Assessment of optimum volume of sand mining in an urban river system
The illegal river sand mining activity has taken place in a sand-bed river system in Selangor, Malaysia for decades before legalization was initiated in 2008. The present study focuses on the determination of optimum sand extraction by considering sand during the critical period (dry season). The...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
2018
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/84396/1/FPAS%202019%2012%20-%20ir.pdf |
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| Summary: | The illegal river sand mining activity has taken place in a sand-bed river system in
Selangor, Malaysia for decades before legalization was initiated in 2008. The present
study focuses on the determination of optimum sand extraction by considering sand
during the critical period (dry season). The sand replenishment rate was used as the
benchmark in determining the threshold level of the extractable rate in Langat River
system, with a specific focus in relating the temporal variation and extraction frequency
as the dominant influencing factors. This analysis was executed using Yang equation to
predict the sediment replenishment rate. The equation suitability was developed with
43% of similarity by using the discrepancy ratio (ratio of calculated values to measured
values) of sediment transport. The sample of sand from different critical locations, flow
data, and other physical river parameters were used. Concentrating on sand
replenishment rate during the critical period, the optimal sand mining is calculated by
reducing 10% from total replenishment rate, which is then converted into Truck Loads
per month (taking standard 25 tons truckload). The comparison of sand replenishment
rate in high and low flow season proved that the river system has quicker capabilities in
sand replenishment rate at the extraction point during the wet season compared to the
latter by 83%. Therefore, the quantifiable volume of the extractable sand rate at each
extraction points is proposed specifically during dry months (May to September)
whereby the slower replenishment rate is critical and riskier. |
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