Environmental Impact Assessment of Sand Mining from the Small Catchment Rivers in the Southwestern Coast of India: A Case Study

Abstract

In the past few decades, the demand for construction grade sand is increasing in many parts of the world due to rapid economic development and subsequent growth of building activities. This, in many of the occasions, has resulted in indiscriminate mining of sand from in-stream and floodplain areas leading to severe damages to the river basin environment. The case is rather alarming in the small catchment rivers like those draining the southwestern coast of India due to limited sand resources in their alluvial reaches. Moreover, lack of adequate information on the environmental impact of river sand mining is a major lacuna challenging regulatory efforts in many developing countries. Therefore, a scientific assessment is a pre-requisite in formulating management strategies in the sand mining-hit areas. In this context, a study has been made as a case to address the environmental impact of sand mining from the in-stream and floodplain areas of three important rivers in the southwestern coast of India namely the Chalakudy, Periyar and Muvattupuzha rivers, whose lowlands host one of the fast developing urban-cum-industrial centre, the Kochi city. The study reveals that an amount of 11.527 million ty(-1) of sand (8.764 million ty(-1) of in-stream sand and 2.763 million ty(-1) of floodplain sand) is being mined from the midland and lowland reaches of these rivers for construction of buildings and other infrastructural facilities in Kochi city and its satellite townships. Environmental Impact Assessment (EIA) carried out as a part of this investigation shows that the activities associated with mining and processing of sands have not only affected the health of the river ecosystems but also degraded its overbank areas to a large extent. Considering the degree of degradation caused by sand mining from these rivers, no mining scenario may be opted in the deeper zones of the river channels. Also, a set of suggestions are made for the overall improvement of the rivers and its biophysical environment.

Sand, rarer than one thinks

“…Negative effects on the environment are unequivocal and are occurring around the world. The problem is now so serious that the existence of river ecosystems is threatened in a number of locations (Kondolf, 1997;Sreebha and Padmalal, 2011). Damage is more severe in small river catchments.…”

“…There is limited collaboration/co-ordination between the marine scientific research establishments and the marine aggregates industry . Except in the European Union, regulation efforts are few, especially in developing countries (Sreebha and Padmalal, 2011). Lack of monitoring systems, regulatory policies and environmental impact assessments have led to indiscriminate mining, triggering severe damage to the environment and related ecosystem services.…”

“…The lack of adequate information is limiting regulation of extraction in many developing countries (Sreebha and Padmalal, 2011). Access to data is difficult, and data are not standardised.…”

“…The mining of aggregates in rivers has led to severe damage to river basins (Sreebha and Padmalal, 2011), including pollution and changes in levels of pH (Saviour, 2012). Removing sediment from rivers causes the river to cut its channel through the bed of the valley floor (or channel incision) both upstream and downstream of the extraction site.…”

Partial replacement of river sand with volcanic pyroclastics as fine aggregates in concrete production

“…The water quality of the rivers are lowered due to increased short-term turbidity at the mining site caused by suspended sediments from stockpiling, organic particulate matter, and oil spills or leakage from excavation machinery and transportation vehicles. These concerns have also been reported in China [3,4]; Ghana [5]; Nigeria [6]; Malaysia [7] and India [8,9]. To mitigate this indiscriminate sand mining, initial environmental impact assessment (EIA) for resource extraction should be carried out followed by subsequent ones, as the growing demand renders the existing extraction capacity insufficient [10].…”