Ampar Shetty

A geoelectrical and hydrogeological study for the assessment of groundwater resources in Wadi Al Bih, UAE

Drilling information, historical water table levels, groundwater salinity records of the existing water wells in Wadi Al Bih area, United Arab Emirates, were stored in a geodatabase and used to characterize the geological and hydrogeological settings of this area. A 2D earth resistivity imaging survey was conducted for the first time in the Northern UAE to determine the potential of the Quaternary aquifer and its groundwater quality in the areas where there are no monitoring wells. The results of the chemical analyses of the collected groundwater samples together with the inversion results of the resistivity data were used to draw a total salinity map and determine the spatial variations in groundwater quality. The inversion results of the 2D earth resistivity imaging data indicated that the Quaternary aquifer in the study area is in a good connection with the underlying carbonate aquifer. It also indicated that the carbonate aquifer is of major regional and vertical extension and it contains the fresh water in this area. The data stored in the developed database were used to produce different types of geopotential maps.

Freshwater Storage in Brackish Aquifers

In this paper, MODFLOW was used to investigate the long-term injection and recovery of freshwater in the brackish aquifer of Wadi Ham, United Arab Emirates. The simulations were conducted for six successive cycles of injection and recovery with constant recharge and recovery rates and also constant durations. The simulations were also performed for various rates of injection and recovery and the recovery efficiency of the system was evaluated. The recovery efficiency varied between 32% and 88% and increased significantly during the first three cycles and then slightly in the following runs. The effect of the injection and recovery rates and the duration of the recharge were also investigated.

Seawater Intrusion Assessment and Mitigation in the Coastal Aquifer of Wadi Ham

The United Arab Emirates (UAE) typifies an arid environment with limited freshwater resources and harsh climatic conditions. Rainfall is scarce, random and can be regarded as an integral element of the water resources at UAE. Groundwater resources, although non-renewable, contribute by more than 50 % of the total water demand in the country. Due to the excessive pumping of groundwater to meet the agriculture demands, groundwater levels have declined in the coastal aquifer of Wadi Ham and the quality of the water has deteriorated due to the seawater intrusion problem.

Drainage Analysis of Mountainous Watersheds in Ras Al Khaimah Emirate, UAE

Many Wadis in the Arab Emirates (UAE) are active during rainy periods. Geomorphologically, the UAE is composed of mountains, gravel plains, sand dunes, and coastal zones. The runoff generation in these Wadis represents a complex phenomenon because of the topography of drainage basin. Morphological parameters were estimated and analyzed for the surface runoff generation and flooding possibility of twelve catchments in Ras Al Khaimah area of UAE. Hydrologic Engineering Center-Hydrologic Modeling System model is used to estimate the water yield in Wadi Al Bih due to rainfall events. Simulated results were compared with the observed water storage data of several historical storm events for the calibration of the model. The obtained results were compared with the observed yield and are found accurate and within an average of error 10%. Rainfall-runoff/yield curves were developed based on the duration and intensity of rainfall distribution. These curves can be used for prediction of surface water runoff and water storage in dams due to different rainfall events. Keywords-Geomorphology, Watershed, Flood, Rainfall-runoff, United Arab Emirates.

Rainfall and Intensity-Duration-Frequency (IDF) Curves in the United Arab Emirates

This paper discusses the spatial and temporal rainfall characteristics in UAE. The country is divided into for climatic regions including the east coast, mountainous area, gravel plains, and the desert foreland. Available data, from 42 rain gauge stations, were used to develop relations among the four climatic regions and define the changes in the rainfall pattern during the last decade. The double mass curve technique was used to investigate the homogeneity of the data. Statistical moments of annual rainfall events were estimated for all stations. The 24-h annual maximum and the mean annual rainfall data for the four regions were analyzed for estimating the expected rainfall at different return periods using different methods. The rainfall data are presented using the intensity-duration-frequency curves which were derived from the point rainfall frequency analysis and the possible occurrence of flash floods in the different areas is discussed. It is concluded that the four regions have similar rainfall patterns but with significantly different magnitudes. The results of this study serve as a baseline data for all hydrological studies including design of dams, rehabilitation projects and mitigation of possible flood hazardous.