ABSTRACT
In most reservoirs that are constructed by damming a river (such as water-supply or hydropower reservoirs), sedimentation processes lead to an undesired capacity loss. A major part of the sediment is deposited at the head of the reservoir where it directly affects the active storage. These deltaic sediment deposits in reservoirs develops usually progressively in both downstream and upstream direction, e.g. see figure 1. Because of its direct threat to the capacity and lifetime of a reservoir, most attention is paid to the downstream progress of the deltaic deposits into the active storage. Nevertheless, the deposition extending in upstream direction, i.e. the tail reach, becomes increasingly important when it causes water levels over significant reaches. Due to sedimentation in the backwater reach local water-surface elevations are increased, creating additional backwater and deposition even further upstream. This feedback mechanism allows the depositional environment to propagate much further upstream than the initial backwater curve might suggest.
