Erosion and Accretion of a Placer Mining Beach of SW Indian Coast

Abstract

The erosion/accretion pattern in a placer mining beach on the southwest Indian coast was monitored for five years to study the role of different driving forces. The beach has maximum width during the fair weather months and least in the rough monsoon months. Apart from hydrodynamic processes, sand mining and presence of sea wall are found to be the driving forces for erosion/accretion. Impact of sand mining is not felt on the beach when the mining is within an optimum level, equivalent to the natural replenishment. It is concluded that, though sand mining will cause erosion in the innershelf, the time taken for a measurable impact can be long if the mining volumes are much less than the annual volume changes.

Keywords:

• SW Indian coast
• beach erosion
• beach volume changes
• placer mining
• littoral environmental characteristics
• driving forces of beach processes

Acknowledgement

Dr. M. Baba, director, Centre for Earth Science Studies, has given all support and encouragement for this work. We thank the Indian Rare Earths Ltd. for funding the study and for the kind permission to publish this work. Drs. K.P. Black and Joseph Mathew have provided very useful consultations during the course of the work. The success of the field programs owed largely to the committed support of a big team. We thank Dr. T.S. Murty and the reviewers for the scrutiny of the manuscript and critical comments.