H063-0002
Assessing hydrological processes of managed tropical peatland using groundwater lysimeter
Abstract:
We installed polyvinyl chloride piles to the depth of clay layer (~3.75 m) for establishing two groundwater Lysimeter plots (30 x 20 m2) under Acacia crassicarpa plantation in tropical peatland of Sumatra, Indonesia. These plots represent the largest undisturbed groundwater lysimeter experiment published to date. The main objectives of this study are 1) to investigate the hydrological processes from high temporal resolution measurements; 2) to quantify the effects of groundwater table on tree growth and water use; 3) to parameterize a hydrological model to facilitate understanding of local-scale hydrological processes.
We installed artificial water recharge and discharge mechanisms in both plots to maintain two distinct groundwater table targets (40 and 80 cm below the ground surface). We measured tree height, diameter at breast height, leaf area index, and tree stability. Transpiration and tree water stress were measured using in-situ xylem sap flow meter and psychrometer, respectively. Rainfall, air temperature, relative humidity, solar radiation, and wind data were monitored using an automatic weather station. We conducted baseline measurements of in-situ infiltration rate and saturated hydraulic conductivity. Peat samples were collected to determine bulk density, water retention characteristics, macro-micro nutrient content, and pH.
The purpose of this paper is to provide an overview of the experimental design and performance of the manual groundwater table regulating system. Future work will be focused on the link between groundwater table and tree growth, water use and modelling.