This river is easily accessible. It is very near to Chevalier Garden(富安花園) in Ma On Shan(馬安山). The key feature of this river is Hero Cliff(英雄崖). If one wants visit the Hero Cliff only, one can use the middle entrance of the river at about 80M. There are some villages at the upper stream of the river, therefore I don't think the MaiDai water is suitable for drinking. It is however, for swimming purpose, the water there is good enough.
This is the entrance of the MaDai river next to Chevalier Garden.
On the left of the picture you can find some people walking through a tunnel-like feature. That "tunnel" is called Time Tunnel(時光隧道). The name is written at the entrance of the "tunnel". Actually, the "tunnel" is nothing but a big gap among rocks.
There is a big pothole which is a very good place for taking rest and water fun.
After you pass the middle exit at about 80M, you will discover a very magnificent cliff with a stunning waterfall. This is The Hero Cliff(英雄崖).
The cliff is about 10M tall. There is very deep water pool beneath the waterfall. A few years ago, there was a rope hanging over the pool such that one can hold the rope and swing over the pool surface like TaiShan. It is however, the rope has found vanished in my last visit.
It is called Hero Cliff because some "heroes" jump from the very top of the cliff down to the water pool. If you really do, you are a hero. The guy in the picture did not really jump from the top. It is very dangerous to be a real "hero".
After the Hero Cliff, the river becomes flattened off. You will find no more waterfalls.
At about 155M, you will reach a junction. If you want to leave now, you can take the right off-shoot.
A few minutes later, you'll be blocked by a dam. You can leave the river on the left side of the dam.
Be careful, the exit lies within a small farm which is guarded by unfettered dogs.