High Water Usage Research Articles

Evaluation of Remote-Sensing based Estimates of Actual Evapotranspiration over (Diverse Shape and Sized) Palmiet Wetlands

Accurately quantifying actual evapotranspiration (ETa) over wetlands is important for the improved management of these ecosystems, since 65% of them are threatened by clearing or drainage in South Africa. This study evaluated a range of available estimates of ETa over six palmiet wetlands, which are key ecological structures in terms of water regulation and sediment trapping. The research compared three remote sensing based products (a local product, FruitLook, and two global data products, MOD16 ET and EEFlux) across different rainfall years (2008 to 2019). Their outputs were validated, where possible, with limited ground-based scintillometer data on the Krom palmiet wetland, which indicated that MOD16 and EEFlux were most representative of ground-based measurements. We also compared the small pixel size EEFlux data over three wetlands with ETa over increasing buffers of land cover (100, 500, 1000 m) in order to validate the perception of these wetlands being high water users. While larger wetlands had slightly higher evaporative demands than adjacent areas, ETa over a small wetland was similar to neighboring land cover. The results indicate that palmiet wetland ETa is highly variable and dependent on external factors such as climate, wetland size and seasonality.

High temperature heat and water recovery in steam injected gas turbines using an open absorption heat pump

The advantages of reinjecting steam from the heat recovery steam generator (HRSG) in the preceding gas turbine are increased power and electrical efficiency at low specific cost and a high operating flexibility. The discharge of the injected steam to the ambient has however two major drawbacks: (1) a relevant water consumption and (2) a large thermal loss related to the latent heat of steam. An open absorption heat pump cycle downstream of the HRSG can solve both problems, as it allows to recover the steam from the flue gas and use its condensation heat at elevated temperature. This paper presents for the first time a concept to efficiently integrate both technologies and assesses the potential and limitations of the absorption system for a steam injected gas turbine. For high network return temperatures (60 °C), the “High Temperature Condensation Boiler Technology” (HT-CBT) performs significantly better than a conventional flue gas condenser over the entire STIG operating range, both with respect to fuel efficiency and water recovery. For steam injection rates up to 1.16 kg/s (60 °C) and 0.96 kg/s (40 °C) fuel efficiency remains constant at ca. 95% resp. 102% and power can hence be increased without the associated energetic penalty. Within this range, full water recovery eliminates the high water usage of the Cheng Cycle, making it a suited technology for flexible cogeneration also in dry areas. For higher steam injection rates, the added benefit of the HT-CBT was found to be restricted by the limited availability of desorber heating from the HRSG, suggesting the integration of external desorber heating. The possibility to increase the power output for a given heat demand, with limited impact on fuel efficiency, increases the economic viability of the technology compared to heating only applications.

Barriers and opportunities for behavior change in managing high water demand in water scarce Indigenous communities: an Australian perspective

Abstract Managing water demand by reducing water consumption and improving water use efficiency has become essential for ensuring water security. This research aimed to identify the primary determinants of household water consumption in an Australian Indigenous community to develop evidence-based water demand management policies and strategies that might be implemented by the water service provider. A behavior change framework was applied to investigate the opportunity, ability, and motivational determinants affecting household water consumption and conservation in an Australian Indigenous community. The lack of water conservation knowledge and skills of high water users could be barriers to saving water. Low water users have positive attitudes towards water conservation and a higher level of awareness about their own water use. While there is a lack of a belief that water shortages will occur, low water users do have concerns of vulnerability to droughts, and that could be a driver for their sense of obligation to engage in water conservation practices. The research recommended communication messages and tools to address identified barriers to enabling positive changes to water use behaviors, which have wider applications in remote Australian Indigenous communities.

Fees and governance: Towards sustainability in water resources management at schools in post-apartheid South Africa

Water scarcity is increasingly staking a claim next to energy as a threat to the sustainability of large cities, especially in developing countries with limited resources. The recent crisis brought on by Cape Town’s “Day Zero” drought created the impetus to expand on existing research on water demand management to include analysis of school usage patterns and key determinants thereof. With the effects of apartheid still visible in society and in school infrastructure coupled with the high water usage rates at schools, this paper evaluates the impact of school affluence (whether it is fee-paying or not, and self-governing or not) on water usage. We find that poor schools use substantially more water, partially because of poor maintenance, with mean water efficiencies of poor schools around 50% and 80% for affluent schools. Bayesian models were used to further determine which characteristics of a school are good proxies for the higher usage to help administrators and policy makers in the resource constrained educational environment. In addition to the obvious detrimental impact of poor maintenance, the results also point an incriminatory finger at early morning-school usage, early afternoon usage, and Saturday usage.

CONVERSE TRENDS OF THE TERRESTRIAL AND GROUND WATER STORAGE CHANGES IN CANADA AND THE UNITED STATES

Abstract. We study the terrestrial water storage (TWS) and groundwater storage (GWS) changes in Canada and United States. We employ the separation approach from Wang et al. (2013) together with the improved GRACE data of Release 6 for a longer time span until December, 2016. The TWS signals from lake levels are derived from satellite altimetry data over the lakes while TWS signals due to soil moisture (SM) and snow water equivalent (SWE) changes from hydrology models. There are four significant trend anomalies in North America for both TWS and GWS changes. Two positive anomalies are found in Canada with their centers in the provinces of Saskatchewan and Quebec, respectively, due to increased precipitation and/or increased runoff in their surroundings. Two negative anomalies are shown in the United States with their centers in California and the northwest of Texas, respectively, which are due to decreased precipitation and, especially for California, high water usage for agriculture.

Non-condensable gas Co-Injection with steam for oil sands recovery

To combat the challenge of high water usage and environmental foot prints, Steam-Assisted Gravity Drainage (SAGD) operators are beginning to combine steam and non-condensable gas (NCG) injection, as described in Butler's Steam and Gas Push (SAGP) recovery process. Recent field reports have also shown significant reductions of the steam-to-oil ratio, a key performance indicator for SAGD. However, there is still a limited understanding of the interaction of the NCG and steam and how this affects fluid flow and heat transfer dynamics within the reservoir. This research examines the operation of the SAGD-SAGP hybrid as applied in the MEG Christina Lake reservoir with the aim of clarifying the underlying mechanisms that occur in the reservoir as the process evolves. The results demonstrate that replacement of steam with NCG lowers the amount of steam injected with consequent reduction of the saturation pressure, and thus, saturation temperature of the steam. Although this adversely impacts the amount of mobilized bitumen, its impact is relatively small and the reduction of injected steam improves the steam-to-oil ratio. The interplay between NCG and steam at the edge of the chamber affects heat transfer leading to reduced heat transfer to the overburden and sides of the depletion chamber.

Value of Sedum species as companion plants for nectar-producing plants depends on leaf characteristics of the Sedum

Introducing nectar-producing plants to green roofs and other urban green infrastructure has been attempted to support pollinator activities. Green roofs can be drought-prone, placing limitations on the success of plant growth and nectar production in the absence of irrigation. Plant species differ greatly in water usage patterns, so companion planting with low and high water users has been proposed to increase performance of high water use species, including species important for urban pollinators. Additionally, crassulacean acid metabolism (CAM) plants such as Sedum tend to have low water usage and are reported to improve health condition of neighbors. However, Sedum species differ in morphological and physiological traits such as leaf shapes and the speed at which they switch to CAM, resulting in water usage differences during drought that could affect neighboring plants. This study quantifies the effects of companion planting with CAM plants (Sedum album, Sedum kamtschaticum) on nectar-producing plants (Fagopyrum esculentum, Trifolium repens), focusing on target plant growth form and leaf traits of neighboring Sedum. The health condition of F. esuculentum and soil water contents were improved significantly when they were planted together with S. album, which has small leaves and rapid CAM induction. Therefore, suppression of evapotranspiration of neighboring CAM plants could have positive effects on erect growth form nectar species. In contrast, the health condition of T. repens, which shows prostrate growth, was not affected by neighboring CAM plant species. Judging from these results, growth characteristics including leaf traits of neighboring Sedum and growth forms of the target plants could be important factors determining the effects of companion planting in urban green infrastructure.

Challenges of Researching Showering Routines: From the Individual to the Socio-Material

In the UK, water supplies are under pressure from climate, population and lifestyle change. Showering is the largest component of domestic water consumption. Young adults are high water-users at a transitional life-stage, when practices are dynamic, and habits shaped. This paper presents the methodology, early findings and reflections on challenges of working with different data types and scales, to explore real-world water-saving through a mixed-methods approach, focusing on showering patterns of first year university students in campus accommodation at the University of the West of England, Bristol, UK. Combining household meter, logged water-fixture micro-component, personal-use questionnaire, user diary and stakeholder focus group data with the Scottish Government Individual-Social-Material model, typical showering demand reduction interventions were evaluated and insights into alternative interventions were generated. Results indicate Estates’ routine equipment maintenance and database management affect data quality and consistency. Despite these issues a profile of daily student water use was derived (equivalent to 114 L per person per day) but with high variability between different households (from 83 to 151 L per person per day). Average shower durations (self-reported 10–12 min) were higher than reported UK norms, although frequency was similar to the UK daily shower norm. Average measured shower volumes (51 L in one house) were not excessive, indicating shower fixtures provided a contribution to water saving.

Using Cognitive Dissonance to Theoretically Explain Water Conservation Intentions

Water is a scarce resource in Florida. There is an immediate need to reduce the stress on water resources and make the availability of water more sustainable by encouraging engagement in water conservation among the residents of Florida. This study examined how the future intentions of high water users in Florida] to conserve water outdoors were influenced by cognitively dissonant attitudes and behaviors. The independent variables used in the study were: government trust, current water conservation practices, political beliefs, and homeowners’ associations (HOA) membership. The results to study indicated that higher trust in government and current engagement in water conservation behaviors promotes water conservation, while conservative political belief and HOA membership restrict water conservation. The independent variables (government trust, current water conservation practices, political beliefs, and HOA membership) also significantly predicted 30% of the variation in water conservation behavioral intentions. Level of engagement in current water conservation behaviors had the highest effect on future intent to conserve water. Extension educators, managers at water utility companies, and other agricultural educators are encouraged to consider cognitive dissonance among their target audiences as it can be used to promote water conservation.

Modelling environmental value: An examination of sustainable business models within the fashion industry

Abstract The business models of enterprises in the global fashion industry produce highly negative outcomes for the environment. High water usage, pollution from chemical treatments used in dyeing and preparation and the disposal of large amounts of unsold stock through incineration or landfill deposits combine to make clothing one of the highest impact industries on the planet. This paper uses the sustainable logics of narrowing, slowing and closing the loop of resources used during the production, design, manufacture and distribution of fashion garments to analyse emerging business models that seek to reduce the environmental impact of the fashion system. Taking the business model conceptualization of an enterprise as a system designed to create value for the customer and capture value for the firm, we add a consideration of environmental value and derive propositions that test the possibility that emerging sustainable business models in fashion will replace the dominant, unsustainable model. The paper argues that lack of scalability, incompatibility with fashion customers value propositions plus obstacles to supply chain changes militate against the prospect of the currently designed sustainable business models becoming the standard model of the fashion industry.

The effect of different ecosystems on groundwater consumption in an agro-pastoral ecotone of northern China from an innovative perspective

Water has always been the core resource for ecological security and social development of human life, especially in arid regions. The effects of different land-use types on the local groundwater resources were studied in Guyuan county, Hebei province, China. The results showed that the higher biomass was measured in cabbage, corn silage, potatoes, and oat plots, and the least biomass was measured in the natural grassland. The greatest fresh:dry ratio of biomass and water contents in cabbage was 24.2 and 155.4 t/hm2, respectively. Potatoes, corn silage, and oats had higher water contents, which were 72.4, 66.3, and 37.0 t/hm2, respectively. Driven by economic interests, vegetables and potatoes that were grown in the local area used a large amount of water and were mainly sold to the other parts of the country or even abroad. The high water usage is a threat to groundwater resources and the local ecological security. In the future, both the economic benefits and emergy should be analyzed to determine the real value and to objectively evaluate the input and the output of the ecosystem to save scarce ecological resources and to protect the local ecological security. Rain-fed artificial grassland including Chinese leymus and corn silage has a high development potential from the perspective of water consumption and productivity.

Drought-avoiding plants with low water use can achieve high rainfall retention without jeopardising survival on green roofs

Green roofs are increasingly being used among the suite of tools designed to reduce the volume of surface water runoff generated by cities. Plants provide the primary mechanism for restoring the rainfall retention capacity of green roofs, but selecting plants with high water use is likely to increase drought stress. Using empirically-derived plant physiological parameters, we used a water balance model to assess the trade-off between rainfall retention and plant drought stress under a 30-year climate scenario. We compared high and low water users with either drought avoidance or drought tolerance strategies. Green roofs with low water-using, drought-avoiding species achieved high rainfall retention (66–81%) without experiencing significant drought stress. Roofs planted with other strategies showed high retention (72–90%), but they also experienced >50days of drought stress per year. However, not all species with the same strategy behaved similarly, therefore selecting plants based on water use and drought strategy alone does not guarantee survival in shallow substrates where drought stress can develop quickly. Despite this, it is more likely that green roofs will achieve high rainfall retention with minimal supplementary irrigation if planted with low water users with drought avoidance strategies.

Supply and Demand for Water Use by New Forest Plantations: A Market to Balance Increasing Upstream Water Use with Downstream Community, Industry and Environmental Use?

This study examines the use of water by existing downstream entitlement holders and their possible market interactions with upstream interests in new forestry plantations in the case of the Macquarie River Catchment, NSW. Demand for offset water to allow upstream plantation establishment is estimated as a function of tree product value and direct and opportunity costs in six sub-catchment areas with different rainfalls and locations with respect to urban and other high security water users (UHS). This upstream demand is aggregated with downstream demand for water. The aggregate supply of downstream water entitlements is posited in terms of marginal values to each of three sectors [stock & domestic (SD downstream losses, not counting damages to the wetlands, are $233M and $236M (summing the IRR and SD further, uncompensated losses of 154 and 156 GL in annual river flow would be suffered by the wetlands. With the requirement to purchase water for establishing new tree plantations, upstream surpluses are projected to be $192M and $220M in the FRESH and SALTY cases, respectively, while downstream sums of IRR and S&D surpluses are $138M and $151M, given 90 and 97 GL of water traded upstream with no damages to the wetlands. Greater surpluses in the hypothetical SALTY cases are due to subsidies paid by UHS for tree planting to reduce water yields from the very salty sub-catchment, thereby lowering river salinity to acceptable levels for domestic use. Although sale of downstream water entitlements may just balance reductions in river flow due to new tree plantations, water delivery efficiency may be reduced and overhead costs increased for those not selling entitlements. Our analysis has not counted these costs.

Integrating starchy substrate into cellulosic ethanol production to boost ethanol titers and yields

Starchy grains as current major feedstocks for bioethanol production are competing with food supply; therefore, lignocellulosic biomass was pursued as an alternative feedstock for bioethanol production due to its high availability and low price. Commercial production of second-generation bioethanol from lignocellulosic biomass is still under development as significant challenges of low fermentation efficiency, low ethanol titers, high enzyme cost, and high water usage remain to be addressed. In this research, sugar-rich substrates such as starchy grains were integrated into cellulosic ethanol production, which could boost ethanol titers and ethanol yields. The substrates with various ratios of corn flour and hydrothermal treated corn stover (4:12; 8:8; 12:4; 12:12) were evaluated on the ethanol concentration and ethanol yield via simultaneous saccharification and fermentation. Ethanol concentration and ethanol yield decreased with increasing amounts of treated corn stover in the mixtures. The maximum ethanol concentration (68.7g/L) was achieved at the corn flour and corn stover ratio of 12:12 using raw starch granular enzyme with the ethanol yield of 86.0%, whereas the maximum ethanol yield was obtained at the corn flour and corn stover ratio of 12:4 as it contained higher amounts of corn flour. All the ethanol concentrations from various mixtures of corn flour and corn stover were higher than 37.9g/L from the control with 100% of treated corn stover (16%, w/v). Saccharification and fermentation processes were optimized to reduce energy cost and the optimized process was able to complete ethanol fermentation within 48h.

Enhancing Extension Program Effectiveness by Examining Regional Differences in High Water Users

Competition for water sources in urban areas of Florida has increased due to increased population and human activities. High water users have been identified as a specific group on which Extension should focus water conservation education due to their low awareness of water issues and active landscape water use. In order to ensure the effectiveness of Extension programs targeting high water users statewide, this study sought to explore regional differences in water conservation behavior engagement within Florida high water users. An online survey was conducted to capture responses of high water users (N = 932) in three distinct regions for this comparative study. Respondents were asked to indicate their current engagement in water use behavior, application of water conservation strategies, and likelihood of engaging in water conservation and related societal behaviors. Regional differences were found in all four examined constructs. The findings imply Extension educators should tailor educational programs to regional audiences’ behavior patterns instead of designing statewide programs to ensure program effectiveness.

A systems approach for assessing water conservation potential through demand-based water tariffs

Sustainable and responsive water management policies are essential to provide high-quality, reasonably priced drinking water to consumers at any time, while simultaneously ensuring a profit for the water utility. Such goal can be typically achieved through two different types of policy, namely increasing water supply, or managing water demand; the latter can be performed, among others, through water pricing. Pricing, especially when demand-based, can lead to a behavioural change in customer water use, but it is arduous to introduce for a number of political and social reasons; it is essential to engage with relevant stakeholders to clearly recognize pros and cons of implementing a new water tariff. As a consequence, in this paper, economic and social implications of demand-based tariff structures, and their potential for greater water conservation, are assessed through a participatory approach. The variation of residential water demand and revenue outcomes were simulated through an integrated participatory systems approach by assuming that an inclining block tariff was introduced on the Gold Coast region, Australia. Such connection between price, demand, and revenue is highly complex and the choice of System Dynamics for this modelling exercise is considered ideal as it can explicitly handle the non-linearity, feedbacks and interconnections of such system. The simulation model was developed by collaborating with relevant stakeholders, thus ensuring the logical inclusion of all the relevant inputs and connections. Such model integrates three components, namely revenue forecasting; water billing; and demand feedback sub-model. The results show that: a) the inclining block tariff can effectively lead to behavioural change and water consumption reduction, especially within the high water users group, although the predicted water savings would be lower than when adopting water restrictions; b) customers’ feedback to an increased cost can be used to achieve revenue neutrality; c) based on customer feedback and modelling simulations, the ideal proportion of customers to be charged with the second block tariff is 20%, however this can be recalculated and varied during wet seasons or dry seasons to optimise water availability. The developed model allows water planners to explore a wide range of policy alternatives (e.g. alternative pricing scenarios to influence demand) over medium to long-term periods and to optimise best-practice decision making for urban water conservation and management.

Water Risk Drives Investment in Water Reuse, Alternative Business Models

As much of the US continues to face water scarcity and drought conditions, longstanding solutions to water supplies, including wastewater reuse, will play an increasing role in key water‐stressed markets. High population growth and high water usage are driving investment in alternative water supplies. Companies competing in the water space must rethink their business models to adjust to this ongoing reality.

Designing a new cropping system for high productivity and sustainable water usage under climate change

The food supply is being increasingly challenged by climate change and water scarcity. However, incremental changes in traditional cropping systems have achieved only limited success in meeting these multiple challenges. In this study, we applied a systematic approach, using model simulation and data from two groups of field studies conducted in the North China Plain, to develop a new cropping system that improves yield and uses water in a sustainable manner. Due to significant warming, we identified a double-maize (M-M; Zea mays L.) cropping system that replaced the traditional winter wheat (Triticum aestivum L.) –summer maize system. The M-M system improved yield by 14–31% compared with the conventionally managed wheat-maize system, and achieved similar yield compared with the incrementally adapted wheat-maize system with the optimized cultivars, planting dates, planting density and water management. More importantly, water usage was lower in the M-M system than in the wheat-maize system, and the rate of water usage was sustainable (net groundwater usage was ≤150 mm yr−1). Our study indicated that systematic assessment of adaptation and cropping system scale have great potential to address the multiple food supply challenges under changing climatic conditions.

Exploring the Relationship between Critical Thinking Style and Water Conservation Behavior: Implications for Extension

In the past several years Cooperative Extension has focused on developing educational programs that address water conservation, specifically for individuals using exorbitant amounts of water, with limited success. However, few research studies have examined how the way people think, including their critical thinking styles, can be used to inform extension program development. The purpose of this study was to address this gap in the literature by examining how people who use a lot of water think critically and whether their critical thinking style influenced their engagement in water conservation (or lack thereof). Responses were obtained from 932 Florida residents identified as high water users via an online survey. The findings revealed respondents engaged in a low level of landscape water conservation behaviors. The results also showed relationships did exist between critical thinking style and level of engagement in landscape water conservation behaviors implying critical thinking styles should be considered when developing extension programs in this area. Recommendations include using critical thinking style to tailor programs that bring educational awareness of landscape water conservation to high water users.

Engaging High Water Users in Water Conservation #3: High Water Users’ Opportunities to Learn about Water Conservation

Homeowners who use excessive amounts of water to irrigate their landscapes have specified demographic characteristics and have been identified as high water users. This 3-page fact sheet is the third in a series discussing how Extension can improve high water users' engagement in water conservation, focusing on how to effectively communicate with high water users about water conservation education. Written by Pei-wen Huang and Alexa J. Lamm, and published by the Department of Agricultural Education and Communication, August 2016. AEC595/WC257: Engaging High Water Users in Water Conservation #3: High Water Users' Opportunities to Learn about Water Conservation (ufl.edu)