Tuesday, July 29, 2014

River sand dredging at Punatsangchhu

The NRDCL holds valid clearances for operating the sand-dredging machine, which is under operation at Punatsangchu River near Wangdue Bridge. Nevertheless, i personally feel that the dredging of sand may not be really feasible in our fast moving river system as NRDCL proved to be successful. Through my literature review, it was found that dredging of sand with a mechanical digger usually destroys, or at least disrupts creating a less stable and less diverse environment. 

According to Clark, J. (n.d.), dredging would inevitably affect deposition, which takes place in gravel substrates, and juvenile fish that inhabit the substrate. On ecological ground, the dredging will have an effect on the direct loss of stream reserve habitat; disturbances of species attached to deposits, and reduced feeding opportunities (The Ojos Negros Research Group, n.d.).

On other hand, it may affect the respiratory system of fish and growth may also be affected since food supply and feeding success are reduced in the turbid conditions (Clark, J, n.d.). The Ojos Negros Research Group. (n.d.) states that, the dredging will lead to collapse of riverbanks, downstream changes in patterns of deposition, and changes in channel bed and habitat type. 

It is quite obvious that, the loss and alteration of natural habitats caused by dredging could have serious ecological impacts, in both the short-and long-term. Numerous publications have been written with respect to these effects, and the next step is what to do to prevent these environmental effects. Hence, i feel it is extremely crucial to carry out detail study on sociological and ecological impacts of sand dredging particularly at Punatsangchu before it is established permanently.

Clark, J. (n.d.). Rivers and their catchments: river dredging operations. Rivers and their catchments: river-dredging operations. Retrieved April 16, 2014, from http://www.snh.org.uk/publications/on-line/advisorynotes/23/23.htm
The Ojos Negros Research Group. (n.d.). Three issues in sustainable management in the Sand Mining. Retrieved April 16, 2014, from http://threeissues.sdsu.edu/three_issues_sandminingfacts01.html