ISSUES AND CHALLENGES IN RIVER MANAGEMENT DUE EXCESSIVE SAND MINING

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ISSUES AND CHALLENGES IN RIVER MANAGEMENT DUE

TO EXCESSIVE SAND MINING

Seminar Report

Submitted in partial fulfillment of the requirements for the degree of

MASTER OF TECHNOLOGY in

WATER RESOURCES ENGINEERING & MANAGEMENT

By

SUJAY RAGHAVENDRA N

(12WR10F)

Under the guidance of

Dr. S.G. MAYYA

DEPARTMENT OF APPLIED MECHANICS & HYDRAULICS

NATIONAL INSTITUTE OF TECHNOLOGY KARNATAKA

SURATHKAL, MANGALORE - 575 025

April 2013


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C E R T I F I C A T E

This is to certify that the P.G. Seminar Report entitledISSUES AND CHALLENGES IN

RIVER MANAGEMENT DUE TO EXCESSIVE SAND MININGsubmitted by SUJAY

RAGHAVENDRA. N (Register Number: 12WR10F) as the record of the work carriedout by

her is accepted as the P.G. Seminar Report submission in partial fulfillment of the

requirements for the award of degree of Master of Technology in Water Resources

Engineering & Management in the Department of Applied Mechanics & Hydraulics

Dr. S.G. MAYYA.

Professor

Department of Applied Mechanics & Hydraulics

NITK, Surathkal

Head of the Department

Department of Applied Mechanics & Hydraulics

NITK, Surathkal


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ACKNOWLEDGEMENT

I would like to express my deep sense of gratitude to my project guide Dr.S.G Mayya.,

Professor, Department of Applied Mechanics & Hydraulics, NITK, Surathkal for his valuable

suggestions and guidance, which played a definite role in bringing this report to good shape

and extending all facilities to carry out this seminar.

I also extend my sincere thanks to each and every faculty who had helped directly or

indirectly, and my friends for the preparation of this seminar report. Above all, I thank my

parents who gave me the firm platform for the successful completion of this seminar report.

NITK SURATHKAL SUJAY RAGHAVENDRA N.

Date: 15.04.2013


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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. Rapid urbanization, the major cause for sand demand is responsible for

unsustainable extraction of sand from dried river paths. The layers of sand deposits are

exploited almost up to the bottom. This in turn, has increased initial and premature failure of

irrigation wells in riparian areas. This, in many of the occasions, has resulted in

indiscriminate mining of sand from instream and floodplain areas leading to severe damages

to the river basin environment. Moreover, lack of adequate information on the environmental

impact of river sand mining is a major lacuna challenging regulatory efforts in many,

developing countries.


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TABLE OF CONTENTS

1 INTRODUCTION. 1.

2 SAND MININING. 1.

2.1 DEFINITION. 1.

2.2 SOURCES OF SAND/GRAVEL. 2.

2.3 SAND DREDGING. 5.

3 SAND MINING IN INDIA. 6.

3.1 SAND MINING IN COASTAL REGULATION ZONE. 6.

4 IMPACTS OF SAND/GRAVEL MINING. 9.

4.1 IMPACTS ON RIVER MORPHOLOGY. 10.

5 ENVIRONMENTAL EFFECTS OF SAND/GRAVEL MINING. 12.

5.1 ENVIRONMENTAL ISSUES OF SAND MINING. 12.

5.2 CURRENT RULES AND POLICIES IN OPERATION. 14.

6 SCIENTIFIC MINING OF SAND/GRAVEL. 15.

7 MANAGEMENT PLANS. 18.

7.1 IN-STREAM MINING RECOMMENDATIONS. 18.

7.2 OFF-CHANNEL/ FLOODPLAIN EXTRACTION RECOMMENDATIONS. 20.

7.3 RECLAMATION PLANS. 21.

8 APPROPRIATE EXTRACTION METHODS. 22.

9 SUMMARY AND RECOMMENDATIONS. 25.

10 REFERENCES. 26.


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LIST OF FIGURES

2.1 Aggregate extraction can take place in a number of in-stream or near-stream

environments (Langer, 2003).............3

2.2 Distribution of sediment and extraction zones in Reservoir..........4

2.3 Dredger tailings, Mississippi Bar, American River, California..........4

3.1 Integrated Coastal Zone Management Plan.8

4.1 Extensive Modification to Stream Channel caused by gravel Extraction.........11

8.1 Aggregate being skimmed off the surface of a bar (Langer, 2003).......22

8.2 Wet-pit channel mining.........23

8.3 Bar Excavation......24

8.4 Idealized gravel trap (Source: Bates 1987).......24


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1.INTRODUCTION.

Rivers are the most important life supporting systems of nature. For centuries, humanshave been enjoying the natural benefits provided by rivers without understanding much on

how the river ecosystem functions and maintains its vitality. Man has changed the nature ofmany of the worlds rivers by controlling their floods, constructing large impoundments,

overexploitation of living and non-living resources and using rivers for disposal of wastes.

Among these, indiscriminate extraction of non-living resources like sand and gravel from

riverbed is the most disastrous as this activity threatens the very existence of the river

ecosystem.

A review of literature reveals that indiscriminate extraction of river sand and gravel

manifolds higher than natural replenishments and can impart serious offsite and onsite

impacts. This ultimately leads to changes in channel form, physical habitats, food webs andengineering structures associated with river channels and inland sediment supply to coastal

and nearshore environments. As these adverse effects become increasingly recognised and

understood, instream sand mining/aggregate extraction has recognised increasing scientificscrutiny. Although more focussed researches leading to restoration of river environments are

progressing in many developed countries, much attention has not been made in the rest of the

world.

In-stream sand mining can damage private and public properties as well as aquatic

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

stream channel. By removing sediment from the active channel bed, in-stream mines interrupt

the continuity of sediment transport through the river system, disrupting the sediment massbalance in the river downstream and inducing channel adjustments (usually incision)

extending considerable distances (commonly 1 km or more) beyond the extraction site itself.The magnitude of the impact basically depends on the magnitudes of the extraction relative to

bed load sediment supply and transport through the reach (Kondolf et al., 2001).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.

2.SAND MINING

2.1. DEFINITION

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 and

inland dunes and dredged from ocean beds and river beds.

Besides resource extraction, ultimate objectives of riverbed sand mining should be:-i. Protection and restoration of the ecological system,

ii. To prevent damages to the river regime,

iii. To work out the sediment influx/ replenishment capacity of the river,

iv. To restore the riverine configuration (landforms and fluvial geomorphology such as

bank erosion, change of river course gradient, flow regime, etc.),v. To prevent contamination of ground water regime,


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vi. To prevent depletion of ground water reserves due to excessive draining out of

groundwater.

vii. To restore the riparian rights and instream habitats.

2.2. 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 island, occurring in the

intertidal zone, where sand grains are deposited by littoral drift. The beaches vary from

narrow strips parallel to the coastline to broad inland deposits of more than a kilometre inwidth. Although these deposits were extensively mined in the past, the extraction of sand

from the maritime zone is prohibited. Some large sand deposits occur in the back beach zone.

These are usually found as sand dunes and series of consecutive ancient beaches. Although itis possible to extract a portion of the dune without eliminating the coastal protection, the

determination of the extraction area and the buffer zone is difficult without detailed geologic

studies.

The most common places from which sand is mined include:

i. Dredging river channels.

ii. Dredging the river floodplains.iii. Extraction of inland residual sandy soils.

iv. Dredging submerged deposits.v. Extraction from coastal dunes.

vi. Exploiting renewable beaches.

Fluvial Gravels as Sources of Construction Aggregate

Sand and gravel deposited by fluvial processes are used as construction aggregate for

roads and highways (base material and asphalt), pipelines (bedding), septic systems (drain

rock in leach fields), and concrete (aggregate mix) for highways and buildings. In many

areas, aggregate is derived primarily from alluvial deposits, either from pits in river

floodplains and terraces, or by in-channel (instream) mining, removing sand and gravel

directly from river beds with heavy equipment.

Fluvial and Glacial Outwash Deposits

Sand and gravel that have been subject to prolonged transport in water (such as active

channel deposits) are particularly desirable sources of aggregate because weak materials areeliminated by abrasion and attrition, leaving durable, rounded, well sorted gravels (Dunne et

al. 1981, Barksdale 1991). Sand and gravel are commercially mined from the active channel

(instream mining) and from floodplain and terrace pits (Figure 11). Instream gravels thus

require less processing than many other sources, are easily worked by heavy equipment, and

suitable channel deposits are commonly located near the markets for the product or on

transportation routes, reducing transportation costs (which are the largest costs in the

industry). Moreover, instream gravels are commonly of sufficiently high quality to be


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classified as "PCC-grade" aggregate, suitable for use in production of Portland cement

concrete (Barksdale 1991).

Figure 2.1. Aggregate extraction can take place in a number of in-stream or near-

stream environments (Langer, 2003)

River channels and floodplains are important sources of aggregate in many settings by

virtue of the durability of river-worked gravels and their sorting by fluvial processes. Therelative importance of alluvial aggregates is a function of the quality, location, and processing

requirements of alluvial aggregates, and the availability of alternative sources in a given

region.

Other Potential Aggregate Sources:

i. Reservoir Deltas:

Reservoir sediments are a largely exploited source of building materials. In general,

reservoirs deposits will be attractive sources of aggregates to the extent that they are sorted

by size. The depositional pattern within a reservoir of gravel, sand, silt and clay depends onreservoir size and configuration, and the reservoir stage during floods. Small diversion damsmay have a low trap efficiency for suspended sediments and trap primarily sand and gravel,

while larger reservoirs will have mostly finer-grained sand, silt, and clay (deposited fromsuspension) throughout most of the reservoir, with coarse sediment typically concentrated in

deltas at the upstream end of the reservoir. These coarse deposits will extend farther if the

reservoir is drawn down to a low level when the sediment- laden water enters. In many

reservoirs, sand and gravel occur at the upstream end, silts and clays at the downstream end,

and a mixed zone of interbedded coarse and fine sediments in the middle.(Figure 2)

ii. Dredger Tailings:Dredger tailings are long linear deposits left by historical gold mining operations. The

tailings are stratified: sand and silt are overlain by mounds of clean gravel and cobble, whichhold no interstitial water and thus support little vegetation. These inert ridges of gravel and

cobble cover large areas of floodplains of rivers in former gold- mining areas.(figure 3)


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Figure 2.2. Distribution of sediment and extraction zones in Reservoir.

Figure 2.3.Dredger tailings, Mississippi Bar, American River, California


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2.3. SAND DREDGING

Sand Dredging is an excavation activity or operation usually carried out at least partlyunderwater, in shallow seas or fresh water areas with the purpose of gathering up bottom

sediments and disposing of them at a different location. This technique is often used to keepwaterways navigable.

ADVANTAGES DISADVANTAGES

It opens up our water ways for easy

access and movement for local

fishermen.

If done in advance and through a

modern method the water way could be

open for large vessels to pass through it

bringing a lot of people into thecommunity.

It provides employment especially forthe ready to work and vibrant youths

of the town.

The dredging provides a good and

natural habitat for fishes, which makesthem have an increasing population.

A release of toxic chemicals (including

heavy metals and PCB) from bottom

sediments into the water column.

Secondary effects from water column

contamination of uptake of heavy metals,

DDT and other persistent organic toxins,

via food chain uptake and subsequentconcentrations of these toxins in higher

organisms including humans.

Secondary impacts to aquatic and benthic

organisms' metabolism and mortality

Possible contamination of dredge spoils

sites.


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3. 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 threatened its rivers with extinction. Mining of sand, for instance, is depleting the waters

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

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

In M.P. the major rivers like Narmada, Chambal, Betwa or Wainganga or numerous rivulets

and streams all are being ravaged for their sands. The state government has wittingly lent a

helping hand by exempting the grant of Environmental Clearance to be taken for mining of

sand and gravel, neutralising the provisions made in several central legislations on

conservation of environment and mineral resources. A social activist has approached the statehigh court for quashing of the unconstitutional exemptions so that indiscriminate mining ofsand could be put a stop to.

Similarly River Bharathapuzha in Kerala has become a victim of indiscriminate sand mining.

Despite numerous prohibitions and regulations, sand mining continues rapidly on the riverbed

of the Bharathapuzha. Water tables have dropped dramatically and a land once known for its

plentiful rice harvest now faces scarcity of water. In the villages and towns around the river,

groundwater levels have fallen drastically and wells are almost perennially dry.

Study conducted at Neyyar basin Kerela, India reported that channel bank failed due to over

deepening of the channel, with standing coconut palm trees uprooted and lost in largenumber. This led to estimated loss of nearly one million rupees annually.

The malaise is pretty widespread as many other states, like Gujarat, Karnataka, Tamilnadu,

etc are also victims of unchecked illegal sand-mining the consequences of which are very

serious. Rivers of India are already seriously sick. Polluted by industrial and urban effluents,

they are also victims of deforestation in their catchments, sequential damming and

degradation because of unchecked sand-mining on their banks and beds. Besides, erratic

monsoons, induced by changing climate is taking its toll, adversely impacting their capacity

to sustain the current levels of economic activities, especially agricultural productivity.

3.1. SAND MINING IN COASTAL REGULATION ZONE

The Central Government hereby declares the following areas as CRZ and imposes the

following restrictions on the setting up and expansion of industries, operations or processesand the like in the CRZ,-

i. The land area from High Tide Line (hereinafter referred to as the HTL) to 500mts on

the landward side along the sea front.

ii. CRZ shall apply to the land area between HTL to 100 mts or width of the creek

whichever is less on the landward side along the tidal influenced water bodies that are

connected to the sea and the distance upto which development along such tidalinfluenced water bodies is to be regulated shall be governed by the distance upto


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which the tidal effects are experienced which shall be determined based on salinity

concentration of 5 parts per thousand (ppt) measured during the driest period of the

year and distance upto which tidal effects are experienced shall be clearly identified

and demarcated accordingly in the Coastal Zone Management Plans (hereinafter

referred to as the CZMPs).

iii. The land area falling between the hazard line and 500mts from HTL on the landwardside, in case of seafront and between the hazard line and 100mts line in case of tidal

influenced water body. The word hazard line denotes the line demarcated byMinistry of Environment and Forests (hereinafter referred to as the MoEF) through

the Survey of India (hereinafter referred to as the SOI) taking into account tides,

waves, sea level rise and shoreline changes.

iv. Land area between HTL and Low Tide Line (hereinafter referred to as the LTL)

which will be termed as the intertidal zone.

v. The water and the bed area between the LTL to the territorial water limit (12 Nm) in

case of sea and the water and the bed area between LTL at the bank to the LTL on the

opposite side of the bank, of tidal influenced water bodies.

Mining of off shore sand became a topic of interest recently because of the increasingdemand and spiralling 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 storm 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. A complex relationship exists between

sand banks, coral reefs, marine biota, current circulation, waves and swells patterns.

Sand mining in coastal regions is subject to different regulations throughout the world.

While a minimum water depth is commonly used as a restrictive criterion for providingmining licenses in numerous countries.


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8Figure 3.1. Integrated Coastal Zone Management Plan


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4. IMPACTS OF SAND/GRAVEL MINING

Mining from, within or near a riverbed has a direct impact on the streams physicalcharacteristics, such as channel geometry, bed elevation, substratum composition and

stability, instream roughness of the bed, flow velocity, discharge capacity, sedimenttransportation capacity, turbidity, temperature, etc. Alteration or modification of the above

attributes may cause hazardous impact on ecological equilibrium of riverine regime. This

may also cause adverse impact on instream biota and riparian habitats. This disturbance may

also cause changes in channel configuration and flow-paths.

The major hazards caused due to mining of sand/gravel include the following:

i. Instream habitat: The impact of mining may result in increase in river gradient,

suspended load, sediment transport, sediment deposition, turbidity, change in

temperature, etc. Excessive sediment deposition for replenishment/ refilling of the pits

affect turbidity, prevent the penetration of the light required for photosynthesis ofmicro and macro flora which in turn reduces food availability for aquatic fauna.

Increase in river gradient may cause excessive erosion causing adverse effect on the

instream habitats.

ii. Riparian habitat: This includes vegetative cover on and adjacent to the river banks,

which controls erosion, provide nutrient inputs into the stream and prevents intrusion

of pollutant in the stream through runoff. Bank erosion and change of morphology of

the river can destroy the riparian vegetative cover.

iii. Degradation of Land: Mining pits are responsible for river channel shifting as well

as degradation of land, causing loss of properties and degradation of landscape.

iv. Lowering of groundwater table in the floodplain area: Mining may cause lowering

of riverbed level as well as river water level resulting in lowering of groundwater

table due to excessive extraction and draining out of groundwater from the adjacent

areas. This may cause shortage of water for the vegetation and human settlements in

the vicinity.

v. Depletion of groundwater: Excessive pumping out of groundwater during sand

mining especially in abandoned channels generally result in depletion of groundwaterresources causing severe scarcity and affecting irrigation and potable water

availability. In extreme cases it may also result in creation of ground fissures and land

subsidence in adjacent areas.

vi. Polluting groundwater: In case the river is recharging the groundwater, excessive

mining will reduce the thickness of the natural filter materials (sediments), infiltration

through which the ground water is recharged. The pollutants due to mining, such as

washing of mining materials, wastes disposal, diesel and vehicular oil lubricants andother human activities may pollute the ground water.

vii. Choking of filter materials for ingress of ground water from river: Dumping of

finer material, compaction of filter zone due to movement heavy machineries andvehicles for mining purposes may reduce the permeability and porosity of the filter


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material through which the groundwater is recharging, thus resulting in steady

decrease of ground water resources.

viii. Acid Mine Drainage- Threat to water resources: The potential for acid mine

drainage is a key question. The answer will determine whether a proposed mining

project is environmentally acceptable. When mined materials (such as the walls ofopen pits and underground mines, tailings, waste rock, and heap and dump leach

materials) are excavated and exposed to oxygen and water, acid can form if ironsulfide minerals (especially pyrite, or fools gold) are abundant and there is an

insufficient amount of neutralizing material to counteract the acid formation.

4.1. IMPACTS ON RIVER MORPHOLOGY.

Some sections of a stream are more conducive to aggregate extraction than others.

Most stream erosion takes place during high-flow events. Constant variations in the flow of

the river make the channel floor and riverbanks a dynamic interface where some materials arebeing eroded while others are being deposited. The net balance of this activity, on a short

term basis, is referred to as scour or fill. On a long-term basis, continued scour results in

erosion (degradation), while continued fill results in deposition (aggradations). Removal of

gravel from some aggrading sections of a river may be preferable to removing it from eroding

sections. A general indicator of the stability of a stream relates to the amount of vegetation

present. Gravel bars that are vegetated, or where the gravel is tightly packed, generally

indicate streams where the gravel supply is in balance. Streams with excessive gravel

generally have gravel bars with little or no vegetation, and are surfaced with loosely packed

gravel.

Even if a stream reach is eroding, aggregate mining may take place without causing

environmental damage if the channel floor is, or becomes, armoured by particles that are toolarge to be picked up by the moving water. For example, some sections of rivers underlain

with large gravel layers deposited under higher flow rates than those prevailing at the current

time may support gravel extraction with no serious environmental impacts.

The impacts from stream avulsion and pit capture can be avoided by constructing a

levee along the stream. The levee is designed with armoured spillways that control where the

levee will be breached by the stream during flooding. The spillway allows water to leave

the channel and temporarily flow over the floodplain but keeps stream from creating a new

channel and keeps the bed load in the stream.

Over-extraction of gravel can destabilise channels and banks, and/or affect the ecologicfunctioning of rivers particularly if undertaken at the wrong time, or in the wrong place, or in

a way that damages the river bed or margins.


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Figure 4.1. Extensive Modification to Stream Channel Caused by Gravel Extraction

(Langer, 2003)


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5. ENVIRONMENTAL EFFECTS OF SAND/GRAVEL MINING

i. Sand and gravel extraction can result in a number of physical, chemical, andbiological effects on mined streams. Sand and gravel mining can change the

geomorphic structure of streams (Sandecki 1989; Kondolf 1994), often resulting inchannel degradation and erosion from mining operations located either in or adjacent

to a stream.

ii. Instream mining typically alters channel geometry, including local changes in stream

gradient and width-to-depth ratios. Point-bar mining increases gradient by effectively

straightening the stream during floods.

iii. Thalweg relocation can occur when flooding connects the stream to floodplain mines.

iv. Local channel scouring and erosion can occur as a result of increased water velocity

and decreased sediment load associated with mined areas.

v. Where mining activities are numerous and concentrated an upstream progression of

channel degradation and erosion can occur-a process referred to as headcutting.

Headcuts induced by sand and gravel mining can cause dramatic changes in a stream

bank and channel that may affect instream flow, water chemistry and temperature,

bank stability, available cover, and siltation.

vi. Channel erosion from headcuts can cause loss of upstream property values; reduce

recreational, fishing, and wildlife values; and contribute to the extirpation andextinction of stream fauna (Hartfield 1993).

vii. The combined processes of channel incision and headcutting also can undermine

bridge piers and other structures.

viii. Channel incision caused by instream gravel mining on the San Luis Rey River in

California exposed aqueducts, gas pipelines, and footings of highway bridges

(Kondolf 1997). Sedimentation and increased turbidity also can accrue from miningactivities, wash-water discharge, and storm runoff from active or abandoned mining

sites.

ix. Turbidity is generally greatest at mining and wash-water discharge points and

decreases with distance downstream. Sedimentation and increased turbidity as a result

of mining can have varying effects on fishes.

x. Mining-induced changes to the geomorphic structure of the stream can significantly

affect fish habitat and abundance. Instream mining can reduce the occurrence of

coarse, woody debris in a channel, an important habitat for fish and invertebrates.

5.1. ENVIRONMENTAL ISSUES OF SAND MINING

In Tamil Nadu, with a view to drawing the attention of the government to the

magnitude of the problem and sensitising people about the risks involved, the Campaign forthe Protection of Water Resources-Tamil Nadu arranged a State-level "public hearing" on the


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impact of sand mining (on river basins, streams, coastal areas and hill regions). After intense

studies in different regions and interaction with the affected people, the Campaign for the

Protection of Water Resources, Tamil Nadu has identified 15 adverse consequences of sand

mining. They include the depletion of groundwater; lesser availability of water for industrial,

agricultural and drinking purposes; destruction of agricultural land; loss of employment to

farm workers; threat to livelihoods; human rights violations; and damage to roads andbridges. Representatives of victims from 13 of the 28 districts of the State gave evidence on

the damage caused to the environment and livelihoods in these districts.The affected river basins included those of the Palar and its tributaries Cheyyar, Araniyar and

Kosathalaiyar (Kanchipuram and Thiruvallur districts); the Cauvery (Karur district); the

Bhavani (Erode district); the Vellar (Perambalur district); the Vaigai (Madurai and Theni

districts); and the Thamiraparani (Tirunelveli district). Victims from the coastal districts of

Nagapattinam, Tuticorin, Ramanatha-puram and Kanyakumari.

In Kerala, there has been a significant increase in sand mining since the beginning of

the 1990s following a boom in the construction industry, and the activity reached alarmingproportions in several areas, particularly in the southern and western regions of the State,

after court restrictions on sand mining came into effect in neighbouring Kerala in 1994.Similarly River Bharathapuzha in Kerala has become a victim of indiscriminate sand mining.

Despite numerous prohibitions and regulations, sand mining continues rapidly on the riverbed

of the Bharathapuzha. Water tables have dropped dramatically and a land once known for its

plentiful rice harvest now faces scarcity of water. In the villages and towns around the river,

groundwater levels have fallen drastically and wells are almost perennially dry.

Illegal and excessive sand mining in the riverbed of the Papagani catchment area in

Karnataka has led to the depletion of groundwater levels and environmental degradation in

the villages on the banks of the river in both Andhra Pradesh and Karnataka. In Karnataka,legal sand mining from the Papagani river catchment area in Kolar district, been going on forsix to seven years. Initially, the Karnataka government gave sand mining rights to some

contractors, but due to increased illegal and excessive mining, it has led to environmental

degradation and problems for the people by the depletion of groundwater levels in the

villages situated on the river banks. Moreover, as these villages are situated in the border

between Andhra Pradesh and Karnataka, both the states are affected by this problem.

In Megalaya, pollution of the water is evident by the colouration of water which in

most of the rivers and streams in the mining area varies from brownish to reddish orange.Low pH (between 2-3), high electrical conductivity, high concentration of ions of sulphate

and iron and toxic heavy metals, low dissolved oxygen (DO) and high BOD are some of thephysico-chemical and biological parameters which characterize the degradation of water

quality. Contamination of Acid Mine Drainage (AMD) originating from mines and spoils,

leaching of heavy metals, organic enrichment and silting by sand particles are major causes

of degradation of water quality in the area. Mining operation, undoubtedly has brought

wealth and employment opportunity in the area, but simultaneously has led to extensive

environmental degradation and disruption of traditional values in the society. Environmental

problems associated with mining have been felt severely because of the regions fragile

ecosystems and rich biological and cultural diversity. Large scale denudation of forest cover,

scarcity of water, pollution of air, water and soil and degradation of agricultural lands are

some of the conspicuous environmental implications of coal mining (Swer and Singh, 2004).


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6. SCIENTIFIC MINING OF SAND/GRAVEL

Following geoscientific considerations are suggested to be taken into account for sand/ gravelmining:-

i. Abandoned stream channels on terrace and inactive floodplains may be preferred

rather than active channels and their deltas and floodplains. Replenishment of ground

water has to be ensured if excessive pumping out of water is required during mining.

ii. Stream should not be diverted to form inactive channel.

iii. Mining below subterranean water level should be avoided as a safeguard against

environmental contamination and over exploitation of resources.

iv. Large rivers and streams whose periodic sediment replenishment capacity are larger,

may be preferred than smaller rivers.v. Segments of braided river system should be used preferably falling within them lateral

migration area of the river regime that enhances the feasibility of sediment

replenishment.

vi. 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 and to promote mining on naturally

building (aggrading) meander components.

vii. Scraping of sediment bars above the water flow level in the lean period may be

preferred for sustainable mining.

viii. It is to be noted that the environmental issues related to mining of minerals including

riverbed sand mining should clearly state the size of mine leasehold area, mine lease

period, mine plan and mine closure plan, along with mine reclamation and

rehabilitation strategies, depth of mining and period of mining operations, particularly

in case of river bed mining.

ix. The Piedmont Zone (Bhabbar area) particularly in the Himalayan foothills, where

riverbed material is mined. This sandy- gravelly track constitutes excellent conduitsand holds the greater potential for ground water recharge. Mining in such areas should

be preferred in locations selected away from the channel bank stretches. Areas where

channel banks are not well defined, particularly in the braided river system,

midstream areas should be selected

x. for mining of riverbed materials for minimizing adverse effects on flow regime and

instream habitat.

xi. Mining of gravelly sand from the riverbed should be restricted to a maximum depth of3m from the surface. For surface mining operations beyond this depth of 3m (10 feet),

it is imperative to adopt quarrying in a systematic bench- like disposition, which isgenerally not feasible in riverbed mining. Hence, for safety and sustainability

restriction of mining of riverbed material to maximum depth of 3m.is recommended.


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xii. Mining of riverbed material should also take cognizance of the location of the active

channel bank. It should be located sufficiently away, preferably more than 3m away

(inwards), from such river banks to minimize effects on river bank erosion and avoid

consequent channel migration.

xiii. Continued riverbed material mining in a given segment of the river will induceseasonal scouring and intensify the erosion activity within the channel. This will have

an adverse effect not only within the mining area but also both in upstream anddownstream of the river course. Hazardous effects of such scouring and enhanced

erosion due to riverbed mining should be evaluated periodically and avoided for

sustainable mining activities.

xiv. Mineral processing in case of riverbed mining of the sandy gravelly material may

consist of simple washing to remove clay and silty area. It may involve crushing,

grinding and separation of valueless rock fragments from the desirable material. The

volume of such waste material may range from 10 to 90%. Therefore, such hugequantities of mine wastes should be dumped into artificially created/ mined - out pits.

Where such tailings / waste materials are very fine grained, they may act as a sourceof dust when dry. Therefore, such disposal of wastes should be properly stabilized and

vegetated to prevent their erosion by winds.

xv. Identification of river stretches and their demarcation for mining must be completed

prior to mining for sustainable development.

xvi. The mined out pits should be backfilled where warranted and area should be suitably

landscaped to prevent environmental degradation.

xvii. Mining generally has a huge impact on the irrigation and drinking water resources.These attributes should be clearly evaluated for short-term as well as long-term

remediation.

Ministry of Environment & Forest (MoEF) also stipulates the following

recommendations on mining of minor minerals/ construction materials:

i. Mining Lease (ML) area should be demarcated on the ground with Pucca Pillars.

ii. For river sand mining, area should be clearly specified for mining operations in theregion. The area should be properly surveyed and mapped with the help of GPS to

assign geo-coordinates and accordingly erect boundary pillars so as to avoid illegal

unscientific mining.

iii. Within the ML area, if any forest land is existing, it should be distinctly shown on the

map along with coordinates.

iv. While considering the sanction of ML area, due attention should be paid to thepresence of any National Park/Sanctuary/Ecologically Sensitive landscape. In such

cases order of the Honble Supreme Court in .W.P (C) No. 337/1995) should be

strictly followed.


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v. For mining lease within 10 km of the National Park/Sanctuary, recommendation/

permission of National Board of Wild Life (NBWL) have to be obtained as per the

Honble Supreme Court order in I.A. No. 460/2004.

vi. Site-specific plans with eco-restoration should be considered/ implemented.

Therefore, adverse impacts of mining mentioned here should be avoided orminimized. Remedies include restoration of riparian and instream habitats, restoration

of river geometry causing degradation in upstream, downstream and in the miningarea, depletion and prevention of contamination of ground water etc.


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existing riparian vegetation, there is a greater potential for widening and braiding of the low

flow channel.

v. Concentrate Activities to Minimise DisturbanceIn-stream extraction activities should be concentrated or localised to a few bars rather

than spread out over many bars. This localisation of extraction will minimise the area ofdisturbance of upstream and downstream effects. Skimming decreases habitat and species

diversity - these effects should not be expanded over a large portion of the study area.

vi. Review Cumulative Effects of Sand and Gravel ExtractionThe cumulative impact of all mining proposals should be reviewed on an annual basis

to determine if cumulative riverine effects or effects to the estuary are likely and to ensure

that permits are distributed in a manner that minimises long-term impacts and inequities in

permits between adjacent mining operations.

vii. Maintain Flood CapacityFlood capacity in the river should be maintained in areas where there are significant

flood hazards to existing structures or infrastructure.

viii. Establish a Long-term Monitoring ProgramMonitoring of changes in bed elevation and channel morphology, and aquatic and

riparian habitat upstream and downstream of the extraction would identify any impacts of

sand and gravel extraction to biologic resources. Long-term data collected over a period of

decades as sand and gravel extraction occurs will provide data to use in determining trends.

ix. Minimise Activities That Release Fine Sediment to the RiverNo washing, crushing, screening, stockpiling, or plant operations should occur at orbelow the streams "average high water elevation," or the dominant discharge. These and

similar activities have the potential to release fine sediments into the stream, providing

habitat conditions harmful to local fish.

x. Retain Vegetation Buffer at Edge of Water and Against River BankRiparian vegetation performs several functions essential to the proper maintenance of

geomorphic and biological processes in rivers. It shields river banks and bars from erosion.

Additionally, riparian vegetation, including roots and downed trees, serves as cover for fish,

provides food source, works as a filter against sediment inputs, and aids in nutrient cycling.More broadly, the riparian zone is necessary to the integrity of the ecosystem providing

habitat for invertebrates, birds and other wildlife.

xi. Limit In-stream Operations to the Period between May and SeptemberThe in-stream mining should only be allowed during the dry season.

xii. An Annual Status and Trends ReportThis report should review permitted extraction quantities in light of results of the

monitoring program, or as improved estimates of replenishment become available. The report

should document changes in bed elevation, channel morphology, and aquatic and riparian

habitat. The report should also include a record of extraction volumes permitted, and

excavation location. Finally, recommendations for reclamation, if needed should be

documented.


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7.2. Off-Channel or Floodplain Extraction Recommendations

i. Floodplain Extraction Should Be Set Back from the Main ChannelIn a dynamic alluvial system, it is not uncommon for meanders to migrate across a

floodplain. In areas where sand and gravel occurs on floodplains or terraces, there is a

potential for the river channel to migrate toward the pit. If the river erodes through the area

left between the excavated pit and the river, there is a potential for "river capture," a situation

where the low flow channel is diverted though the pit. In order to avoid river capture,

excavation pits should set back from the river to provide a buffer, and should be designed towithstand the 100-year flood (100-year ARI). Adequate buffer widths and reduced pit slope

gradients are preferred over engineered structures which require maintenance in perpetuity.

Hydraulic, geomorphic, and geotechnical studies should be conducted prior to design and

construction of the pit and bund. In addition to river capture, extraction pits create the

possibility of stranding fish. To avoid this impact, all off-channel mining should be

conducted above the 25-year ARI level.

ii. The Maximum Depth of Floodplain Extraction Should Remain above the ChannelThalweg

Floodplain pits should not be excavated below the elevation of the thalweg in theadjacent channel. This will minimise the impacts of potential river capture by limiting the

potential for headcutting and the potential of the pit to trap sediment. A shallow excavation

(above the water table) would provide a depression that would fill with water part of the year,

and develop seasonal wetland habitat. An excavation below the water table would provide

deep water habitat.

iii. Side Slopes of Floodplain Excavation Should Range from 3:1 to 10:1Side slopes of a floodplain pit should be graded to a slope that ranges from 3:1 to

10:1. This will allow for a range of vegetation from wetland to upland. Steep side slopes

excavated in floodplain pits on other systems have not been successfully reclaimed, since it isdifficult for vegetation to become stabilised. Terrace pits should be designed with a large

percentage of edge habitats with a low gradient which will naturally sustain vegetation at a

variety of water levels.

iv. Place Stockpiled Topsoil above the 25-year Return Period or ARI LevelStockpiled topsoil can introduce a large supply of fines to the river during a flood

event and degrade fish habitat. Storage above the 25-year flood (25-year ARI) inundation

level is sufficient to minimise this risk.

v. Floodplain Pits Should Be Restored to Wetland Habitat or Reclaimed for AgricultureThere are very few examples of successfully restored or reclaimed extraction pits on

river systems. The key to successful restoration or reclamation is to conserve or import

adequate material to re-fill the pit, while ensuring that pit margins are graded to allow for

development of significant wetland and emergent vegetation.

vi. Establish a Long-term Monitoring ProgramA long-term monitoring program should provide data illustrating any impacts to river

stability, groundwater, fisheries, and riparian vegetation. The monitoring program should

assess the success of any reclamation or restoration attempted.


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vii. An Annual Status and Trends ReportThe status and trends report described previously should include a section on the

hydrologic and biologic components of floodplain pit reclamation.

7.3. Reclamation Plans

In-stream reclamation plans should include:

i. A baseline survey consisting of existing condition cross-section data. Cross-sectionsmust be surveyed between two monumental endpoints set back from the top of bank,

and elevations should be referenced to JUPEMs bench mark;

ii. The proposed mining cross-section data should be plotted over the baseline data to

illustrate the vertical extent of the proposed excavation;

iii.

The cross-section of the replenished bar should be the same as the baseline data. Thisillustrates that the bar elevation after the bar is replenished will be the same as the bar

before extraction;

iv. A planimetric map showing the aerial extent of the excavation and extent of the

riparian buffers;

v. A planting plan developed by a plant ecologist familiar with the flora of the river for

any areas such as roads that need to be restored;

vi. A monitoring plan.


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8. APPROPRIATE EXTRACTION METHODS

i. Bar scalping or skimming.

Bar scalping or skimming is extraction of sand and gravel from the surface of bars.Historical scalping commonly removed most of the bar above the low flow water level,

leaving an irregular topography. Present method generally requiresthat surface irregularities

be smoothed out and that the extracted material be limited towhat could be taken above an

imaginary line sloping upwards and away from thewater from a specified level above the

river's water surface at the time of extraction(typically 0.3 - 0.6 m (1-2 ft)).

Bar scalping is commonly repeated year after year. To maintain the hydraulic control

provided to upstream by the riffle head, the preferred method of bar scalping is now generally

to leave the top one-third (approximately) of the bar undisturbed, mining only from thedownstream two-thirds.

Figure 8.1. Aggregate being skimmed off the surface of a bar (Langer, 2003)

ii. Dry-Pit Channel MiningDry-pit channel mines are pits excavated within the active channel on dry intermittent

or ephemeral stream beds with conventional bulldozers, scrapers and loaders. Dry pits are

often left with abrupt upstream margins, from which headcuts are likely to propagate

upstream.


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iii. Wet-Pit Channel Mining.Wet-pit mining involves excavation of a pit in the active channel below the surface

water in a perennial stream or below the alluvial groundwater table, requiring the use of a

dragline or hydraulic excavator to extract sand and gravel from below the water surface.In some areas, such as low terraces, some glaciofluvial deposits, and some ephemeral

streambeds, sand and gravel mining may penetrate the water table and may be mined wet ordry. In some geologic settings, wet pits can be made dry by collecting the groundwater in

drains in the floor of the pit and pumping the water out of the pit.

Figure 8.2. Wet-pit Channel Mining.

iv. Bar ExcavationA pit is excavated at the downstream end of the bar as a source of aggregate and as a

site to trap sand and gravel. Upon completion, the pit may be connected to the channel at its

downstream end to provide side channel habitat. On the Russian River, California, recent

proposals for bar mining include leaving the bar margins untouched and excavating from theinterior of the downstream part of the bar, but above the water surface elevation, a variant

intermediate between bar scalping and bar excavation.


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Figure 8.3. Bar excavation

v. In-stream Gravel TrapsSand or bed load traps have been used to reduce sand in downstream channels for

habitat enhancement in Michigan. Such traps can also be potential sources of commercial

aggregate, provided the amounts so collected are sufficient to be economically exploited. One

advantage of the traps as a method for harvesting sand and gravel are the concentration of

mining impacts at one site, where heavy equipment can remove sand and gravel withoutimpacting riparian vegetation or natural channel features. Sand and gravel can be removed

year after year from the bed load trap.An idealized trap has short dikes to create a constriction downstream and to hold the

resultant higher stages. Sand and gravel are removed from the downstream end of the deposit,and a grade control structure at the upstream end of the trap prevents headcutting upstream

from the extraction. There is no hydraulic impact upstream due to the extraction, because the

engineered constriction is the hydraulic control during high flows. The concentrated flow

scours a deep pool immediately downstream from the constriction, which may be important

habitat in aggrading reaches where pool formation is limited by deposition.

Figure 8.4. Idealized gravel trap (Source: Bates 1987).

vi. Channel-wide In-Stream MiningIn rivers with a highly variable flow regime, sand and gravel are commonly extracted

across the entire active channel during the dry season. The bed is evened out and uniformly

(or nearly so) lowered.


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9. SUMMARY AND RECOMMENDATIONS

In the past 34 decades, rivers in the densely populated areas of the world aresubjected to immense pressures due to various kinds of human interventions, among which

indiscriminate mining for construction grade sand from alluvial reaches is the most disastrousone. 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.

Given below are some of the recommendations suggested to improve the overallenvironmental quality of the river systems of India, in particular.

i. An integrated environmental assessment, management and monitoring program

should form part of the sand extraction processes. Also, there is an urgent need for

integrating the studies on various disciplines on the human induced degradation of the

small catchment rivers of India.

ii. Evaluate physical, chemical and biological effects of instream mining on a river basin

scale, so that cumulative effects of extraction on the aquatic and riparian resources

can be recognised and addressed at various levels for proper remedial measures.

iii. Examine and encourage alternatives to river sand for construction purposes.

Immediate steps are to be taken to intensify research activities leading to the finding

of a suitable, low cost and easily available alternative to river sand.iv. Evaluate control measures such as bank stabilisation, revegetation of buffer strips,

influences of connected floodplain pits etc. Restoration efforts should concentrate on

techniques that will optimise fish production, promote aquatic diversity and restore

biotic integrity.

v. Awareness campaign should be conducted at various levels about river sand mining,

present state of environment of rivers and immediate need for control measures.


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SAND MINING 201310.REFERENCES

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 28:225243

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

Binoy Aliyas Mattamana, Shiney Varghese, Kichu Paul., River Sand Inflow Assessment and

Optimal Sand Mining Policy Development. International Journal of Emerging Technology

and Advanced Engineering, ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 3,

Issue 3, March 2013.

CSE (Centre for Science and Environment) (2012), Grains of Despair: Sand mining in

India,[Online] Available: http://www.cseindia.org/node/3878(Accessed 11th Dec, 2012)

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

Documents

ISSUES AND CHALLENGES IN RIVER MANAGEMENT DUE EXCESSIVE SAND MINING