1. Assess the impacts of river sand extraction
to bank erosion at Co Chien River, Vinh
Long Province
Ngo Thanh Hau1)
, Huynh Trung Tin1)
, Trinh Cong Luan2)
, Bui Trong Vinh1)
1) Faculty of Geology & Petroleum Engineering – HCMUT, Vietnam
2) Mientay Construction University, Vinh Long Province, Vietnam
E-mail: haungothanh@gmail.com
December 2013

2.  Introduction
 Methods
 Discussion
 Conclusion

3. Study area
East sea
(Vietnam
sea)
Introduction
Tien river
Hau river
85km

4. Method
 Analysis the composition of bank material
 Assessment the wave impacts
 River sand activity

5. Figure: Taking cored soil sample

6. Loam and sandy of alluvial Quaternary (aQ2
3
)
Results show that, these soft soils can easily be destroyed by any
external forces

7. Figure: Wind wave and wave by boat (Bui Trong Vinh, 2009)
Wave by boat
Wave impact

8. Bed-river sand mining provides volume of construction
materials that without affect to agricultural land
Advantage:
Help to dredge to navigations
Train river
Disadvantage:
Main cause to bank erosion seriously
Affect the natural habitat and environment
River sand activity

9. Sand mining Sensitive area
Coordinate East North
UTM – WGS
84 (48P)
601928 1136304
602865 1136125
604123 1135090
604723 1134480
Coordinate East North
UTM – WGS
84 (48P)
607805 1134885
608676 1134704
609565 1134923
610309 1134565

10. Method
Using the numerical modeling MIKE 21C (DHI)
to evaluate the river bank erosion impacts
from excavation of sand
The results obtained from testing were
extracted by cross-section form

11. Field survey
Measure
The cumulative width (m)
Left bank Right bankCross – section VI - VI

12. Condition 1
•Number of facilities: 1 vessel/mine
•Capacity per vessel: 0.7m3
•Velocity: 0.14m3
/min
•Operated time: 10 h/day
=> Total removed sand: 153,300 m3
/yr
Modelling

13. SECTION IV - IV
Right bankLeft bank

14. Left bank Right bank
SECTION V - V
Initial modeling
Modeling
condition 1
Elevation(m)
The cumulative width (m)

15. Condition 2
•Number of facility: 3 vessels/mine
•Capacity per vessel: 0.7m3
•Velocity: 0.14m3
/min
•Operated time: 10 h/day
=> Total removed sand: 459,900m3
/yr
Modelling

16. Condition 1
Condition 2
Cumulative width (m)
Elevation(m)

18. By field survey results, a number of facilities were used for sand
extraction was twice to three times as many as its affordable
which operated continuously from 12 to 14 hour per day. That
had led to increasing of quantity of extraction, changing the flow
direction and creating the local bed scours which cause of
imbalance in sand replenishment rate and serious erosion.
Discussion

19. River sand mining activities caused bed river change
and flow change.
The overmining activities of river sand mining can directly
impacted to flow direction, disturbed the bottom sediment,
and damaged the balance of sediment transport of the river.
Conclusion

20. • Bui Trong Vinh, Ichiro Deguchi, Keiji Nakatsuji, (2008).“Beach Erosion Caused by
Development in Littoral Region – Effect of Sand Extraction around River Mouth”.
Proceedings of the 8th
General Seminar on Environmental Science & Technology
Issues, Japan, Osaka, Nov. 2008, pp. 114-119.
• Ha Xuan Chuan (2009), “Assessing the effect of dredging activities”, Journal of
Science & Technology Maritime, August 2009, p14-17.
• Trinh Cong Luan (2012).“Assess the impacts of river sand extraction on bank
erosion and propose the prevention methods in Tien river – Co Chien river, Vinh
Long province”, Master Thesis, Ho Chi Minh City University of Technology.
• Wiebe P. de Boer et. Al. (2011). “Impact of mega-scale sand extraction on tidal
dynamics in semi-enclosed basin. An idealized model study with application to the
Southern North Sea”, Journal of Coastal Engineer 58, 678-689.
• Dries Van den Eyde, Alain Norro (2009). “Modeling the effect of sand extraction on
the Kwintebank”, European Marine sand and gravel group, May, 2009.
Reference

21. THANK YOU FOR YOUR
ATTENTION !