ISSUES AND CHALLENGES IN RIVER MANAGEMENT DUE TO EXCESSIVE SAND

MINING

PRESENTATION BY,SUJAY RAGHAVENDRA N

12WR10F

UNDER THE GUIDANCE OFDr. S.G. MAYYA

CONTENTS• INTRODUCTION.

• SAND MININING.

• SAND MINING IN INDIA.

• SAND MINING IN COASTAL REGULATION ZONE.

• IMPACTS OF SAND/GRAVEL MINING.

• ENVIRONMENTAL EFFECTS OF SAND/GRAVEL MINING.

• SCIENTIFIC MINING OF SAND/GRAVEL.

• MANAGEMENT PLANS.

• APPROPRIATE EXTRACTION METHODS.

• SUMMARY.

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INTRODUCTION Rivers are the most important life supporting systems of nature.

Indiscriminate extraction of river sand and gravel manifolds higher than natural replenishments and can impart serious offsite and onsite impacts.

Excessive removal of sand may significantly distort the natural equilibrium of a stream channel.

In view of the severity of environmental degradation caused by indiscriminate river sand mining and also considering its potential impacts on the developmental initiatives of the area, a study has to be undertaken to assess the environmental impact of sand mining in the rivers.

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SAND MININIG Sand Mining is a coastal activity referring to the process of the actual

removal of sand from the foreshore including rivers, streams and lakes. Sand is mined from beaches, inland dunes and dredged from ocean beds and river beds.

Besides resource extraction, ultimate objectives of riverbed sand mining should be:-• Protection and restoration of the ecological system,• To prevent damages to the river regime,• To work out the sediment influx/replenishment capacity of the

river,• To restore the riverine configuration,• To prevent contamination of ground water regime,

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SOURCES OF SAND/GRAVEL The sources of sand are classified as marine and terrestrial deposits.

The two most common marine sources are the deposits on the shore and offshore.

The most common terrestrial sources are the river channel deposits, floodplain alluvial deposits, and residual soil deposits.

There are extensive deposits of sand on the shores of the islands, occurring in the intertidal zone.

Some large sand deposits occur in the back beach zone. These are usually found as sand dunes and series of consecutive ancient beaches.

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OTHER POTENTIAL AGGREGATE SOURCES

Reservoir Deltas:

Contd…. 6

Dredger tailings: Dredger tailings are long linear deposits left at historical gold mining operations.

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SAND MINING IN INDIA Sand Mining in India is adversely affecting the rivers, sea, forests &

environment.

Illegal mining of Sand and the lack of governance, in a big way is causing land degradation and threatening the existence of primary river streams.

Weak governance and rampant corruption are facilitating uncontrolled and illegal mining of sand and gravel in the rivers, threatening their very existence.

This unrestrained and unregulated activity is posing threats of widespread depletion of water resources which may lead to unavoidable food shortages and hardships for the people.

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SAND MINING IN COASTAL REGULATION ZONE

Government of India issued the coastal zone regulation on 19 February 1991 under Section 3(1) and Section 3(2)(v) of the Environment (Protection) Act, 1986

The land area from High Tide Line (HTL) to 500mts on the landward side along the sea front.

Land area between HTL and Low Tide Line (LTL) which will be termed as the intertidal zone.

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Contd… Mining of offshore sand became a topic of interest recently

because of the increasing demand and increasing cost of river sand for construction purposes.

Often proposed as an alternative to beach mining, is offshore sand mining. Extensive (and expensive) studies must be conducted before any offshore mining can be attempted.

Offshore sand banks, coral reefs and sea-grass beds diffuse the energy of strong waves; if large quantities of sand are removed from offshore sand banks in locations where replenishment would not occur, serious coastal damage would result in the event of a major storm.

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IMPACTS OF SAND MININGThe major hazards caused due to mining of sand/gravel include the following:

Instream habitat.

Riparian habitat.

Degradation of Land.

Lowering of groundwater table in the floodplain area.

Depletion of groundwater.

Polluting groundwater.

Choking of filter materials for ingress of ground water from river.

Impacts on river morphology.

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ENVIRONMENTAL EFFECTS OF SAND/GRAVEL MINING

Sand and gravel extraction can result in a number of physical, chemical, and biological effects on mined streams.

Sand and gravel mining can change the geomorphic structure of streams, often resulting in channel degradation and erosion from mining operations located either in or adjacent to a stream.

Instream mining typically alters channel geometry, including local changes in stream gradient and width-to-depth ratios.

Local channel scouring and erosion can occur as a result of increased water velocity and decreased sediment load associated with mined areas.

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Contd…. The combined processes of channel incision and headcutting can

undermine bridge piers and other structures.

Channel erosion from headcuts can cause loss of upstream property values; reduce recreational, fishing, and wildlife values; and contribute to the extinction of stream fauna.

Mining-induced changes to the geomorphic structure of the stream can significantly affect fish habitat. Instream mining can reduce the occurrence of coarse, woody debris in a channel, an important habitat for fish and invertebrates.

Sedimentation and increased turbidity of water can occur from mining activities.

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ENVIRONMENTAL ISSUES OF SAND MINING

In Karnataka

In Tamil Nadu

In Kerala

In Meghalaya

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CURRENT RULES AND POLICIES IN OPERATION

In Karnataka.- “Uniform sand mining policy”

In Kerala.- “Protection of river banks and regulation on

removal of sand act,2001”

In Maharashtra.

In Andra Pradesh.

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SCIENTIFIC MINING OF SAND/GRAVEL

Abandoned stream channels on terrace and inactive floodplains may be preferred rather than active channels and their deltas and floodplains. Replenishment of groundwater has to be ensured if excessive pumping out of water is required during mining.

Stream should not be diverted to form inactive channel.

Mining below subterranean water level should be avoided as a safeguard against environmental contamination and over exploitation of resources.

Large rivers and streams whose periodic sediment replenishment capacity are larger, may be preferred than smaller rivers.

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Contd… Mining at the concave side of the river channel should be avoided to

prevent bank erosion. Similarly meandering segment of a river should be selected for mining in such a way as to avoid natural eroding banks.

Scraping of sediment bars above the water flow level in the lean period may be preferred for sustainable mining

Identification of river stretches and their demarcation for mining must be completed prior to mining for sustainable development.

The mined out pits should be backfilled, area should be suitably landscaped to prevent environmental degradation.

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MANAGEMENT PLAN.

In-Stream Mining Recommendations

Off-Channel or Floodplain Extraction Recommendations

Reclamation Plans

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APPROPRIATE EXTRACTION METHODS

Bar scalping or skimming.

Dry-Pit Channel Mining.

Wet-Pit Channel Mining.

Bar Excavation.

In-stream Gravel Traps.

Channel-wide In-Stream Mining.

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SUMMARYIn the past 3–4 decades, rivers in the densely populated areas of the world are subjected to immense pressures due to various kinds of human interventions, among which indiscriminate mining for construction grade sand from alluvial reaches is the most disastrous one. This is mainly because of the fact that uncontrolled scooping of sand aggravates river degradation and threatens its tropic structure. The situation is rather alarming in the small rivers of India, which support the life and greenery of the region. Loss of riparian and instream vegetation, changes in the feeding, breeding and spawning grounds of aquatic organisms including fishes not only impose stress in the river ecology but also create damages in the terrestrial and nearshore marine environments as well.

There is very much need for laying down strategies for regulating the mining activities on environment friendly basis and also for creating awareness on the impact of river sand mining on the physical and biological environment of these life support systems.

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REFERENCES Coastal Regulation Zone Notification (2011), Ministry of Environment

and Forests. The Gazette of India, Extraordinary, Part-II, Section 3, Sub-section (ii) of dated 6th January, 2011)

River sand mining management guidelines 2009, Ministry of Natural Resources and Environment. Department of Irrigation and Drainage, Malaysia

Kundolf, G.M., 1997. Hungry Water: Effects of dams and gravel mining on river channels. Environmental management, Vol.21, No.4; pp.533-551.

Kondolf G M (1994) Geomorphic and environmental effects of instream gravel mining. Landuse and Urban Planning 28:225–243

M. Naveen Saviour. Environmental Impact of Soil and Sand mining: A Review. International Journal of Science, Environment and Technology, Vol. 1, No 3, 2012, 125 – 134 (2012).

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THANK YOU..

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