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The purpose of this paper is: to track the methods by which farmers access groundwater for irrigation in the North China Plain (NCP); to explore whether climate factors influence farmers’ decisions on the methods of groundwater access for irrigation; and to examine whether the amount of groundwater use for irrigation and crop yield systematically differ across groups of farmers using various methods of groundwater access, and how climate factors affect them.

Descriptive statistical analysis and econometric models are used on household survey data collected over several years and county-level climate data.

Over the past few decades, a significant share of farmers have switched the methods of groundwater access from collective tubewells to own tubewells or groundwater markets. Farmers who bought water from groundwater markets applied less water to wheat plots than those who had their own tubewells. However, wheat yield was not negatively affected. Both average climate conditions and long-term variations were found to be related to farmers’ choice of methods of groundwater access for irrigation. More frequent droughts and increasingly volatile temperatures both increased the likelihood of farmers gaining groundwater irrigation from markets.

The analysis results suggest farmers are using groundwater markets to help them adapt to climate change. Applying empirical analysis to identify the impact of the methods by which farmers access groundwater for irrigation on the amount of groundwater use and crop yield will help policy makers design reasonable adaptation policies for the NCP.

Water resources play a significant role in economic growth and socio-economic development. Jordan experiences water scarcity. As the water resources can be used in manufacturing and agriculture, their sustainable use and solutions to water scarcity problem can contribute to the sustainable economic and socio-economic development in Jordan. Furthermore, there are political and economic aspects of Jordan’s water scarcity. Jordan is trying to solve its water scarcity problem through projects. Based on an in-depth literature review, this chapter aims to investigate Jordan’s water scarcity problem, highlighting its political and economic aspects and their impacts on socio-economic development, and to propose solutions to the water scarcity problem in Jordan. Water is vital for economic development and political stability in Jordan. It is important for Jordan to use its water resources in an efficient, effective and sustainable way so that socio-economic development of Jordan can be supported. Unsustainable use of water resources can cause depletion of Jordan’s scarce water resources, which can exacerbate magnitude of water resource problem and hinder socio-economic development. This chapter can be beneficial to economists, politicians and academics.

Groundwater plays a critical part in both natural and human existence. When surface water is scarce in arid climates, groundwater becomes an immensely valuable resource. Dak Lak is an area that frequently lacks water resources for everyday living and production, and the scarcity of water resources is exacerbated during the dry season. As a result, it is critical to do study and understand about groundwater to meet the region's water demand. This study aims to extend the use of the MODFLOW model for groundwater simulation and assess the overall groundwater reserves and water demand in the highland province Dak Lak.

The MODFLOW model is used in this work to compute and analyze the flow, prospective reserves of groundwater from which to plan extraction and estimate groundwater variation in the future.

The application of the MODFLOW model to Dak Lak province demonstrates that, despite limited data, particularly drilling hole data for subterranean water research, the model's calculation results have demonstrated its reliability and great potential for use in other similar places. The use of the model in conjunction with other data extraction modules is a useful input for creating underground flow module maps for various time periods. The large impact of recharge and evaporation on groundwater supplies and water balance in the research area is demonstrated by simulations of climate change scenarios RCP4.5 and RCP8.5.

None of the studies has been done previously to analyze water resources of Dak Lak and the scarcity of water resources is exacerbated during the dry season. Therefore, this study will provide useful insights in the water resource management and the conservation of Dak Lak. The groundwater in Dak Lak can meet the area's water demand, according to the results obtained and water balance in the study area. However, the management of water resources and rigorous monitoring of groundwater extraction activities in the area should receive more attention.

Major land use changes can have a significant impact on the environment, e.g. increased leaching and run‐off losses of nutrients and water contamination. Nitrate (NO₃^–) can be easily leached and, when present at high concentrations in drinking water, can be a health hazard. This paper seeks to report an easy‐to‐use computer model designed to provide predictions of possible impacts on groundwater NO₃^– concentration on a regional scale.

The model takes into account NO₃^–‐N concentrations from various land use activities, land surface recharge rates (as affected by soil water retention capacity, land management, irrigation and rainfall), and mixing of surface recharge and river recharge. Spatial information on land use and groundwater recharge sources are lumped into groundwater management zones (100‐500 km²), and vertical concentration profiles of NO₃^– in groundwater are estimated from a one‐dimensional dispersion model. The model is applied to the 2,300 km² Central Canterbury Plains of New Zealand.

A scenario analysis for the Bankside groundwater management zone showed that the NO₃^–‐N concentration at the groundwater surface could increase from 7.8 mg N L^‐1 to 11.3 mg N L^‐1 if all the land used for sheep farming is replaced by dairy farming (increasing dairy land from 21 per cent to 64 per cent of the total land area). However, the impact of such land use changes on the NO₃^–‐N concentration 50 m below the groundwater surface was relatively small, resulting in an increase of NO₃^–‐N concentration from 0.4 to 0.5 mg N L^‐1. This is because of the significant mixing of surface recharge with river recharge at this depth.

The model can serve as a useful tool for first‐order estimation of possible trends of NO₃^–‐N concentration profiles in aquifers as a result of land use changes.

The purpose of this paper is to indicate the limitations of the studies that address the impact of climate change on groundwater resources and to suggest an improved approach.

A general review, both from a groundwater hydrological and a climatological viewpoint, is given, oriented on the impact of climate change on groundwater resources.

The impact of climate change on groundwater resources is not the subject of many studies in the scientific literature. Only rarely sophisticated downscaling techniques are applied to downscale estimated global circulation model (GCM) future precipitation series for a point or region of interest. Often it is not taken into account that different climate models calculate considerably different precipitation amounts (conceptual uncertainty). The joint downscaling of the meteorological variables that govern potential evapotranspiration (ET) is never done in the context of a study that assessed the impact of climate change on groundwater resources. It is desirable that actual ET is calculated in (groundwater) hydrological models on a physical basis, i.e. by coupling the energy and water balance at the Earth's surface.

This review signalises a number of problems with published studies on the impact of climate change on groundwater resources. In many studies the method to downscale meteorological variables from a climate model to a hydrological model is not adequate. ET is often calculated in a strongly simplified manner and not all hydrological processes are modelled in a fully coupled fashion. More sophisticated downscaling approaches, physically based schemes to calculate ET and well‐calibrated, integrative hydrological models are needed.

The elevated level of nitrate in groundwater is a serious problem in Texas aquifers. To control and manage groundwater quality, the characterization of groundwater contamination and identification of the factors affecting the nitrate concentration of groundwater are significant. The purpose of this paper is to determine factors which have significant impacts on the elevated groundwater nitrate concentrations of the Southern High-Plains and the Edwards-Trinity aquifers.

The characterization of groundwater nitrate contamination was undertaken by analyzing the hydrochemical data of groundwater within a statistical framework. The multivariate statistical analysis (ordinary least square) and geographically weighted regression (GWR) models were used to study the relationship between groundwater nitrate contamination and land use of the study areas.

Results show groundwater nitrate contamination is typically due to an overapplication of N fertilizers to cotton in the Southern High-Plains aquifer and to grassland in the Edwards-Trinity aquifer. Adjusted R² (0.45) explains variations of nitrate concentration by well-depth, cotton production, shrubland and grassland in the Edwards-Trinity aquifer. The results of an analysis of variations in N concentration with well depth for all 192 wells indicate that nitrate concentrations in water from wells in the Southern High-Plains and Edwards-Trinity aquifers tend to decrease with increasing well-depth.

In this study, the GWR model was built to identify nitrate concentration within a geographic framework to ensure sustainable use of groundwater, which is important for local management purposes. The analysis should include local spatial variations of elements such as hydrologic characteristics and the land use activities if groundwater nitrate contamination causes adverse effects on human and ecosystem health.

Groundwater is an important source of water supply in arid and semi-arid areas. The purpose of this study is to predict the impact of climate change on groundwater recharge in an arid environment in Ilam Province, west of Iran.

A three-dimensional transient groundwater flow model (modular finite difference groundwater FLOW model: MODFLOW) was used to simulate the impacts of three climate scenarios (i.e. an average of a long-term rainfall, predicted rainfall in 2015-2030 and three years moving average rainfall) on groundwater recharge and groundwater levels. Various climate scenarios in Long Ashton Research Station Weather Generator were applied to predict weather data.

HadCM3 climatic model and A2 emission scenario were selected as the best methods for weather data generation. Based on the results of these models, annual precipitation will decrease by 3 per cent during 2015-2030. For three emission scenarios, i.e. an average of a long-term rainfall, predicted rainfall in 2015-2030 and three years moving average rainfall, precipitation in 2030 is estimated to be 265, 257 and 247 mm, respectively. For the studied aquifer, predicted recharge will decrease compared to recharge calculated based on the average of long-term rainfall.

The decline of groundwater level in the study area was 11.45 m during the past 24 years or 0.48 m/year. Annual groundwater depletion should increase to 0.75 m in the coming 16 years via climate change. Climate change adaptation policies in the basin should include changing the crop type, as well as water productivity and irrigation efficiency enhancement at the farm and regional scales.

Suggests a spatial conjunctive use model of an irrigation project in which the utility invest optimally for the water distribution system and charge farmers the shadow price of surface and groundwater. Seepage from the irrigation canal and on the field are assumed to recharge the groundwater aquifer. Particular attention was given to the effects of conveyance on the allocation of both surface and groundwater resources and the distribution of rents. An empirical model indicated that higher conveyance costs skew the distribution of water as well as rents over the project area. This suggests that the tail farmers need to face a substantially higher price for water if the system deteriorates and conveyance costs increase in the long run.

To illuminate the underlying logic of western Kansas farmers’ decisions to irrigate at unsustainable rates and the state’s regulatory policies and practices that enable depletion of the Ogallala aquifer.

Ethnographic interviewing of 39 western Kansas farmers, state water management personnel, and archival research.

Farmers occupy an ambiguous position as petty capitalists who focus attention on their own farms with seasonal planning horizons, and they hold a view of “good stewardship” that melds economic and noneconomic considerations, and that provides a rationale for unsustainable irrigation practices. The state resolves the contradiction between the finite groundwater resource and ideological commitments to economic growth by devolving responsibility for water management to groundwater users.

While the small sample size is likely to be representative of the larger pool of irrigators, further research with other farmers representative of the region will be necessary to verify findings.

Depletion of the Ogallala aquifer contributes to farm consolidation and community decline, and the ecological costs will leave future farmers and remaining communities without the benefits of groundwater. Western Kansas will likely have to revert to a system of dryland farming.

The chemical analysis of wells in the Ardabil area, Ardabil Province NW of Iran, was evaluated to determine the hydrogeochemical processes and ion concentration background in the region. The purpose of this study is to analyze the hydrochemical quality of groundwater in Ardabil aquifer in order to assess the suitability of the waters for different uses.

The chemical analysis of 75 water wells in the Ardabil area, was evaluated. Over the entire area, the dominated hydrochemical types are: Na-Cl, Na-HCO3-Cl-Mg, Ca-SO4, Ca-Mg-SO4-Cl and Ca-Mg-HCO3. The abundance of the major ions is as follows: Na⁺>Ca²⁺>Mg²⁺>K⁺ and SO₄^2–> Cl^–>HCO₃^– and major ion concentrations are below the acceptable level for drinking water. Most of groundwater samples fell in the soft water category. All of groundwaters belong to the excellent category and can be used safely for irrigation.

The chemical analysis of 75 water wells in the Ardabil area, Ardabil Province NW of Iran, was evaluated to determine the hydrogeochemical processes and ion concentration background in the region. Over the entire area, the dominated hydrochemical types are: Na-Cl, Na-HCO3-Cl-Mg, Ca-SO4, Ca-Mg-SO4-Cl and Ca-Mg-HCO3. The abundance of the major ions is as follows: Na⁺>Ca²⁺>Mg²⁺>K⁺ and SO₄^2–> Cl^–>HCO₃^– and major ion concentrations are below the acceptable level for drinking water. Most of groundwater samples fell in the soft water category. All of groundwaters belong to the excellent category and can be used safely for irrigation.

The chemical analysis of 75 water wells in the Ardabil area, Ardabil Province NW of Iran, was evaluated to determine the hydrogeochemical processes and ion concentration background in the region. Over the entire area, the dominated hydrochemical types are: Na-Cl, Na-HCO3-Cl-Mg, Ca-SO4, Ca-Mg-SO4-Cl and Ca-Mg-HCO3. The abundance of the major ions is as follows: Na⁺>Ca²⁺>Mg²⁺>K⁺ and SO₄^2–> Cl^–>HCO₃^– and major ion concentrations are below the acceptable level for drinking water. Most of groundwater samples fell in the soft water category. All of groundwaters belong to the excellent category and can be used safely for irrigation.