A simulation of estuary response to training wall construction using a regime approach

A method, based on regime theory, for the long-term prediction of the effects of civil engineering works on estuaries with muddy sediment conditions is described. The method involves the use of a hybrid model consisting of a 1D flow model, to describe the estuary geometry, coupled with a discharge/area algorithm to simulate the changes in estuary morphology. The flow model and the morphological algorithm are used in an iterative mode to model the changes in estuary hydraulic conditions and bathymetry over time. The application of the model to simulate the effects of training wall construction in the estuary of the River Lune (UK) is described and the results compared with historical observations. These observations showed that there was considerable siltation as a result of the construction of the training walls. It is acknowledged that the application of the method to this scenario, involving a 2D problem, presents a difficult test. However, although the model generally underestimates the accretion in the case of the River Lune, it is still a potentially useful tool for the long-term prediction of the effects of engineering works.