التحريات الهيدرولوجية لبعض الترب المحاذية لجنوب بحر النجف-العراق

Abstract

The study area was selected in the Najaf Governorate. It's adjacent to the southern part of Al- Najaf Sea and its area (17150.5 ha), located between the longitudes 425594E and 445138E and between the Latitudes 3521842N and 3538169N (UTM), it's covered all the soil types and geomorphological units which located within the sedimentary environment of Al- Najaf Sea.. The grade method was used to obtain hydrological measurements through 94 auger holes, which were located in a library with a 1000 m interval between a hole and another, and geographically using a GPS device. Some hydrological investigations were carried out to soil in the study area, including permeability of the soil, depth of the ground water, calculation of the distances between the field drainage, and the water infiltration rate in the soil. The results of field measurements of soil permeability ranged from 0.65 to 4.60 m. Day-1 , were classified between Class III and Class VI (Medium Slow and Fast), with clear dominance of Class IV and V (Medium and Medium Fast) which reached 91.5% of the examination sites. The depth of the ground water in the region ranged from 1.08 to 2.24 m. According to the cartographic analysis of the map of this hydrological index, the dominance depth was (1.50-1.75m) with percentage 34.81%. While the depth (1.75-2.00 m) showed the lowest percentage reached 9.20%. The calculations of distances between the deranges based on the hydrological characteristics ranged between (47 - 140 m) with a clear effect of the physiological unit in the values of this indicator, noting the need to take them into account when designing the drainage system network in the future. In reference to the recommendations of the National Center for Water Resources Management for the distances between the drainages, the cartographic analysis of the shape of this parameter showed that the class of B (75 m) was the dominance with percentage 60.14%, while class A (100 m) recorded the lowest percentage of 7.86% The water infiltration rate according to sub great group which classified in the region was ranged from 0.18 to 8.50 cm.h-1 , which classified between slow to moderately m velocity, and the heterogeneity recorded in the values of this characteristic was due mainly to the texture class of the surface layer