Assess Water Use Research Articles

Assessing Water Use in WaterSense-Labeled Homes and Quantifying the Savings.

Key TakeawaysAfter the local Water Smart Homes program ended in 2020, the US Environmental Protection Agency began the WaterSense‐labeled homes Version 2.0 program, launched as a pilot.The study evaluated indoor and outdoor metered water use of 160 WaterSense‐labeled homes in the Las Vegas metropolitan region.Metered data show that WaterSense‐labeled homes used a median of 44,000 gpy and exceeded their water savings goal.

Climate adaptation guidance: New roles for hydroeconomic analysis

Climate water stress internationally challenges the goal of achieving food, energy, and water security. This challenge is elevated by population and income growth. Increased climate water stress levels reduce water supplies in many river basins and elevate competition for water among sectors. Organized information is needed to guide river basin managers and stakeholders who must plan for a changing climate through innovative water allocation policies, trade-off analysis, vulnerability assessment, capacity adaptation, and infrastructure planning. Several hydroeconomic models have been developed and applied assessing water use in different sectors, counties, cultures, and time periods. However, none to date has presented an optimization framework by which historical water use and economic benefit patterns can be replicated while presenting capacity to adapt to future climate water stresses to inform the design of policies not yet been implemented. This paper's unique contribution is to address this gap by designing and presenting results of a hydroeconomic model for which optimized base conditions exactly match observed data water use and economic welfare for several urban and agricultural uses at several locations in a large European river basin for which water use supports a population of more than 3.2 million. We develop a state-of-the arts empirical dynamic hydroeconomic optimization model to discover land and water use patterns that optimize sustained farm and city income under various levels of climate-water stress. Findings using innovative model calibration methods allow for the discovery of efficient water allocation plans as well as providing insight into marginal behavioral responses to climate water stress and water policies. Results identify that water trade policy under climate water stress provides more economically efficient water use patterns, reallocating water from lower valued uses to higher valued uses such as urban water. The Ebro River Basin in Spain is used as an example to investigate water use adaptation patterns under various levels of climate water stress. That basin's issues and challenges can be of relevance to other river basins internationally.

Potential Environmental Impacts of Peanut Using Water Footprint Assessment: A Case Study in Georgia

The recent decade has witnessed an increase in irrigated acreage in the southeast United States due to the shift in cropping patterns, climatic conditions, and water availability. Peanut, a major legume crop cultivated in Georgia, Southeast United States, has been a staple food in the American household. Regardless of its significant contribution to the global production of peanuts (fourth largest), studies related to local or regional scale water consumption in peanut production and its significant environmental impacts are scarce. Therefore, the present research contributes to the water footprint of peanut crops in eight counties of Georgia and its potential ecological impacts. The impact categories relative to water consumption (water depletion—green and blue water scarcity) and pesticide use (water degradation—potential freshwater ecotoxicity) using crop-specific characterization factors are estimated for the period 2007 to 2017 at the mid-point level. These impacts are transformed into damages to the area of protection in terms of ecosystem quality at the end-point level. This is the first county-wise quantification of the water footprint and its impact assessment using ISO 14046 framework in the southeast United States. The results suggest inter-county differences in water consumption of crops with higher blue water requirements than green and grey water. According to the water footprint analysis of the peanut crop conducted in this study, additional irrigation is recommended in eight Georgia counties. The mid-point level impact assessment owing to water consumption and pesticide application reveals that the potential freshwater ecotoxicity impacts at the planting and growing stages are higher for chemicals with high characterization factors regardless of lower pesticide application rates. Multiple regression analysis indicates blue water, yield, precipitation, maximum surface temperature, and growing degree days are the potential factors influencing freshwater ecotoxicity impacts. Accordingly, a possible impact pathway of freshwater ecotoxicity connecting the inventory flows and the ecosystem quality is defined. This analysis is helpful in the comparative environmental impact assessments for other major crops in Georgia and aids in water resource management decisions. The results from the study could be of great relevance to the southeast United States, as well as other regions with similar climatic zones and land use patterns. The assessment of water use impacts relative to resource availability can assist farmers in determining the timing and layout of crop planting.

A Comparative Assessment of Municipal Water Use in Turkey

A Comparative Assessment of Municipal Water Use in Turkey

Evaluating Distributed Policies for Conjunctive Surface Water‐Groundwater Management in Large River Basins: Water Uses Versus Hydrological Impacts

AbstractIt is imperative to understand the interconnectedness of water use and hydrological impacts for water policy design underlying varying hydrological conditions across space and over time. However, such analysis remains difficult, constrained by the lack of appropriate modeling tools that fully integrate water policies, water use, and hydrological processes with high spatiotemporal resolutions. To address this challenge, this study proposes a distributed policy design scheme featuring spatially variable and temporally dynamic policies for conjunctive surface water‐groundwater management in large river basins. A fully integrated modeling framework is developed to tightly couple (a) an agent‐based model for farmers' water use under distributed water policies and (b) a physically based hydrological model for surface water‐groundwater processes. The modeling framework is applied to the Heihe River Basin to assess water use and hydrological impacts under distributed water policies. By using the distributed policy scheme to adjust a water policy (e.g., groundwater tax) across space and over time, we found that hydrological outcomes can be improved without adversely reducing agricultural water supply. For example, by shifting the implementation of a high groundwater tax from dry to wet years, a rise of the water table by 0.28 m (0.03–0.95 m across different irrigation districts) can be achieved while the total water supply is maintained at a similar level. Furthermore, hydrological externality effects among nearby districts can be explicitly identified and quantified based on assessments of spatially varying water policies. This study highlights the need for water policy design to consider spatiotemporal variations in the physical hydrological system.

System Dynamics Based Carbon Footprint Assessment of Industrial Water and Energy Use

System Dynamics Based Carbon Footprint Assessment of Industrial Water and Energy Use

Estimating Spatially Explicit Irrigation Water Use Based on Remotely Sensed Evapotranspiration and Modeled Root Zone Soil Moisture

AbstractEstimation of irrigation water use (IWU) is critical to assessing water use efficiency and optimizing water resource allocation. However, diversity in irrigation scheduling, irrigation system, and crop type has imposed restrictions on deriving the accurate spatial distribution of IWU. Existing approaches of deriving IWU may have large uncertainty, due mostly to methodological limitations, inadequate inputs, and the mismatch in spatiotemporal scale between IWU estimates and in situ counterparts. Remote sensing has the potential to provide valuable information on moisture transport, which could unravel water consumption by crops. First, we developed a robust relationship between root zone soil moisture (RZSM) and the ratio of actual evapotranspiration (ETa) to reference ET from the land components of European ReAnalysis‐5 (ERA5L) without an irrigation module across the Contiguous United States (CONUS). Second, RZSM under irrigation was derived from the developed relationship and remotely sensed ETa from the operational Simplified Surface Energy Balance (SSEBop) model during 2000–2020. Third, IWU over the two decades was derived based on increases in RZSM and ETa due to irrigation using remotely sensed and model‐based variables, along with our derived formulas considering groundwater recharge originating from irrigation. The IWU estimates were fairly reliable compared with reported IWU from the Farm and Ranch Irrigation Survey at the state‐level in four years, with the coefficient of determination ranging from 0.74 to 0.84, root mean square error ranging from 1.90 to 2.33 km3/yr, and bias ranging from −0.11 to 0.15 km3/yr. Integration of remotely sensed ETa with ERA5L output resulted in IWU estimates of much higher accuracy than published studies. The IWU estimates across the CONUS reflected an increasing trend (∼2.71 km3/yr2) during 2000–2007 but a decreasing trend (∼0.90 km3/yr2) during 2008–2020, due to efficient irrigation practices and increased precipitation.

Performance of Linear Move Irrigation System under Egyptian Conditions

The efficiency of irrigation as a standard engineering measure has been traditionally used to assess water use management. The objective of this study was to evaluate the technical performance of linear move sprinkler irrigation such as operating speeds for different specifications. Catch cans method was conducted to evaluate the distribution uniformity (DUlq) and the Christiansen coefficient uniformity (CU), evaluation was done at a private farm for two linear move irrigation systems: LM1 (linear move, 6 diameter number of the nozzle orifice 17 attached with 10 L min⁻ˡ flow) and LM2 (linear move, 8 diameter number of the nozzle orifice 25 attached with 20 L min⁻ˡ flow) under three different system speeds. The collected water after the irrigation system full passing over the can’s lines was measured using the graduated funnel to calculate the DUlq and CU. Ideal operating LM1 at the intermediate system speed (75% of the standard irrigation system speed equivalent to 22.5 m h⁻ˡ), operating LM2 at the lowest system speed (50% of the standard irrigation system speed equivalent to 15 m h⁻ˡ) recommended for the uniform irrigation water distribution. The results will improve the selection of travel speed when the water application uniformity of linear move irrigation system is evaluated.

Multiscale Assessment of Agricultural Consumptive Water Use in California's Central Valley.

Spatial estimates of crop evapotranspiration with high accuracy from the field to watershed scale have become increasingly important for water management, particularly over irrigated agriculture in semiarid regions. Here, we provide a comprehensive assessment on patterns of annual agricultural water use over California's Central Valley, using 30‐m daily evapotranspiration estimates based on Landsat satellite data. A semiempirical Priestley‐Taylor approach was locally optimized and cross‐validated with available field measurements for major crops including alfalfa, almond, citrus, corn, pasture, and rice. The evapotranspiration estimates explained >70% variance in daily measurements from independent sites with an RMSE of 0.88 mm day−1. When aggregated over the Valley, we estimated an average evapotranspiration of 820 ± 290 mm yr−1 in 2014. Agricultural water use varied significantly across and within crop types, with a coefficient of variation ranging from 8% for Rice (1,110 ± 85 mm yr−1) to 59% for Pistachio (592 ± 352 mm yr−1). Total water uses in 2016 increased by 9.6%, as compared to 2014, mostly because of land‐use conversion from fallow/idle land to cropland. Analysis across 134 Groundwater Sustainability Agencies (GSAs) further showed a large variation of agricultural evapotranspiration among and within GSAs, especially for tree crops, e.g., almond evapotranspiration ranging from 339 ± 80 mm yr−1 in Tracy to 1,240 ± 136 mm yr−1 in Tri‐County Water Authority. Continuous monitoring and assessment of the dynamics and spatial heterogeneity of agricultural evapotranspiration provide data‐driven guidance for more effective land use and water planning across scales.

Decadal gross level assessment of green and blue consumptive water use over Indian agro-ecosystems

ABSTRACT Assessment of consumptive water use (CWU) and water productivity at the regional scale is important to diagnose vulnerable zones to improve water use efficiencies in cropland to achieve the sustainable development goal 6.0 prescribed by the United Nations. The present study was carried out to segregate and quantify CWU into agricultural green (CWUg) and blue (CWUb) water use and water productivity (AWP) on seasonal, annual, and decadal (2009–2018) scales over the Indian region using satellite remote-sensing data from geostationary and polar-orbiting platforms. A logical algorithm was used to determine partitioned water use from a combination of satellite-based estimates of key variables such as agricultural water demand (AWD), actual evapotranspiration (ETa), and effective rainfall (ER). Satellite-based estimates of CWU were evaluated with respect to ground reference that showed underestimation of the order of 15–32% but with a strong Pearson’s correlation coefficient (r = 0.80–0.99) and coefficient of determination (R 2 = 0.64–0.98). The reasons for this difference and uncertainties in satellite-based inputs have been explained. The decadal mean of CWU at annual scale showed wide spatial variation over India with 84% and 16% share of CWUg and CWUb, respectively, in kharif season and 27% and 73%, respectively, in rabi season. A non-significant increasing trend in CWUg,kharif (0.57%) and a decreasing trend in CWUb,kharif (–5.18%), CWUg,rabi (–2.81%), and CWUb,rabi (–1.77%) were observed over 10 years. A decreasing trend in green AWP (AWPg) (–0.18%) in kharif season reveals a lack of sustainable adoption of green water management practices while a significantly increasing trend in AWPb (2.65%) in rabi season reveals sustainable adoption of efficient irrigation management practices over 10 years. These long-term estimates would help in smoothing out trade-offs of water use versus water productivity, reducing the vulnerability and aiding in decision-making for water savings, controlled water allocation, strategic policy formulations for water, and food security especially through sustainable management practices in rainfed agriculture.

Virtual water trade and water footprint of agricultural goods: the 1961–2016 CWASI database

Abstract. To support national and global assessments of water use in agriculture, we build a comprehensive database of country-specific water footprint and virtual water trade (VWT) data for 370 agricultural goods. The water footprint, indicating the water needed for the production of a good including rainwater and water from surface water and groundwater bodies, is expressed as a volume per unit weight of the good (or unit water footprint, uWF) and is here estimated at the country scale for every year in the period 1961–2016. The uWF is also differentiated, where possible, between production and supply, referring to local production and to a weighted mean of local production and import, respectively. The VWT data, representing the amount of water needed for the production of a good and virtually exchanged with the international trade, are provided for each commodity as bilateral trade matrices, between origin and destination countries, for every year in the period 1986–2016. The database, developed within the CWASI project, improves upon earlier datasets because it takes into account the annual variability of the uWF of crops, it accounts for both produced and imported goods in the definition of the supply-side uWF, and it traces goods across the international trade up to the origin of goods' production. The CWASI database is available on the Zenodo repository at https://doi.org/10.5281/zenodo.4606794 (Tamea et al., 2020), and it welcomes contributions and improvements from the research community to enable analyses specifically accounting for the temporal evolution of the uWF.

Rice Inundation Assessment Using Polarimetric UAVSAR Data.

Irrigated rice requires intense water management under typical agronomic practices. Cost effective tools to improve the efficiency and assessment of water use is a key need for industry and resource managers to scale ecosystem services. In this research we advance model‐based decomposition and machine learning to map inundated rice using time‐series polarimetric, L‐band Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) observations. Simultaneous ground truth observations recorded water depth inundation during the 2019 crop season using instrumented fields across the study site in Arkansas, USA. A three‐component model‐based decomposition generated metrics representing surface‐, double bounce‐, and volume‐scattering along with a shape factor, randomness factor, and the Radar Vegetation Index (RVI). These physically meaningful metrics characterized crop inundation status independent of growth stage including under dense canopy cover. Machine learning (ML) comparisons employed Random Forest (RF) using the UAVSAR derived parameters to identify cropland inundation status across the region. Outcomes show that RVI, proportion of the double‐bounce within total scattering, and the relative comparison between the double‐bounce and the volume scattering have moderate to strong mechanistic ability to identify rice inundation status with Overall Accuracy (OA) achieving 75%. The use of relative ratios further helped mitigate the impacts of far range incidence angles. The RF approach, which requires training data, achieved a higher OA and Kappa of 88% and 71%, respectively, when leveraging multiple SAR parameters. Thus, the combination of physical characterization and ML provides a powerful approach to retrieving cropland inundation under the canopy. The growth of polarimetric L‐band availability should enhance cropland inundation metrics beyond open water that are required for tracking water quantity at field scale over large areas.

Assessment of water presence and use at sand dams in Kenya

Levels of water access provided by sand dams were assessed by measuring water presence and use in a representative sample of 97 dams in Kenya. Most dams were filled with sediment capable of holding water, with a 25% median reduction of water capacity due to siltation when using a high estimate for sediment specific yield. Multiple sediment cores taken from each dam indicated the presence of water in over half of sediment cores from 57% of dams. Although there is individual variation, generally dams in the region were therefore capable of accumulating water. Analysis of Landsat satellite images indicated that this did not translate into an average increase in vegetative greening and moisture indices at dam sites compared to controls sites. Observational data on activities at dams indicated variable levels of water use; only 43% of dams had active water harvesting present, and only 39% of dams had current agricultural activities adjacent to the sand dam site. Cross-sectional comparison of data did not indicate consistently higher levels of water harvesting or agricultural use at dams with more water. Results point towards a high level of community understanding of sand dam benefits, but a lower rate of actually realizing those benefits.

Bacteriological and Parasitological Assessment of Water use in Selected Abattoirs in Port Harcourt Metropolis, Rivers State, Nigeria

In the abattoir, large amount of water is being used in processing operations; and this produces huge amount of wastewater which empty into the surrounding water bodies. The cross-sectional study followed the conventional microbiological techniques of macroscopy, microscopy, isolation, and identification to assess the bacteriological and parasitological examination of water sources in selected abattoirs in Port Harcourt Metropolis, Rivers State, Nigeria. The result of microbial population showed Total Coliform ranging from 5 x 101cfu/ml – 2.80 x 102cfu/ml and Faecal Coliform bacteria of 2.80 x 101 cfu/ml -1.85 x 102 cfu/ml. Total Heterotrophic bacteria ranged from 7.8 x101cfu/ml to 4.2 x102cfu/ml. The mean microbial counts; 4.86 x101 cfu/ml Fecal Coliform, 9.65 x 101cfu/ml Total Coliform and 1.82 x 102cfu/ml Heterotrophic Count. The isolates identified were Klebsiella spp, Shigella spp., Salmonella typhymurium, E. coli, Proteus spp., Salmonella paratyphi, Vibrio cholera. Nkpor village abattoir recorded highest occurrence of bacteria isolate with a total of 50(22.03%) followed by Iwofe 48(21.15%). Water sample from ponds had a higher parasitic contamination while samples from the borehole were free from parasitic infestation. Water samples for parasitological assessment were filtered and examined for parasitic organism using standard methods. Four different parasites were identified in the study, they include Ascaris lumbricoides (32.5%), Entamoeba histolytica (22.5%), Giardia lamblia (17.5%) and the least Taenia spp (7.5%). Nkpor-village abattoir had the highest level of contamination with (30.0%) parasite occurrence, followed by Mgboshimini abattoir (15.0%). The use of unsafe water for meat processing by butchers, portends a serious public health risk to consumers who purchase the meat, from these abattoirs. Therefore, government should endeavour to make borehole water available to all the abattoirs in Port Harcourt.

Building consensus on water use assessment of livestock production systems and supply chains: Outcome and recommendations from the FAO LEAP Partnership

The FAO Livestock Environmental Assessment and Performance (LEAP) Partnership organised a Technical Advisory Group (TAG) to develop reference guidelines on water footprinting for livestock production systems and supply chains. The mandate of the TAG was to i) provide recommendations to monitor the environmental performance of feed and livestock supply chains over time so that progress towards improvement targets can be measured, ii) be applicable for feed and water demand of small ruminants, poultry, large ruminants and pig supply chains, iii) build on, and go beyond, the existing FAO LEAP guidelines and iv) pursue alignment with relevant international standards, specifically ISO 14040 (2006)/ISO 14044 (2006), and ISO 14046 (2014). The recommended guidelines on livestock water use address both impact assessment (water scarcity footprint as defined by ISO 14046, 2014) and water productivity (water use efficiency). While most aspects of livestock water use assessment have been proposed or discussed independently elsewhere, the TAG reviewed and connected these concepts and information in relation with each other and made recommendations towards comprehensive assessment of water use in livestock production systems and supply chains. The approaches to assess the quantity of water used for livestock systems are addressed and the specific assessment methods for water productivity and water scarcity are recommended. Water productivity assessment is further advanced by its quantification and reporting with fractions of green and blue water consumed. This allows the assessment of the environmental performance related to water use of a livestock-related system by assessing potential environmental impacts of anthropogenic water consumption (only “blue water”); as well as the assessment of overall water productivity of the system (including “green” and “blue water” consumption). A consistent combination of water productivity and water scarcity footprint metrics provides a complete picture both in terms of potential productivity improvements of the water consumption as well as minimizing potential environmental impacts related to water scarcity. This process resulted for the first time in an international consensus on water use assessment, including both the life-cycle assessment community with the water scarcity footprint and the water management community with water productivity metrics.Despite the main focus on feed and livestock production systems, the outcomes of this LEAP TAG are also applicable to many other agriculture sectors.

Stimulating environmental degradation: A global study of resource use in cocoa, coffee, tea and tobacco supply chains

Stimulants play a central role in modern human society. Consumption of stimulants transcends culture, demography, and income group. As cash crops, stimulants (such as cocoa, coffee, tea and tobacco) also act as a source of economic security for producers in low-income countries. However, satisfying the demand for stimulants entails a potentially large environmental cost. This burden demands careful attention given the potentially negative impact of stimulant production on local food security. To date, stimulants have been peripheral to the research and policy agenda on sustainable food systems. We undertake the first global assessment of water, land and fertiliser use associated with cocoa, coffee, tea and tobacco production, consumption and trade, across 254 countries, between 2002 and 2017. Globally, resource use associated with these stimulants (except for tobacco) grew substantially over this period. In 2017, the stimulant economy required i) land use equivalent to the total land area of Italy; ii) green and blue water equivalent to the food sectors of Brazil and Portugal, respectively; and iii) fertiliser use equivalent to India's total fertiliser demand in the same year. We show that the main centres of resource use and demand associated with stimulants implicate a few major countries, presenting management opportunities through supply chain screening of resource-intensive production sources and targeted demand-side policies. Differences between stimulant's resource use also highlights the potential for substitution of consumption to reduce environmental pressures across this system.

Water Use in Global Livestock Production—Opportunities and Constraints for Increasing Water Productivity

AbstractIncreasing population, change in consumption habits, and climate change will likely increase the competition for freshwater resources in the future. Exploring ways to improve water productivity especially in food and livestock systems is important for tackling the future water challenge. Here we combine detailed data on feed use and livestock production with Food and Agriculture Organization of the United Nations (FAO) statistics and process‐based crop‐water model simulations to comprehensively assess water use and water productivity in the global livestock sector. We estimate that, annually, 4,387 km3 of blue and green water is used for the production of livestock feed, equaling about 41% of total agricultural water use. Livestock water productivity (LWP; protein produced per m3 of water) differs by several orders of magnitude between livestock types, regions, and production systems, indicating a large potential for improvements. For pigs and broilers, we identify large opportunities to increase LWP by increasing both feed water productivity (FWP; feed produced per m3 of water) and feed use efficiency (FUE; protein produced per kg of feed) through better crop and livestock management. Even larger opportunities to increase FUE exist for ruminants, while the overall potential to increase their FWP is low. Substantial improvements of FUE can be achieved for ruminants by supplementation with feed crops, but the lower FWP of these feed crops compared to grazed biomass limits possible overall improvements of LWP. Therefore, LWP of ruminants, unlike for pigs and poultry, does not always benefit from a trend toward intensification, as this is often accompanied by increasing crop supplementation.

Regionalization of characterization factor in Brazil: freshwater eutrophication category

Brazil is privileged to have the most important natural resource in its territory, the water. But currently, the increased concentration of phosphorus (P) affects the water quality. It has two main routes to get into aquatic environmental: through the dump of untreated sewage and fertilizers runoff. The P excess may promote eutrophication, a process characterized by microalgae uncontrolled growth, affecting several parameters of freshwater. Due to the great differences at the Brazilian regions, the current Life Cycle Impact Assessment methodologies are not capable to evaluate properly the eutrophication impact in Brazil. The most viable method to obtain a more suitable model is regionalizing it by estimating the characterization factor (CF). Therefore this is the first study that presents a regionalized model to estimate Brazilian CF for freshwater eutrophication. The regionalization was based on the models proposed by Helmes et al. (2012) and Azevedo et al. (2013), which are considered the most complete and suitable models. Due to the lack of data it was possible to calculate the CF for Alto Iguaçu micro watershed and four more subwatersheds: Paraíba do Sul, Parnaíba, Litorânea do Ceará and Litorânea Pernambuco Alagoas. The processes assessment of advection, retention and water use provides valuable information of each region and also results in more realistic Fate Facto (FF), since Brazilian sanitation is completely uneven, and the sewage treatment must be modelled to not overestimated or sub estimated the FF. At Alto Iguaçu is the advection rate is the most relevant and its CF is 7.43 103. m3 .KgP-1 day. For that reason, the same amount of emitted phosphorus promotes a bigger eutrophication potential at Paraíba do Sul and Parnaíba than other basins. Phosphorus income rates estimate is possible to know the origin of its most significant input. Based on this information, financial resources can be better used. This was the first attempt to develop a Brazilian CF and some improvements need to be done. Firstly, new studies ought to concentrate to promote good quality of data, because the unavailability of data was one of the greatest difficulties of this study. Then the regionalized model should be improved modeling treatment of industrial sewage and, finally, CF needs to be calculated for all subwatershed.
 Keywords: Eutrophication. Characterization factor. Freshwater. Brazil. Life Cycle Impact Assessment.

THE PARTICULARITIES OF WATER USE IN THE CENTRAL REGION OF THE REPUBLIC OF MOLDOVA

The purpose of this study is assessment of water use in the Central Region of the Republic of Moldova. The main topics presented in this paper are: 1) assessment of water resources in the Central Region of the Republic of Moldova; 2) tendencies of water consumption on the abstracted sources and on the main usage categories; 3) spatial and branch analysis of water use; 5) the main problems of water use and protection in the region of study. In the region of study are concentrated about 2/3 of groundwater reserves of Republic of Moldova. From surface sources is abstracted ≈3/4 of total volume of water used and over 60% of water is used by households. Outside of Chisinau, over 70% of the water is abstracted from underground sources and is used for various agricultural needs. In the 2007-2017 years, the volume of water use registers a significant decrease which is conditioned, mainly, by decreasing of water abstracted from surface sources and used for agricultural activities, especially for irrigation.

Assessment of Water and Nitrogen Use Efficiencies Through UAV-Based Multispectral Phenotyping in Winter Wheat.

Unmanned aerial vehicle (UAV) based remote sensing is a promising approach for non-destructive and high-throughput assessment of crop water and nitrogen (N) efficiencies. In this study, UAV was used to evaluate two field trials using four water (T0 = 0 mm, T1 = 80 mm, T2 = 120 mm, and T3 = 160 mm), and four N (T0 = 0, T1 = 120 kg ha–1, T2 = 180 kg ha–1, and T3 = 240 kg ha–1) treatments, respectively, conducted on three wheat genotypes at two locations. Ground-based destructive data of water and N indictors such as biomass and N contents were also measured to validate the aerial surveillance results. Multispectral traits including red normalized difference vegetation index (RNDVI), green normalized difference vegetation index (GNDVI), normalized difference red-edge index (NDRE), red-edge chlorophyll index (RECI) and normalized green red difference index (NGRDI) were recorded using UAV as reliable replacement of destructive measurements by showing high r values up to 0.90. NGRDI was identified as the most efficient non-destructive indicator through strong prediction values ranged from R2 = 0.69 to 0.89 for water use efficiencies (WUE) calculated from biomass (WUE.BM), and R2 = 0.80 to 0.86 from grain yield (WUE.GY). RNDVI was better in predicting the phenotypic variations for N use efficiency calculated from nitrogen contents of plant samples (NUE.NC) with high R2 values ranging from 0.72 to 0.94, while NDRE was consistent in predicting both NUE.NC and NUE.GY by 0.73 to 0.84 with low root mean square errors. UAV-based remote sensing demonstrates that treatment T2 in both water 120 mm and N 180 kg ha–1 supply trials was most appropriate dosages for optimum uptake of water and N with high GY. Among three cultivars, Zhongmai 895 was highly efficient in WUE and NUE across the water and N treatments. Conclusively, UAV can be used to predict time-series WUE and NUE across the season for selection of elite genotypes, and to monitor crop efficiency under varying N and water dosages.