Epitome
1.

2.

3.

4.

5.

• Introduction
• Impacts of sand mining / gravel extraction
• Fundamental considerations in al...
Large scale mining of sand and gravel
Increasing demand in the construction sector
Short term benefits
Instream sand minin...
For thousands of years, sand and gravel have
been used in the construction of roads and
buildings

Excessive instream sand...
Pollution of the water is evident by the
coloration of water which in most of the rivers
and streams in the mining area

C...
Direct impact on the stream’s physical habitat
characteristics











Channel geometry
Bed elevation
Substra...
The detrimental effects to biota resulting from
bed material mining are caused by three main
processes
1. Alteration of th...
Aggregate mining involves the channel and
boundary but requires land access and material
storage

Instream habitat
Potenti...
Figure 2.1: Instream habitat (Left) and Riparian habitat (Right)

The Impact on River Sand Mining on Environment

W.A.Dula...
Kinds of instream sand mining
 Dry-pit
 Wet pit mining
 Bar skimming or "scalping."
 Pits on the adjacent floodplain o...
Types of instream habitats
a)
b)
c)
d)
e)
f)
g)
h)
i)

Log structures
Log jams
Cover structures
Boulders structures
Gabion...
a. Extraction of bed material in excess
of
natural
replenishment
by
upstream transport
o

This causes bed degradation, inc...
• Suspended sediment load
• Reduction in light penetration
• Loss of photosynthesis in micro and macrophytes
• Resulting i...
b. Bed degradation, changes
morphology of the channel

the

o Potential for diversion of flow through
o Migration blockage...
c. Operation of heavy equipment in the
channel bed
o Can directly destroy spawning habitat for fish and
macroinvertebrate ...
d. Altering channel hydraulics
o Stockpiles and overburden in the floodplain can
alter channel hydraulics during high flow...
e.

Removal or disturbance
instream roughness elements

of

o It negatively affects both quality and quantity of
instream ...
Many hectares of fertile streamside land are lost
annually
Degraded stream habitats result in lost of
fisheries productivi...
All species require specific habitat conditions to
ensure long-term survival
Unstable stream channels are inhospitable to
...
a. Destruction of the riparian zone
It serves as buffer to pollutants entering a stream from
runoff, controls erosion, and...
b. Lowered floodplain groundwater
o Riparian vegetation reliant on the groundwater
will subsequently be stressed

c. Perma...
d. Destruction of riparian vegetation
o This is caused by heavy equipment, processing
plants at or near the extraction sit...
f. Removal of large woody debris
from the riparian zone
o It negatively affects the plant community.
g. Reduced vegetative...
Further impacts ……..
 Sand budget
Determining the sand budget for a particular
stream
reach
requires
site-specific
topogr...
1

4

2

5

3

6

The Impact on River Sand Mining on Environment

W.A.Dulanjali M. Wijethilake
 Impacts for groundwater
Bed degradation from instream mining lowers the
elevation of stream flow
Saline water may intrud...
Physical

The Impact on River Sand Mining on Environment

Water
quality

Ecological

W.A.Dulanjali M. Wijethilake
The potential impacts of sand
mining are :
Bed degradation and consequent effects on
channel and bank stability

Figure 2....
Increased sediment loads, decreased water clarity
Changes in channel morphology and disturbance of
ecologically important ...
Direct destruction from heavy equipment
operation
Discharges from equipment and refueling
Impacts on structures and access...
Figure 2.4 : Extensive Modification to Stream Channel Caused by sand mining

The Impact on River Sand Mining on Environmen...
Special attention …
Acid Mine Drainage- Threat to
water resources
 Acid mine drainage also dissolves toxic metals such as...
Figure 2.5 : Yellow boy in a streams

The Impact on River Sand Mining on Environment

W.A.Dulanjali M. Wijethilake
There are several factors consider when sand
mining in particular area
1. Sand mining sites should be situated outside the...
3. bar skimming should not be allowed.
4. Pit excavations located on adjacent floodplain or terraces
should be separated f...
Epitome
1.

2.

3.

4.

5.

6.

• Introduction

• Impacts of sand mining / gravel extraction
• Fundamental considerations ...
The geomorphic effects of river sand mining have
involved extraction rates lasting over a decade or more
Instream sand min...
Basically sand mining carrying in two locations. Those
are instream sand mining and riparian zone sand
mining

In addition...
The Impact on River Sand Mining on Environment

W.A.Dulanjali M. Wijethilake
Concise report of the study done by Volunteer team of Net water. Impact of
river sand mining in Ratnapura district in Saba...
Impact of river sand mining on environment by Dulanjali M. Wijethilake
Impact of river sand mining on environment by Dulanjali M. Wijethilake
Impact of river sand mining on environment by Dulanjali M. Wijethilake
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Impact of river sand mining on environment by Dulanjali M. Wijethilake

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  • An instream flow is a water right for the stream and the resources that depend on it. It has a priority date like any other water right.  Instream flows are the stream flow levels that will protect and preserve instream resources and values.The term “instream flow” identifies a specific stream flow level (measured in cubic feet per second, cfs) at a specific location on a given stream. The weather causes natural flow variations throughout the year so an instream flow is a range (a “regime”), usually changing month-to-month, instead of a single number.Instream flows do not affect existing (senior) water rights, rather, they protect the river from future withdrawals.Setting instream flows does not put water in streams.In state law, the terms “base flow” and “minimum instream flow” have the same meaning as “instream flow.”A riparian zone or riparian area is the interface between land and a river or stream. Riparian is also the proper nomenclature for one of the fifteen terrestrial biomes of the earth. Plant habitats and communities along the river margins and banks are called riparian vegetation, characterized by hydrophilic plants.
  • These elements are important in controlling channel morphology and stream hydraulics, in regulating the storage of sediments, gravel and particulate organic matter, and in creating and maintaining habitat diversity and complexity
  • These elements are important in controlling channel morphology and stream hydraulics, in regulating the storage of sediments, gravel and particulate organic matter, and in creating and maintaining habitat diversity and complexity
  • All species require specific habitat conditions to ensure long-term survival. Native species in streams are uniquely adapted to the habitat conditions that existed before humans began large-scale alterations. These have caused major habitat disruptions that favored some species over others and caused overall declines in biological diversity and productivity. In most streams and rivers, habitat quality is strongly linked to the stability of channel bed and banks. Unstable stream channels are inhospitable to most aquatic species.
  • The riparian zone includes stream banks, riparian vegetation and vegetative cover.Destruction of the riparian zone during sand / gravel extraction operations can have multiple deleterious effects on instream habitat. Damaging any one of these elements can cause stream bank destabilization, resulting in increased erosion, sediment and nutrient inputs, and reduced shading and bank cover leading to increased stream temperature.
  • Larger rivers and streams are preferable because they have more sand/gravel with a wider floodplain. The proportionally smaller disturbance in large systems will reduce the overall impact of sand/gravel extraction.
  • Impact of river sand mining on environment by Dulanjali M. Wijethilake

    1. 1. Epitome 1. 2. 3. 4. 5. • Introduction • Impacts of sand mining / gravel extraction • Fundamental considerations in all sand mining operations • Summary • References
    2. 2. Large scale mining of sand and gravel Increasing demand in the construction sector Short term benefits Instream sand mining may not be visible Sand mining disturbs the equilibrium of a river channel The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    3. 3. For thousands of years, sand and gravel have been used in the construction of roads and buildings Excessive instream sand mining is a threat to bridges, river banks and nearby structures Continued extraction Sand is an important mineral for our society in protecting the environment The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    4. 4. Pollution of the water is evident by the coloration of water which in most of the rivers and streams in the mining area Contamination of Acid Mine Drainage (AMD) The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    5. 5. Direct impact on the stream’s physical habitat characteristics           Channel geometry Bed elevation Substrate composition and stability Instream roughness elements Depth Velocity Turbidity Sediment transport Stream discharge Temperature The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    6. 6. The detrimental effects to biota resulting from bed material mining are caused by three main processes 1. Alteration of the flow patterns resulting from modification of the river bed 2. An excess of suspended sediment 3. Damage to riparian vegetation and instream habitat The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    7. 7. Aggregate mining involves the channel and boundary but requires land access and material storage Instream habitat Potential impacts of sand mining Riparian habitat The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    8. 8. Figure 2.1: Instream habitat (Left) and Riparian habitat (Right) The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    9. 9. Kinds of instream sand mining  Dry-pit  Wet pit mining  Bar skimming or "scalping."  Pits on the adjacent floodplain or river terraces The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    10. 10. Types of instream habitats a) b) c) d) e) f) g) h) i) Log structures Log jams Cover structures Boulders structures Gabion Brush bundle Spawning pads Rubble mats Sediment traps The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    11. 11. a. Extraction of bed material in excess of natural replenishment by upstream transport o This causes bed degradation, increases suspended sediment, sediment transport, water turbidity and sand/gravel siltation o Becomes unsuitable for many aquatic organisms o Gravel removal not only impacts for the extraction site The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    12. 12. • Suspended sediment load • Reduction in light penetration • Loss of photosynthesis in micro and macrophytes • Resulting in reduced food availability and plant biomass • Reduced visibility of pelagic food, reduced availability of benthic food due to smothering • Clogging of gill rakers and gill filaments • Ultimeately fish become die The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    13. 13. b. Bed degradation, changes morphology of the channel the o Potential for diversion of flow through o Migration blockages for fish during low flows o If the gravel extraction activity is conducted away from the active river channel during low water periods o As active channels naturally meander, the channel may migrate into The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    14. 14. c. Operation of heavy equipment in the channel bed o Can directly destroy spawning habitat for fish and macroinvertebrate habitat, and produce increased turbidity and suspended sediment downstream. Figure 2.2: Turbid water due to sand mining The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    15. 15. d. Altering channel hydraulics o Stockpiles and overburden in the floodplain can alter channel hydraulics during high flows. The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    16. 16. e. Removal or disturbance instream roughness elements of o It negatively affects both quality and quantity of instream habitat. o Instream roughness elements - particularly large woody debris, play a major role in providing structural integrity to the stream ecosystem. The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    17. 17. Many hectares of fertile streamside land are lost annually Degraded stream habitats result in lost of fisheries productivity, biodiversity, and recreational potential. Severely degraded channels may reduce land and aesthetic values. The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    18. 18. All species require specific habitat conditions to ensure long-term survival Unstable stream channels are inhospitable to most aquatic species The complete removal of vegetation and destruction of the soil profile destroys The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    19. 19. a. Destruction of the riparian zone It serves as buffer to pollutants entering a stream from runoff, controls erosion, and provides habitat and nutrient input into the stream. The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    20. 20. b. Lowered floodplain groundwater o Riparian vegetation reliant on the groundwater will subsequently be stressed c. Permanent flooding o Subsequently causes annual flooding into the disturbed site. The Impact on River Sand Mining on Environment or frequent W.A.Dulanjali M. Wijethilake
    21. 21. d. Destruction of riparian vegetation o This is caused by heavy equipment, processing plants at or near the extraction site e. Disturbing the natural hydraulics of the riparian zone o Generation of recruitment may be lost The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    22. 22. f. Removal of large woody debris from the riparian zone o It negatively affects the plant community. g. Reduced vegetative bank cover o Resulting in reduced shading and increased water temperatures. The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    23. 23. Further impacts ……..  Sand budget Determining the sand budget for a particular stream reach requires site-specific topographic, hydrologic, and hydraulic information. The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    24. 24. 1 4 2 5 3 6 The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    25. 25.  Impacts for groundwater Bed degradation from instream mining lowers the elevation of stream flow Saline water may intrude into the fresh water body  Impacts for Water Quality Increased riverbed and bank erosion Increased short-term turbidity Suspended solids can increase water treatment costs The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    26. 26. Physical The Impact on River Sand Mining on Environment Water quality Ecological W.A.Dulanjali M. Wijethilake
    27. 27. The potential impacts of sand mining are : Bed degradation and consequent effects on channel and bank stability Figure 2.3: Slumped/Exposed Bank due to Unrestricted Mining Activities The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    28. 28. Increased sediment loads, decreased water clarity Changes in channel morphology and disturbance of ecologically important roughness elements in the river bed Ecological effects on bird nesting, fish migration etc. Modification of the riparian zone including bank erosion The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    29. 29. Direct destruction from heavy equipment operation Discharges from equipment and refueling Impacts on structures and access Biosecurity and pest risks Impacts on coastal processes The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    30. 30. Figure 2.4 : Extensive Modification to Stream Channel Caused by sand mining The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    31. 31. Special attention … Acid Mine Drainage- Threat to water resources  Acid mine drainage also dissolves toxic metals such as copper, aluminum, cadmium, arsenic, lead and mercury from the surrounding rock  Yellow boy  The impacts to aquatic life may range from immediate fish kills to sub lethal, impact affecting growth, behavior or ability to reproduce The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    32. 32. Figure 2.5 : Yellow boy in a streams The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    33. 33. There are several factors consider when sand mining in particular area 1. Sand mining sites should be situated outside the active floodplain and excavation should not take place from below the water table. 2. Larger rivers and streams should be used preferentially than small rivers and streams. The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    34. 34. 3. bar skimming should not be allowed. 4. Pit excavations located on adjacent floodplain or terraces should be separated from the active channel. 5. The removal or disturbance of instream roughness elements during gravel extraction activities should be avoided. 6. Turbidity levels should be monitored 7. Sand extraction in vegetated riparian areas should be avoided. 8. Operation and storage of heavy equipment within riparian habitat should be restricted. The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    35. 35. Epitome 1. 2. 3. 4. 5. 6. • Introduction • Impacts of sand mining / gravel extraction • Fundamental considerations in all sand mining operations • Status of Sri Lanka • Summary • References
    36. 36. The geomorphic effects of river sand mining have involved extraction rates lasting over a decade or more Instream sand mining results in the destruction of aquatic and riparian habitat through large changes in the channel morphology Physical impacts cause degradation of riparian and aquatic biota The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    37. 37. Basically sand mining carrying in two locations. Those are instream sand mining and riparian zone sand mining In addition sand mining alter the sand budget, ground water and water quality. Special attention goes to Acid Mine Drainage (AMD) There are 103 river basins in Sri Lanka The situation is more severe in certain major rivers including Kalu Ganga, Walawe ganga, Kelani ganga , Nilwala ganga , Deduru Oya, Ma Oya and Kirindi Oya The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    38. 38. The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
    39. 39. Concise report of the study done by Volunteer team of Net water. Impact of river sand mining in Ratnapura district in Sabaragamuwa province Hill, L., Kleynhans, C.J., (1999). Preliminary Guidance document for Authorization and Licensing of Sand Mining / Gravel Extraction, in terms of Impacts on Instream and Riparian Habitats Impacts of sand mining http://threeissues.sdsu.edu/three_issues_sandminingfacts01.html from Rathnayake, R., (2012). Unregulated / Illicit River Sand Mining in Sri LankaImpact of Awareness Campaign and Legal Recourse River sand mining management guideline , Ministry of natural resources and environment. Department of irrigation and management in Malaysia. pp 15-20 Saviour, N.M., (2012). Environmental impact of soil and sand mining : A review, International Journal of Science, Environment and Technology, Vol. 1, No 3. pp 126 – 127, 132 The Impact on River Sand Mining on Environment W.A.Dulanjali M. Wijethilake
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