The sensitivity of hydrochemical runoff of mountain rivers to environmental factors

The method of system-analytical modeling of complex natural systems is proposed to construct the simulation balance models for hydrochemical runoff of mountain rivers. Basing on the example of 34 mid-size and small rivers of the Altai-Sayan mountain country as a regional case study, we developed the balance models of 7hydrochemical runoff components: three nitrogen mineral forms ( ), phosphates ( ), ions, totaldissolved iron, and suspended matter. To calculate the seasonal and long-term hydrochemical runoff, four hydro-logical periods/seasons were specified. The sensitivity of models to variations of their input factors was evaluated. The sensitivity is expressed as a contribution of a particular factor to the variance of hydrochemical runoff values. A quantitative assessment of the hydrochemical runoff sensitivity (for each of 7 components) was obtained for the following factors: landscape structure of river basins, basin lateral slope, precipitation, arable land area.