The 3D simulation and optimized management model of groundwater systems based on eco-environmental water demand

Through the study of mutual process between groundwater systems and eco-environmental water demand, the eco-environmental water demand is brought into groundwater systems model as the important water consumption item and unification of groundwater抯 economic, environmental and ecological functions were taken into account. Based on eco-environmental water demand at Da抋n in Jilin province, a three-dimensional simulation and optimized management model of groundwater systems was established. All water balance components of groundwater systems in 1998 and 1999 were simulated with this model and the best optimal exploitation scheme of groundwater systems in 2000 was determined, so that groundwater resource was efficiently utilized and good economic, ecologic and social benefits were obtained.

Water and nitrogen footprint assessment of integrated agronomic practice management in a summer maize cropping system

The footprints of water and nitrogen(WF and NF)provide a comprehensive overview of the type and quantity of water consumption and reactive nitrogen(Nr)loss in crop production.In this study,a field experiment over two years(2019 and 2020)compared three integrated agronomic practice management(IAPM)systems:An improved management system(T2),a high-yield production system(T3),and an integrated soil-crop management system(ISCM)using a local smallholder farmer’s practice system(T1)as control,to investigate the responses of WF,Nr losses,water use efficiency(WUE),and nitrogen use efficiency(NUE)to IAPM.The results showed that IAPM optimized water distribution and promoted water use by summer maize.The evapotranspiration over the whole maize growth period of IAPM increased,but yield increased more,leading to a significant increase in WUE.The WUE of the T2,T3,and ISCM treatments was significantly greater than in the T1 treatment,in 2019 and 2020respectively,by 19.8-21.5,31.8-40.6,and 34.4-44.6%.The lowest WF was found in the ISCM treatment,which was 31.0%lower than that of the T1 treatment.In addition,the ISCM treatment optimized soil total nitrogen(TN)distribution and significantly increased TN in the cultivated layer.Excessive nitrogen fertilizer was applied in treatment T3,producing the highest maize yield,and resulting in the highest Nr losses.In contrast,the ISCM treatment used a reduced nitrogen fertilizer rate,sacrificing grain yield partly,which reduced Nr losses and eventually led to a significant increase in nitrogen use efficiency and nitrogen recovery.The Nr level in the ISCM treatment was34.8%lower than in the T1 treatment while NUE was significantly higher than in the T1 treatment by 56.8-63.1%in2019 and 2020,respectively.Considering yield,WUE,NUE,WF,and NF together,ISCM should be used as a more sustainable and clean system for sustainable production of summer maize.

Exploration of Water and Soil Conservation's Function in Construction of Eco-environment

Eco-environment lays foundation for human existence and development, and social and economy evolvement. Therefore, it is a fundamental principle to pro- tact and construct eco-environment and achieve sustainable development. With ur- ban development, and destruction on natural environment, however, the issue of water and soil losses has become a serious problem, affecting people＇s life and production. The research, therefore, explored the role of water and soil conservation in ecological civilization construction, including bomprehensive treatment of water storage and sand reduction, improving agricultural structure and advancing rural econ- omy, relieving the conflict between supply and demand of water resources, improv- ing eco-environment in mountainous regions and accelerating eco-construction.

Rice Yield and Water Use as Affected by Soil Management Practices

A field experiment was conducted at the Shenyang Experimental Station ofEcology, Chinese Academy of Sciences, to study the effects of soil management practices on water useand rice (Oryza sativa L.) yield in an aquic brown soil during 2001 and 2002. A completely randomexperimental design with three replications was employed, having four soil management practices astreatments, namely: an undisturbed plow layer (CK), a thin plastic film (TN), a thick plastic film(TI) and subsoil compacting (CP). Results indicated no significant differences among all treatmentsfor rice biomass and grain yields. Also, water consumption was about the same for treatments TN andCK, however the treatments TI and CP were much lower with more than 45% and 40% of the irrigationwater in the treatments TI and CP, respectively, saved each year compared to CK. Therefore, wateruse efficiency was higher in the treatments TI and CP. These results will provide a scientific basisfor the water-saving rice cultivation.

Effects of Land Management Practices on Soil Water in Southwestern Mountainous Area, China

The effects of selected land management practices （cross-sloping tillage, ridge culture, organic manure, and straw mulch） on soil water conservation in a southwestern mountainous area, China, were studied during November 2002 to November 2004. The experimental field is divided into three parts based on soil layer depths, 0-60 cm （part Ⅰ）, 0-40 cm （part Ⅱ）, and 0- 20 cm （part Ⅲ）, and they all had the same slope azimuth （SE）, slope （10°）, and slope type （linear）. The experimental plots were subjected to the following treatments： cross-sloping tillage （CST）; cross-sloping tillage with organic manure （CST/ OM）; cross-sloping tillage with straw mulch （CST/SM）; contour ridge culture （CRC）; contour ridge culture with organic manure （CRC/OM）; and contour ridge culture with straw mulch （CRC/SM）, to identify the effects of management practices on soil water. Water contents were determined for soil samples collected, using a 2.2 cm diameter manual probe. Soil water was monitored once every five days from Nov. 20, 2002 to Nov. 20, 2004. The results indicated that, in the study stages, an integration of rainfall, evaporative losses, and crop transcription controlled the basic tendencies of profile （mean） soil water, while land management practices, to a certain extent, only modified its amount, distribution, and routing. Moreover, these modifications also mainly focused on the first 20 cm depth of topsoil layer. When each management practice was compared with control treatment, season changes of profile （mean） soil water were pronounced, while interannual changes among them were not significant. More comparisons indicated that, in the study stages, contour ridge culture had better effects than cross-sloping tillage. And under the same tillage, the combination of organic manure could achieve more than straw mulch. These management practices should be recommended considering the effectiveness of soil and water management techniques in the southwestern mountainous area, China.

Interactions of Water Management and Nitrogen Fertilizer on Nitrogen Absorption and Utilization in Rice

The interactions of water management and nitrogen fertilizer on nitrogen absorption and utilization were studied in rice with Wuxiangjing9 (japonica). The results showed that the nitrogen uptake and remaining in straw increased and the percentage of nitrogen translocation (PNT) from vegetative organs, nitrogen dry matter production efficiency (NDMPE) and nitrogen grain production efficiency (NGPE) decreased with nitrogen increasing. The nitrogen uptake and NGPE decreased when severe water stressed. However, rice not only decreased the nitrogen uptake but also increased the PNT from vegetative organs, NDMPE and NGPE when mild water stressed. There were obvious interactions between nitrogen fertilizer and water management, such as with water stress increasing the effect of nitrogen on increasing nitrogen uptake was reduced and that on decreasing NDMPE was intensified.

A simulation-based two-stage interval-stochastic programming model for water resources management in Kaidu-Konqi watershed,China

This study presented a simulation-based two-stage interval-stochastic programming （STIP） model to support water resources management in the Kaidu-Konqi watershed in Northwest China. The modeling system coupled a distributed hydrological model with an interval two-stage stochastic programing （ITSP）. The distributed hydrological model was used for establishing a rainfall-runoff forecast system, while random parameters were pro- vided by the statistical analysis of simulation outcomes water resources management planning in Kaidu-Konqi The developed STIP model was applied to a real case of watershed, where three scenarios with different water re- sources management policies were analyzed. The results indicated that water shortage mainly occurred in agri- culture, ecology and forestry sectors. In comparison, the water demand from municipality, industry and stock- breeding sectors can be satisfied due to their lower consumptions and higher economic values. Different policies for ecological water allocation can result in varied system benefits, and can help to identify desired water allocation plans with a maximum economic benefit and a minimum risk of system disruption under uncertainty.

SWOT Analysis and Challenges of Nile Basin Initiative:An Integrated Water Resource Management Perspective

River Nile is one of the longest transboundery rivers and it is shared and used by Burundi,Democratic Republic of Congo,Egypt,Ethiopia,Eritrea,Kenya,Rwanda,Sudan,Tanzania and Uganda.As of today,the Nile is a crucial resource for the economic development of the Nile Basin countries and a vital source of livelihood for 160 million inhabitants as well as 300 million people living in the 10 riparian countries.The Nile Basin Initiative(NBI) is one of the international cooperative river basin management program and regional partnership where all the Nile Basin countries except Eritrea unite to pursue long-term sustainable development,improved land use practices and management.This review therefore focused on the challenges not faced on NBI in terms of integrated use of the river and conducted analysis of strengths,weaknesses,opportunities and threats(SWOT) based on secondary data.The result of the review revealed that for decades,the Nile Basin people have been facing many complex environmental,social,economic and political challenges that have made it difficult for the proper management and sustainability of Nile water.The initiative provides training to develop skills in government ministries,non-governmental organizations and local communities in each country.It is also working to raise awareness of critical environmental issues by strengthening networks of environmental education practitioners;developing curriculum in the education sector.The challenges of NBI include the involvement and funding of World Bank,lack of sufficient staff,procedural and policies conflicts,lack of coordination and linkage with other regional institutions and lack of recognition as river basin organization.Considering the complex nature of the project,it is recommended that the NBI should come up with a strong multi-disciplinary monitoring and evaluation team to follow up all implemented projects.The NBI should carry out participatory land use planning in communities along the river basin.Moreover,livelihood analysis should be carried out especially in communities along the Nile to come up with poverty eradication projects which are socially acceptable,applicable,economically viable and affordable.

Natural water purification and water management by artificial groundwater recharge

Worldwide,several regions suffer from water scarcity and contamination.The infiltration and subsurface storage of rain and river water can reduce water stress.Artificial groundwater recharge,possibly combined with bank filtration,plant purification and/or the use of subsurface dams and artificial aquifers,is especially advantageous in areas where layers of gravel and sand exist below the earth's surface.Artificial infiltration of surface water into the uppermost aquifer has qualitative and quantitative advantages.The contamination of infiltrated river water will be reduced by natural attenuation.Clay minerals,iron hydroxide and humic matter as well as microorganisms located in the subsurface have high decontamination capacities.By this,a final water treatment,if necessary,becomes much easier and cheaper.The quantitative effect concerns the seasonally changing river discharge that influences the possibility of water extraction for drinking water purposes.Such changes can be equalised by seasonally adapted infiltration/extraction of water in/out of the aquifer according to the river discharge and the water need.This method enables a continuous water supply over the whole year.Generally,artificially recharged groundwater is better protected against pollution than surface water,and the delimitation of water protection zones makes it even more save.

Assessment of Fish Farming Practices, Operations, Water Resource Management and Profitability in Katsina State, Nigeria

This study assessed the fish production, culture facilities, operations, water resource management and profitability of fish farming in Katsina State, Nigeria, with a view of understanding the status of aquaculture development in Katsina State. Data were collected using structured questionnaire administered to 35 out of the active 42 farms in Katsina State at the period and the data obtained were analyzed using descriptive statistics and linear regression. Among the respondents, 37.1% used concrete tank alone and another 37.2% used concrete tank with other types of culture facilities, 57.1% practised mono-culture techniques and 77.1% used stagnant renewal system as culture system. Management of water quality was done by majority(82.9%) with mere visual evaluation, while 68.6% did not use any forms of water treatment. Most of the farms(80%) depended on imported feed for feeding their fish and gross profits of ■7.29±1.81 and ■157.83±118.08 were obtained on fingerlings and adult fish, respectively. The tested explanatory variables were responsible for 45.4% change in profitability and profitability was found to be dependent on feeding cost(t=–3.38 and p=0.002) and size of fish at harvest(t=2.70 and p=0.011). The research findings established that fish farming in Katsina State was under developed.

Reliability model of organization management chain of South-to-North Water Diversion Project during construction period

In order to analyze the indispensability of the organization management chain of the South-to-North Water Diversion Project （SNWDP）, two basic forms （series connection state and mixed state of both series connection and parallel connection） of the organization management chain can be abstracted. The indispensability of each form has been studied and is described in this paper. Through analysis of the reliability of the two basic forms, reliability models of the organization management chain in the series connection state and the mixed state of both series connection and parallel connection have been set up.

Virtual Water Trade as a Strategy to Water Resource Management in Iran

Agriculture has historically played a central role in the economy, life and culture of the Iranian population. Nowadays, this sector is facing the reality that its natural fresh water resources become fully utilized. Considering the climate conditions and limitation of using new water resources and the necessity of increasing agricultural product as a result of population growth, there is a general doubt about Iran’s ability to maintain this level of production amid the mounting water challenges, among other obstacles. Therefore, the evaluation of virtual water and water footprint can provide new indicators for informing water policy decisions. So, in order to study the situation at the national level, we estimated virtual water consumption in term of virtual water theory as well water footprint in agriculture sector of Iran. Data from 2001-2008 were used to account for yearly. The results of this study show that Iran has water import dependency and also net water import is 12.7 billion m3 averages. So Iran country saved 12.7 billion m3 from their domestic water resource for utilization in other sectors. Finally, it should be concluded that virtual water trade as a policy measure to water resources management will be provided to a great extent in order to reach both significant water saving and environmental sustainability.

Comparison of water resources management between China and the United States

As the world’s top two economies,the United States(U.S.)and China face a number of similar water resources problems.Yet,few studies have been done to systematically compare policies and approaches on water resources management between China and the U.S.This study compares water resources policies of China and the U.S.in the areas of national authority,water supply,water quality,and ecosystem use of the water to draw lessons learned and shed light on water resources management in China,the U.S.,and the rest of the world.The lessons learned from the comparison include six aspects.1)New paradigms of people-water harmony and a water-saving society are urgently needed to address the pressing water crisis and achieve the United Nations Sustainable Development Goals(UN SDGs).2)A comprehensive,consistent,forward-looking national policy is necessary to achieve sustainable use of water resources.3)Empowerment of river basin commissions with comprehensive authority over the integrative management of air,land,water,and biological resources in the river basin could significantly enhance the benefits and effectiveness of economic development and environmental protection.4)Expansion of water exchange through market mechanisms among water users promotes efficient and beneficial water uses.5)Use of water for ecosystem services should be an integral part of water resources management.China has set up a national blueprint for achieving ecological civilization;maintaining appropriate amounts of flow in rivers and lakes for maintenance of wildlife and fisheries and ecosystems should be institutionalized as part of this national strategy as well.6)By sharing their rich experiences and lessons in water resources management,economic development,and ecological protection with other countries,China and the U.S.can help the world to achieve global human-water harmony and the UN SDGs.

Exploring effective policies for underground water management in artificial oasis: a system dynamics analysis of a case study of Yaoba Oasis

The development of oasis along the edge of the Tengerli Desert, where underground water is available, is one of the major strategies to reallocate 'ecological refuges' from their seriously degraded grasslands to agriculturally cultivable land. Yet, underground water resources, the major constraint, hate not been fully integrated in the development process. Therefore, the decline of water resources and deterioration of water quality caused by over-consumption of water resources has begun to hinder further development and has even fed to the abandonment of some oasis. A system dynamics modeling approach is applied to analyze the water use and water management structures in Yaoba Oasis as a case study. The study attempts to identify the characteristics of major feedback loops, which dominate the over-use of underground water resources leading to the deterioration of water resources in quantity and quality.

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.

θ-improved limited tolerance relation model of incomplete information system for evaluation of water conservancy project management modernization

The modernization of water conservancy project management is a complicated engineering system involving a management system, a management method, management personnel, the exertion of social, economic, and ecological effects, and so on. However, indices for evaluating the modernization of water conservancy project management are usually unobtainable in practical applications. Conducting appropriate extension of the classical rough set theory and then applying it to an incomplete information system are the key to the application of the rough set theory Based on analysis of some extended rough set models in incomplete information systems, a rough set model based on the θ-improved limited tolerance relation is put forward. At the same time, upper approximation and lower approximation are defined under this improved relation. According to the evaluation index system and management practices, the threshold for θ is defined. An example study indicates the practicability and maneuverability of the model.

An integrated measurement and modeling methodology for estuarine water quality management

This paper describes research undertaken by the authors to develop an integrated measurement and modeling methodology for water quality management of estuaries. The approach developed utilizes modeling and measurement results in a synergistic manner. Modeling results were initially used to inform the field campaign of appropriate sampling locations and times, and field data were used to develop accurate models. Remote sensing techniques were used to capture data for both model development and model validation. Field surveys were undertaken to provide model initial conditions through data assimilation and determine nutrient fluxes into the model domain. From field data, salinity re- lationships were developed with various water quality parameters, and relationships between chlorophyll a concentrations, transparency, and light attenuation were also developed. These relationships proved to be invaluable in model development, particularly in modeling the growth and decay of chlorophyll a. Cork Harbour, an estuary that regularly experiences summer algal blooms due to anthropogenic sources of nutrients, was used as a case study to develop the methodology. The integration of remote sensing, conventional fieldwork, and modeling is one of the novel aspects of this research and the approach developed has widespread applicability.

Nitrogen and Phosphorus Loss Law and Emission Reduction Effects Under Water and Fertilizer Management Integrated Mode in Dike Paddy Field

To achieve the purpose of reducing farm non-point source pollution, we integrated site specific nitrogen management precise irrigation, controlled drainage, and wetland eco-repair system in dike area of Taihu basin. During investigation, it had given prominence for the water and fertilizer coupling effects of precise irrigation and site specific nutrient management, the characteristics of integration on controlled irrigation, controlled drainage and wetland ecosystem non-point source pollution control. Then the water and fertilizer integrated management mode of paddy field was put forward in Taihu basin where the water production efficiency increased to 1.64 kg. m-3, water saved 37.8%, fertilizer use efficiency raised 15,4%, yield raised 10%, and N, P load decreased 26%-72%. The modern agricultural and farmland ecosystems that control and cut down the farm non-point source pollution came into being, which can be a reference by Taihu basin to control its agricultural non-point source pollution and eutrophicated water body.

Modelling of Nature-Based Solutions (NBS) for Urban Water Management—Investment and Outscaling Implications at Basin and Regional Levels

This manuscript is an attempt to demonstrate effectiveness of nature-based solutions (NBS) and measures to reduce risk of flooding and environmental impact in urban settings. The nature-based solutions (NBS) were assessed as scenarios from experience of urban storm drainage and sewerage systems based on practices that improve urban water management through modelling using urban stormwater management model (SWMM). The model has been applied in a typical urban environment in the second city in Botswana, the City of Francistown, which has a population of more than one hundred thousand. By considering the 2-yr and 10-year storm events in a calibrated SWMM, NBS scenarios from a mix of low impact and drainage measures were considered. The considered NBS scenarios were used to determine their effectiveness in terms of reducing and controlling peak runoff, flood volumes, infiltration and evapotranspiration in the study area, which are vital in assessing the opportunity and challenge for sustainable management of water resources and associated tradeoff of investments in the urban contexts. The study demonstrates the usefulness of implementing effective measures for achieving NBS in urban context and possibility of outscaling at basin and regional levels.

Water and Nitrogen Management Effects on Biomass Accumulation and Partitioning in Two Potato Cultivars

Biomass accumulation and partitioning into different plant parts is a dynamic process during the plant growing period, which is influenced by crop management and climate factors. Adequate knowledge of biomass partitioning is important to manage the crops to gain maximum partitioning of assimilates into plant parts of economic significance, i.e. tubers in potato. This study was conducted using two potato cultivars grown in a sandy soil with center pivot irrigation under full irrigation (FI;irrigation to replenish 100% of water loss by evapotranspiration [ET]) and deficit irrigation (DI;replenish only 80% ET) and two nitrogen(N) rates (pre-plant + in-seasonN rates of 56 + 112 or 168 + 336 kg/ha). Plant samples were taken on 22, 44, 66, and 98 days after seedling emergence (DAE). With high N rate, tuber biomass of ‘Umatilla Russet’ cultivar in relation to total plant biomass varied from 23% - 88% and 25% - 86% over 22 to 98 DAE for the FI and DI treatments, respectively. The corresponding partitioning ranges were 30% - 93% and 38% - 93% at the low N rate. With respect to the‘Ranger Russet’ cultivar, biomass partitioning to tubers ranged from 36% - 82% and 23% - 84% for the FI and DI, respectively, at the high N rate, and 29% - 87% and 39% - 95% at the low N rate. Overall, this study demonstrated that within the range of N rate and irrigation treatments the biomass portioning into tubers was largely similar in both cultivars.