Flood damages are usually concentrated along certain reaches of the main watercourse. However, a successful flood-control project must look beyond the damaged reaches by studying the contribution of headwater subwatersheds to the flood magnitude at downstream locations. Flood-control measures may then be initially planned in identified flood tributary areas of the watershed that strongly affect the flood peak at downstream river reaches. A simple iterative simulation technique is introduced, whereby the contribution of each subwatershed unit or group of subwatershed units to the flood peak response can be disaggregated. A flood index may then be assigned to each contributing unit to determine the change in response of outlet flood discharge caused by removal of that unit. The technique is similar to the unit response approach in groundwater studies. The proposed technique is applied to a watershed; and the effect of such different factors as design return period, storm duration, and size of the contributi...

Wind erosion is one of the most serious problems in the Sistan region, located in the East ofIran and near the border of Afghanistan. During the dry and hot seasons, strong winds locally called the "Sadobist Roozeh", which means "120 windy days" blow from Northern and Northwestern directions to the Southeast. This wind entrains and transports dust and sand from the dry beds of ephemeral lakes, affecting the Sistan region in Iran, southern Afghanistan and northern Pakistan. In order to investigate the land surface sensitivity to aeolian transport, 74 graduated pins were embedded randomly in the ephemeral Baringak Lake bed and the aeolian transport rates were measured for three events in 2013 individually as well as for the total study period. The spatial and temporal variation of the aeolian transport was also mapped using GIS and geostatistical methods for these events and for the total duration of 103 days. The resulting variograms revealed a high spatial dependence of the different events and showed that geostatistical techniques are a valid tool for the mapping of aeolian sediment transport. The average transport rate in terms of the detected drift height on the dry lake bed was 1.93 cm or 31 kg/m² between the 5^th of August and the 17^th of November in 2013.