| Sedimentation in the Fly River Delta |
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Report: PDF (2671kB) Author: Dr G. Pickup Date: February 2007 It is generally assumed that sediment disposed from the Ok Tedi Mine into the Ok Tedi has little or no effect on the South Fly (below Everill Junction) and the Fly Delta. As this assumption has never been tested directly, this report examines recent changes in the South Fly and the Delta as observed on satellite imagery. It covers the period 1972-2006 and so includes a significant period of pre-mine behaviour. The aim is to identify changes, determine if there are any trends, and to compare pre-mining behaviour with changes that have occurred during mine operation. Recommendations are then made for further investigation through sampling of river bed sediments in selected areas. Satellite imagery has been processed to identify coastal boundaries, river and island edges, and large exposed bars. Changes below water level cannot be identified with certainty because of variations in water colour due to tidal and flood conditions, both of which affect the suspended sediment content. In spite of this limitation, clear trends can be identified in some parts of the river system and these give a good indication of long-term changes. |
