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Although the Fraser River delta front supports coastal structures including ports, a lighthouse, jetties, submarine power cables, and sewage pipelines, the stability of the delta front is little understood. Five large-scale mass-wasting events at the mouth of the Main Channel near Sand Heads have been detected by comparing successive bathymetric surveys conducted by Public Works Canada between 1970 and 1986. These events can involve the downslope movement of more than 1 × 106 m3 of silty sand and the landward retrogression of the delta-front crest of up to 350 m or more. Morphologic and sedimentologic evidence suggests that these events are slope failures which result from the liquefaction of silty sand. Rapid deposition at the river mouth is likely a prerequisite for failure, although interstitial gas, tidal currents, waves, and earthquakes also may contribute to failure. These results have important implications for the foundation stability of the Sand Heads Lighthouse and future coastal structures in the area. Key words : bathymetry, mass wasting, liquefaction, hazard, Fraser River delta.

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Environmentally acceptable reclamation solutions for the decommissioned tailings ponds can be achieved by integrating the tailings deposits into the landscape either by turning the tailings pond/deposit into a lake and maintaining a permanent water cover over the deposit or by stabilisation of the deposits as a “dry” landform. Conceptually, the dry landscape reclamation involves three remedial steps: 1) Placement of an interim cover on the tailings surface to provide the consolidation load and create a stable working platform. 2) Building of a surface contour providing suitable run off conditions for the surface water. 3) Capping the surface with a final cover to control infiltration into the tailings. For reliable predictions of consolidation, proper sequencing of remedial steps/measures and cost efficient reclamation of soft tailings it is necessary to use Non Linear Finite Strain (NLFS) codes. The advantage of the NLFS program system Consol2D is that it allows the reconstruction of the history of the tailings discharge, the evaluation of the material parameters, the calculation of settlement in inhomogeneous deposits, the 3D quantification of the settlement trough and the evaluation of the drainage effect of the vertical drains.