Annual Water Savings Research Articles

Planting Dates and Transplant Establishment Methods on Early-yield Strawberry in West-central Florida

Earlier fall planting dates for strawberry (Fragaria ×ananassa) in west-central Florida tend to promote earlier onset of flowering and fruiting. However, warm air temperatures (>28 °C) can result in excessive growth and runner production. Sprinkler irrigation is a common practice to reduce air temperature in the first 10 to15 days after transplanting, requiring large volumes of irrigation water. An alternative to sprinkler irrigation is the application of crop protectants such as kaolin clay after transplanting. The objectives of this study were to determine the optimal planting dates and to assess the most appropriate establishment practices for strawberry bare-root transplants in Florida. Four establishment practices—10 days of sprinkler irrigation (DSI), 10 DSI + kaolin clay, 7 DSI, and 7 DSI + kaolin clay were evaluated for ‘Florida Radiance’ and Sweet Sensation® ‘Florida127’ transplanted in mid September, late September, and early October in consecutive seasons. For ‘Florida127’, September planting dates increased early yield compared with early-October traditional planting dates, with no difference in total yield. Seven DSI followed by the foliar application of kaolin clay at day 8 was also found to increase early yield compared with 10 DSI for strawberry establishment, with annual water savings of 108.7 mm.

Potential of efficient toilets in Hanoi, Vietnam

Abstract Many water authorities have promoted the installation of water-saving devices as an effective way of managing residential water demand. However, there has been some controversy about the effectiveness of such devices in studies in developed countries, and few studies have considered the use of water-saving devices in developing countries, where a rapid increase in water demand is expected. This study focused on toilet replacement and the residential water-saving potential in urban Hanoi, Vietnam – a country presently enjoying remarkable economic growth and increasing water demand – using the Monte Carlo simulation, i.e., stochastic, approach. We surveyed the toilets of 134 households. Annual water savings were not large – 2.2 liters per person per day (1.9% of total residential consumption) – despite the assumption that all toilets would be replaced with efficient ones within three years. Based on this study, a rebate to encourage toilet replacement would have limited effect for saving water, contrary to experience in developed countries. Comparing the volume of water saved, the simple analytical model, i.e. the deterministic approach, under-estimated the water-saving potential.

Generalized equations, climatic and spatial variabilities of potential rainwater savings: A case study for Sydney

Optimised harvesting of rainwater has been a challenge as the reliability of this water supply depends on many factors i.e. rainfall amount, tank size, roof area and rainwater demand. Various studies have been done in this context considering water usages, rainfall & roof area; and different methods were proposed to maximise the water supply reliability for an optimum rainwater tank. Among the analysis methods, a daily water balance method is the most acceptable and reasonably accurate, although, general end-users hardly can interpret outcomes of these analyses. This paper presents relationships of expected water savings under different climatic conditions for specific tank sizes with two major contributing factors; demand and roof area for an Australian city, Sydney. Expected annual water savings were calculated for different combinations of tank size, roof area and demand using an earlier developed daily water balance model, eTank. For a given tank size expected water savings for different roof areas and demands are presented in the form of charts for a user-friendly presentation to the end-users. Also, produced charts for a particular climatic condition were converted to a generalized equation having independent variables of roof area, tank size and demand to facilitate quick calculations through apps or computer. For the validity check of the developed equations, results from the equations were compared with the eTank simulated results and it is found that the results from the generalized equations are very close to the eTank produced results. To present spatial variability, similar charts and equations were produced for four different regions of Sydney.

Design of optimal tank size for rainwater harvesting systems through use of a web application and geo-referenced rainfall patterns

The current study describes the development of a Decision Support System (DSS) for estimating the optimal tank size of rainwater harvesting systems (RHS). Site-specific conditions are incorporated into the analysis, including those of the local rainfall regime and domestic demand for water, in addition to the desired level of confidence.The developed DSS is accessible via the interface of a web application, in which the annual efficiency of potential water savings by RHSs is analyzed by a simulation based on historical rainfall data and rainfall distribution.The developed DSS was applied and validated for nine case studies in the State of Mexico, considering three distinct rainfall regimes and catchments area. According to estimates, an annual potential water savings of up to 46,500 L per household may be achieved under average conditions.

An analysis of the factors that influence industrial water use in Tianjin, China

This study identifies the driving forces behind maximizing Tianjin’s industrial water use efficiency in China. For this purpose, a decomposition method is developed to quantify the degree of the impact of each factor. The results show that industrial expansion was responsible for an increase in annual water use of 78 million m³, while technical advances and water efficiency measures contributed annual water savings of about 76 million m³. Further, the results highlight that Tianjin has not considered the rise in water efficiency to be the primary goal of restructuring local industries over the past decade.

Conventional Water Filter (Sand and Gravel) for Ablution Water Treatment, Reuse Potential, and Its Water Savings

<p>Ablution process consumes a huge amount of water especially in mosques for cleaning certain part of the body before performing prayers. The high volume of ablution water produced in mosques and its low strength in quality makes it a feasible option to be reused. This paper introduced an assessment of conventional filtration (sand and gravel) in treating ablution water for reuse purposes and its water savings potential in mosques. The treatment system has assessed its capability for reuse and its water savings potential. A pilot scale of filtration system was developed and was run with the ablution water from the Parit Raja mosque and the Pintas Puding mosque. The samples were taken during Friday noon prayer between January to March 2013. The efficiency of the conventional filtration system was tested for the effluent quality of NH<sub>3</sub>, TSS, COD, and BOD. The case study of water savings estimation for the proposed system was undertaken at Pintas Puding mosque. It was determined based on the quantity of ablution water, water consumption, water demand, and water bills record. The results deduced that the conventional sand filtration can improve the water quality parameters; 0.60-0.05mg/L reduction of nitrogen ammonia (NH<sub>3</sub>), 6.0-1.53mg/L of suspended solids (TSS), 3.12-0.15mg/L of chemical oxygen demand (COD), and 27.67-4.16mg/L of biochemical oxygen demand (BOD). The treatment system was projected to save water consumption by 41.73% and RM180.16 of water saving per month. Water consumption was estimated to be further reduced to 50.83% if reused activities such as irrigation and toilet flushing were applied. Hence, annual water savings could reach up to RM2161.92 per year. With the current instability of water resources, the implementation of the conventional filtration system for ablution water in the mosques provides water security and water resources conservation option for the country.</p>

Applying an integrated methodology toward non-revenue water reduction: the case of Nicosia, Cyprus

Non-Revenue Water (NRW) is one of the major issues water utilities are facing today, especially in areas with severe water scarcity conditions. The WATERLOSS-DSS, a user friendly decision support system (DSS), was developed to help water operators decide which NRW reduction measure(s) to apply in their water networks. The DSS evaluates the water network performance level and finally proposes a list of prioritized NRW reduction measures. This DSS was checked for Nicosia’s (capital of Cyprus) urban water network. Three problematic District Metered Areas (DMAs) were chosen. The DSS provided a list of prioritized NRW reduction measures targeting at various NRW causes for each DMA. Nicosia’s water utility officials decided to apply some of the short-listed measures in those DMAs, resulting in significant NRW reduction and additional benefits. The annual water savings came up to 1 million m3, equal to 4.8% of the water entering the network. Economic benefits of more than 700,000 € are noted. Additional benefits are important energy savings, reduced overtime, and better knowledge of the network. These were incredibly important for Nicosia, as Cyprus is facing severe water scarcity conditions.

Effects of post-harvest deficit irrigation in ‘Red Beaut’ Japanese plum: Tree water status, vegetative growth, fruit yield, quality and economic return

In early maturing fruit crops, post-harvest is usually the preferred period to apply regulated deficit irrigation (RDI) because it offers the opportunity of reducing vegetative growth and saving water without interfering with fruit growth. There are few studies of RDI on Japanese plum, in comparison with the number available for other fruit crops. We examined the effect of RDI over the post-harvest seasons of 2009–2013 on tree water status, vegetative growth, yield, fruit quality and economic return in an adult orchard of early maturing ‘Red Beaut’ Japanese plum. All treatments received the same pre-harvest irrigation of 100% of crop evapotranspiration (ETc) and post-harvest irrigation treatments were: irrigated at 100% of ETc (Control); applying 60% of water in Control (RDI-60); and applying 30% of water in Control (RDI-30). The average annual irrigation water applied to Control was 639mm. Maximum annual water savings with respect to Control were 39% for RDI-60 and 70% for RDI-30. Intercepted photosynthetically active radiation at solar noon displayed a similar pattern throughout the years with no significant differences between irrigation treatments in any year. However, the RDI treatments were suitable for reducing total pruning weight. Fruit yield in RDI-30 was similar to Control for each of the five years following deficit irrigation. In the long-term (five seasons), the effect of post-harvest RDI had no negative cumulative effect on tree productivity. Therefore, for early maturing Japanese plum it can be concluded that allowing a progressive post-harvest water stress that limits the decline in Ψstem to values of −1.65MPa in early August, with a maximum decrease of 0.014MPaday−1, corresponding in this study to RDI-30, appears not only to be an effective way of saving water, but also acts as a useful tool to control vegetative growth (considered as total pruning), maintain fruit yield and quality and increase grower's final return.

Impacts of climatic variability on rainwater tank outcomes for an inland city, Canberra

A daily water balance model is used for the performance analysis and design optimisation of household rainwater tank for an inland Australian city, Canberra. To investigate the climatic variabilities of rainwater tank outcomes nine representative years (three for each dry, average and wet condition) are selected from historical rainfall data. For the three climatic conditions, a number of rainwater tank outcomes (water savings, townwater augmentation, overflow and reliability) are presented in relations to tank volume, roof area, number of people in a house (i.e., water demand). It is found that 100% reliability cannot be achieved even in wet year with a large tank (10,000 L) connected with a large roof (300 m2). Also, it is observed that significant climatic variabilities exist in regards to studied rainwater tank outcomes, except for very few conditions having very large tank (10,000 L) connected with a small roof (100 m2). However, computed variabilities are still lower than the expected climatic variabilities in regards to annual water savings, annual townwater uses and reliabilities computed for Australian coastal cities, i.e., Sydney and Melbourne.

Estimation of the effects of price and billing frequency on household water demand using a panel of Wisconsin municipalities

A demand function of residential water consumption is developed from a 1997 to 2006 panel of 200 Wisconsin water utilities. A double-log functional form is assumed and parameters are estimated using a random effects model. The results suggest that the price is inelastic yet negative and statistically significant and this elasticity response grows stronger as the marginal price level is increased. Additionally, the model reveals water savings due to monthly billing and also the annual water savings from technology adoption.

Comparison of irrigation scheduling strategies for achieving water use efficiency in highbush blueberry

A glasshouse experiment was carried out to assess the feasibility of applying partial rootzone drying (PRD) to highbush blueberries (Vaccinium corymbosum). A subsequent field experiment was established to assess four irrigation strategies with the aim of improving water use efficiency in blueberry production. Applying PRD to plants during a glasshouse experiment reduced stomatal conductance without reducing plant water potential. Hindered by high rainfall, a physiological response to PRD was not repeated in field grown plants. However, irrigation scheduled using a Kc (crop coefficient) curve constructed from Food and Agriculture Organization (FAO) 56 guidelines and post-harvest regulated deficit irrigation (RDI) delivered annual water savings of 0.8 ML ha−1 and 1.3 ML ha−1, respectively, compared with a total 3.6 ML ha−1 applied using a ‘rule-of-thumb’ approach commonly adopted by Australian blueberry growers. These savings were achieved without reducing berry yield or quality. This study is the first to report on the feasibility of applying FAO 56 guidelines, RDI and PRD as strategies to maximize water use efficiency in highbush blueberry production.

Rainwater harvesting in Greater Sydney: Water savings, reliability and economic benefits

Due to greater environmental awareness and mandatory water restrictions in many Australian cities, rainwater tanks have become popular in recent years. This paper investigates the water savings potential of rainwater tanks fitted in detached houses at 10 different locations in Greater Sydney, Australia. A water balance simulation model on daily time scale is developed and water savings, reliability and financial viability are examined for three different tank sizes, 2kL, 3kL and 5kL. It is found that the average annual water savings from rainwater tanks are strongly correlated with average annual rainfall. It is also found that the benefit cost ratios for the rainwater tanks are smaller than 1.00 without government rebate. It is noted that a 5kL tank is preferable to 2kL and 3kL tanks and rainwater tanks should be connected to toilet, laundry and outdoor irrigation to achieve the best financial outcome for the home owners. The results from this study suggest that government authorities in Sydney should maintain or possibly increase the rebate for rainwater tanks to enhance its acceptance.

Regulated deficit irrigation reduces water use of almonds without affecting yield

A plant-based regulated deficit irrigation (RDI) experiment in the northern Sacramento Valley determined that crop consumptive water use and irrigation could be reduced without significant detrimental effects on almond production. Tree stress was measured by recording midday stem water potential, a direct measure of tree water stress. With a water stress level of -14 to -18 bars during the hull-split period, average annual water savings were about 5 inches. Over 5 years, no significant yield reductions were observed, although average kernel weight was slightly lower. The results suggest that water savings can be achieved without affecting yield, even in soils with low water-holding capacity.

Rainwater tanks in multi-unit buildings: A case study for three Australian cities

Rainwater tanks have become popular in large Australian cities due to water shortage and greater public awareness towards sustainable urban development. Rainwater harvesting in multi-unit buildings in Australia is less common. This paper investigates the water savings potential of rainwater tanks fitted in multi-unit residential buildings in three cities of Australia: Sydney, Newcastle and Wollongong. It is found that for multi-unit buildings, a larger tank size is more appropriate to maximise water savings. It is also found that rainwater tank of appropriate size in a multi-unit building can provide significant mains water savings even in dry years. A prediction equation is developed which can be used to estimate average annual water savings from having a rainwater tank in a multi-unit building in these three Australian cities.

Urban and Agricultural Water Conservation in California

This article discusses how, by obtaining sustainable water savings through on‐going demand management programs, the state of California and specifically the El Dorado Irrigation District (EID) will extend the existing water supply. The article gives an overview of EID's conservation program, discusses the components of its urban and agricultural water conservation programs, lists statistics on annual water savings of its specific programs, and discusses its grant funding programs.

Residential water conservation in a noncrisis setting: Results of a New Jersey Experiment

East Brunswick Township, New Jersey, conducted a water conservation program in 1980 by distributing to 564 households free packets of water‐saving devices purchased with municipal funds. The program was not a response to a current water supply crisis, and appeals for cooperation were based on the private economic benefits of water conservation. Statistical procedures were developed to measure the proportions of households installing each of the devices distributed, water savings and program costs. Two‐thirds of the households receiving the packets installed at least one device. Average annual water savings per home receiving a packet were estimated at 5010 gallons (18.96 kl). Amortized over ten years at a 10% discount rate, the program cost was approximately 35 cents per 1000 gallons of water saved (9.2 cents per kl). The East Brunswick results compare well to the results obtained from similar conservation programs in a pair of California communities during the 1976–1977 drought.