Abstract
The Nura river is the main water artery of the vast Tengiz–Korgalzhyn depression. The river originates from the confluence of several small springs. In its upper course (up to the confluence with the Akbastau river), it is known as Keregetas, Karashoky, and Baykozha. The spring flood begins almost simultaneously throughout the basin in mid-March and lasts until mid-May, and on some watercourses — until mid-June. During the flood period, more than 80% of the annual runoff occurs. The flood usually takes place in the first half of April. Its total duration ranges from 16 to 42 days, with a maximum of 36–100 and a minimum of 1–18 days. The high-water level lasts from several hours to 1–3 days, while the decline of water levels is gradual and may extend up to two months (from early April to late May). The study uses hydrological data provided by “Kazhydromet.” An analysis was performed on the calculated maximum discharges of the river during spring floods, its flood volumes, water-level fluctuation amplitudes and water levels of different probabilities. Flood inundation analysis was carried out using cartographic materials at a 1:1.000.000 scale. Preventive measures for protecting territories and settlements from flooding are proposed. Longitudinal profile along the Nura–Yesil watershed has been constructed. Calculations were performed using construction norms (SNiP) and methodologies referenced. This article is of particular value for hydrology, life safety, hydraulic engineering, and highway construction, and it may be useful for adjusting the SKIOVR documentation.