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Potential management solutions are subject to review and agreement amongst 
primary stakeholders; given the primacy of water management and defence as national 
priorities, these would include the Public Utilities Board, Ministry of Defence and 
National Parks Board. Management solutions can be broadly classified to address five 
issues of concern for the forest: hydrological integrity, erosion and sedimentation, 
ecological integrity, the impact of the spillway, and impacts of construction and 
development. 
Maintaining hydrological integrity 
a) Irrigation via the introduction of water sources (point sources) in the catchment 
upstream could be an option to mitigate future extreme drought. There would be major 
implications over water availability from other sources, cost, physical and ecological 
effects, risks of introducing alien aquatic species, and water quality, as well as costs, 
all of which would need to be included in an evaluation. 
b) Retention ponds could be an option to mitigate flooding and simultaneously 
promote additional habitats for flora and fauna. The study showed that retention 
ponds with a depth of about 1 m could effectively reduce the flooded areas by about 
90% but such steps would require evaluation of many factors similar to those for 
irrigation solutions to address drought. 
c) Reduction of maximum water-levels by i) reducing disturbance of communities via 
reduced input from the spillway; ii) riparian and forest planting to reduce peak flows. 
d) Maintenance of minimum water-levels in small streams in particular to support the 
diversity of aquatic fauna found within the freshwater swamp forest, in particular more 
rare taxa such as stoneflies which are generally not well supported in other catchments 
in Singapore. 
Mitigating erosion and sedimentation 
a) Manage recreation: Restricting visitors to the catchment and repairing damage to 
the tracks and bridges would help serve to reduce erosion. 
b) Mitigation of stream-cha nn el erosion: fill in the re-sectioned channel to restore the 
hydrological functioning of the swamp. However, this should be accompanied by an 
assessment of potential effects on fish communities that have since established in the 
channel. 
c) Mitigation of stream-bank erosion: Investigation of sedimentation and potentially 
sediment transport into and within the forest streams to formally examine the sources 
of sediments, effects of erosion on stream fauna as well as trailing potential mitigation 
techniques such as “soft engineering” of stream banks through planting of appropriate 
plant species. 
