There has been increasing concern in recent years regarding the environmental impact of sediment laden runoffs discharged from land disturbing activities in Alberta. Settling ponds represent the most common control technology for the treatment of these wastewaters. Settling reservoirs are designed and constructed to impound contaminated
waters long enough for the desired portion of the incoming sediment load to settle out.
Settling ponds are used in Alberta to limit the amount of sediment in waters discharged from land disturbing activities. Pond design is an iterative process in which various pond characteristics are assumed and the associated pond responses evaluated until a set of pond characteristics is established which satisfies the specified performance criteria.
There are a wide variety of predictive models that have been developed for the design of settling ponds. The simplest of these models are typically easy to use and understand but limited in their ability to realistically simulate settling basin performance. The more sophisticated models provide relatively accurate predictions of pond
capabilities but their complexity increases the time and expense involved in the design process. For any design model, the quality of the input data has a strong influence on the accuracy of the predicted outputs. There is no design approach that will provide meaningful results if input data is poorly correlated to site specific conditions.
There are a number of augmentative technologies that can be used to improve the efficiency of an existing settling reservoir. Inlet and outlet structures can be modified and in-pond baffles installed to reduce the amount of dead space in the pond and maximize its efficiency. Artificial flocculants can be used to increase the size and hence the
settleability of the sediment particles.