Abstracts of the AOGS - AGU (WPGM) Joint Assembly, 13-17 Aug, 2012, Singapore. (HS19-A021)

The Hydrology Component of the SAFE Project in Sabah, Malaysian Borneo: Design and Some First Results

Anand NAINAR1#+, Kawi BIDIN1, Rory WALSH2, Jamil HANAPI3 1Universiti Malaysia Sabah, Malaysia, 2Swansea University, United Kingdom, 3Royal Society SE Asia Rainforest Research Programme, Malaysia #Corresponding author: [email protected] +Presenter The SAFE (Stability of Altered Forest Ecosystems) project located in the headwaters of the Brantian catchment in Sabah, is conducting one of the world’s largest ecological experiments to understand how logging, partial conversion to oil palm plantation and forest fragmentation affect the functioning of remaining tropical rainforests, impair their ability to deliver ecosystem services and reduce their ability to support biodiversity. The hydrology component is focusing on the impacts of retaining riparian buffer zones of differing width on stream channel suspended sediment, nutrients, discharge and morphology following logging of secondary rainforest and partial conversion into oil palm plantation. Six experimental catchments (c.2.5 km2) with different designated riparian zone width (0 m, 5 m, 15 m, 30 m, 60m and 120 m) and 4 control catchments (old growth forest; logged forest; primary forest; and established oil palm) are being studied. Each is equipped with sensors to record turbidity, conductivity, water depth every 5 minutes and a tipping-bucket raingauge connected to a solar-powered Campbell CR850 data logger. Repeat measurements of bankfull cross-sections along each stream will assess anticipated changes in channel size and shape. A monthly water sampling programme, supplemented by opportunistic sampling of high flows, is being used to assess changes in water quality, notably NO3- , PO4- and K+. Finally a sediment fingerprinting and dating approach analyzing changes in geochemistry of downstream sediment cores is being used to assess changes in sedimentation rate and upstream sediment sources. Initial results prior on suspended sediment, conductivity and nutrient dynamics of the study catchments prior to conversion are presented and compared with the established oil palm plantation catchment and the primary forest control. Both flushing and dilution of NO3- and PO4- concentrations are found to characterize some of the storm responses.