Impact of Borçka Dam on Total Suspended Solids Carried by the Çoruh River and the Murgul Stream, Northeast Turkey


KENANOĞLU M., BAYRAM A.

9th World Congress of EWRA, Water Resources Management in a Changing World: Challenges and Opportunities, İstanbul, Turkey, 10 - 13 June 2015, pp.281-282

  • Publication Type: Conference Paper / Full Text
  • City: İstanbul
  • Country: Turkey
  • Page Numbers: pp.281-282

Abstract

 

The Çoruh River, having a main branch length of 400 km, a catchment area of 19,872 km2, a mean annual surface water potential of 6.3 billion cubic meters, and a gross head of 1420 m within the borders of Turkey, is of high economic importance because of its largely undeveloped but economically exploitable hydropower potential. The Çoruh River Basin, where a lot of hydropower dams have been constructed and are in operation (e.g., Borçka Dam with an installed capacity of 300.6 MW), is one of the basins experiencing severe erosion. This river carries sediments and deposits of 5.8 million cubic meters.

This study investigated the effects of Borçka Dam reservoir, with surface area of 10.84 km2 and volume of 419 million cubic meters, the Lower Çoruh River Basin, on the total suspended solids (TSS) carried by the Çoruh River and the Murgul Stream by studying its variation versus nephelometric turbidity. The effects of discharge from a copper mine to Murgul Stream draining into the Borçka Dam reservoir were also evaluated. In situ turbidity monitoring and surface water sampling were done monthly at the three monitoring stations selected in the Çoruh River, Artvin Province, in the Murgul Stream, Murgul Town, and at the hydroelectric power plant (HEPP) outlet of the Borçka Dam, Borçka Town, respectively, from December 2010 to November 2011.

On an annual basis, it was determined that the TSS carried by the Çoruh River was 375 mg/L and the turbidity was 339 NTU while the TSS carried by the Murgul Stream was 15,693 mg/L and the turbidity was over 664 NTU. Based on the TSS of 39.4 mg/L and the turbidity of 43 NTU measured at the HEPP outlet of the Borçka Dam, it was concluded that the Borçka Dam could trap a great part of the TSS and could reduce turbidity considerably thanks to its long hydraulic residence time, and so reduce the possible silting in the downstream reservoir, the Muratli Dam having a dead storage of 55 million cubic meters.