Phosphorus accumulation in a lowland reservoir during the spring flood

Abstract

On the basis of detailed observations of 1984, 2012 and 2016 we estimated the accumulation of reactive phosphorus in the Mozhaysk reservoir during the spring flood. The results of this assessment depend on the completeness and origin of the used data: the absence of discharge gauging stations on the tributaries of the reservoir introduces an error of 30-40%, a decrease in the frequency of water quality monitoring from daily to 2 times a month or the use of empirical dependences in the absence of monitoring - up to 50-60% or more. During the flood, an overwhelming amount of reactive phosphorus accumulates in the reservoir due to a significant inflow (50-60% of the annual) and low outflow (from 1 to 13% of the annual). Over the past 30 years, there has been a significant reduction in the external phosphorus load on the reservoir.