Utilization Of Water Resources Research Articles

Preliminary Analysis of the Chemical Characteristics and Boron Sources of Surface Water and Groundwater in the Cherchen River Basin of Xinjiang

The climate of the Cherchen River Basin （CRB） is dry and rainless and the water resources are relatively scarce. Identifying the chemical characteristics and high boron sources of surface water and groundwater in the basin is important for the sustainable development and utilization of water resources and the protection of animals, plants, and human health. To preliminarily explore the chemical characteristics and the main sources of boron （B） in the CRB, a total of 46 groups of water samples （including six groups of river water and 40 groups of well water） were collected in 2023. The chemical characteristics of surface water and groundwater and the sources of boron in the CRB were preliminarily analyzed using a Piper diagram, Gibbs chart, correlation analysis, hydrogeochemical simulation, and absolute principal component analysis （PCA-APCS-MLR） and the contribution of different factors to boron and other chemical components was quantitatively evaluated. The results showed that the water resources in the CRB were weakly alkaline, with an average pH of 7.99. The groundwater was mostly brackish water and salt water and the anions and cations were mainly Cl- and Na+. Many types of water chemistry were present, among which the river water was mainly SO4·Cl-Na type and HCO3·SO4·Cl-Na type. The groundwater was mainly SO4·Cl-Na type. The average content of boron in river water in the area was 1.80 mg·L-1 and the over standard rate was 66.7%. The average content of boron in groundwater was 1.48 mg·L-1 and the exceeding standard rate was 45.0%. APCS-MLR receptor model analysis further revealed that the major sources of water chemical components and boron were leaching-enrichment, anthropogenic activity, and primary geological factors and unknown sources. The phenomenon of boron exceeding the standard in the water of the Cherchen River Basin was obvious, mainly due to agricultural activities （fertilizers and pesticides） and unknown sources. Isotope technology may further identify the main sources of boron in water.

Distribution Characteristics and Formation Mechanism of Main Hydrochemical Ions in Qingshui River

Qingshui River is a vital source for human life and industrial production in Zhangjiakou City. Determination of the formation mechanism of the main hydrochemical ions is important for the sustainable development and utilization of surface water resources in the Qingshui River. In view of this, 20 surface water samples were collected from the agricultural and urban reaches of the Qingshui River in July 2022. Based on the detection of hydrochemical ions and stable isotopes （δ2H-H2O and δ18O-H2O）, the hydrogeochemical methods, multivariate statistical analysis, and positive matrix factorization model （PMF） were used to comprehensively understand the chemical formation mechanism of surface water from qualitative to quantitative perspectives. The results showed that the average pH value in the Qingshui River was 8.66, indicating weakly alkaline water. The average concentrations of cations and anions decreased in the orders of Ca2+ > Na+ > Mg2+ > K+ > NH4+ and HCO3- > SO42- > NO3- > Cl- > F- > NO2- in the river water, respectively. The main hydrochemical type was identified as HCO3-Ca·Mg water. For the natural background, surface water was mainly controlled by rock weathering and evaporation crystallization and rock weathering was identified as the primary driving factor. The main hydrochemical compositions in the Qingshui River were derived from the dissolution of carbonate rocks and silicate rocks. Regarding anthropogenic activities, the portions of river water in the agricultural reaches were mainly affected by the excessive application of chemical fertilizers. Furthermore, the concentration of NO3- （1.88-47.4 mg·L-1） exceeded the standard for drinking purposes （10 mg·L-1）. The concentration of F- （0.38-1.92 mg·L-1） was above the acceptable limit for drinking purposes （1.0 mg·L-1） in the southern urban reaches portion of the river water, which could have been attributed to the industrial sewage discharge. The obtained results from the PMF model showed that the hydrochemical compositions in the river water of agricultural reaches were mainly controlled by four factors, namely synthetic fertilizers （29.6%）, livestock manure （16.4%）, rock weathering （17.4%）, and natural geology （13.7%）, while hydrochemical compositions in the river water of urban reaches were mainly affected by the domestic pollutants （30.5%）, industrial discharges （20.1%）, natural geology （18.4%）, and rock weathering （16.7%）.

A Comprehensive Evaluation of Water-Saving Society Construction in Xinxiang, Henan Province, China

Water is a crucial and fundamental resource. It is well known that agricultural cultivation, industrial production, and human daily life are not possible without water. Efficiently utilizing water resources is of great significance for achieving global Sustainable Development Goals (SDGs). In order to improve water use efficiency in various industries and promote water-saving development, China has been implementing water-saving society construction since 2002. Henan Province is the main grain-producing area in China, with wheat production accounting for a quarter of the country’s total. As the core area of “Central Plains Agricultural Valley” in Henan Province, Xinxiang City plays an important role in agricultural technology innovation and agricultural production. However, Xinxiang City is facing problems of water scarcity and pollution, which constrain the sustainability of agricultural production. Therefore, building a water-saving society can solve the current water problems faced by Xinxiang City and ensure the sustainable development of the economy and society. This study built an evaluation index system for water-saving society construction in Xinxiang, Henan Province, China. The proposed evaluation index system includes 20 evaluation indices from six aspects—integrated, agricultural water, industrial water, domestic water, water ecology and environment, and water-saving management—and then divides its development level into several stages. The Analytical Hierarchy Process (AHP) was adopted to calculate the index weight. Then, a comprehensive evaluation model for water-saving society construction in Xinxiang City was established by combining it with grey relative analysis (GRA). The results showed that the overall level of water-saving society construction in Xinxiang City is in the excellent stage, whereas water consumption per CNY 10,000 of GDP, the effective utilization coefficient of irrigation water, the reuse rate of industrial water, and the leakage rate of urban water supply network are all in the good stage. However, the urban recycled water utilization rate is still in the poor stage. These research results can effectively and reasonably reflect the development level of water-saving society construction in Xinxiang City and guide the continued implementation of water-saving society construction. At the same time, the comprehensive evaluation of water-saving society construction helps to formulate and adjust water resource management policies and measures; it also holds significant value for sustainable water management and combating water scarcity.

Optimal Allocation of Urban Water Resources Based on Multi-Objective Nutcracker Optimization Algorithm

The imbalance between water supply and demand (WSD) has been growing noticeable as a result of the economy’s fast expansion which can be effectively alleviated using optimal allocation of water resources. An urban water resources allocation (WRA) model based on the innovative Multi-Objective Nutcracker Optimization Algorithm (MONOA) is proposed in this study. Taking into account economic, social and ecological benefits, a comprehensive multi-objective optimization (MOO) model is established. By introducing the opposite learning strategy, non-dominated sorting approach and crowding distance mechanism to a recently reported intelligent optimization algorithm called the Nutcracker Optimization Algorithm (NOA), the novel nature-inspired metaheuristic algorithm MONOA is proposed to solve the multi-objective optimization model. The MONOA is evaluated on ten benchmark test functions, and it exhibits superior distribution and convergence by comparing with some highly cited algorithms. The proposed model is applied to Handan, China, in order to obtain a reasonable water allocation scheme in the planning year. The simulation results reveal that the economic benefit is in the range CNY [1.36, 1.44] × 1011, water shortage is in the range [0.66, 0.98] × 108 m3 and COD emission is in the range [3.70, 3.91] × 104 t in all the obtained Pareto solutions. The water resources management departments might create customized water allocation plans by balancing different goals and taking preferences into account. Moreover, the proposed method is a general approach that can be applied to many other cities. Hence, it is of great significance to the sustainable development and utilization of urban water resources.

Study on the pattern and driving factors of water scarcity risk transfer networks in China from the perspective of transfer value—Based on complex network methods

The transfer value of risk, measured by the asymmetric impact of virtual water flows, is vital for regions addressing the global water crisis, achieving Sustainable Development Goal 6 (SDG6), and implementing sustainable water management. This study uses multi-regional input-output models, complex network analysis, and the Exponential Random Graph Model (ERGM) to construct and analyze China's water scarcity risk transfer network. Findings show frequent but weakly connected risk transfers between provinces, with significant spatial clustering. The network displays both random and hierarchical features, with clustered development being prominent. Reciprocal cooperation and extensive connections are crucial to avoiding the “prisoner's dilemma” in water conservation. High levels of “dual circulation” and water resource utilization enhance risk transfer value, while lower industrialization and digitization levels facilitate value reception. The efficiency of water resource use is key in shaping high-risk value pathways, underscoring the need for risk management at both source and sink ends. This study offers a scientific basis for improving water resource management, ensuring national water security, and redefining risk flow patterns.

National estimation of regulated water storage of reservoirs in China

The need for man-made reservoirs has increased with the growing population and changing climate. One of the most intensive human-induced alterations of the hydrological cycle is the regulated water storage in reservoirs, however, its quantification in large-scale reservoirs in China is inadequate. The lack of such information limits the rational management and utilization of water resources in reservoirs. To address this issue, we first mapped the dense time series of high-resolution (10 m) water inundation areas based on Sentinel-2 image scenes from 2017 to 2022 and then composed the annual surface water frequency (WF) maps of Chinese reservoirs. We calculated the water area of each reservoir at different WFs and estimated the corresponding water storage using our previously developed machine learning model. The water storage difference between the maximum water area (WF ≥ 5 %) and year-long (WF ≥ 75 %) water area was assumed as the regulated water storage of reservoirs. Results show that the multiyear-averaged water storage of all Chinese reservoirs at the maximum water area is estimated at 784.60 km3 from 2017 to 2022, and the water storage at the year-long water area is approximately 318.86 km3. The average annual regulated water storage of the reservoirs is estimated at 465.74 km3, accounting for 43.72 % of the total designed water storage of reservoirs in China. Among the basins, the Yangtze River Basin and Pearl River Basin have the highest average annual regulated water storage of 152.52 and 84.94 km3, respectively. The basins with larger irrigation areas and higher populations tend to have higher reservoir regulated water storage. The normalized water storage (NS) shows high spatial variations across reservoirs in different basins, with most basins in the south having higher NS than those in the north.

A Groundwater Quality Assessment Model for Water Quality Index: Combining Principal Component Analysis, Entropy Weight Method, and Coefficient of Variation Method for Dimensionality Reduction and Weight Optimization, and Its Application.

Groundwater underpins water supply for most of the world's regions, yet its sustainable utilization has been markedly compromised by inappropriate exploitation and a multitude of pollution sources. Water quality evaluation has emerged as an essential strategy to guarantee the optimized utilization and vigilant conservation of water resources. In this study, principal component analysis (PCA), entropy weight method (EWM), coefficient of variation method (CVM), and Water Quality Index (WQI) were used to construct an integrated WQI groundwater quality assessment model that integrates PCA-CVM-EWM for dimensionality reduction and weight optimization. Taking a village in Shandong Province, China, as an example, PCA identified seven evaluation indicators. The CVM-EWM were coupled to calculate comprehensive weights through the principle of minimum information entropy, followed by a comprehensive assessment of groundwater quality based on WQI values. The results indicated that Class III groundwater predominated in the study area, accounting for 74%, with localized pollution present. The hydrochemical type of the groundwater was primarily SO4·HCO3-Ca, significantly influenced by human activities. The coefficients of variation for Fe, Mn, and NH4-N all exceeded 1. Compared to other methods, the optimized WQI model demonstrated superior performance in the selection of evaluative indicators, weight distribution, and comprehensive water quality assessment, showing a distinct advantage for water quality data with numerous hydrochemical indicators and substantial coefficients of variation. The findings provided a scientific reference for diagnosing groundwater quality issues and formulating preventive and control measures. PRACTITIONER POINTS: A comprehensive water quality index evaluation model was constructed. Optimized steps for selecting indicators and assigning weights for the water quality index model. Selection of evaluation indicators based on indicator correlation analysis. The variability of hydrochemical data is considered.

Rubber additives and relevant oxidation products in groundwater in a central China region: Levels, influencing factors and exposure

This study investigated the presence of rubber additives and relevant oxidation products (RAROPs) in groundwater in central China's aboveground river region. Seven RAROPs were detected, and their levels in shallow groundwater showed a mild decreasing trend from the area near the Yellow River (Avg: 8.49 ng·L-1) to the area on the far bank of the Yellow River (Avg: 5.01 ng·L-1). In contrast, deep groundwater's RAROPs contents showed a dramatic decrease to only 0.26 ng·L-1. The dominant contaminant was found to be N-(1, 3-dimethylbutyl) -N′-phenyl -p-phenylenediamine (6PPD). The vicinity of the garages and car parks was often characterized as contamination hotspots. Correlation analyses further indicated that aquaculture was likely to be a potential pathway for shallow groundwater contaminant inputs. The amount of RAROPs intake by humans through groundwater is nearly 30 times different due to the imbalanced development between urban and rural areas. Children were the most vulnerable to RAROPs. Therefore, human activities (transportation, waste tire storage, water resource allocation and utilization patterns, diversion of Yellow River water to aquaculture ponds) may exacerbate RAROPs pollution in groundwater by leaching contaminants through the surface soil. These results are important for developing appropriate utilization and protection strategies for groundwater resources in developing countries.

Environmental Influences on Evapotranspiration in Wheat-Maize Rotation Systems under Diverse Hydrological Regimes in the Guanzhong Plain, China

Evapotranspiration (ET) is a crucial hydrological process in terrestrial and agricultural ecosystems, and is a key factor driving climate change dynamics. Understanding the variability of ET and how it responds to controlling factors helps describe the impact of environmental changes on agricultural ecosystems. This study analyzes long-term continuous measurements from an Eddy Covariance (EC) system in wheat-maize rotation fields in the Guanzhong Plain in China. Using structural equation modeling (SEM), we investigated the regulatory roles of environmental and biological factors on ET, and the mechanisms controlling ET for summer maize and winter wheat under varying hydrological and climatic conditions. The results indicate that the eight-year average ET during the summer maize season ranged from 259 to 348mm; during the winter wheat season, it ranged from 369 to 513mm. The adjusted SEM explained 64% of the variation in daily ET during the summer maize season and 80% during the winter wheat season. Photosynthetically active radiation (PAR) was the primary controlling factor for both seasons, with air temperature (Tair) also playing a significant role. Leaf area index (LAI) was an important mediator for ET, and had a greater effect during the winter wheat season than during the summer maize season. Vapor pressure deficit (VPD) and soil water content (SWC) had a more significant impact on ET during the summer maize season than during the winter wheat season. The ET response to environmental factors varied significantly under different hydrological and climatic conditions. Specifically, the total effect of PAR on ET increased with increased moisture availability and decreased temperature; the trend was opposite for Tair. This indicates that high temperatures and drought conditions may increase the sensitivity of ET to temperature changes, and decrease the sensitivity of ET to radiation changes. This study explains the variability of evapotranspiration in agricultural ecosystems and associated controlling factors, providing important insights about how agricultural evapotranspiration responds to vegetation phenology under future climate change scenarios. These investigations help optimize water resource utilization and allocation in agricultural fields.

Nutrient efficiency unlocked: Water-soluble fertilizers in horticultural crop production

Horticultural crops are invaluable to the lands of small and marginal farmers across the nation, making a substantial contribution to the national economy. The significant productivity gap in horticulture is mostly attributable to the inefficient utilization of water and fertilizer resources. Soil fertility has been declining, driven by nutrient depletion and excessive fertilizer application with low nutrient-use efficiency, which hampers productivity despite the steady increase in cultivated area. Numerous research has investigated the application of water-soluble fertilizers to enhance the yield of horticulture crops, achieving greater profitability while minimizing environmental effects. Water-soluble fertilizers are closely linked to improvements in growth, yield attributes, and soil fertility in various horticultural crops. These fertilizers offer numerous advantages, such as controlling weed growth, reducing the need for herbicides, and enhancing the quality of vegetables and fruits, leading to widespread adoption. Additionally, drip irrigation systems in horticulture have conserved nearly half of the fertilizers and water resources used. Achieving self-sufficiency and sustainability in food production further supports precision farming through water-soluble fertilizers. Consequently, higher nutrient use efficiency (NUE) can be attained, making water-soluble fertilizers an essential component of precision agriculture and site-specific nutrient management.

Purification Effect of Fish–Algae Coupling on Nitrogen and Phosphorus in Shrimp Aquaculture Effluent

As the scale of shrimp aquaculture continues to expand, the environmental impacts of shrimp effluents have become increasingly severe. The purification of aquaculture effluents can no longer be overlooked. Effectively reducing the discharge of aquaculture wastewater and mitigating its potential pollution risks to the surrounding aquatic ecological environment are key issues that need to be addressed to promote the industry’s development towards a greener, more environmentally friendly, and sustainable path. This study explored the purification effect of the integration of tilapia and Spirulina on tail water from a zero-water-exchange aquaculture of whiteleg shrimp (Litopenaeus vannamei) in seawater, with the aim of assessing the growth performance of tilapia and the efficacy of the fish–algae integration in purifying tail water from the perspective of tail water resource utilisation. The study found that the removal rates of the biofloc sedimentation volume and total suspended particle concentration in the fish–algae group were 42.6% and 29.6%, respectively. The removal rates of phosphate and total phosphorus in the fish–algae group were 26.3% and 20.8%, respectively. Research indicates that tilapia effectively removes suspended organic matter from water. Introducing Spirulina into this water body aids in the removal of soluble nitrogen and phosphorus from the effluent, and tilapia exhibit a favourable feeding response to Spirulina.

Study on the Evolution of the Mountain Ecological Environment Based on Remote Sensing and Water Footprints: Case Study of Northwestern Sichuan, Southwest China

The unique geographical conditions in southwestern China lead to a fragile ecological balance and uneven geographical distribution of water resources. This study takes the Aba Tibetan and Qiang Autonomous Prefecture as its research subject, investigating the connection between water resources and the ecological environment in the Aba Tibetan and Qiang Autonomous Prefecture, which is of paramount importance. Given this, the current study constructs the remote sensing ecological index and water footprint for the period spanning from 2000 through 2020, analyses the coordination status of the two by using the coupling coordination degree, and then combines it with a detector to determine the primary drivers impacting the state of the ecological environment. The outcomes reveal that: (1) The ecological environment of the Aba Tibetan and Qiang Autonomous Prefecture gradually improved from 2000 through 2020, and the excellent ecological environment area observed within the study’s scope is primarily focused in the eastern part. The poor ecological environment area is focused mainly in the northwestern part within the study’s scope. (2) The total water footprint of the Aba Tibetan and Qiang Autonomous Prefecture has increased year by year, with agricultural water consumption comprising an immense 78% proportion, dominating the total water footprint. (3) The coupled coordination degree of the remote sensing ecological index and the water footprint shows a rising trend in general, turning from a barely coordinated stage to an intermediate coordinated stage. (4) The geodetector results show that all factor interactions were dual-factor enhancement or nonlinear enhancement, and the WET, NDBSI and NDVI factors contributed the most. The above results can provide important guidance for utilizing water resources and protecting the ecological environment in the Aba Tibetan and Qiang Autonomous Prefecture.

Assessment of water retention dynamic in water resource formation area: A case study of the northern slope of the Qinling Mountains in China

Study RegionThe northern slope of Qinling Mountains (NQL) is an important water retention (WR) area in China, which guarantees the utilization of water resources in the plain area. However, the effects of significant changes in climate and land cover on WR have not been quantitatively studied in recent years. Study FocusIn this study, we quantified the relative impacts of climate and land cover changes on WR at NQL and predicted the future changes of WR under different climate scenarios (SSP2–4.5 and SSP5–8.5). New Hydrological Insights for the RegionThe results indicated that WR in NQL has exhibited an overall increase from 1985 to 2020 at a rate of 1.10 mm/a, with climate and land cover change explaining 86.3 % and 13.7 % of this change, respectively. Although precipitation has increased since 1998, the compounding effects of land cover change and precipitation intensity increase have led to a slight decline of WR magnitude and efficiency due to their offsetting impacts. Under future climate change, the WR capacity changes in the SSP2–4.5 are relatively stable, while the significant increase in temperature under the SSP5–8.5 lead to a decreasing trend in WR efficiency. In addition, we proposed an indicator framework to evaluate WR using WR efficiency and baseflow lag time. Our results may provide valuable insights for sustainable utilization and scientific management of water resources.

Changes in ecosystem carbon sequestration and influencing factors from a ’Past-Future’ perspective: A case study of the Tarim River

Amid global warming and intensified human activities, the carbon sequestration (CS) capacity of terrestrial ecosystems faces significant pressure. Ecological Water Conveyance (EWC) projects, by altering land use patterns, have become a key approach to addressing this issue. Therefore, the critical question this study aims to solve is how to enhance regional CS by optimizing EWC measures, based on understanding the relationship between land use changes and CS. To address this, we propose an integrated framework that couples the PLUS-InVEST-OPGD models, adopting a ’past-future’ perspective to explore the relationship between CS and land use changes in the context of EWC. The study found that during the historical period (2000–2020), CS in the Tarim River (TR) area exhibited a pattern of ’ first increasing, then stabilizing.’ Between 2000 and 2010, the total CS increased by 3.5 × 10^6 Mg, accompanied by an expansion of forested areas along the riverbanks and within national parks. However, from 2010 to 2020, the total CS increased by only 0.3 × 10^6 Mg, with forested areas along the riverbanks and within national parks remaining relatively stable. Under three future development scenarios—Natural Increase (NIS), Farmland Protection (FPS), and Ecological Protection (EPS)—CS differences between NIS and FPS are minimal at 0.01 × 10^6 Mg, as both continue existing EWC policies without optimization, with NIS following natural growth and FPS prioritizing farmland preservation. In contrast, the EPS, which introduces optimized EWC strategies to limit urban expansion and enhance ecological sustainability, results in a significant CS increase of approximately 1.1 × 10^6 Mg, with farmland areas also expanding. Through single factor and interactive detection analyses, we found that potential evapotranspiration and annual average groundwater depth play crucial roles in vegetation restoration in arid regions, as EWC helps maintain groundwater levels, reducing plant water stress and supporting vegetation growth, while managing evapotranspiration ensures that the water provided through EWC is efficiently utilized for ecosystem recovery and CS. Under the current EWC model and prevailing climate and human activity conditions, the CS capacity of ecosystems appears to stabilize. To further enhance the region’s CS potential, optimizing EWC strategies is essential. It is recommended to construct a ’surface’ water conveyance network through engineering measures, in addition to the existing ’linear conveyance’ model, to improve water resource utilization efficiency. The findings of this study offer valuable insights not only for the TR region but also for other arid inland river basins worldwide, providing a replicable framework for ecological restoration and water management.

Policy effects of water rights trading (WRT)

China's emphasis on rapid economic growth in the past years has led to irrational exploitation and utilization of water resources. Water rights trading (WRT), as an important initiative carried out by the Chinese government, has been implemented for eight years but mainly in some pilot provinces. In this paper, a multi-point difference-in-difference model is constructed to study the causality of WRT policies in China from 2012 to 2021 and verifies the scientific validity of the research results through parallelism test, time and individual placebo test, endogeneity test of Logit reverse causality, and robustness test. The impact of the WRT system on the utlization efficiency of water resources, as well as its mechanism and heterogeneity characteristics, is mainly explored. The research results demonstrate that WRT helps to improve the utilization efficiency of water resources in polot provinces, which is even more pronounced in the presence of government expenditures. In addition, the effect of WRT implementation is signigicantly related to regional industrial technological empowerment and residents' awareness of environmental protection and insignificantly related to regional agricultural sophistication. The findings of this study will provide empirical support for the Chinese government's local strategy of establishing a unified national WRT market.

Hydrochemical characteristics, cross-layer pollution and environmental health risk of groundwater system in coal mine area: a case study of Jiangzhuang coal mine.

Long-term coal mining activities have significantly disturbed the groundwater system, resulting in aquifer water characterized by high levels of Na+, SO42-, and total dissolved solid (TDS), posing environmental health risks. To investigate the disturbance effects of coal mining activities on the groundwater system and ascertain the goaf water (OGW) environmental impacts, this study focuses on the surface water (SW), major aquifers, and OGW of Jiaozhuang Coal Mine. Through ion analysis and self-organizing map (SOM) clustering, the study analyzes the hydrochemical characteristics of the aquifer water, summarizes the accumulation patterns of OGW, and evaluates water quality of irrigation and drinking using sodium adsorption ratio (SAR), sodium percentage (SSP), and comprehensive pollution index (F). The results show that the hydrochemical characteristics of the groundwater system are influenced by a combination of cation exchange, dissolution, and mixing processes, with deep aquifers exhibiting high Na+ and SO42- levels. The OGW mainly originates from the coal roof sandstone aquifers water (RSW) and 3rd limestone aquifer water (3LW). Additionally, the groundwater shows high alkalinity and salinity hazards, with irrigation water quality assessments falling into general and unsuitable water quality area. Moreover, the groundwater quality is below Class III standards, with the worst being Class V, rendering it unsuitable as a drinking water source. Untreated discharge of OGW to the surface can easily threaten human drinking water health. The study results are helpful in identifying and controlling groundwater pollution caused by coal mining, ensuring the safety and sustainable utilization of water resources in mining areas and surrounding regions.

Optimization of A Dynamic Program for Water Resources Utilization in the Mambal Irrigation Area

The Irrigation Area (D. I.) Mambal, which passes through Badung Regency, Denpasar City, and Tabanan Regency, is the largest irrigation water supplied by the Ayung River, covering an area of 5.963 Ha. Despite the Ayung River’s substantial water potential, the D. I. Mambal experiences water shortages during certain months. This research aims to improve the effectiveness and efficiency of irrigation water use based on the Global Planting Management Plan (RTTG) using simulation methods and dynamic program optimization. Simulations were carried out under low conditions, normal and sufficient dependable discharges, using both existing and alternative RTTG. The objective function of the dynamic optimization seeks to maximize revenue gain from the applied RTTG. The existing cropping pattern at the beginning of planting in October showed an average proportion of fulfillment of water irrigation needs at 85%. Under the Alternative I condition, with planting beginning in November, the average proportion of fulfillment of irrigation water needs was 89%. In Alternative II conditions, with planting beginning in December, the average proportion of fulfillment of irrigation water needs was 87%. By optimizing the water discharge using the dynamic program, the irrigation profit for the existing cropping pattern (October) amounted to IDR 491,816,154,938. The highest profit was obtained using the Alternative II cropping pattern (December), totaling IDR 606,675,369,830. Meanwhile, the lowest profit was obtained in the Alternative I cropping pattern (November), which was IDR 360,767,292,361. The analysis showed that the Alternative II cropping pattern, starting with the first rice planting period in December, yields the most optimal results. The analysis considers the optimized air allocation and irrigation benefits obtained from the third cropping pattern.

Daily runoff prediction based on lightweight Mamba with partial normalization

ABSTRACT Runoff prediction serves as the cornerstone for the effective management, allocation, and utilization of water resources, playing a key role in hydrological research. This study employs a newly reported deep learning model, Mamba, to forecast river daily runoff and compared the proposed model with various benchmark methods, including statistical models, machine learning methods, recurrent neural networks, and attention-based models. Application of these models is implemented on three hydrological stations situated along the middle and lower reaches of the Mississippi River. Daily runoff from 1983 to 2023 were used to build the model for 7-day prediction. Findings demonstrate the superiority of the Mamba model over its counterparts, showcasing its potential as a backbone model. In response to the necessity for a more lightweight approach, a refined variant of the Mamba model is proposed, called LightMamba. LightMamba incorporates partial normalization and MPM (Multi-Path-Mamba) to enhance its efficacy in discerning nonlinear trends and capturing long-term dependencies within the streamflow data. Notably, LightMamba achieves commendable performance with an average NSE of 0.904, 0.907, and 0.900 on the three stations. This study introduces an innovative backbone model for time series forecasting, which offers a novel approach to hybrid modeling for future daily runoff prediction.

Identifying solute loss from karst conduit to fissures under concentrated recharge conditions

The aquifer within karst areas exhibits significant heterogeneity, accompanied by intricate runoff processes and swift hydrological responses. The solute transport process within karst conduits is influenced by various factors, including karst development characteristics and variations in hydrodynamic conditions, thereby displaying a high level of complexity. This complexity plays a crucial role in governing the safe utilization of karst water resources and the prevention of groundwater pollution. In this paper, a typical karst conduit system in southern China is chosen to investigate the influence mechanism of hydrodynamic conditions on the solute transport process within the karst conduit. This investigation is conducted through multiple sets of field artificial tracer tests. An intriguing phenomenon was observed: When the mean flow velocity of the conduit flow is either low (<200 m/h) or high (>1000 m/h), the solute concentrations and recovery rates are low. Conversely, the solute concentration and recovery rate are highest at a medium flow velocity (560 m/h), with the recovery rates ranging from 0.13 % to 92.44 %. A theoretical formula has been derived to estimate the solute loss from conduit flow to fissure flow. When the conduit is filled with water, an increase in the mean flow velocity leads to an augmentation in the amount of water recharged from the conduit into the fissures, as well as an increase in the stored solute mass, which results in a decrease in the solute recovery rate. The condition that poses the highest risk of groundwater pollution occurs at a medium flow velocity, where the solute concentration and recovery rate are all at their maximum levels. When the recharge rate at the sinkhole is very small, both the cross-sectional area and the mean flow velocity of the karst conduit are reduced. The rough bottom of the karst conduit leads to an increase in dispersivity, resulting in low solute concentration and recovery rate. The results elucidate the reasons behind the significant variations in solute recovery rates under different hydrodynamic conditions. They provide novel evidence for comprehending the water and solute exchange processes between conduits and fissures under concentrated recharge conditions. Furthermore, these findings offer a valuable reference for assessing the risk of groundwater pollution in karst areas.

Analysis of Existing Area, Clean Water Treatment, and Distribution Network Evaluation in Nagari Magek, Agam Regency, West Sumatra

Nagari Magek Village in Agam Regency, West Sumatra, faces significant challenges in managing clean water resources. To address these challenges comprehensively, a holistic approach is essential, involving through area analysis, water treatment, and evaluation of distribution networks to ensure efficient and equitable water distribution. It is crucial to adhere to the principles of water resource conservation, utilization, and management as stipulated in Law Number 17 of 2019 on water resource management, which must be observed to ensure legal clarity in water management practices. The community service team handles clean water problems in Nagari Magek by designing a clean water treatment system that includes aeration, sedimentation, and filtration units. This process improves water quality by reducing yellowish color and eliminating unpleasant odors. However, the capacity of the treatment plant is not able to meet the increasing water demand, while the galvanized pipe distribution network has not been functioning optimally. Based on simulations using EPANET 2.2 software, it was found that the water flow speed in the pipes was still below the optimal range due to the diameter of the pipes being too large. The solution applied was to increase the processing discharge to 10 L/s (0,01 m3/s), which succeeded in increasing the flow rate according to the regulatory criteria. This recommendation improves the efficiency of the distribution system and ensures better water quality for the people in Nagari Magek.