The document discusses the environmental impacts of river sand mining. It finds that sand mining can have long-lasting physical impacts by degrading river channels over decades of extraction. This destroys aquatic and riparian habitats through changes in channel morphology. Specifically, it leads to increased sediment loads and turbidity, along with altering ecologically important features in the river bed. Sand mining also modifies riparian zones and lowers groundwater levels. In Sri Lanka, unregulated sand mining has severely impacted several major rivers like Kalu Ganga and Kelani Ganga. The document calls for limiting mining to floodplains and following guidelines to reduce environmental damage.

3. Epitome
1.
2.
3.
4.
5.
• Introduction
• Impacts of sand mining / gravel extraction
• Fundamental considerations in all sand
mining operations
• Summary
• References

4. 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

5. 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

6. 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

7. Direct impact on the stream’s physical habitat
characteristics
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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

8. 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

9. 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

10. Figure 2.1: Instream habitat (Left) and Riparian habitat (Right)
The Impact on River Sand Mining on Environment
W.A.Dulanjali M. Wijethilake

11. 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

12. 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

13. 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

14. • 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

15. 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

16. 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

17. 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

18. 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

19. 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

20. 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

21. 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

22. 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

23. 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

24. 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

25. 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

26. 1
4
2
5
3
6
The Impact on River Sand Mining on Environment
W.A.Dulanjali M. Wijethilake

27.  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

28. Physical
The Impact on River Sand Mining on Environment
Water
quality
Ecological
W.A.Dulanjali M. Wijethilake

29. 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

30. 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

31. 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

32. 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

33. 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

34. Figure 2.5 : Yellow boy in a streams
The Impact on River Sand Mining on Environment
W.A.Dulanjali M. Wijethilake

35. 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

36. 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

37. 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

38. 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

39. 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

40. The Impact on River Sand Mining on Environment
W.A.Dulanjali M. Wijethilake

41. 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