Enhancing Evapotranspiration Estimation: A Bibliometric and Systematic Review of Hybrid Neural Networks in Water Resource Management

Accurate estimation of evapotranspiration(ET)is crucial for efficient water resource management,particularly in the face of climate change and increasing water scarcity.This study performs a bibliometric analysis of 352 articles and a systematic review of 35 peer-reviewed papers,selected according to PRISMA guidelines,to evaluate the performance of Hybrid Artificial Neural Networks(HANNs)in ET estimation.The findings demonstrate that HANNs,particularly those combining Multilayer Perceptrons(MLPs),Recurrent Neural Networks(RNNs),and Convolutional Neural Networks(CNNs),are highly effective in capturing the complex nonlinear relationships and tem-poral dependencies characteristic of hydrological processes.These hybrid models,often integrated with optimization algorithms and fuzzy logic frameworks,significantly improve the predictive accuracy and generalization capabilities of ET estimation.The growing adoption of advanced evaluation metrics,such as Kling-Gupta Efficiency(KGE)and Taylor Diagrams,highlights the increasing demand for more robust performance assessments beyond traditional methods.Despite the promising results,challenges remain,particularly regarding model interpretability,computational efficiency,and data scarcity.Future research should prioritize the integration of interpretability techniques,such as attention mechanisms,Local Interpretable Model-Agnostic Explanations(LIME),and feature importance analysis,to enhance model transparency and foster stakeholder trust.Additionally,improving HANN models’scalability and computational efficiency is crucial,especially for large-scale,real-world applications.Approaches such as transfer learning,parallel processing,and hyperparameter optimization will be essential in overcoming these challenges.This study underscores the transformative potential of HANN models for precise ET estimation,particularly in water-scarce and climate-vulnerable regions.By integrating CNNs for automatic feature extraction and leveraging hybrid architectures,HANNs offer considerable advantages for optimizing water management,particularly agriculture.Addressing challenges related to interpretability and scalability will be vital to ensuring the widespread deployment and operational success of HANNs in global water resource management.

Critical issues in the characteristics and assessment of China's water resources

This study provides a comprehensive analysis of the concepts and assessment processes of water resources in China,focusing on the characteristics of water resources and variations in water cycle fluxes.It reveals that the distribution of water resources in China is uneven,with more south and less north,and human activities have led to a decline in water resources,particularly in northern arid and semi-arid regions.Further analysis shows that duplicated measurements of surface water and groundwater significantly affect water balance calculation and water resource assessments,serving as a crucial factor guiding water resource development and utilization.The study also finds that consistency correction of runoff series is insufficient to meet the requirements of accurate water resource assessment.It is urgent to strengthen fundamental research in hydrology and hydrogeology,and to establish a dynamic assessment system for the efficient management and rational use of surface water and groundwater in the current changing environment.

Discussion on Influencing Factors of Water Resources Environment and Strategies for Protecting Water Ecology

At present,the major problems facing the water resource environment worldwide include water pollution,water resource shortage,and water ecosystem degradation.The discharge of industrial wastewater,agricultural non-point source pollution,and the discharge of urban sewage lead to a serious decline in water quality,which directly affects the safety of human drinking water and the living environment of aquatic organisms.Additionally,the unbalanced distribution and excessive exploitation of water resources lead to the problem of water shortage in many areas,which then leads to social and economic contradictions and ecological crises.In terms of ecosystems,the phenomena of water ecological degradation and reduction of biodiversity are increasingly obvious,and the carrying capacity of aquatic ecosystems are gradually declining.This paper aims to analyze the natural,social,and economic factors affecting the water resource environment,and propose effective strategies to protect the water ecology.To provide a theoretical basis and practical guidance for the sustainable utilization of water resources and the long-term development of the water ecosystem.

Influence of Anthropogenic Activities on Surface Water Resources—Case of the Sub-Prefecture of Kamsar-Boké

Living fishery resources, although rich and important for human populations, are subject to strong anthropization, thus causing a change in the environmental parameters of aquatic ecosystems. These multiple combined pressures: chemical, hydro-morphological, thermal or trophic, affect and disrupt the functioning of aquatic organisms. The objective of this study was to assess the main human pressures influencing the surface water resources of the Kamsar sub-prefecture, in order to propose mitigation measures. The following methodological approach was adopted: 1) Survey of managers and analysis records;2) Survey of stakeholders;3) Assessment of the effect of human activities on surface water resources;4) Data processing;5) Corrective measures. The survey farmers working near aquatic environments, revealed a low use of chemical substances, in particular 3 to 11 kg of fertilizer and 0 to 3 boxes of herbicide on fields of 40 m2 to 2 ha. Some physico-chemical parameters have been determined: Temperature (28.5˚C, 23.7˚C, 22.8˚C, 21.3˚C, 21.6˚C), Salinity (26.9‰, 21.9‰, 21.5‰, 15‰, 15.3‰) and Turbidity (21.3 UTN, 19.3 UTN, 17.8 UTN, 16.7 UTN, 17 UTN). These values show a fluctuation in the environmental parameters of aquatic ecosystems, which constitutes an obstacle to the development and survival of the resources.

A multi-objective fuzzy optimization model for cropping structure and water resources and its method

Cropping structure has a close relationship with the optimal allocation of agricultural water resources. Based on the analysis of the relationship between agricultural water resources and sustainable development, this paper presents a multi objective fuzzy optimization model for cropping structure and water allocation, which overcomes the shortcoming of current models that only considered the economic objective,and ignored the social and environmental objectives. During the process, a new method named fuzzy deciding weight is developed to decide the objective weight. A case study shows that the model is reliable, the method is simple and objective, and the results are reasonable. This model is useful for agricultural management and sustainable development.

Assessment on the Water Resources Carrying Capacity in Karst Area Based on the Cosine Vector Included Angle

[Objective] The research aimed to assess the water resources carrying capacity in Guizhou Province based on the cosine vector included angle method. [Method] By using the cosine vector included angle method, the index weight was determined. The projection value of water resources carrying capacity in Guizhou Province was counted by using the multi-objective gray relational projection method. Moreover, the projection value which was counted by the index weight determined by the mean-variance method was as the control. [Result] The projection values which were obtained by two kinds of methods were very close, and the ordering result was consistent. [Conclusion] In the assessment of water resources carrying capacity, it was feasible to use the cosine vector included angle method to determine the index weight.

Analysis of Water Resources Supply and Demand and Security of Water Resources Development in Irrigation Regions of the Middle Reaches of the Heihe River Basin, Northwest China

Based on the data for meteorology, hydrology, soil, planting, vegetation, and socio-economic development of the irrigation region in the middle reaches of the Heihe River basin, Northwest China, the model of balance of water supply and demand in the region was established, and the security of water resource was assessed, from which the results that the effects of unified management of water resources in the Heihe River basin between Gansu Province and Inner Mongolia on regional hydrology are significant with a decrease in water supply diverted from Heihe River and an increase in groundwater extracted. In addition, it was found that the groundwater level has been steadily decreasing due to over pumping and decrease in recharges. In present year （2003）, the volume of potential groundwater in the irrigation districts is far small because of the groundwater overdraft; even in the particular regions, there is no availability of groundwater resources for use. By 2003, water supply is not sufficient to meet the water demand in the different irrigation districts, the sustainable development and utilization of water resources are not secured, and the water supply crisis occurs in Pingchuan irrigation district. Achieving water security for the sustainable development of society, agriculture, economy, industry, and livelihoods while maintaining or improving the abilities of the management and planning of water resources, determining of the reasonable percentage between water supply and groundwater utilization and water saving in agricultural irrigation are taken into account. If this does not occur, it is feared that the present performance of water development and planning may further aggravate the problem of scarcities of water resources and further damage the fragile ecological system.

Water resources utilization and eco-environmental safety in Northwest China

Northwest China includes Xinjiang Ugyur Autonomous Region, Qinghai Province, Gansu Province, Ningxia Hui Autonomous Region and Shaanxi Province, covering 308×10^4km^2. It is located in the warm-temperate zone and the climate is arid or semi-arid. Precipitation is very scarce but evaporation is extremely high. The climate is dry, the water resources are deficient, the ecoenvironment is fragile, and the distribution of water resources is uneven. In this region, precipitation is the only input, and evaporation is the only output in the inland rivers, and precipitation, surface water and groundwater change with each other for many times, which benefits the storage and utilization of water resources. The average precipitation in this region is 232 mm, the total precipitation amount is 7003×108m^3/a, the surface water resources are 1891×10^8m^3/a, the total natural groundwater resources are 1150×10^8m^3/a, the total available water resources are 438×10^8 m^3/a, and the total water resources are 1996×10^8m^3/a and per capita water resources are 2278 m^3/a. The water resources of the whole area are 5.94×10^4m^3/（a.km^2）, being only one-fifth of the mean value in China. Now, the available water resources are 876×10^8m^3/a, among which groundwater is proximate 130×10^8m^3/a.

SAFETY ANALYSIS OF WATER RESOURCES AND ECO-ENVIRONMENT IN SHIYANG RIVER BASIN

The research on the present situation of soil and water development and utilization in Shiyang River Basin shows that water resources and eco-environment situation in this area are near the edge of collapse. Since the water crises occurred in the 1970s, problems caused by continuous decrease of water resources have been becoming serious year by year and eco-environment crisis occurred as a consequence. Up to now, 10 380ha of irrigated lands have been abandoned due to sand coverage and water shortage in the basin. Ground water was over exploded in Wuwei and Minqin because of water shortage. Ground water table in many places dropped under 5m （which is the ecology water table level）, thus about 3000ha ofElaeagnus angustifolia forest come to dead and another 5800ha become feeble, and wind-drift sand near the oasis become alive. According to the current situation, if water utilization scope was not enlarged, a water transfer volume of 600×10^6m^3/a from other areas will be suitable to keep water resources and eco-environment safety in the basin, and also 70×10^6m^3/a will be left as spare water. Under this condition the water resources and eco-environment of the basin can reach the critical safety line of 2.032×10^6m^3/a; or if 180×10^6m^3 of water can be transferred from other areas, the water resources can reach the safety warning line of 1.732×10^9m^3/a.

Evaluation of the water resources carrying capacity of Shandong peninsula, China

Research on the carrying capacity and security of water resources is vital for its contribution to implementing sustainable development goals. The limitation of water resources is one of the most important factors that influence the sustainable utilization of resources. Studying the carrying capacity of water resources will not only facilitate monitoring and forecast of national resources and environmental carrying capacity, but also be valuable for building ecological civilization. According to the principles of evaluation system, the carrying capacity of water resources on Shandong peninsula is explored. A comprehensive evaluation model of the carrying capacity of water resources is constructed based on the carrying capacity of water resources index and the composite of water resources index. The results show that the capacity of water resources on Shandong peninsula is generally consistent with overexploitation, and that the development and utilization of water resources has reached a considerable scale under existing economic and technological conditions. The carrying capacity of water resources in this region is relatively small, and the contradiction between supply and demand of water resources is alarming. Relative countermeasures are put forward, to improve the water resources carrying capacity and to provide a basis for future sustainable development and utilization of water resources in this region.

Emergency Plan for Water Supply in Consecutive Droughts and Sustainable Water Resources Management in Beijing

Beijing, the capital city of China, has suffered from acute water shortage, with only 300 m3/a of water resources available per capita. In addition, Beijing has experienced a prolonged period of consecutive droughts from 1999 to 2010. Water crisis has constrained the socio-economic development of Beijing. Meanwhile, the national "South-to-North Water Transfer"（STNWT） project, which is expected to provide some relief to the water crisis in Beijing, is still under development. In order to ensure the security of water supply in Beijing before the completion of the STNWT project, several measures have been implemented to cope with droughts, including pumping groundwater from emergency well fields,water saving, recycling of water, rain and flood water harvesting, and the diversion of water from neighboring rivers and groundwater basins. Groundwater from four emergency well fields contributes the most to the public and domestic water supplies in Beijing, supplying a total volume of 1.8×10;m;.The water crisis is supposed to be mitigated by the completion of the STNWT project. After the completion of this project, more sustainable management of water resources will be implemented,including the use of aquifers as groundwater reservoirs and conjunctive use of surface water and groundwater resources.

Analysis on the Contribution of Artificial Precipitation Enhancement Amount to Annual Water Resources in Liaoning

Based on the water resource balance,the correlation between both the Liaoning water resource and precipitation and total amount of water resource from 1991 to 2004 was analyzed by assuming Liaoning to be an enclosed region.And the calculation methods were developed to quantitatively determine the increase of rainfall due to artificial precipitation,and consequently ascertain the contribution of artificial rainfall amount to water resources.

Evaluation Model of Carrying Capacity of Water Resources Based on Standardized Indices of Radial Basis Function

[Objective] The aim was to study on RBF model about evaluation on carrying capacity of water resources based on standardized indices. [Method] The indices were transformed and the averages of standard values in different levels were taken as the standardized values of components of central vectors for basic functions of RBF hidden nodes. Hence, the basic functions are suitable for most indices, simplifying expression and calculation of basic functions. [Result] RBF models concluded through Monkey-king Genetic Algorithm with weights optimization are used in evaluation on water carrying capacity in three districts in Changwu County in Shaanxi Province, which were in consistent with that through fuzzy evaluation. [Conclusion] RBF, simple and practical, is universal and popular.

Study on functions and rational allocation of Shule River Basin groundwater resources

Based on Investigation and Assessment on Rational Exploitation and Utilization of Groundwater Resources in Typical Areas of the Hexi Corridor, the thesis studies on groundwater and environmental problems arising from the large-scale agricultural development projects in Shule River Basin. The thesis analyzes problems in exploiting and utilizing water resources, defines the function zoning of groundwater resources in key areas and evaluates them. Finally, the thesis uses three-dimensional unsteady flow simulation and regional social and economic development plan to study on the allocation of groundwater in Shule River Basin. A proposal for rational allocation of Shule River Basin water resources has been put forward.

Evaluation on water resources carrying capacity of Changchun-Jilin Region

Based on such principles as sustainable development and ecological cycle, this paper evaluates the water resources carrying capacity(WCC) of Changchun-Jilin region using a population-economy-water resources correlation evaluation model built on the basis of WCC evaluation method as elaborated in the methodology of Functional Zoning of Population Development. Results show that the annual WCC of Changchun-Jilin region is able to support the population there, as a basic balance is struck between population and water resources. The incorporation of WCC into overall urban planning is one of the building blocks for sustainable city development with an advisable size.

Evaluation of Environmental Carrying Capacity of Water Resources in Jiangxi Province

In order to quantitatively evaluate the sustainable development status of water resources in Jiangxi Province, the dynamic changes in ecological footprint, carrying capacity and load index of water resources in Jiangxi Province during 2009-2013 were analyzed according to the primary principle and calculation model of ecological footprint. The results showed that in Jiangxi Province during 2009- 2013, the water resources ecological footprint per capita was relatively low; the wa- ter resources utilization level was relatively low; the overall development potential of water resources was great; the water resources ecological carrying capacity per capita and ecological footprint per capita were trended to be increased overall. The changes in water resources ecological footprint are closely related to the social and economic development. Therefore, the industrial structure should be fully adjusted, and the water resources should be scheduled and utilized reasonably so as to pro- mote the protection of water resources and sustainable development of society and economic in Jiangxi Province.

Equitable utilisation and effective protection of sharing transboundary water resources: international rivers of western China

Western China includes 12 provincial divisions (the 7 provinces of Sichuan, Guizhou, Yunnan, Shaanxi, Gansu, Qinghai and; 5 autonomous regions of Tibet, Ningxia, Xinjiang, Inner Mongolia and Guangxi; and one city of Chongqing), which comprise 71.4% of the national land area, 28.5% of the national population and produce 17.5% of the national GDP in China. There are 17 countries that have riparian relationships with western China, most of which are water-short countries. All are listed by UN ESCAP as countries with potential water crisis. The co-operative development and coordinated management of international rivers in western China is an important step toward the implementation of the national Great Western Development program. Taking into account of the national strategy and object hierarchy, as well as the development demand of the western region, it is necessary to pursue the multi-disciplinary study of the equitable allocation, utilisation, and eco-environment protection of transboundary water resources in the region. Such efforts will undoubtedly provide scientific evidence and support for the decision-making of the environmental protection and ecological construction and management in the western regions, the enforcement of the sub-regional economic co-operation, mitigation of trans-boundary conflicts, and enhancing bio-diversity conservation.

Integrated Water Resources Management in the Sandougou Catchment Area(Senegal):Going beyond Soil Defence and Restoration(SDR)

The Sandougou River is the last major right bank tributary of the Gambia River.It has a catchment area of 11,668 km² and is located in Senegalese territory.The flow in this sloping basin(1‰)is favoured by the conservation of soils and vegetation.Since 1970,global rainfall trends(below the average of 800 mm)have shown a drought affecting the whole basin with an average deficit of 100 mm per year.In addition,erosion phenomenon combined with high rainfall intensities explains the rapid run-off.This constitutes a considerable loss of water resources,up to 20%in the Sandougou basin.In this rural area where primary activities predominate,anthropogenic pressure is considerable.Indeed,overexploitation of firewood,resulting from the strong dependence of local populations on this resource,is at the origin of deforestation in the Sandougou basin.Such a situation contributes to environmental degradation and also has repercussions on soil erosion.Erosion affects the water retention capacity of the soil making it more susceptible to extreme conditions such as drought.The impact of soil erosion on more remote sites is not always as apparent as the impact of erosion on the site itself.Sediment reaching watercourses can accelerate slope erosion,silt up drainage ditches and streams,silt up reservoirs,cover spawning areas and reduce water quality.Fertilizers frequently transported with soil particles can contaminate or pollute water sources.To cope with this dynamic,soil defence and restoration(SDR)techniques have long been considered as the solution to the problems.However,the multifaceted nature of environmental problems and their persistence leads to the consideration of a more holistic approach.In the Sandougou catchment area,the application of article R50 of the Senegalese Forestry Code,the implementation of planning tools(AP-IWRM),institutional development in the framework of integrated water resources management(IWRM)prove the interest of such an approach for the protection of water resources.

Water Resource and Regional Economic Growth Study Based on Panel Data

Empirical analysis to the relationship between water resource scarcity degree and economic growth were done by building relationship model between water resource scarcity degree and regional economic growth with provincial panel data of 30 provinces during 2000-2009. The analysis results show that, in water resource scarcity regions, the shortage of water resource is the key factor of restricting economic development. In order to alleviate the shortage of water resource and meet the needs of economic development to water resource, it is necessary to speed up the establishment of water right trading market and finally achieve the goal of water-saving and regulation of water resource by economic leverage. The specific countermeasures include： first, comprehensively considering the endowment difference of water resource when carrying out industrial planning and layout; second, speeding up the establishment of water right trading market and revising water-saving incentive mechanism; third, increasing fiscal transfer payment ability to the provinces of outputting water resource; fourth, strengthening industrial guidance, making moderate industrial transfer and population movement; fifth, paying attention to science, technology and education investment, to improve utilization efficiency of water resource.

Reviews of the research on water resources management system at home and abroad

The reform of the system of water resource management abroad has started since the 50s of last century, it has left us a lot of experiences in many aspects with the innovation of system, such as the legal environment in water resources, water rights, water market theory, and the ＂participation＂ management of water resources, these experiences has been promoted in more than 40 developing countries. Based on analyzing the theory and experiences of water resources management both at home and abroad, especially the theory and experiences of agricultural water resources management, this paper puts forward the main problems waiting for further investigation in China＇s water resources management and provides some reference and inspiration for the innovation of the system of water resource management in China.