![]() In the preparation of concrete, for each tonne of cement, the building industry needs about six to seven times more tonnes of sand and gravel (USGS, 2013b). Sand and gravel are used extensively in construction. Where access roads cross riparian areas, the local environment may be impacted. Sand mining generates extra vehicle traffic, which negatively impairs the environment. Continued extraction may also cause the entire streambed to degrade to the depth of excavation. These physical impacts cause degradation of riparian and aquatic biota and may lead to the undermining of bridges and other structures. Impacts include bed degradation, bed coarsening, lowered water tables near the streambed, and channel instability. Instream sand mining results in the destruction of aquatic and riparian habitat through large changes in the channel morphology. Sand mining also affects the adjoining groundwater system and the uses that local people make of the river. Any volume of sand exported from streambeds and coastal areas is a loss to the system.Įxcessive instream sand mining is a threat to bridges, river banks and nearby structures. The effect of mining is compounded by the effect of sea level rise. It may also lead to saline-water intrusion from the nearby sea. Depletion of sand in the streambed and along coastal areas causes the deepening of rivers and estuaries, and the enlargement of river mouths and coastal inlets. Instream mining lowers the stream bottom, which may lead to bank erosion. ![]() Any volume of sand exported from streambeds and coastal areas is a loss to the system.Įxcessive instream sand-and-gravel mining causes the degradation of rivers. In-stream mining lowers the stream bottom, which may lead to bank erosion. Mining operators, in conjunction with cognizant resource agencies, must work to ensure that sand mining is conducted in a responsible manner.Įxcessive in-stream sand-and-gravel mining causes the degradation of rivers. Today, demand for sand and gravel continues to increase. Full Project – IMPACT OF SAND AND GRAVEL DREDGING ON THE ENVIRONMENTĬlick here to Get this Complete Project Chapter 1-5įor thousands of years, sand and gravel have been used in the construction of roads and buildings.
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