduction in water use, Ψ, and sap flow for affected trees when compared with nonaffected trees. Citrus water use of healthy trees during the 2-year study was 31% and 27% greater than HLB-affected trees for ‘Hamlin’ and ‘Valencia’, respectively. Lower water use of HLB-affected trees resulted in 10% and 15% greater available soil water content than healthy ‘Hamlin’ and ‘Valencia’ trees, respectively. Therefore, reducing the water supply for HLB-affected trees than healthy trees may be a desirable practice that would lead to significant water savings.

Agricultural Irrigation Water Use in a Closed Basin and the Impacts on Water Productivity: The Case of the Guadalquivir River Basin (Southern Spain)

This paper analyses the agricultural irrigation water use in a closed basin and the impacts on water productivity, and examines how they have affected the ‘closure’ process of the Guadalquivir river basin observed in recent decades. Following a period of expansion in irrigation, an administrative moratorium was declared on new irrigated areas in 2005. Since then, the main policy measure has been aimed at the modernisation of irrigated agriculture and the implementation of water conservation technologies. The analysis carried out in this paper shows a significant increase in mean irrigation water productivity in the pre‐moratorium period (1989–2005), driven by the creation of new irrigated areas devoted to high value crops and with a dominant use of deficit irrigation strategies, while a second phase (2005–2012) is characterised by slower growth in terms of the mean productivity of irrigation water, primarily as a result of a significant reduction in water use per area. Findings show that productivity gains seem to have reached a ceiling in this river basin, since technological innovations (such as new crops, deficit irrigation, and water‐saving and conservation technologies) have reached the limits of their capacity to create new value.

From Water-Constrained to Water-Driven Sustainable Development—A Case of Water Policy Impact Evaluation

A water allocation policy that aimed to balance water demand with water availability to ensure sustainability was implemented in an arid region of China over ten years ago. This policy’s success was assessed across three dimensions: society, the environment, and the economy. While the assessment was not intended to be comprehensive, it highlighted the best outcomes of the policy intervention while revealing some hidden issues. It was found that although the policy was successful in placing a ceiling on water use in the middle reaches of the Heihe River, the Water User Association, one of the main actors in water policy implementation, was under-recognized, even though it functioned well. Moreover, the economic structural adjustment at the macro level had not led to any significant reduction in water use, the reasons for which were explored.

Business Survival Requires Sustainability

We live in an interesting world when an issue of a water journal that is devoted to business factors has theme articles on water efficiency, supply uncertainty, climate change, and total water solutions. However, that is the reality we face. In fact, during the planning for this year's editorial calendar, June was labeled as the month to tackle business and sustainability issues. Without sustainability there is no business in our future. There are four mega‐trends in the water utility business landscape: the need for diverse water supplies, significant reductions in water use, a desperate need for infrastructure replacement, and dramatic changes in rate structures.

Increasing water use efficiency of irrigated sugarcane production in South Africa through better agronomic practices

In South Africa (SA) approximately 30% of sugarcane is grown under irrigation and there is increasing pressure to demonstrate efficient use of limited water resources. Agronomic practices such as the use of a crop residue layer, changed row spacing, growing suitable varieties and accurate irrigation scheduling could potentially increase water use efficiency (WUE) by saving water and/or increasing yield. The aim of the study was to investigate to what extent WUE of irrigated sugarcane production in SA can be improved by better agronomic practices, and to gain a better understanding of the mechanisms involved in crop response to these factors.An overhead irrigated field experiment was conducted near Komatipoort, South Africa on a shallow, well-drained, sandy clay loam over a four year period (one plant (P) and three ratoon crops (R1, R2 and R3)). Treatments consisted of factorial combinations of variety (N14 and N26), row spacing (single rows spaced at 1.5m and dual rows spaced at 1.8m) and soil surface cover (bare soil and crop residue layer). Measurements included tiller population, interception of photosynthetically active radiation (FIPAR), soil water content, and cane yield at harvest. Crop water use (CWU) was estimated using the water balance approach.This study showed that significant reductions in water use and irrigation requirements, and increases in WUE, are possible by using a crop residue layer to cover the soil. Water savings were largest in P (26% in CWU and 32% in irrigation requirement) but substantial savings were also achieved in R crops (about 15%). It is essential to practice accurate irrigation scheduling to realise these savings, taking into account soil cover and cultivar effects, especially during the period of partial canopy. Although the residue layer caused small reductions in yield in the P, R1 and R2 crops (on average 9%) these were not statistically significant. The combined effect of large CWU reductions and small changes in cane yield resulted in increased WUE (on average 18%).These responses to a residue layer were achieved through a reduced rate of canopy development due to delayed emergence of tillers, causing less green canopy cover and reduced CWU, especially during the period of partial canopy cover when stalk growth has not yet commenced. CWU and FIPAR were affected much less during the subsequent period of stalk growth, thus affecting cane yield minimally, provided irrigation scheduling was adjusted.Variety N14 consistently developed a canopy more rapidly, intercepted more radiation and achieved a higher yield than N26. Row configuration had a significant impact on canopy development, seasonal FIPAR, final stalk population but did not affect cane yield or WUE.The study produced quantitative data for parameterising crop models which will improve their reliability in irrigation management and yield prediction applications.

Water use optimisation based on the concept of Partial Rootzone Drying

Partial Rootzone Drying (PRD) is the creation of simultaneous wet and dry (or drying) areas within the root zone. Only part of the root zone is irrigated and kept moist at any one time. This new irrigation strategy allows the exploitation of drought-induced abscisic acid (ABA) based root to stomata signaling system to water saving. In this research, the PRD technique is examined and simulated for wheat and maize crops in the Mashtul Pilot Area (MPA), Egypt using Saltmed model. The technique causes the stimulation of physiological responses which are normally associated with water stress and this result in a significant reduction in water use through the production of chemical signals in drying roots. The results confirmed an increase in irrigation water productivity using PRD comparing with conventional flood irrigation. The research highly recommends applying the PRD method in new reclaimed areas in Egypt to save water and improve crop quality.

Implications to stormwater management as a result of lot scale rainwater tank systems: a case study in Western Sydney, Australia

Rainwater tanks are increasingly adopted in Australia to reduce potable water demand and are perceived to reduce the volume of stormwater discharge from developments. This paper investigates the water balance of rainwater tanks, in particular the possible impacts these tanks could have in controlling the stormwater discharge volume. The study collected water quantity data from two sites in the Hawkesbury City Council area, New South Wales, Australia and utilised the collected data in a simple water balance model to assess the effectiveness of rainwater tanks in reducing the stormwater discharge volume. The results indicate that a significant reduction in discharge volume from a lot scale development can be achieved if the rainwater tank is connected to multiple end-uses, but is minimal when using irrigation alone. In addition, the commonly used volumetric runoff coefficient of 0.9 was found to over-estimate the runoff from the roof areas and to thereby under-estimate the available volume within the rainwater tanks for retention or detention. Also, sole reliance on the water in the rainwater tanks can make the users aware of their water use pattern and water availability, resulting in significant reductions in water use as the supply dwindles, through self-imposed water restrictions.

Cleaner production measures in small-scale slaughterhouse industry – case study in Bosnia and Herzegovina

The goal of this project was to demonstrate to Bosnian and Herzegovinian industries that significant reductions in water use, wastewater discharge and pollution load can be obtained at little or no cost and that efficient use of resources and reduction of waste generation at source are clearly preferable compared with the end-of-pipe wastewater treatment. The project was performed on a small-scale slaughterhouse industry “Sahbaz” using a methodology prescribed by the Regional Activity Center for Cleaner Production from Barcelona and the Ministry of Environment of Spain. Upon detailed diagnosis of the industrial process and waste flows generated, the opportunities for environmental improvement were identified and CP measures were recommended and implemented. In the first three months of project implementation the amount of water saved and BOD reduced was 32 percent while salt consumption was reduced by 40 percent. Total annual net savings resulting from the application of selected measures were 669 €/year.

Utilizing a Social-Ecological Framework to Promote Water and Energy Conservation: A Field Experiment1

The present study utilized a social-ecological framework to design an intervention to reduce residential water and energy use in a local community. An experimental design was used to study the influence of information leaflets, attunement labels, and socially comparative feedback on the actual levels of energy and water consumption in 166 households over a 6-month period. The results suggest that the labels, designed to attune residents to the environmental-impact affordances of various appliances around their homes, led to a 23% reduction in water consumption. Neither information leaflets nor socially comparative feedback produced significant reductions in water use, compared to controls. No significant reductions in energy consumption were observed for any of the intervention conditions. The results are discussed in terms of their theoretical implications and their application to public policy promoting environmentally sustainable behavior.

Effects of Elevated CO2 on Cotton and Wheat As Determined from FACE Experiments

In order to determine the effects of the increasing atmospheric CO2 concentration on future crop productivity and water requirements, free-air CO2 enrichment (PACE) experiments at 550μmol/mol CO2 have been conducted in an open field at Maricopa, Arizona, U.S.A., on cotton (Gossypium hirsutum L., cv. Deltapine 77) and wheat (Triticum aestivum L. cv. Yecora Rojo) crops at ample (Wet) and limiting (Dry) levels of water supply. With ample water, canopy net photosynthesis rates of cotton and wheat crops increased about 30-40%, with little evidence of down-regulation. Under the Dry treatment, the stimulation was about the same for cotton but much larger for wheat. Cotton growth was stimulated about 30% at both wet and Dry water levels, with lint yield being stimulated even more, up to 80% under wet and 50% under Dry. Wheat growth was stimulated less than that of cotton, about 20% at mid-season. Moreover, the final wheat grain yields increased only about 10% under Wet, whereas under Dry, the increase was about 20%. The FACE treatment had very little effect on the water use of cotton, but, for wheat, there appeared to be a small (4%) but significant reduction in water use, as determined by the soil water balance. Water use efficiency increased due to the larger growth and yields.

Conserving Water Resources Through Integrated Water Management

ABSTRACT Today we face the challenges ofproviding goodfood, good air, and good water for a humanpopulation that is doubling every 40-50 years. The challenges are real and were evident enough during 1988 for Time magazine to dedicate its first 1989 issue to „Planet of the Year….Endangered Earth“. Great technological progress has been made over the past few years, enabling many industries and municipalities to significantly reduce airpollution and water pollution in locally defined areas. But thepictureglobally is not thatpromising Much of the available technology is costly, only affordable by the few. This paper describes the pollutioncontrol efforts of an 1800megawatt coal-fredpowerplant in thesouthwestern United States. Over $100 million was spent to totally eliminate water dischargefrom the plant. More importantly for many readers, however, were the lessons learned in people management, water resource management, and conservation training. These resulted in significant reductions in water use and proces...

EFFECTS OF RATE STRUCTURE KNOWLEDGE ON HOUSEHOLD WATER USE1

ABSTRACT: Socioeconomic determinants of individual household water use were estimated using regressions of these characteristics with actual household water use for winter and summer. Results were disaggregated between those consumers who were aware of an increasing block rate price structure and those who were not. Most of the informed group members believed that this price structure did result in significant reductions in water use. Nevertheless, overall water use was greater for the informed group. The determinants of water use were found to differ between informed and uninformed users as well as between winter and summer. The uninformed users were influenced by a larger set of variables in each season than the informed group. In winter, the informed group members with swimming pools and/or arid landscaping used less water than their uninformed counterparts. Summer water use increased with length of tenancy in home for the uninformed group but not for informed, while increasing with ownership for informed consumers.

The Influence of Paclobutrozol, a New Growth Regulator, on Sunflowers1

Abstract Paclobutrozol PP333 = (2R,3R + 2S,3S)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl) pentan-3-ol at concentrations of 11.6, 58.0, and 116.0 mg of active ingredient per liter caused significant reductions in water use of sunflowers (Helianthus annuus L.) but there was no significant influence on leaf diffusive resistance. The primary mechanism for reduced water use is by a reduction in leaf expansion. PP333 inhibited internode elongation which causes increased leaf shading. Under nonstress conditions there was no effect on leaf water potential or its components. At the highest concentration, photosynthetic rate was reduced. Fresh and dry weight of shoots was reduced proportional to leaf area. Gibberellic acid reversed the effect of PP333 of shoot height, leaf area, evapotranspiration, and shoot fresh and dry weight.