This diploma thesis deals with the reconstruction of small reservoir in collaboration with the company VZD Invest s. r. o. The first part aims at the basic description of the thesis subject – the small reservoir. Characteristics of small reservoir and calculations are processed in the second part. The third part is focused on the description of the current conditions. The main part consist of characteristics calculations of the small reservoir and proposal of the necessary reconstruction for future technical function. In conclusion, safety assessment of the proposed measures are evaluated.

This thesis deals with the evaluation of influence of small water reservoirs on the extreme runoff events (floods and drought) in the upper Úpa River basin. It summarizes knowledge about both hydrological extremes and their manifestations in the basin of interest as well as about small water reservoirs in the sense of water retention measures and their possible importance during the periods of low flows or floods. In this thesis two localities of possible reservoirs at place of former splash dams in Obří důl and on the Lysečinský Brook were chosen. To assess the influence of small water reservoirs on runoff during two chosen flood events and two periods of drought, the hydrological model HEC-HMS was applied. The results of model simulation proved a positive influence of reservoirs on the reduction of flood peaks (except for a concurrence of transformed flood waves in the outlet that occurred during one flood event), but the effect was decreasing with the increasing catchment area and the intensity of precipitation and with smaller storage capacity of a reservoir. During the low flows, a positive influence of reservoirs was observed as well, relating to the release of stored water. However, the ability of a reservoir to reduce deficit volume and to balance the flow was decreasing with smaller...