Abstract

Assessments of Hydrologic Systems Responses to Excessive Droughts
Track: Water Resources
Authors: Assaf Alhawas

During excessive droughts and elongated zero-runoff time spans drainage systems under go several changes imposed by exogenous variables. The length of the time spans separating runoff generating rainy events in a specific location besides the severity of the exogenous factor determines the significance of changes imposed on ephemeral drainage systems by aerobic variables. Those processes of a degenerative nature, include, but not limited to, bank wind corrosion and bank collapses, sand, dust bio-remains and other windblown materials accumulation in channel bottoms.
Significant changes in suspended sediment concentrations, flood hydrograph shape, runoff generation and peaking time are noted in all drainage systems. The changes are more significant when following a longer dry span and are noticeable in the first runoff event in the season. No significant morphometric changes in the drainage systems were detected. Several tools were utilized in this analysis especially those of the spatial analyst hydrology tools in ArcGIS.