Roy Halliwell, Brian O'Connor


The results of an extensive field study undertaken in the Mersey Estuary and its approach channels are briefly described. These measurements were undertaken to obtain a quantitative understanding of the movement and circulation of water and sediment in the area. There is considerable dredging activity required in the area and the spoil from such operations is, at the present time, deposited at an offshore site in Liverpool Bay. A simple model is presented which attempts to quantify the movement of sedimentation and within the Mersey system. The field measurements showed that considerable quantities of sediment return to the docks, estuary and approach channels from the spoil ground. The model includes this fact and attempts to quantify the amounts returning to various areas. The model equations were applied to each year of the period 1955-65 to determine the various factors and to test its validity: this required the use of the annual hydrographic surveys and dredging records as well as the results of the field measurements. Finally, the model was used to compare the probable results of a number of possible schemes including re-siting of the spoil ground, pumping all dredged material ashore and free-dumping of dock dredgings in the estuary itself.


spoil; spoil disposal

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DOI: https://doi.org/10.9753/icce.v14.%25p