Linear wave theory and wave hindcasting are applied to derive an expression for the depth of water needed to prevent the wind-wave-induced suspension of sediments in mine tailings ponds. The depth is expressed as a function of four factors: the threshold velocity, the wind velocity, the fetch over which the wind blows, and a factor based on the statistical distribution of wave heights. This study was motivated by the need to determine the thickness of water required to prevent the suspension of sludge solids in existing and proposed tailings ponds at Syncrude Canada Ltd.'s oil sands plant. Although data relevant to this problem are used to provide a specific example, the results are applicable whenever sediment suspension is caused by fetch-limited, deep water, wind waves. The results should be of particular use when the available data set is limited, e.g., for proposed tailings ponds. Key words: linear wave theory, wave hindcasting, wind-wave-induced suspension, threshold velocity, sludge capping, reclamation ponds, mine tailings ponds.