STUDY on IMPACT of DREDGING on SHORELINE CHANGES Assessment of Impact on Shoreline Due to the Proposed Dredging Has Been Studied by IIT Chennai
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STUDY ON IMPACT OF DREDGING ON SHORELINE CHANGES Assessment of impact on shoreline due to the proposed dredging has been studied by IIT Chennai. The study area is demarcated and is spatially georeferenced from the Google earth using spatially referenced points. The change in shoreline will be either erosion or accretion values along the coast. The erosion and accretion value is calculated using the shape area and with the corresponding shape length along the coast. The study indicates the shore line changes demarcated for 12 years and in the particular area namely Ernakulam the erosion rate is 1.38m/year which is maximum due to mouth opening. The erosion occurs in the other areas namely High court, Embarkation, Vypeen, Ponnarimangalam, Mulavukad hospital, Thevara yard, Kumbalam, Paliyamthuruthu and Kadamakuddy. There is no alarming erosion at any place. The maximum accretion rate is 32.91m in Fort Kochi for 12 years (2.74m/year). In the accretion areas namely Fort Kochi, Mattancherry, Bolgatty, Mulavukad Panchayat, Nettoor, Najrackal and Elakunnapuzha the coast is very much stable .The coast is stable in the no change areas such as Vytilla, Eroor, Kakkanad, Infopark, Mulavukad North, Korumkotta, Moolampilly, South chitoor, Thykoodam, Pizhala, Kothad, Chennur, Cheranalloor, Eloor, Varapuzha, Thundathumkadavu, Chariyamthuruth, Amritha hospital and Aster medicity. The accretion values are shown in Table-1 and it is represented in graph in the Figure-1. The maximum magnitude of erosion is 2.74m/yr and the coast is stable or accreting at most of the locations. Table-1: Shoreline Change due to erosion and accretion S.No Location Erosion/Aggression (m/year) Status 1 High court 0.64 Erosion 2 Fort Kochi 2.74 Aggression 3 Vypeen 1.34 Erosion 4 vyttila 0.00 No Change 5 Eroor 0.00 No Change 6 Kakkanad 0.00 No Change 7 Info Park 0.00 No Change 8 Embarkation (W/I) 0.03 Erosion 9 Mattancherry 1.06 Aggression 10 Ernakulam 1.38 Erosion 11 Bolgatty 0.84 Aggression 12 Thanthonnithuruth 0.00 No Change 13 Ponnarimangalam 0.19 Erosion 14 Mulavukad hospital 0.61 Erosion 15 Mulavukad Panchayat 0.35 Aggression 16 Mulavukad North 0.00 No Change 17 Korumkotta 0.00 No Change 18 Moolampilly 0.00 No Change 19 South Chitoor 0.00 No Change 20 Thevara Yard 0.41 Erosion 21 Nettoor 0.95 Aggression 22 Kumbalam 0.74 Erosion 23 Edakochi 0.76 Aggression S.No Location Erosion/Aggression (m/year) Status 24 Thykoodam 0.00 No Change 25 Thoppumpady 0.72 Aggression 26 Pizhala 0.00 No Change 27 Kothad 0.00 No Change 28 Chennur 0.00 No Change 29 cheranalloor 0.00 No Change 30 Eloor 0.00 No Change 31 Varapuzha 0.00 No Change 32 Njarackal 0.61 Aggression 33 Elakunnapuzha 1.33 Aggression 34 Paliyamthuruthu 0.05 Erosion 35 Kadamakkudy 0.12 Erosion 36 Thundathumkadavu 0.00 No Change 37 Chariyamthuruth 0.00 No Change 38 Amritha hospital 0.00 No Change 39 Aster medcity 0.00 No Change Figure-1: Erosion/Accretion values of Various location .