Water Resources Management Policies Research Articles

Inverted Algorithm of Groundwater Storage Anomalies by Combining the GNSS, GRACE/GRACE-FO, and GLDAS: A Case Study in the North China Plain

As the largest groundwater drainage region in China, the per capita water resources in the North China Plain (NCP) account for only one-seventh of the country’s available water resources. Currently, the NCP is experiencing a serious water shortage due to the overexploitation of groundwater resources and a subsequent series of natural disasters. Thus, accurate regional assessments and effective water resource management policies are of critical importance. To accomplish this phenomenon, the daily terrestrial water storage anomaly (TWSA) over the NCP is calculated from the combination of the GNSS vertical deformation sequences (seasonal items) and GRACE (trend items). The groundwater storage anomaly (GWSA) in the NCP is obtained by subtracting the canopy water, soil water, and snow water equivalent components from the TWSA. The inversion results of this study are verified by comparisons with the Global Land Data Assimilation System (GLDAS) data products. The elevated annual amplitude areas are located in Beijing and Tianjin, and the Pearson correlation coefficient (PCC), root mean square error (RMSE), and Nash–Sutcliffe efficiency (NSE) between the two GWSA results are 0.67, 4.01 cm, and 0.61, respectively. This indicates that the methods proposed in this study are reliable. Finally, the groundwater drought index was calculated for the period from 2011 to 2021, and the results showed that 2019 was the driest year, with a drought severity index value of −0.12, indicative of slightly moderate drought conditions. By calculating and analyzing the annual GWSA, this work shows that the South–North Water Transfer Project does provide some regional drought mitigation.

Prediction of water resource carrying status based on the ‘three red lines’ water resource management policy in the coastal area of Jiangsu Province, China

Abstract Recently, the Chinese government has issued various policies to regulate water resource management. The ‘three red lines’ policy is one of the most important. To quantify the influence of the ‘three red lines’ policy on water resource carrying status (WRCS), analyze the shortcomings of the current water resource management and provide support for adjusting the direction of water resource management, we constructed a system dynamics model that considered ‘red line’ constraint feedback and simulated changes in WRCS characterization indicators from the period 2019 to 2040 in coastal cities of Jiangsu Province. The WRCS in Nantong city from 2019 to 2035 was medium and that from 2036 to 2040 was poor; that in Yancheng city from 2019 to 2037 was medium and that from 2038 to 2040 was poor; that in Lianyungang city from 2019 to 2036 was medium and that from 2037 to 2040 was poor. We then constructed three schemes with strategies to improve the WRCS. Compared with the initial scheme, Scheme I, involving further enhanced water resource utilization efficiency and reduced discharge of pollutants, improved the WRCS. Based on Scheme III, the economic scale can be expanded by increasing economic development at an appropriate speed, while the WRCS remains almost consistent with the initial scheme.

Changes in abrupt alternations between wet and dry over the Great Lakes Region of Central Asia during the period 1976–2015

• GLRCA experienced an overall wetting trend. • Both D-W and W-D alternation events slightly decreased at the regional scale. • DWAA events decreased in 1976–1995 but increased in 1996–2015. • The variation of DWAA events was closely related to the dry and wet months. Under climate warming, the frequency of dry-wet abrupt alternation (DWAA) events was largely increased at the global scale. In this study, we identified DWAA events, including dry-wet (D-W) alternation events and wet-dry (W-D) alternation events, based on the Standardized Precipitation Evapotranspiration Index (SPEI) for the Great Lakes Region of Central Asia (GLRCA), and analyzed temporal and spatial variation of DWAA during the period 1976–2015. Over the entire study period, GLRCA experienced an overall wetting trend, and a heavy dry trend was mainly distributed in the southwest. Although both D-W alternation events and W-D alternation events showed a slight decrease at the regional scale, there were two clearly opposite trends between 1976 and 1995 and 1996–2015, with a decrease in 1976–1995 and an increase in 1996–2015. Spatially, the variation in the number of D-W alternation events and W-D alternation events exhibited a large heterogeneity. A significant increase in the frequency of D-W alternation events and W-D alternation events was observed in the southwest of arid climate zone, which may be attributed to the increased frequency of dry months and wet months in the region. This study in DWAA events is of importance to the implementation of water resources management, disaster prevention and mitigation policies in the GLRCA under the challenge of future climate change.

Comprehensive evaluation on water resources carrying capacity based on water-economy-ecology concept framework and EFAST-cloud model: A case study of Henan Province, China

Water is the basic need for human survival and the development of economy and ecology. Water resources carrying capacity (WRCC) modelling is a fundamental task to explore the interaction mechanism between economy-ecology development and water resources carrying system. To reasonably quantify the regional WRCC, an evaluation method based on Water-economy-ecology (WEE) concept framework and EFAST-Cloud model is proposed in this study, and Henan Province of China is selected as a typical study area. It can both identify the inter-feeding relationships between sub-systems and evaluate the proportion of each grade in detail by reflecting the randomness and fuzziness of the evaluation. A total of 15 indicators including water system, economy system, and ecology system are constructed. The study analyzes the sensitivity of indicators by using Simlab software and then calculates the weight of indicators by using EFAST method. Compared with other traditional methods, EFAST algorithm is a special method for model sensitivity analysis, which can fully consider the coupling effect between indicators. According to the statistical data of 2010, 2015, and 2020, the WRCC at the watershed scale and municipal scale in Henan Province are evaluated through the EFAST-Cloud model. At the watershed scale, the ecology system criterion layer performs best over the multiple years, the Huaihe and Yangtze River basin have better WRCC at the target layer. At the municipal scale, Xuchang, Luohe, and Zhumadian have better WRCC, Puyang, Zhoukou, and Jiaozuo are slightly worse. The results show that WRCC of the study area has shown an overall improvement, but there is still much space for its development. Therefore, targeted recommendations are made for the water, economy, and ecology system respectively. The conclusion of this paper can provide a reference for the government in making water resources management policies.

Spatial heterogeneity and driving factors of ecosystem water yield service in Yunnan Province, China based on Geodetector

Water yield is an important ecosystem service. It is the key to maintain ecological security and sustainable development to accurately grasp the spatial heterogeneity characteristics and identify the key driving factors of water yield in different regions. Taking Yunnan Province with significant geospatial heterogeneity as the research area, we used InVEST model to simulate the temporal and spatial variations of water yield in Yunnan Province from 1992 to 2019. The spatial characteristics of driving factors, such as climate, vegetation, soil, terrain, land use, on water yield service were analyzed through Geodetector. The results showed that water yield of Yunnan Province showed a fluctuating trend of increasing at first and decreasing later from 1992 to 2019, with a similar spatial distribution pattern in each year, and an overall trend of gradually decreasing from northwest, west and southwest to central and east. Climatic factors (precipitation and actual evapotranspiration) were the main driving factors leading to spatial differentiation of water yield. In different watershed divisions, the impact of each driving factor on water yield had significant spatial heterogeneity: the watersheds dominated by precipitation were mainly distributed in the west of Yunling-Yuanjiang line, the Irrawaddy River, the upper reaches of Nujiang River, the lower reaches of Nujiang River, the upper reaches of Lancang River, the upper reaches of Jinsha River, Yuanjiang River and Lixian River areas. As for the east of Yunling-Yuanjiang line, in karst landform areas (Nanguang River, Chishui River, Wujiang River, Youjiang River and Panlong River) and the lower reaches of Jinsha River with high population density and shortage of cultivated land, actual evapotranspiration and land use type were the leading factors controlling the spatial pattern of water yield. The results could provide a reference for water resources management policy and ecological civilization construction in Yunnan Province, with a certain guiding significance to promote the optimization and sustainable development of ecosystem services in complex plateau-mountain area.

Monitoring and Analysis of Drought Characteristics Based on Climate Change in Burundi Using Standardized Precipitation Evapotranspiration Index

Drought is a global issue with profound implications worldwide on biodiversity, equal safety, poverty eradication, sustainable development, and social-economic stability due to the significant role that water resources play in the growth of the world economy. Burundi is one of the highly vulnerable countries to the effects of climate change-related events because of its low adaptive capacity and high dependence on rainfed agriculture for livelihood. This research aimed to identify drought incidents and their characteristics in terms of duration, severity, and intensity and analysis of their trends in Burundi using the Standardized Precipitation Evapotranspiration Index (SPEI). Monthly precipitation and temperature data of seven meteorological stations across Burundi (1981–2020) were obtained from Burundi Geographical Institute (IGEBU). The SPEI index of -2, -6 and -24 month timescales were generated to understand drought characteristics and the Mann–Kendall (MK) test combined with Sen’s slope estimator were utilized to analyze the drought trend based on the calculated SPEI values. The overall analysis of the computed SPEI time series demonstrated that drought is more frequent and severe in Burundi, especially in the northern and eastern parts. The results showed that the most prolonged and severe drought occurred during the 1990–2010 decades, and 1993, 1994, 1995, 1999, 2000, 2001, 2004, 2005, 2006, 2009, and 2016 were extremely dry years. Proactive drought mitigation activities, climate change mitigation and water resources management policy are highly recommended in order to reduce drought risk and its effect on both population and the natural environment.

Spatiotemporal Evolution and Driving Mechanisms of Water Footprint with Input-Output Paradigm: A Case Study of China

The evaluation and quantification of water consumption based on water footprint (WF) is important for sustainable utilization of water resources and is becoming one of the key bases for formulating water resources management policies. However, there are few systematic assessments of both temporal changes and spatial patterns of WF in China, and the driving of water footprint intensity (WFI) is rarely reported. Based on the research background, this paper takes China, the world’s largest developing country, as an example to analyze the spatiotemporal evolution of WF through the input–output model. The total WF in China increased by 11.76% from 2002 to 2017. National WFI decreased from 550 m³/104 yuan (2002) to 152 m³/104 yuan (2017). The regions found to have the highest WF in China include Shandong, Henan, and Hebei, and regions with higher WFI are distributed in East China. From 2002 to 2017, the total WF of each province in China changed significantly. Guangdong, Fujian, and Zhejiang provinces’ total WF decreased markedly during the study period. The results show that the grain output per capita and GDP per capita have a significant driving effect on WFI. By adjusting the agricultural structure and improving the comprehensive ability of scientific and technological innovation, it is possible to reduce the WFI in China.

Integrated assessment of drought vulnerability for water resources management of Bina basin in Central India

Drought is an extreme event and its frequency is expected to increase in future under the imminent threats of climate change. The areas vulnerable to drought are increasing due to increase in the spatial extent and severity of droughts. This necessitates the need for development of an integrated framework for assessment of drought vulnerability, which will be vital for water resources management policies focused towards such vulnerable areas. An integrated drought vulnerability assessment framework has been developed considering the physical indicators that vary spatially, social indicators that vary spatially but their temporal variation may be at longer time-frames, and spatio-temporal drought indicators that vary spatially and temporally during various months during drought years. This framework has been tested for Bina basin located in the drought prone Bundelkhand region of Madhya Pradesh. The drought indicators used in the study include (i) Standardized Precipitation Index (SPI) for evaluating meteorological drought characteristics, (ii) Surface water Drought Index (SDI) for evaluating streamflow drought characteristics, and (iii) Groundwater Drought Index (GDI) for evaluating groundwater drought characteristics. Groundwater levels arebeing observed at quarterly (3 monthly) time steponly. So the relationships between GDI and 3-m SPI, 6-m SPI, and 12-m SPI have been investigated. Based on the best correlation, the 12-m SPI can be used to represent the groundwater drought in Bina basin and has therefore been used to assess the monthly variability in the groundwater drought characteristics. The spatially varying physical indicators including basin reach (elevation band), land use pattern and soil type; the spatio-temporal drought indicators including soil moisture drought, surface water drought and groundwater drought, rainfall departure and number of consecutive dry days; and the spatially varying social indicators including infants and young children, illiterate population, marginal workers and rural population have been used for the development of a Drought Vulnerability Index (DVI). The integrated drought vulnerability assessment framework has been conceptualized on the basis of DVI. Four vulnerability classes have been defined and the study area falls in mild to moderate vulnerable class, based on the analysis carried out for the various drought years in the basin. Appropriate drought management plans and mitigation strategies need to be developed to target these vulnerable areas in Bina basin.

Assessing the Impact of the Strictest Water Resources Management Policy on Water Use Efficiency in China

The strictest water resources management policy plays a critical role in response to the challenge of water shortage, water security, and sustainable water development in China. Despite the varied analyses of the strictest water resources management policy, the relations between the strictest water resources management policy and water use efficiency remain under-researched. This study uses an interval event-analysis method to assess the strictest water resources management policy’s impact on water use efficiency in China based on data from 2007 to 2020. In addition, the study breaks down water use efficiency into eight indicators and divides the strictest water management policy into “pre-, middle, and post-” phases. The research results show the strictest water resources management policy has a significant positive effect on water use efficiency. Further research shows the total water consumption control system and water efficiency control system have the most significant effect. The strictest water resources management policy has a lasting impact on water use efficiency. This study contributes to the global knowledge body of water governance and provides a reference value for water policy decision-making and optimization in other countries.

Agricultural Reservoir Operation Strategy Considering Climate and Policy Changes

Agricultural water is affected by climate change and water management. Agricultural reservoirs are increasing demand on the environmental water supply because the Korean government has recently implemented an integrated water resource management policy. However, agricultural reservoirs are still in operation solely to supply agricultural water. To examine sustainable agricultural water management under climate change, we analyzed the strategy of operating regulations to efficiently distribute agricultural water as environmental water. We simulated the agricultural reservoir operation, analyzing its water supply capacity by applying operation regulations. The simulation predicted that future water supply capacity would decrease if the existing operation were maintained, and agricultural reservoir operation will be necessary in the future. The proposed reservoir operating strategy decreased the maximum water shortage and number of water shortage days compared with the existing operation with the required water supply. Our results can contribute to agricultural reservoir operation strategies and sustainable water management in response to climate change and provide decision-making guidance on water distribution for environmental use in response to water management policy changes.

Morphometric characterization and land use of the Pajeú river basin in the Brazilian semi-arid region

The watershed are units controlling hydrological processes and essential for implementation of water resources management policies. The present study aims to integrate the morphometry and land use of the Pajeú river Basin and the Boa Vista micro-basin (headwater of the Pajeú river) using satellite data and a set of remote sensing techniques in open-source software (QGIS). The studied areas are in the semi-arid region of the Pernambuco State, Brazil. Physical morphometric parameters (area, perimeter, axial length, compactness factor, form factor, elongation ratio, and circularity ratio), hydrological parameters (length and distribution of the drainage network, drainage density, hydrographic density, constant of channel maintenance, textural ratio, sinuosity, concentration time, and extension of surface course) and relief (slope and altitude map) were produced. Furthermore, in the micro-basin, we determined the distribution of surface reservoirs using the Modified Normalized Difference Water Index (MNDWI). The Pajeú river basin and the micro-basin have an elongated shape (form factor <0.4 and a capacity coefficient greater than 1.8), approximately 65% of areas with a slope of less than 8%, and moderately developed drainage network; thus, the regions studied are not prone to flooding. However, more than 70% of the basin has soils that have a low infiltration capacity, which, when associated with the conditions of removal of native vegetation, tends to favor the occurrence of floods. Through the integration of land use and morphometry, we found that about 40% of the areas that should be riparian forests are under agricultural activities. A more detailed analysis of the morphometry-coverage-soil-hydrology interactions in watersheds helps understand the hydrological processes and basin management. The presented results can be useful for modeling studies in the basin and for future water resources management plans.

Responses of Soybean Water Supply and Requirement to Future Climate Conditions in Heilongjiang Province

Understanding future changes in water supply and requirement under climate change is of great significance for long-term water resource management and agricultural planning. In this study, daily minimum temperature (Tmin), maximum temperature (Tmax), solar radiation (Rad), and precipitation for 26 meteorological stations under RCP4.5 and RCP8.5 of MIRCO5 for the future period 2021–2080 were downscaled by the LARS-WG model, daily average relative humidity (RH) was estimated using the method recommended by FAO-56, and reference crop evapotranspiration (ET0), crop water requirement (ETc), irrigation water requirement (Ir), effective precipitation (Pe), and coupling degree of ETc and Pe (CD) for soybean during the growth period were calculated by the CROPWAT model in Heilongjiang Province, China. The spatial and temporal distribution of these variables and meteorological factors were analyzed, and the response of soybean water supply and requirement to climate change was explored. The result showed that the average Tmin, Tmax, and Rad under RCP4.5 and RCP8.5 increased by 0.2656 and 0.5368 °C, 0.3509 and 0.5897 °C, and 0.0830 and 0.0465 MJ/m², respectively, while the average RH decreased by 0.0920% and 0.0870% per decade from 2021 to 2080. The annual average ET0, ETc, Pe, and Ir under RCP4.5 for 2021–2080 were 542.89, 414.35, 354.10, and 102.44 mm, respectively, and they increased by 1.92%, 1.64%, 2.33%, and −2.12% under the RCP8.5, respectively. The ranges of CD under RCP4.5 and RCP8.5 were 0.66–0.95 and 0.66–0.96, respectively, with an average value of 0.84 for 2021–2080. Spatially, the CD showed a general trend of increasing first and then decreasing from west to east. In addition, ET0, ETc, and Pe increased by 9.55, 7.16, and 8.77 mm per decade, respectively, under RCP8.5, while Ir decreased by 0.65 mm per decade. Under RCP4.5 and RCP8.5, ETc, Pe, and Ir showed an overall increasing trend from 2021 to 2080. This study provides a basis for water resources management policy in Heilongjiang Province, China.

Comprehensive Evaluation of Water–Energy–Food System Security in the China–Pakistan Economic Corridor

The safety of the water–energy–food (WEF) system in the China–Pakistan Economic Corridor (CPEC) is critical to the sustainable development of resources, the economy, and society in the region. This paper uses the projection pursuit model of a real-code accelerated genetic algorithm (RAGA-PP) to comprehensively evaluate the WEF system security of the CPEC for the period 2000–2016. The results show that from 2000 to 2016, the projection value of the WEF system was reduced from 2.61 to 0.53, and the overall system security showed a downward trend. Moreover, the CPEC increased by 6.13 × 107 people, resulting in a rapid decrease in per capita water resources and decreased security of the water resources subsystem. With the rising social and economic development in recent years, the per capita energy consumption has likewise risen, leading to a decline in the energy subsystem. At the same time, the per capita grain output in the study area has increased from 185 to 205 kg, and the safety of the food subsystem has been enhanced. However, the significant increase in irrigated areas (from 1.82 × 1010 to 1.93 × 1010 hectares) has further highlighted the contradiction between the supply and demand of surface water resources, and the number of tube wells increased by 7.23 × 105, resulting in the consumption of a large amount of electricity and diesel resources. The water–energy (WE) subsystem also became less safe. With the implementation of water resources management policies over the past few decades, the proportion of agricultural water consumption dropped from 95.06% in 2000 to 93.97% in 2016, and the safety of the water–food (WF) subsystem increased. Unfortunately, agricultural irrigation consumes a large amount of power resources, leading to a reduction in the security of the energy–food (EF) subsystem. The research results from the present study could provide a scientific basis for the coordinated development of WEF systems across the CPEC region.

Assessment of Sectoral Virtual Water Flows and Future Water Requirement in Agriculture Under SSP-RCP Scenarios: Reflections for Water Resources Management in Zhangye City

Water scarcity is a core issue that constraints the high-quality development of arid areas in northwestern China. Zhangye is an oasis city located in the Heihe River Basin in northwestern China. It is populated with an agriculture-dominated economy and faces more and more serious water crises. Virtual water is an indicator that can measure the embodied water in the traded products, which has been widely applied for making rational policies for water resources management. In addition, clarifying water requirements in agricultural sectors under future climate change scenarios is essential to develop more appropriate adaptation strategies. From this perspective, this study aims to evaluate and compare virtual water flows among various sectors in Zhangye for the years 2012 and 2017 with a single regional input-output model and to further clarify the future water requirement tendency in agriculture during 2020–2050 under different shared socioeconomic pathways and representative concentration pathways (SSP-RCP) scenarios. The results showed that the planting sector directly contributed most of the total water consumption with the highest direct coefficient of 3307.5 m3/yuan in 2012, whereas the manufacture of food products and tobacco processing sector had the largest proportion of indirect water consumption (99%) mainly from intermediate inputs of agricultural products. Water consumption intensity of all sectors on average decreased by 22% during 2012–2017, indicating an increasing water utilization efficiency in economic industries. Household consumption also can improve water utilization efficiency as the major pathway for final consumption (86.4% in 2017). Water scarcity in Zhangye was becoming increasingly prominent since virtual water net exports were higher than local consumption, especially in the agriculture, manufacturing, and energy supply industries. Moreover, under climate change scenarios, we found the highest level of water requirement per unit area occurred in 2000, but it still had an incremental potential by 2050, especially in SSP585. The high requirement intensity and large-scale maize planting caused a rising tendency of total crop water requirement with an annual increasing rate of 8.4% from 1980 to 2050. This makes it possible to adapt to climate change through scientific management measures and technical means. We further made policy implications for adaptive management of water resources in Zhangye.

Optimal Crop Composition in the Light of Water Resources Management Policies in Assiut Governorate

Optimal Crop Composition in the Light of Water Resources Management Policies in Assiut Governorate

Water quality assessment in the region of Vale dos Sinos trough the alternative model Caenorhabditis elegans

The determination of the condition of river water quality is critical to establishing sustainable water resource management policies. The use of bioindicators tests for the evaluation of water quality is a valuable tool, and the nematode C. elegans is described as a good organism to assess toxicological risks in aquatic and soil environments. The samples of water were collected in three stretches of the Paranhana and Ilha rivers (P1, P2 and P3) in November (spring) of 2018, January (summer) of 2019, April (autumn) of 2019, and August (winter) of 2019. The physic-chemical parameters were analyzed according to the standard methods (Standard Methods for the examination of Water and Wastewater 23rd edition). The nematode strains used are savage lineage N2 and were obtained through the Caenorhabidits Genetics Center (CGC) for the bioindicator test. The development evaluation was verified by the body surface area measurement of 20 nematodes which were quantified thru the ImageJ software. Most of the physic-chemical parameters were within the limits recommended by CONAMA, but aluminum, that presented values ten times higher than the recommended limit. Significant differences were observed in the nematodes development from all the samples when compared to the control group (p&lt;0,001). The analysis of nematode development demonstrated that the bioindicator was sensitive to the research, showing that ecotoxicological assays are important for a more realistic scenario of threats to water quality, and C. elegans allows this assessment to be performed adequately.

Analysis of Regional Differences and Factors Influencing the Intensity of Agricultural Water in China

The output intensity of water resources has become a subject of increasing concern. Based on spatial autocorrelation, the Gini coefficient, the Theil index, and geographically and temporally weighted models, this work studied the spatial correlation and regional differences of the output intensity of agricultural water and the main factors influencing the output intensity of agricultural water from a spatial–temporal perspective in China from 2003 to 2019. The results show that the output intensity of agricultural water showed an upward trend and that the output in the central region was higher than the output in the eastern region, and the eastern region had higher output than the western region. By analyzing the spatial autocorrelation, it was found that the output intensity of agricultural water presented a significant spatial dispersion trend and showed the spatial difference. The overall difference in the output intensity of agricultural water in China showed an increasing trend, but the widening difference showed an alleviating trend; the main reason for this increase in the overall differences is that the intra-group differences in the three regions were increasing, with the largest intra-group differences being observed in the western region followed by the eastern region and the central region. Population scale, water use scale, water use structure, effective irrigation scale, urbanization, and industrial structure create significant spatial differences in the output intensity of agricultural water. However, the level of economic development positively impacts the agricultural water output intensity of all provinces. Therefore, water resource management departments should formulate water resource management policies based on regional water conditions and the differences between influencing factors.

Increasing extreme events in the central Himalaya revealed from a tree-ring based multi-century streamflow reconstruction of Karnali River Basin

The Karnali River is one of the major transboundary rivers of the Nepalese central Himalaya and a major tributary of the Ganges River. In order to investigate regional historical hydroclimate variability, we compiled eleven tree ring-width chronologies based on 354 exactly dated tree cores from five coniferous species for the Karnali River catchment. The chronologies were moisture-sensitive and the composite chronology was significantly correlated with spring-to-early summer (March–July) (R = 0.67, P < 0.001) discharge at the Chisapani gauging station. The robust calibration (R2 = 0.45, 1962–2010) enabled us to reconstruct March–July streamflow variability of Karnali River Basin (KRB) over the past four centuries. The streamflow reconstruction showed prolonged pluvial periods during 1650–1661, 1711–1718, 1723–1731, 1824–1831, 1877–1889, 1924–1931, and 1971–1981, while prolonged low-flow periods occurred during 1639–1649, 1689–1710, 1753–1769, 1777–1784, 1803–1823, 1867–1876, 1942–1959, and 1963–1970. Our reconstructed March–July streamflow series correlated positively with the seasonally averaged drought index and precipitation in the central-west Himalayan region and vicinities. The streamflow reconstruction revealed an increasing frequency of extreme low-flow and pluvial events in the central-west Himalayan region, especially during the past century. We found short (2.1–3.3, 6.2–6.3, and 8.5–8.7 years) to medium (12.2–12.5 years) periodicities in the reconstructed streamflow series, implying teleconnections with broad-scale climate modes like the El Niño-Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO). Our Karnali River streamflow reconstruction represents an update of regional hydroclimate variability, which may serve as a useful reference for water resource management and appropriate water-use policies in the context of current and future climate change.

A Content Analysis of the Strictest Water Resources Management Policy in China

Policy intervention is a critical measure to address water resources challenges and improve water governance capacity. The strictest water resources management (SWRM) policy is an important water policy system that aims to deal with water shortage, water pollution, and institutional dysfunction in China. This study conducts a quantitative analysis for policy text characteristics of the SWRM through the methods of text mining and content analysis. First, we construct an analytical framework with the combination of policy instruments and policy targets, and then code and classify policy instruments in policy text and conduct statistical analysis. Finally, the research conclusions and policy suggestions are put forward. The results show that major policy instruments are structurally imbalanced in China’s SWRM policy. China’s government prefers to issue a mandatory, standardized, and restrictive policies in water resources management. Most of the policy instruments are focused on institutional management, followed by resources allocation, technological progress, and the ecological environment. This study contributes to the knowledge body of water policy evaluation and water governance, provides decision-making references for optimizing and promoting China’s water resources management policy, and offers a peer reference for water governance in other developing countries.

How to provide refined China's water-economy management policy at the regional scale?

With the development of industrialization and urbanization, the water scarcity crisis is among the most critical problems faced by many countries in the 21st century. Investigating the flow processes and induced impacts of classified water resources in complex systems from multiple perspectives can improve the mismatch between limited water resources and economic development. In this study, a water-economy nexus model (WENM) is developed to examine the carrying capacity and economic value of virtual water and direct water in 31 regions of mainland China from the driving relationships of the production-side and the consumption-side. It is found that the regions with high water stresses were concentrated in the economically developed eastern and southern coastal areas. Undeveloped regions with production advantages tend to export large amounts of water-intensive products to economically developed regions with consumption advantages. In order to increase economic benefits and avoid aggravation of water scarcity, efforts should be made to improve the production capacity of developed regions, the consumption capacity of underdeveloped regions, and the water use efficiency. The dependency of China on virtual water is generally lower than that of direct water, but virtual water flow can provide higher economic value. It is necessary to strengthen the multilateral economy among regions and try to reduce dependency on direct water. Policymakers should prioritize the allocation of water resources to regions that have significant economic value for water flows but high-water dependency. Therefore, a quantitative analysis of the water-economy nexus can provide scientific references for water resource management policies from multiple perspectives.