Field data and information from the literature on hydrology, hydraulic and geomorphic characteristics of the ten streams in Bukit Timah Nature Reserve were collected to form a baseline dataset with the aim of evaluating various functions that these streams perform, as well as the stresses and disturbances that they experience. Preliminary results show that majority of the channel reaches studied are functioning well, except that moderate to intense erosion was observed at the middle reaches of Lasia and Dairy Farm, and the lower reaches of Fern Valley and Wallace streams, where instability, undercutting and failure of banks have caused significant channelisation (bank widening and channel down-cutting). In general, the streams in Bukit Timah have little sediment, with low and small-sized bars visible only at the lower reaches of Fern Valley, Lasia and Wallace streams, which should not significantly affect the stream function if culverts and lined drains downstream are well maintained. However, several forced step-pools (artificial ponds) near the outlets of Taban, Seraya and Catchment streams and the middle of Jungle Fall stream continuously receive upstream sediments loads and accumulation of sediment with distinct siltation have obviously degraded the instream habitats. Follow-up actions on stream rehabilitation, adaptive management, future research and future monitoring are discussed.