Application Of AnnAGNPS Model For Soil Loss Estimation And Utrients Loading For Malaysian Conditions
Non-point source (NPS) pollution is one of the major sources of contribution of pollutants to watersheds and stream water. Although awareness has increased in Malaysia over the last few decade, there is still no unified system that can continuously monitor and evaluate watersheds in the countr...
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| Main Author: | |
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| Format: | Monograph |
| Language: | English |
| Published: |
Universiti Sains Malaysia
2006
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| Subjects: | |
| Online Access: | http://eprints.usm.my/58229/1/Application%20Of%20AnnAGNPS%20Model%20For%20Soil%20Loss%20Estimation%20And%20Utrients%20Loading%20For%20Malaysian%20Conditions_Leow%20Cheng%20Siang.pdf http://eprints.usm.my/58229/ |
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| Summary: | Non-point source (NPS) pollution is one of the major sources of contribution
of pollutants to watersheds and stream water. Although awareness has increased in
Malaysia over the last few decade, there is still no unified system that can
continuously monitor and evaluate watersheds in the country. Most studies are limited
to short-term evaluation and do not provide long-term monitoring. This study aims to
apply AnnAGNPS watershed modelling to assess NPS pollution in three selected
watersheds. Rainfall data of 2004 and 2005 are used to calibrate and validate the
model. The results of simulation are generally satisfying. Runoff estimation could
reach a coefficient of determinacy of 0.73, and event based sediment yield produced
2 R of 0.57. The average annual erosion rate of studied area is 62 Mg/ha/yr for 2004
and 123Mg/ha/yr for 2005. The distribution erosion is in agreement with the National
Erosion Risk Map. N and P predictions are slightly inconsistent with 2 R =0.69 and
0.64 respectively but with high standard deviation. The study is able to detect rubber
estate and urban land as major contributor to soil erosion. Rubber estate is also the
main contributor for nitrogen loading. The study also identifies LS factor to be the
most sensitive parameter in influencing erosion and sediment yield. Error and
inconsistency can be caused by reference data that may be not suitable for local
condition. The average result shows that AnnAGNPS is able to perform well under
Malaysian condition and can do even better if proper improvements are made. A
database should be set up to aid local research in improving watershed study,
particularly AnnAGNPS. |
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