Groundwater Over-Pumping and Recent Earthquakes in the Northern United Arab Emirates: A Natural Hazard Accentuated by Human Activity

At the present day the United Arab Emirates (UAE) is on the flank of the Arabian plate, but some way away from the major modern earthquake epicentres. It normally experiences only minor earthquakes whose epicentres lie along the suture between the Arabian and Asiatic plates in Iran, the Arabian Gulf and the Gulf of Oman. In March 2002 a series of earthquakes occurred in several areas in the northern UAE, with foci along fault lines within the UAE. What made these earthquakes different from earlier earthquakes was their strength and frequency. For the first time in the area, earthquakes of a magnitude 5.5 (on the Richter scale) occurred, and continued over a period of three days. The causes appear to involve more than fault zone and plate tectonics, and may be related to human activity. Tracing the earthquakes during the past three decades indicates that the earthquakes followed major groundwater over-pumping, itself a result of population growth, growth in the number of farms and number of bottled water factories.

Optimization of water-urban-agricultural-ecological land use pattern:A case study of Guanzhong Basin in the southern Loess Plateau of Shaanxi Province,China

Extensive land use will cause many environmental problems.It is an urgent task to improve land use efficiency and optimize land use patterns.In recent years,due to the flow decrease,the Guanzhong Basin in Shaanxi Province is confronted with the problem of insufficient water resources reserve.Based on the Coupled Ground-Water and Surface-Water Flow Model(GSFLOW),this paper evaluates the response of water resources in the basin to changes in land use patterns,optimizes the land use pattern,improves the ecological and economic benefits,and the efficiency of various spatial development,providing a reference for ecological protection and high-quality development of the Yellow River Basin.The research shows that the land use pattern in the Guanzhong Basin should be further optimized.Under the condition of considering ecological and economic development,the percentage change of the optimum area of farmland,forest,grassland,water area,and urban area compared with the current land use area ratio is+2.3,+2.4,-6.1,+0.2,and+1.6,respectively.The economic and ecological value of land increases by14.1%and 3.1%,respectively,and the number of water resources can increase by 2.5%.

Evaluation of the performance of a centralized ground-water heat pump system in cold climate region

The aim of this study is to performance of a centralized open-loop evaluate the ground-water heat pump （GWHP） system for climate conditioning in Beijing with a cold climate in China. Thus, a long-time test was conducted on a running GWHP system for the heating season from December 2011 to March 2012. The analysis of the testing data indicates that the average heat-pump coefficient of performance （COP） and the COP of the system （COPs） are 4.27 and 2.59. The low value and large fluctuation in the range of COP are found to be caused by the heat transfixion in the aquifer and the bypass in the circulation loop. Therefore, some suggestions are proposed to improve the performance for GWHPs in the cold climate region in China.

Experimental study of the effect of shallow groundwater table on soil thermal properties

In plains areas with semi-arid climates, shallow groundwater is one of the important factors affecting soil thermal properties. In this study, soil temperature and water content were measured when groundwater tables reached 10 cm, 30 cm, and 60 cm depths （Experiment I, II, and III） by using sensors embedded at depths of 5 cm, 10 cm, 20 cm, and 30 cm for 5 days. Soil thermal properties were analyzed based on the experimental data using the simplified de Vries model. Results show that soil water content and temperature have fluctuations that coincide with the 24 h diurnal cycle, and the amplitude of these fluctuations decreased with the increase in groundwater table depth. The amplitude of soil water content at 5 cm depth decreased from 0.025 m^3·m^-3 in Experiment II to 0.01 m^3·m^-3 in Experiment III. Moreover, it should be noted that the soil temperature in Experiment III gradually went up with the lowest value increasing from 26.0℃ to 28.8℃. By contrast, the trends were not evident in Experiments I and II. Results indicate that shallow groundwater has a ＂cooling＂ effect on soil in the capillary zone. In addition, calculated values of thermal conductivity and heat capacity declined with the increasing depth of the groundwater table, which is consistent with experimental results. The thermal conductivity was stable at a value of 2.3 W.cm^-1·K^-1 in Experiment I. The average values of thermal conductivity at different soil depths in Experiment II were 1.82 W.cm^-1·K^-1, 2.15 W.cm^-1·K^-1, and 2.21 W. cm^-1·K^-1, which were always higher than that in Experiment III.

Influence of the sewage irrigation on the agricultural soil properties in Tongliao City, China

Increasing shortages of fresh water has led to greater use of treated wastewater for irrigation of crops. This study evaluates the spatial variability of soil proper- ties after irrigation with wastewater and freshwater. Geostatistical techniques were used to identify the variability of soil properties at the different sites. A set of physical and chemical soil properties were measured including total nitrogen （TN）, total phosphorus （TP）, organic matter （OM） and soil moisture. The TN concen- tration levels varied from 567 to 700 mg. kg-1, while OC levels ranged from 7.3 to 16.3 mg.kg-1 in wastewater- irrigated zones. The concentration levels of TP were between 371.53 and 402.88 mg-kg-1 for the wastewater- irrigated sites. Wastewater irrigation resulted in higher TN, TP and OM concentrations by 18.4%, 8% and 25%, respectively. The highest TN and OM occurred along the wastewater trunk. It was also observed that nitrogen concentrations correlate with the soil＇s organic matter. The increase of salinity may be associated with the increase of pH, which might suggest that a reduction of pH will be beneficial for plant growth due to the decrease of salinity. The average concentrations of nitrogen in topsoil were higher than those in subsurface soils in irrigated areas. Such differences of the N profile might be due to variations in organic matter content and microbial populations. Consistent with TN and OM, soil C：N decreased significantly with an increase of depth. This phenomenon possibly reflects a greater degree of breakdown and the older age of humus stored in the deeper soil layers. The analysis of pH levels at different depths for the three sites showed that pH values for wastewater irrigation were slightly lower than the controlled sites at the same depths.