CHANNEL SHOALING PREDICTION: A METHOD AND APPLICATION

Abstract

Due to concerns of possible shoaling problems, an extensive field survey program was carried out at the site of the proposed Cerrejon coal port on the Caribbean coast of northeast Colombia. The program yielded considerable data on winds, waves, currents, and sediment factors. Techniques for the primary measurement of sedimentation-related tendency included dredged test pits, scour crosses, and suspended sediment samplers. The port plan includes dredging a 4.6 kilometer long channel varying from 12 to 21 meters in depth. In order to assess the magnitude of maintenance dredging and related problems, a method was developed for incorporating the sediment response measurements into predictions of the areal and seasonal distributions of bed load and suspended sediment deposition. Offshore test pits were monitored for rate of filling and character of the material being deposited. Suspended sediment samplers were similarly observed and also provided data on concentration versus depth. The procedure which was developed for analysis and interpretation of the data included extrapolation of suspended sediment data to the seabed, investigation of correlations between wind activity and deposition rates, application of test pit data to a channel of larger dimensions, and testing of hypotheses regarding transport mechanisms. The procedure concluded that average annual shoaling would be approximately 300,000 m and predicted areal and seasonal variation of deposition rates.