RamuSED
Quantifying sensitivity of suspended sediment dynamics to environmental change within Papua New Guinea
This study uses the latest monitoring technologies (e.g., Campbell Sci. Ltd OBS-3+ turbidity probes) and Time Series Analysis (e.g., CAPTAIN Toolbox) to address seven key objectives and deliverables, building upon experience with these approaches applied within humid tropical Borneo Island.
The seven objectives are:
- To instrument, monitor and sample the Upper Ramu River for accurate suspended sediment load estimation (initially for a 12 month period)
- Derive an accurate value of the annual river discharge, mean turbidity and annual suspended sediment load as a baseline value and for comparison with other large basins in the Asia-Pacific region
- Identify (using CAPTAIN time series analysis) the intra-annual cycles and trends within the suspended sediment flux (mg/s) and interpretation with the aid of similar analyses of the rainfall, discharge and sediment concentration data
- To cross-correlate identified cycles and trends in the rainfall, discharge and sediment concentration time series to discover mechanistic relationships
- Undertake a preliminary survey of the dominant sources for the suspended sediments within the Upper Ramu basin
- Estimate mathematically the sensitivity of the suspended sediment flux from the Upper Ramu basin to future changes in upstream rainfall and anthropogenic activity, and
- Identify river basin management implications and key research needs for the hydrology-sediment system in the Upper Ramu basin
Publications
Chappell, N.A., Tych, W., Shearman, P., Lokes, B., and Chitoa, J. 2011. River sediment monitoring for baseline and change characterisation: a new management tool for the Ramu River Communities in Papua New Guinea. In: Sediment Problems and Sediment Management in Asian River Basins, Walling D (ed) IAHS Publication 349, Wallingford, IAHS Press. 92-102. view abstract (pdf), paper (colour pdf version).
U.S. DOE. 2012. Research Priorities for Tropical Ecosystems Under Climate Change Workshop Report, DOE/SC-0153. U.S. Department of Energy Office of Science (Chapter 11 "Hydrology within Tropical Natural Forests: Implications for Large-Scale Ecosystem Modeling" p77-84 by Chappell, N.A.) view chapter or whole report (pdf).
Chappell, N.A., and Tych, W. 2012. Identifying step changes in single streamflow and evaporation records due to forest cover change. Hydrological Processes, 26, 100-116 doi:10.1002/hyp.8115. view paper (pdf).
Funding sources
BRG (pFACT 46089)
Investigators
Dr Nick A Chappell; Dr Wlodek Tych; Dr Phil Shearman; Ms Barbara Lokes
International collaborations
Impact & policy implications
We observe that the natural variability in the suspended sediment load is much larger within the sedigraphs of the wet season, small changes resulting from anthropogenic disturbances will be more difficult to identify within this wet season. Thus the Ramu River Communities are more likely to observe shifts from the baseline sediment behaviour in the dry season. While the suspended sediment loads within the Upper Ramu are naturally high, mining-related fine sediments may contain much higher heavy metal concentrations in comparison to fine sediment mobilised from natural slopes. Thus small changes in suspended sediment load within the dry season may indicate an anthropogenic shift in the heavy metal load. If sediment monitoring indicates the possibility of enhanced inputs of heavy metals bound to elevated fine sediment inputs, this would provide the impetus for the Ramu River Communities to seek help to initiate the more costly intensive chemical sampling of the Ramu main stem.
Given the different shapes of the sedigraphs and hydrographs and their flashy nature over sub-daily timescales (i.e., rapid rise and fall), it is important that sub-daily monitoring of turbidity (and stage) is maintained to not only help identify behavioural shifts in suspended sediment load within the dry season, but also to allow the calculation of reliable values of seasonal and annual sediment load. The increased reliability and reducing costs of current turbidity and stage monitoring systems means that such systems ought to be deployed more widely in the humid tropics, particularly in environments with high sediment loads, such as New Guinea Island.
Available PhD, MPhil or MSc project topics
1. Simulation of sediment dynamics within the Ramu basin using TRMM data and CAPTAIN modelling.
Email enquires to Dr Nick A Chappell and applications via LEC-PG website
Related research
Bolton, B. (2009) The Fly River, Papua New Guinea: Environmental Studies in an Impacted Tropical River System. Elsevier, Amsterdam.
Douglas, I. & Guyot, J.L. (2005) Erosion and sediment yield in the humid tropics. In: Forests, Water and People in the Humid Tropics (ed by M. Bonell & L.A. Bruijnzeel), 407-421. Cambridge University Press, Cambridge.
Drechsler, M., Ripper, I., Rooke, E. & Warren, E. (1989) The Kaiapit landslide, Papua New Guinea. In: Engineering Geology in Tropical Terrains (Proceedings of the International Conference on Engineering Geology in Tropical Terrains, June 1989, Bangi, Malaysia), 1-10. Universiti Kebangsaan Malaysia, Bangi.
Hall, A.J. (1984) Hydrology in tropical Australia and Papua New Guinea. Hydrol. Sci. J. 29, 399-423.
Kao S.J. & Milliman, J.D. (2008) Water and sediment discharge from small mountainous rivers, Taiwan: The roles of lithology, episodic events and human activities. J. Geol. 116, 431–448.
Lai, F.S., Geoffery, J.G. Hamdan, A.G. & M. Jafri, H. (1999) Post-logging sediment yield of the Sungai Lawing Basin, Selangor, Malaysia. In: Water: Forestry and Landuse Perspectives (ed. by A.R. Nik) (Proceedings of the CFFPR conference, March - April 1999, FRIM, Kepong). Forestry Research Institute of Malaysia, Kepong.
Lourino-Cabana, B., Iftekhar, S., Billon, G., Mikkelsen, Ø. & Ouddane, B. (2010) Automatic trace metal monitoring station use for early warning and short term events in polluted rivers: application to streams loaded by mining tailing. J. Environ. Monit. 12, 1898-1906.
Markham, A. & Repp, K. (1992) Erosion and sediment transport in Papua New Guinea. Network design and monitoring. Case study: Ok Tedi Coppermine. In: Erosion and Sediment Transport Monitoring Programmes in River Basins (ed. by J. Bogen, D.E. Walling & T. Day) (Proceedings of a symposium held at Oslo, August 1992), 517–526. IAHS Publ. 210. IAHS Press, Wallingford, UK.
Milliman, J.K. (1995) Sediment discharge to the ocean from small mountainous rivers: The New Guinea example. Geo Mar. Lett. 15, 127–33.
Milliman, J. D., & Meade, R. H. (1983) World-wide delivery of river sediment to the oceans. J. Geol. 91, 1–21.
Milliman, J.D., & Syvitski, J.P.M. (1992) Geomorphic/tectonic control of sediment discharge to the ocean - the importance of small mountainous rivers. J. Geol. 100, 525–544.
Peart, M. (1991) The Kalapit landslide: events and mechanisms. Quart. J. Eng. Geol. 24, 399-411.
Pickup, G., Higgins, R.J. & Warner, R.J. (1981) Erosion and sediment yield in Fly River drainage basins, Papua New Guinea. In: Erosion and Sediment Transport in Pacific Rim Steeplands (ed. by T.R. Davies. & A.J. Pearce) (Proceedings of a symposium held at Christchurch, January 1981), 438-456. IAHS Publ. 132, IAHS Press, Wallingford, UK.
Shearman, P., Bryan, J., Ash, J., Hunnam, P., Mackey, B. & Lokes, B. (2008) The State of the Forests of Papua New Guinea. University of Papua New Guinea, Port Moresby.
Stewart, B.J. (1993) The hydrology and water resources of humid northern Australia and Papua New Guinea. In: Hydrology and Water Management in the Humid Tropics (ed. by M. Bonell, M.M. Hufschmid & J.S. Gladwell), 68-83. Cambridge University Press, Cambridge.
Walling, D. E. & Webb, B. W. (1981) The reliability of suspended sediment load data. In: Erosion and Sediment Transport Measurement (ed. by D. Walling & P. Tacconi) (Proceedings of the Florence Symposium, June 1981), 177-194. IAHS Publ. 133, IAHS Press, Wallingford, UK.
Walling, D.E. & Webb, B.W. (1983) Erosion and sediment yield. In: Background to Palaeohydrology (ed. by K.J. Gregory), 69-100. Wiley, Chichester,
Yu, B., Chappell, J.M.A. & Fitchett, K. (1991) Natural diversion of the Ramu River in Papua New Guinea. Aust. Geogr. 22, 161-167.
Please email Dr Nick A Chappell for further information on the RamuSED project