Water Endowments Research Articles

Circular water economy performance evaluation based on dynamic network data envelopment analysis

In this study, a looplike dynamic network data envelopment analysis (DEA) framework is proposed to assess technical efficiency in Germany's water economy at the federal state level. In the wake of growing political attempts in Europe to strengthen circular, sustainability-oriented practices in a variety of economic realms, our tailored approach enables, arguably for the first time, simultaneous analysis of public water provision, wastewater services and natural water endowment while accounting for water demand in an encompassing feedback-type context. Our model addresses the issues of water sector infrastructure and environmental sustainability. By measuring divisional efficiencies in addition to composite network efficiency over time, we extend previous static ‘black box’ DEA studies to provide comprehensive and in-depth insight into water economy dynamics. Our framework goes beyond the existing models by unifying distinct yet interrelated water economy processes under an encompassing circular technical efficiency evaluation paradigm to underpin holistic, environmentally-prudent water resource management concerning infrastructure, production, consumption, cleaning, recycling and reuse. Our empirical case study reveals high levels of efficiency in Germany on the whole, and we find little variation among regions in terms of composite water economy efficiency. The natural water endowment segment, which correlates more strongly with the overall water economy than any other network component, exhibits considerable efficiency score volatility. Furthermore, we find that the wastewater treatment section harbours many best-practice regions. Our results also show that the most substantial performance-optimising input reduction required pertains to land area consisting of vegetation and water, which suggests both natural resource endowment efficiency underperformance and sustainability overachievement in the sense of an excess capacity to free up resources for other uses. The largest output increase called for concerns consumers, with regard to water sector value added. Regional water sector infrastructure utilisation appears to be generally adequate, although several federal states fail to meet the optimal levels.

The river sharing problem with incomplete information

This paper considers the river sharing problem with incomplete information. We ask whether the efficient allocation of water in a river network is possible when agents have private information on their satiation levels. First, we introduce a trading model on a tree network with incomplete information. Then, we focus on the river sharing problem for a three-agent river network in which water flows from two upstream agents to one downstream agent. We assume that each agent has a satiation point and this satiation point is his private information. We are interested in allocation mechanisms that map each profile of the satiation points to an allocation of water and a list of monetary transfers between the agents. We show that, if each upstream agent’s endowment of water is sufficiently larger than the downstream agent’s endowment, then there exists an incentive compatible, individually rational, and budget balanced mechanism that allocates the water efficiently.

Virtual water and the inequality in water content of consumption

AbstractWe present evidence that international trade may exacerbate the initial unequal distribution of hydric resources. This result is driven by the fact that countries exporting agricultural goods are relatively abundant (with respect to capital) in the combined availability of water and arable land but, in absolute terms, scarce in capital and not richer in water in comparison to more developed ones. Due to both the scarcity of capital and the lower relative price of natural resources with respect to capital, the total value of production in these developing countries is modest, implying that international trade can lead to a less even distribution of the water content of consumption. Policies sustaining water prices and, more generally, those of natural resources (or lower capital costs) may contribute to offsetting this effect and allow for trade to play a positive role in reducing the uneven distribution of water endowments.

Driving factors of virtual water in international grain trade: A study for belt and road countries

Water resources are distributed in the form of virtual water through international trade, which influences the water supply and consumption of each country. Therefore, it is of significance to study the driving factors of grain virtual water trade to alleviate water stress and guarantee food security. In this paper, the virtual water volume of grain crops traded between China and countries along the Belt and Road (B&R) from 2000 to 2019 was calculated, and a gravity model using panel data was applied to explore the effect of natural and socioeconomic factors on virtual water trade. The virtual water export from B&R countries to China obviously increased in the twenty years and the contributions of various crops to virtual water were more balanced. The regression results indicate that GDP and exchange rate were positively correlated with virtual water inflow, while per capital water resources, arable land, geographic distance, and population were negative factors that hindered virtual water import. The most powerful driving force for grain virtual water trade is water endowment. GDP is an important driver on importing virtual water for countries without water shortage, and a large number of local water resources will not obviously inhibit the driving force of economic strength. By comparing the contribution of factors to virtual water in the past ten years, it can be found that the contribution rate of distance decreased due to the development of transportation industry which reduced the transportation cost of exporting products. The contribution rate of GDP and exchange rate increased, because economic globalization has promoted the effect of economic factors on grain trade. Therefore, the trade structure of agricultural products should be modified based on the characteristics of virtual water flow. For countries without high economic level but water shortage, export crops with high water consumption be reasonably controlled.

Public perceptions of physical and virtual water in China

Ensuring access to water is one of the United Nations' Sustainable Development Goals. Water demand management, which has emerged as an important approach to secure water supply, should be underpinned by a good understanding of how the public perceive their use of water. In this study, we investigated public perceptions of physical and virtual water in China through online surveys using the multi-level regression models (two-level models). Based on 3262 responses, we found that overall, participants underestimated water uses and differences between water uses (daily potable water of an adult, shower, toilet flushing, etc.). Most participants did not possess the knowledge of virtual water embedded in their daily consumed products. Individuals showed rather different perceptions in water use, which were affected by gender, age, education, resource and environmental attitude, water saving behaviors, water price and residential water source. In combination with previous findings in the United States, we concluded that despite different natural water endowment and socio-economic and cultural conditions, underestimation of water use is commonly shared by Chinese and Americans. This highlights a need of strengthening public knowledge of water use. The results are useful in informing policies to enhance the public's awareness of water use towards improved water demand management.

Emergy analysis of the blue and green water resources in crop production systems

Water consumption in grain production consists of blue (i.e., surface water and groundwater) and green water (i.e., rainwater), however, is rarely distinguished in existing emergy analysis. Taking four major grain crop production systems (rice, wheat, maize, and soybean) by provinces in mainland China over the period 2001–2016 as the study case, in this study the blue and green water were differentiated, for the first time, in the emergy analysis for crop production systems based on water footprint assessment. Three indicators were estimated per crop per province per year: water resource emergy input (WEI), water resource emergy contribution ratio (WECR), and water resource emergy use efficiency (WEUE). Results show that during the study period, the total WEI into the major grain crop production systems increased by 16.61%; blue and green WEI accounted for 52.64% and 47.36%, respectively, by 2016. Although the blue WECR was higher than green WECR, it decreased significantly over the study period. The annual average green WEUE was 10.99 sej sej−1, 7.7 times the blue; moreover, it increased by 27.28% over the study period. The annual average total WECRs in nine provinces were higher than the national average, but the corresponding total WEUEs were lower than the national average; of these, four were distributed in arid and rainwater-deficient areas of northwest China. The emergy analysis of blue and green water separately provides information for a more precise and efficient water allocation as well as better cropping structures given corresponding water endowments.

Conflicting Drivers of Virtual Water Trade: A Review Based on the “Virtual Water Concept”

The virtual water concept has been largely applied in the study of regional, national, and global water flows with particular emphasis on water endowment. Despite water traditionally being managed locally, certain forces (drivers) influence the local water resource availability and hence virtual water exchanges. This study reviews available literature to determine those drivers and their influence on virtual water exchanges. Studies show that the drivers are numerous, and there exist several available literatures providing controversial results leading to a high level of uncertainty in the determination of their relative significance. Possible reasons for the contradicting results are discussed and suggestions made.

WASH services and human development: a tangible nexus for achieving water-related SDGs

ABSTRACT This paper examines global statistics on water availability, water demands, access to water, sanitation and hygiene (WASH) services, and human development in 2015, a milestone year for the transition from United Nations’ Millennium Development Goals (MDGs) to the new Sustainable Development Goals (SDGs). The results of nonparametric statistical tests point out that, in most countries, water endowment – or potential water availability – has not been a determining factor for economic prosperity and human development. However, it is possible to delineate a strong nexus between water and human development from the perspective of water demands, particularly when considering primary water uses for drinking and sanitation.

Measurement and Influencing Factors of Industrial Water Resource Utilization Efficiency in Yangtze River Economic Belt

The governance of industrial water environment in the Yangtze River Economic Belt (YREB), the demonstration zone of ecological civilization in China, has attracted a growing attention. In this paper, an evaluation index system (EIS) with undesired output is established for industrial water resource utilization efficiency (IWRUE). Next, the stochastic block model (SBM) was adopted to measure the IWRUEs of the 11 YREB provinces in 2003-2017. After that, the Tobit model was employed to examine the influencing factors of the IWRUE. The results show that the YREB provinces differed sharply in IWRUE through the sample period; the downstream provinces achieved relatively satisfactorily IWRUEs, while most provinces in the upstream and midstream performed unsatisfactorily. The downstream of the YREB realized the highest IWRUE, followed in turn by the upstream, and the midstream. The YREB is significantly promoted by economic development, ownership structure, and opening-up, and significantly suppressed by water endowment, technological progress, and government influence.

Can Water Rights Trading Scheme Promote Regional Water Conservation in China? Evidence from a Time-Varying DID Analysis

Using the panel data of 30 provinces in China from 1998 to 2017, we adopt a time-varying difference-in-differences (time-varying DID) model to estimate the impact of water rights trading scheme on regional water consumption. The results show that water rights trading can significantly promote water conservation in the pilot regions by 3.1% compared to that in the non-pilot regions, and a series of robustness tests show consistent results. Policy effects are mainly driven by improving water-use efficiency and adjusting water structure; that is, by transferring water resources from the agricultural sector to the other sectors, agricultural water efficiency is improved and water conflict among sectors is alleviated; thus, water saving is achieved. In addition, by constructing two indexes of regional water pressure and tradable water resources, our heterogeneity analysis shows that water rights trading performs better in areas with high water pressure and large tradable water resources. Under the high pressure of large water use and low water endowment, water rights trading will evidently reduce water consumption more so than in the low-pressure regions, and with water rights trading, it is hard to achieve a policy effect in regions without sufficient tradable water resources. This paper provides important policy implications for China for further promoting the water rights trading scheme in the field of resource conservation.

Changing global cropping patterns to minimize national blue water scarcity

Abstract. Feeding a growing population with global natural-resource constraints becomes an increasingly challenging task. Changing spatial cropping patterns could contribute to sustaining crop production and mitigating water scarcity. Previous studies on water saving through international food trade focussed either on comparing water productivities among food-trading countries or on analysing food trade in relation to national water endowments. Here, we consider, for the first time, how both differences in national average water productivities and water endowments can be considered to analyse comparative advantages of countries for different types of crop production. A linear-optimization algorithm is used to find modifications in global cropping patterns that reduce national blue water scarcity in the world's most severely water-scarce countries, while keeping global production of each crop unchanged and preventing any increase in total irrigated or rainfed harvested areas in each country. The results are used to assess national comparative advantages and disadvantages for different crops. Even when allowing a maximum expansion of the irrigated or rainfed harvested area per crop per country of only 10 %, the blue water scarcity in the world's most water-scarce countries can be greatly reduced. In this case, we could achieve a reduction of the global blue water footprint of crop production of 21 % and a decrease of the global total harvested and irrigated areas of 2 % and 10 % respectively. Shifts in rainfed areas have a dominant share in reducing the blue water footprint of crop production.

Drivers of domestic grain virtual water flow: A study for China

Trade can conserve water resources in an administrative region if the region imports water-intensive commodities rather than producing them domestically. However, many recent studies of domestic virtual water flows (VWFs) have found that there is a net VWF from water-scarce regions to water-rich regions within large countries such as China. Inter-provincial grain trade will result in a considerable geographical redistribution of water through VWFs, which will make the situation of the water shortage more serious. Therefore, it is necessary to identify the governing factors of the VWFs to understand the less-than-ideal water-use patterns and to build well-informed regulations for saving water. Taking grain production in China as a case study, this paper studies the drivers of inter-regional VWFs. An integrated method combining a Logarithmic mean Divisia index (LMDI) decomposition method and a gravity model is proposed in this work. In the method, the changes in VWFs are decomposed into four portions with the LMDI method firstly. Based on that, a VWF gravity model is developed to analyze the social, economic and natural driving force behind the four changes and the total domestic grain VWFs. The main empirical results are as follows. (1) There is a trend toward the separation of grain consumers and grain producers in China. Net positive VWF within China has occurred from water-scarce north to water-rich south, and there has been a sharp growth trend in the size of this flow over time. The existing pattern of inter-province virtual water trade is exacerbating scarcities in already water-scarce regions. (2) The growth of grain exchanges was responsible for most of the increase in grain VWF. The decreasing unit water footprint of grain production drives down the number of grain VWFs; however, this decrease cannot offset the boost provided by the other effects. (3) Water endowments and geographical distance are demonstrated as have not significant influences in domestic VWFs. The most important drivers of inter-regional VWF within a country is the outward push force of the exporter and the inward pull force of the importer. The technological level of grain production and the economic conditions in the import region are less important drivers. The results indicate that the domestic VWFs of the grain trade are governed primarily by industrial distribution and regional division in the national economy rather than by water endowment. Although implementing water-saving policies in water-scarce and water-export regions further helped to alleviate this situation, the fundamental solution is to change the industrial distribution and regional division in the national economy.

Irrigation technology and water rebound in China's agricultural sector

AbstractBy using the data of 30 provinces from 1998 to 2016 in China, this paper estimates the water rebound effect in the agricultural crop farming by combining Slacks‐based Measure (SBM‐based) of Malmquist Index and Logarithmic Mean Divisia Index (LMDI) method. We find that the average water rebound effect is 70.3%, implying that over two‐thirds of the water saving from irrigation technology improvement is offset by higher water consumption. We find evidence on the regional heterogeneity in terms of the magnitude of rebound: Southwest is the highest, whereas Northwest is the lowest. The heterogeneous rebound effect across regions is mainly due to the difference in water endowment and irrigation land availability. Our results indicate that irrigation technology improvement is not necessarily sufficient for achieving agricultural water conservation. In particular, the difference in natural geography conditions across regions needs to be considered in designing water conservation policies at a sub‐regional level.

The globalization of virtual water flows: Explaining trade patterns of a scarce resource

Abstract Water availability is paramount for security and development, yet many countries suffer from water scarcity. Virtual water trade, or trade in water- embedded agricultural commodities, has been considered a means for countries to overcome water deficits provided they can import food rather than produce locally. Despite a rich literature, research on the subject has not reached a consensus on whether virtual water trade is actually driven by relative water endowment differentials (e.g. countries seeking to alleviate pressure on their own resources) or by comparative advantage in water utilization (e.g. countries using their most abundant and cheap factors of production). Understanding what drives virtual water trade would support water management policies in targeting the roots of water depletion: excessive use due to lack of other available inputs and bad water management due to absence of water use regulation. Using panel data of bilateral virtual water trade flows from 1994 to 2007 applied to a gravity model, we first demonstrate that arid countries do resort to trade as a means to alleviate water scarcity. Second, we demonstrate that there is much inefficiency in water use in some countries where other agricultural inputs (land, labor) are available and cheap. Given the increased urgency related to global water scarcity, our results suggest how agricultural production and trade could help countries preserve and better use precious water resources.

Does the trading of water rights encourage technology improvement and agricultural water conservation?

Although agricultural irrigation technology in China has been steadily improved for decades, the realized water conservation in the agricultural sector is not as good as expected. This paper examines whether water rights trading can encourage agricultural water conservation through technology improvement. Our fixed effects model specification confirms that water rights trading has a moderation effect on agricultural water conservation via technology improvement. We further identify that the moderation effect is driven by two forces which we label as the “revenue-driven” effect and “industrial water pressure-driven” effect. In general, the revenue effect drives farmers to improve the technology. However, the pressure from industrial water demand has more pronounced effects than the revenue-driven channel. Under the dual pressure of high industrial water consumption and low water endowment, farmers tend actively promote irrigation technology and reduce agricultural water use even if there is no revenue-driven effects. In addition, this paper reveals the existence of bottleneck on the moderated technology improvement, due to the reduced capacity on water rights supply in the agricultural sector.

Irrigation Technology and Water Rebound in China's Agricultural Sector

By using the data of 30 provinces from 1998 to 2016 in China, this paper estimates the water rebound effect in the agricultural crop farming by combining Slacks‐based Measure (SBM‐based) of Malmquist Index and Logarithmic Mean Divisia Index (LMDI) method. We find that the average water rebound effect is 70.3%, implying that over two‐thirds of the water saving from irrigation technology improvement is offset by higher water consumption. We find evidence on the regional heterogeneity in terms of the magnitude of rebound: Southwest is the highest, whereas Northwest is the lowest. The heterogeneous rebound effect across regions is mainly due to the difference in water endowment and irrigation land availability. Our results indicate that irrigation technology improvement is not necessarily sufficient for achieving agricultural water conservation. In particular, the difference in natural geography conditions across regions needs to be considered in designing water conservation policies at a sub‐regional level.

Wetland monitoring through the deployment of an autonomous aerial platform

Wetlands in the Andean region have been altered and have been lost as a result of the agricultural frontier expansion and human activities. The disturbance of the paramo ecosystem by the destruction or alteration of the wetlands modifies the load and endowment of water to the hydrological systems, which provide water to main cities in the highlands. Therefore, the present work focuses on setting up the framework for wetland monitoring in the Andean paramo region using Unmanned Aerial Vehicles (UAVs). For this aim, the study was based on a mission profile using a fixed wing UAV incorporated with a RGB camera in one of the most documented wetlands in the Ecuadorian paramo region, Pugllohuma wetland. Furthermore, to assess the saturation of the wetland, field testing data has been collected to set the range values of saturation for the monitoring system. In the same way, a review regarding multispectral imagery for the assessment of water and vegetation indices is explored and highlighted for future work. This work is a first stage in the monitoring process and hence it aims to set a baseline study for the implementation of a more detailed methodology.

Yield and fruit quality of avocado trees under different regimes of water supply in the subtropical coast of Spain

The subtropical Mediterranean climate of southeastern Andalusian coast allows Spain to be the largest European producer of subtropical fruit, with the avocado as the main representative. In this region, precipitations are scarce and erratic and limit water availability for irrigation. Under this climatic uncertainty, appropriate water use is required for assuring crop environmental sustainability and increasing water productivity (WP) of avocado orchards. For this purpose, it is necessary to evaluate if current water endowments in the region match crop water requirements and to what extent water use can be improved. In this study, water productivity was assessed in a mature avocado (cv. ‘Hass’) orchard along six consecutive seasons. The physiological and agronomical responses of avocado trees to five water treatments (T1-T5) were also evaluated during two consecutive seasons. Water amounts supplied by irrigation were compared with FAO’s estimations. For the six seasons, averaged FAO irrigation needs were 7916 ± 395 m3 ha−1 season−1 but averaged water supplied was 6503 ± 328 m3 ha−1 season−1 (˜18% below FAO’s) with yields 11 ± 2 t ha−1, meaning a WP of 1.7 kg m-3. FAO’s recommendations matched T2 and irrigation over or below T2 affected avocado yield, fruit quality (i.e. size) and WP. Water supplies 15% above FAO’s (T3) did not involve better yields but decreased WP. Conventional irrigation for mature orchards (T1) was ˜20% lower than FAO’s and entailed yield decreases (˜16%) but similar fruit sizes and WP. Water supplies 40% and 60% below FAO’s (T4 and T5, respectively) caused significant water stress and decreased yields and fruit quality of avocado trees but increased WP. These effects were more noticeable during the productive season, in which T5 trees showed weakening symptoms and marked fruit drop. Results are discussed in the context of viability of avocado cropping in the Mediterranean region under low water resource scenarios.

Captación de agua pluvial en un plantel educativo de nivel medio superior del valle de Toluca, México

The objective of this project was to design a rainwater collection and treatment system at the Center for Industrial and Service Technological Studies No. 23 “Cetis23” as a corrective measure to prevent the flooding of gardens in the rainy season and increase the endowment of water to the population of the campus. The design began through a field study of the surfaces of the buildings to determine which are the ones with greater area and better surface, in this case were the buildings with gable roofs. Using the Sweet Home 3D software, the system was simulated in each building and a cost study was carried out, budgeting materials and labor. The pre-storage system for rainwater storage was proposed, consisting mainly of a sand and gravel filter. Finally, a ferrocement storage tank was designed. This system is an uncomplicated, economical and ecological technological option to provide water, in quantity and quality, to the population of CETis 23 (1354 people with an expense of 10 L per person per day).

Assessing Temporal and Spatial Inequality of Water Footprint Based on Socioeconomic and Environmental Factors in Jilin Province, China

Freshwater resources are limited and uneven in their spatiotemporal distribution, and substantial increases in water demand from rapidly developing economies and concentrated populations place pressure on the available water. Research on the inequality of water footprint (WF) could provide countermeasures for the rational use and allocation of water resources. We evaluated the temporal and spatial inequality of WF using the Gini coefficient and imbalance index based on socioeconomic and environmental factors in Jilin Province. The results showed that from 2008 to 2015, the overall inequality of WF in Jilin Province was “relative equality”, and the inequalities between the WF and population, cultivated area were “high equality”; between the WF and gross domestic product (GDP) was “relative equality”; and between the WF and natural water endowment was “high inequality”. With respect to space, the differences of WF inequality were significant. In the west, the WF inequality changed greatly, from “relative equality” to “relative inequality” driven by population, GDP, cultivated area, and natural water endowment. In the middle, the WF inequality showed large internal differences with “high inequality” or “high equality” caused by GDP and natural water endowment. In the east, the WF inequality was relatively stable, at “high equality” or “neutral” affected by natural water endowment and population. The varied impact factors reflected the differences in natural resources and socioeconomic conditions in the various regions, and the results might provide a theoretical basis for guiding the rational allocation of water resources.