This research investigated the deposition patterns within six reservoirs (Techi, Qingshan, Guguan,Tianlun, Maan, and Shigang) located in the Dajia River. We utilizes historical a combination of historical sediment level data, satellite images, typhoon rainfall records, and operation logs. Finding categorize the reservoirs’ sedimentation in the Dajia River into four distinct depositional reaches: tail, topset, front, and bottom. The Techi Reservoir uniquely exhibits all four depositional reaches. However, the large area and isolated mountainous terrain of the Techi
Reservoir render traditional excavation strategies for sediment removal impractical. Sediment reduction is best addressed through soil and water conservation practices in the upstream watershed. In contrast, the Guguan, Tianlun, and Maan Reservoirs lack a bottom reach due to their smaller storage. For these reservoirs, sediment management can be
effectively carried out using conventional mechanical and hydraulic dredging techniques. The Qingshan Reservoir,
serves as a stilling pool for the Techi Reservoir and presents a diverse array of deposition types. Hydraulic dredging is the primary method for eliminating sediment in the Qingshan Reservoir to conserve its storage function. The Shigang Reservoir, burdened with an extensive sediment volume, is limited to a tail reach and a topset reach. Given the inefficacy of dredging approaches, the preferred method for sediment management in the Shigang Reservoir is dam removal.
Key Words: deposition patterns, desiltation strategies, tail reach, topset reach, front reach, bottom reach, Dajia River