Info from Hong Kong's Great Outdoors
Former rice growing villages, surrounded by country park. The hamlets are mainly deserted. A golf course was built, but abandoned, and this remains a pleasant area, seemingly far from the city yet little more than a stone’s throw from Ma On Shan new town.
Ferry from Ma Liu Shui pier, less than 10 minutes’ walk from KCR East Rail University Station, departing 8.30am; return ferry 11.25am and 6.05pm weekdays, 2.30pm and 6.05pm Sundays and public holidays (may need to wave at ferry to ensure it stops!) Or, walk from Yung Shue O to the south – perhaps travelling there by taxi from Sai Kung.
Sham Chung articles elsewhere on the Internet
Sham Chung Marsh – Development and Conservation has more info, including on the "Black Paradise Fish" (now known to be Hong Kong Paradise Fish, unique to Hong Kong). A little dated, as from around 2000.
Sham Chung: a revisit summarises surveys in 2004, with records of fish, and a Brown Fish Owl (photo here).
Cycling Tai Wai – Sham Chung briefly covers cycle from near KCR East Rail Tai Wai Station to Sham Chung, then ferry to near Sha Tin.