By Vaishali Jain:
Ever wondered what went on beneath those several inches of water whenever you splashed some of it on your friends or made ripples in it? Beyond the beautiful underwater scenes that our movies show, there is a world unknown to us. There is tremendous amount of silt, sand and sedimentation that eventually fills the bedrock and the harbors. This is where the dredgers come into the picture. Dredging is the removal of material from the bottom of a river, ocean or other marine habitat. It basically is done to maintain the navigation channels, remove contaminated materials, prevent flooding and dispose off the sediments to a different location. Although dredging is recommended to keep the channels under control, the same comes with serious adverse effects. Even if the area does improve due to dredging, there is every possibility of harm to the aquatic animals and plants.
There is an unnatural disturbance of marine habitats from the time the dredging equipments are switched on and it does not cease even after they are switched off. Fishes and other animals choose to move to more favorable conditions on getting disturbed by the intense dredging activities. The mere mechanics of the process kills many animals. The sediment that is contaminated is swirled across the water body through dredging and it acts as a fuel in getting the wildlife disturbed. The aquatic animals shift to the water columns where they might be attacked by the predators thereby harming the entire species.
Dredging disturbs the marine plant life and once destroyed, it becomes very difficult for them to grow in the changed environment. There is a considerable reduction in the biodiversity. Dredging also mixes up the substances in water which decreases the amount of light that perpetrates in the water body and thereby decreases the number of plants that grow. Chronic disturbance caused by dredging has the potential to reduce their survival.
Sediments around cities and industrial areas are introduced to waterways from different sources and these sediments are contaminated with a variety of pollutants. Now, dredging is also done to remove these pollutants that find their place in the soil but even a little stir can spread the contaminated sediments to the whole water body. The pollutants that were fixed at one place now may get transferred to a wide area thereby endangering many different species. There is a good chance that the earlier safe and contamination-free area might now be prone to hazards.
Dredging changes the natural flow of the water, when of course, that is precisely what is intended to be done. But changing the flow can do serious harm to the flood plains. It can also destroy habitats. The natural wave patterns are played with and can impact the oceans in a negative manner, something that cannot be undone.
Keeping these points in mind, it is imperative to keep a check on the dredging activities that take place periodically, sometimes more frequently than needed. The government should be updated about the demonstrated need for dredging of every water body. Continuous analysis of the reports needs to be done. It is also important that a check on licenses of the dredgers should be adequately maintained. The methods of dredging and disposal ethics should be analyzed. A technical framework should be set-up to check if there might be any harm to the habitats if materials are placed in the water. After all, it’s not just a little area but the entire biodiversity that gets affected by any potential threat that looms in.