Gardens’ Bulletin Singapore 70 (Suppl. 1): 175-190. 2018 
doi: 10.26492/gbs70(suppl.l).2018-09 
175 
Projected impacts of climate change on stream flow 
and groundwater of Nee Soon freshwater 
swamp forest, Singapore 
Y. Sun 1 - 2 , D.E. Kim 1 , D. Wendi 1 , D.C.Doan, S.V.Raghavan 1 , 
Z. Jiang 1 & S.Y. Liong 1 -- 3 
tropical Marine Science Institute, National University of Singapore, 
18 Kent Ridge Road, 119227 Singapore 
2 Willis Towers Watson, 51 Lime Street, 
London, United Kingdom 
3 Center for Environmental Sensing and Modeling, SMART, 
1 Create Way, 138602 Singapore 
tmslsy@nus.edu.sg 
ABSTRACT. As Singapore’s only remaining patch of primary freshwater swamp forest, the 
good management of the Nee Soon catchment is of utmost importance if a large proportion 
of the flora and fauna in Singapore is to be conserved. An integrated eco-hydrological 
model is developed for the area, with the objectives to numerically model the hydrological 
variations, to assess the possible impacts of future climate change, and to facilitate future eco- 
hydrological management. The numerical model considers the hydrological processes in a 
holistic manner, including rainfall-runoff, evapotranspiration, the interaction between surface 
water and groundwater, etc. The numerical model makes use of a combination of field survey 
data and alternative remote sensing data. With climate projection inputs from the Regional 
Climate Model (RCM), the numerical model is applied to run future scenarios to assess the 
climate change impact. A few management strategies are considered if favourable hydrological 
conditions are to be maintained for conserving the local ecosystem. 
Keywords. Eco-hydrological model, eco-hydrology management, remote sensing, reservoirs 
Introduction 
Various studies have emphasised the significance of Nee Soon freshwater swamp forest 
to habitat and species conservation in Singapore (Ng & Lim, 1992; Clews et al., 2018). 
Nee Soon is the only remaining locality for hundreds of plant and animal species 
that have been extirpated elsewhere in the country (Tan et al., 2008), supports habitat 
specialists relying on acidic swamp conditions (Turner et al., 1996), contains several 
global endemics (Ng & Lim, 1992), and continues to be a locality for discoveries of 
new species and of species new to Singapore (e.g. Evenhuis & Grootaert, 2002). The 
environment within the Nee Soon catchment depends critically on the local hydrology 
(Clews et al., 2018). Changes in surface water and groundwater is likely to affect both 
the flora and the fauna wherever they occur, while some species will likely prove to 
be more vulnerable than others (Ho et al., 2018). Urbanisation and climate change is 
