Forecast of the development of shallows in the Vilyui River channel: its significance for navigation

Abstract

The paper deals with extrapolation method as applied to channel processes forecasting, to shallows reformation under conditions of both restricted and free development of channel deformations in particular (case study of the lower and middle Vilyui). The method can be applied only on the condition of steady state of the system (i. e. constancy of controlling f actors), the forecast is limited to a few decades. Three trends are distinguished in the channel shallows evolution: flow concentration and deepening, flow diffusion and decrease in depth, relative stability of the channel's depth. Possibilities are discussed of artificial reversal of trends unfavourable for navigation. In the author's opinion, it is economically justified t o establish priorities for channel regulation: first, channel's reaches with shallowing in progress, then constantly shallow ones and finally, those where conditions are changing for better. The forecast of shallows development given in 1977-1980 is assessed on the basis of channel observations during 1981-86, the error of forecast appeared to be 10%.