Hydrogeological Conditions, and Surface Water Drainage System of Wadi Al-Murr Sub Basin, Northernwest of Iraq

Abstract

Al-Murr valley is one of the intermittent valleys in the northernwest of Iraq, in which the water flows in short flood waves after rainfall storms, and eventually flows into Tigris River at the Aski Mosul Town.

The surface drainage watershed of the basin was derived using (Arc GIS 10) based on the space shuttle radar data (SRTM-DEM) which called Digital Elevation Model (DEM), with discriminatory accuracy of (30x30) meters, according to contour lines and surface water divides, the stream orders reached to six, they varied in their numbers from order to another.

The geological and hydrogeological conditions of the basin were studied, and two aquifers were distinguished; Injana as semi-confined aquifer and Quaternary sediments as unconfined aquifer, also groundwater table map was plotted according to data of (101) wells, and then flow net of groundwater were derived and indicate that there are to main groundwater flow directions; the first from the north and northeast toward the center of the area, from ​​Ain Zala and Butma anticlines as recharge areas to Wadi al-Murr as discharge area, the hydraulic gradient is about (0.0087) in the recharge area and (0.0037) in the drainage area, while the second flow direction is from south and southwest toward the center of the study area, from Sinjar, Shkaft, Sasan and Shaikh Ibrahim anticlines as recharge areas to Wadi al-Murr as discharge area, the hydraulic gradient is about (0.01) at the recharge area and (0.0053) in drainage area, and this trend is compatible with the direction of the surface drainage system (valleys) and the slope of land topography of the area.

The hydraulic properties were evaluated according to the pumping rate and groundwater table drawdown data in (81) pumping wells, it was observed that the values ​​of the Transmssivity (T) ranged from (3- 414) m²/day, either hydraulic conductivity ​​(K) ranged from (0.2-12.7) m/day.