you can go park and walk along the highway at the swimming complex there and take a look, or if you're lazy, you can just go to google map drop a pin along the road and look at the color of the water
its not that bad lah, its water, but i wouldn't want to swim in that 'river', i think anyone interested in RC should approach the people at the swimming complex (the cleaners or people working in legend) and ask if are there a lot of flies or mosquitoes in the vicinity (lots of vegetation + 'river' = nice breeding ground)
like bedok reservoir last time got a period a lot of flies, don't know if the same thing will happen to RC or not, i just don't see how that river is a selling point