Prediction of water table in an alluvial aquifer using modflow

Groundwater is the main source of water in the Kingdom of Saudi Arabia (KSA). A larger part of groundwater is founded in alluvial (unconfined) aquifers. Prediction of water table elevations in unconfined aquifers is very useful in water resources planning and management. During the last two decades, many aquifers in different regions of the KSA experienced significant groundwater decline. The declines in these aquifers raised concerns over the quantity and quality of groundwater, as well as concerns over the planning and management policies used in KSA. The main objective of this study was to predict water table fluctuations and to estimate the annual change in water table at an alluvial aquifer at wadi Hada Al Sham near Makkah, KSA. The methodology was achieved using numerical groundwater model (MODFLOW). The model was calibrated and then used to predict water table elevations due to pumping for a period of 5 years. The output of the model was found to be in agreement with the previous records. Moreover, the simulation results also show reasonable declination of water table elevations in the study area during the study period

Prediction of the Effect of Pumping on Al-Wasia Well Field

Al-Wasia Aquifer is one of the major aquifers in Saudi Arabia which is found in the Central and Eastern regions of the country. Al-Wasia well field (62 wells) has been in operation since 1981 to supply water to Riyadh. It is located about 110 km north-east of Riyadh close to Riyadh-Dammam Highway. Amounts and rates of pumping from the well field have been changing during the last few years depending on water demand of Riyadh. The operation of the well field is examined under three different pumping stresses. The choice of a pumping pattern is according to the expected amount of pumped water from the well field to meet water demand of Riyadh. A two-dimensional regional ground water flow model (REGNLGW) is utilized to predict the expected water/piezometric levels in the well field due to the different pumping patterns up to the year 2010. The results of the simulation of the different pumping patterns show that piezometric level, in the year 2010, will not reach the critical depth of 300 m below ground surface. This depth is assumed critical because it is economically infeasible to extract water from depths greater than 300 m

Prediction of flood levels along a stretch of the Langat River with insufficient hydrological data

Malaysia is a tropical country and it is subjected to flooding in both the urban and rural areas. Flood modelling can help to reduce the impacts of flood hazard by taking extra precautions. HEC-RAS model was used to predict the flood levels at selected reach of the Langat River with a total length of 34.4 km. The Langat River is located in the state of Selangor, Malaysia and it is subjected to regular flooding. The selected reach of the Langat River has insufficient data and a methodology was proposed to overcome this particular problem. Since complete floodplain data for the area are not available, the modelling therefore assumed vertical walls at the left and right banks of the Langat River and all the predicted flood levels above the banks were based on this assumption. The HEC-RAS model was calibrated and the values of Manning's coefficients of roughness for the Langat River were found to range from 0.04 to 0.10. The discharge values were calculated for 5, 10, 25, 50, and 100 year return periods and the maximum predicted flood depth ranged from 2.1m to 7.8m. Meanwhile, the model output was verified using the historical record and the error between the recorded and predicted water levels was found to range from 3% to 15%

Diagnosis and management of vitamin D deficiency in the Gulf Cooperative Council (GCC) countries: an expert consensus summary statement from the GCC vitamin D advisory board.

OBJECTIVE A summary of recommendations is given within the Gulf Cooperation Council (GCC) setting on the assessment and management of vitamin D deficiency in the region. METHODS An assembly of 11 regional experts gathered to formulate an all-inclusive approach to vitamin D deficiency within GCC. RESULTS AND CONCLUSION Several gaps were identified before regional guidelines could be developed. These include adequacy and standardization of vitamin D testing, frequency of repeated testing and reference ranges, distinguishing prevention from the treatment of vitamin D deficiency, quality assurance of vitamin D products sold within GCC including contents and origins of products, and cut-points for vitamin D levels in local populations. A platform is created that can be further developed for overall regional implementation