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Table 4. Proposed flood mitigation management system: retention ponds. 
Flood 
cluster 
Map 
Flooded 
area (m 2 ) 
Flood vol¬ 
ume (m 3 ) 
Average 
depth (m) 
Proposed 
dimension 
1 
2 
3 
9,200 
11,200 
12,800 
198.34 
127.77 
859.98 
0.022 
0.011 
0.067 
iBm 
12m 
Reduction 97.5 98.7 93.0 
of flooded 
area (%) 
the growth of trees and even leads to death of the root system. Fig. 11 compares the 
current surface water area extent with the projected future surface water area extent 
(after 2 years) resulting from a model simulation of Scenario 12. The excess surface 
water area, after 2 years, is 36.72 ha with an excess water volume of 73,606 m 3 . To 
mitigate the extent of flooding, and also to promote habitats for fauna, retention ponds 
with a maximum depth of 1 m, various surface areas and different water volumes are 
suggested. 
To demonstrate the flood mitigation management approach, we focus on three 
flooded areas as circled in Fig. 11. Three retention ponds in their respective locations 
are indicated. Detailed information on the flooded areas and retention ponds is 
summarised in Table 4. The suggested retention ponds appear to reduce the flooding 
area by more than 90%. As mentioned above, the retention ponds could also promote 
habitats for fauna if properly designed and managed. 
Conclusions 
An integrated eco-hydrological model for the Nee Soon freshwater swamp forest has 
been developed in this study. The surveyed GIS data, including the stream network, 
the cross-sections and the Digital Elevation Model (DEM), have been incorporated in 
