We evaluated the influence of a hydropower dam, Borcka Dam, on the total suspended solids (TSS) carried by the Coruh River and Murgul Stream, northeast Turkey, by studying its variation versus nephelometric turbidity. The impact of discharge from the copper mining facility to the Murgul Stream draining into the Borcka Dam Reservoir was also evaluated. In situ turbidity monitoring, Secchi disk transparency, reservoir water depth measurements, and surface water sampling were conducted monthly at 12 stations from December 2010 to November 2011. TSS carried by the Coruh River and Murgul Stream showed 3 different deposition behaviors based on the reservoir water levels. On an annual basis, the TSS carried by the Coruh River was 371 mg/L and the turbidity was 332 NTU, whereas the TSS carried by the Murgul Stream was 16,992 mg/L and the turbidity was >712 NTU. Based on the TSS of 41 mg/L and the turbidity of 46 NTU measured at the outlet of the Borcka Dam and hydroelectric power plant, we concluded that the Borcka Dam could trap a large portion of the TSS and could reduce turbidity considerably because of its long hydraulic residence time, and thus reduce possible silting in the downstream reservoir.