WP7: Rainfall-runoff modelling in large tropical poorly gauged basin – The Mahakam River, Kalimantan
Research group
Project leaders:
Dr. A.J.F. Hoitink
Prof. Dr. Ir. R. Uijlenhoet
Researcher:
Mr. Hidayat, MSc
3. Summary of the project
Rainfall-runoff modelling will be carried out to study the discharge dynamics of River Mahakam, a meso-scale poorly gauged basin in Kalimantan, Indonesia. Field measurement and hydrodynamic modelling will be focused in the Mahakam lakes region, a subsiding area characterized by a low relief alluvial plain partly located below mean sea level. Small channels connect the river to about 30 shallow lakes, which modulate the river discharge. Although no evidence exists to date, it is assumed that the Mahakam lakes alternately feed and drain the Mahakam River, preventing extreme floods or low flow conditions. The central aim of this research is to understand the liquid discharge dynamics of the central and lower reaches of the River Mahakam. The water budget of the Mahakam will be studied using a hydrological model, incorporating remote sensing and in-situ measurements of rainfall, water levels, and discharges. The mechanisms behind the interaction between river and lake levels will be studied focusing on the hydraulics in the tie channels and floodplains separating the river from the lakes. Part of the runoff that feeds the Mahakam is derived from peat domes. The aim is to understand the hydrology of a peat dome in the central Mahakam area. The final goal is to establish the dominant hydrological processes both during floods and droughts from a combination of measurements and modelling.
Objectives:
1. Establish the water balance of the Mahakam
2. Understand the hydrology of a peat dome in the central Mahakam area
3. Understand river-lake-floodplain interactions in the central Mahakam area
4. Establish the dominant hydrological processes during floods and droughts in the Mahakam.
Hypotheses:
- Extreme events (flood, drought) become more severe in the Mahakam
- Both lakes and peat domes act as a buffer in the discharge dynamics of the River Mahakam