ABSTRACT

The objective of this study is to give an introduction into the intermittent rivers in Kabul region of Kabul river basin and to outline the major flow and sediment transport characteristics of these special river systems. Intermittent rivers are defined as rivers with a high seasonal variability in water and sediment transport. As dominant hydrological characteristics of intermittent rivers, river discharges with the groundwater levels are compared in lowland as well as in upland rivers, to understand the interaction between groundwater and surface water. Suspended sediment and river bed sediments are studied to understand the sedimentological behavior of these rivers. From the investigated data, it can be seen that monthly measured groundwater levels in the vicinity wells reflect the flow fluctuations in the rivers. Suspended sediment transport mainly occurs during spring (March-May), when the highest discharge rates are measured. The measurements show in addition an order of magnitude higher suspended sediment transport rates in lowland intermittent rivers compared to the upland rivers. Sieve and granulometric analysis of river bed sediment shows a coarser grain size composition for upland rivers compared to lowland rivers.