VULNERABILITY ASSESSMENT OF MAXIMUM WATER DISCHARGES OF AGHSTEV RIVER IN THE CONTEXT OF CLIMATE CHANGE

Abstract

Тhe paper presents an assessment of the vulnerability of the quantities of maximum water discharges of spring floods in Aghstev River basin in the condition of global climate change. In the work there were used historical hydrometeorological observation data from five hydrological observation stations and four meteorological stations currently operating in Aghstev River basin. For vulnerability assessment multiple linear regression method was used. Physical-statistical correlations have been established between the maximum water discharges observed during spring floods and the calculated seasonal data of amount of precipitation and air temperature, and multiple linear regression equations have been developed for each operating hydrological station in the Agstev River basin. Statistical indicators of the quality of obtained equations have been estimated. Using the developed multiple linear regression equations and on the basis of predicted seasonal estimates of the average air temperature and the amount of precipitation in the territory of Armenia, the vulnerability of the quantity of maximum water discharges for the periods up to 2040, 2041–2070 and 2071–2100 has been assessed. The results of the projected seasonal estimates in the territory of Armenia are taken from the "V National Communication on Climate Change", according to which the forecasts are made according to the Community Climate System Model 4-CCSM4 (spatial resolution 100 km) and according to the emission scenarios RCP8.5 (A2) and RCP6.0 (B2), as well as according to the METRAS regional climate model (spatial resolution 12 km) and the pessimistic emission scenario RCP8.5 (A2). According to the obtained results, due to climate change a rather high vulnerability of the quantities of the maximum water discharges of spring floods is predicted in Aghstev River basin. In almost all sections of the study area (with the exception of the "Fioletovo" river section), the values of the maximum water discharges of spring floods in the case of CCSM4 model RCP6.0 scenario until 2040 will decrease by 10–25%, compered with the averages of reference period 1961–1990. The largest growth (2.88 m³/s or 29%) is predicted in the case of the RCP8.5 scenario of the CCSM4 model for the period 2071–2100.