Forecast of coastal changes based on morphodynamical modeling

A new version of the prognostic model is suggested, which differs from the previous version by its structure and method for including long-term variables into the process of coastal modeling. A fundamental prerequisite of the model is the assumption of the quasistationary state of the coast at any arbitrary stage of its evolution. The displacement of the coast under the influence of external factors at given moment is predicted on the basis of the obtained equation for the balance of sediments. The model takes into account a number of properties of the coastline. In particular, the distinguished dependence of the coastline shape on the regime of sediment transport is used to calculate the gradient of the alongshore sediment flux. The model also uses the empirical dependence found earlier, which makes it possible to estimate the second most important component of the sediment balance for selected types of coasts — the cross-shore matter flux. Special attention is focused on adjustment of the model to Arctic conditions. The results obtained are illustrated by the example of forecasting the development of accumulative coasts of the Western Yamal. It is shown that the major part of the Sharapovy Koshki sand islands could disappear within the next 700 years due to erosion.