Decision of The Hydraulic State of Rivers within Growth Cities using GIS: Al-Hneidiyah River as Example

Abstract

Generally, the rivers in both the natural and lined form use the open-section system to carry water, either for distribution or conveyance purposes. With time and depreciation effect, this system needs to be changed or modified to become more indirectly suitable with cities' growth, especially with the transformation of land use from agricultural to residential. The present paper aims to reach a proper decision to select the best hydraulic section for a part of Al-Hneidiyah river in Karbala city by determining the remain agricultural lands within the study area, for the distance between stations (0+000) and (4+000), to choose between keeping up the currently open section or change, (modify), it to a closed conduit. For this study, the cadastral maps were used as a reference to determine the agricultural areas served by the river during its route within the study area, and geographic information system to monitor the change like these areas represented by a gradual transformation from agricultural to residential purpose, by using of satellite images for four different years, 2002, 2007, 2013, and 2016. The results of this study showed a significant recession in the agricultural areas on both sides of the chosen length of river route by a percentage of 13.45%, which leads to an urgent need to change or modify the flow system from opened to closed and use it only for conveyance purposes to protect the water quality and water shares. The geographic information system is a good and helpful technique for evaluation and makes water-related subjects decisions by giving a clear vision of the studied problem.