We investigate evolution of mountain channel morphology and riverbed surface roughness by conducting laboratory experiments. The experimental flume is 4m long by 0.1m wide with a working length of 2.5m. We control initial sediment size distribution, flume slope, water discharge, and sediment feed rate. Measurements include topographic profiles, flow depth, surficial grain-size distribution, sediment transport rate, and sediment size distribution. Experiments begin with a gravel bed of a broad sediment size distribution, at two initial flume slopes: 8.2% and 12.4%. Discharge is held constant until transport rates and topographic changes indicate the system is at near steady state. Coarse sand is then fed into the channel at 1,000 g/min as a means to perturb the system. Sediment feed is held constant until the perturbed bed reach steady-state conditions. The feed is subsequently ceased and measurements continue until sediment transport rates and topography stabilize. These laboratory experiments provide first-hand observations of channel systems evolving after perturbations. Transport rates decay exponentially following perturbations and remain very low when the channel bed is stabilized. The introduction of coarse sand acts to smooth the channel bed by filling in topographic lows in the 8.2% sloped channel. At a 12.4% slope, increased mobility of sand allows steady state conditions to be met with little smoothing of the bed. The sand also increases the mobility of coarser sediment that was previously stable, likely due to local surface smoothing at grain scale. The increased fraction of surface sand cover maintains increased scouring and mobilization of coarser grains. These post-perturbation mechanisms are interpreted to be responsible for topographic adjustments as the system readjusts towards new steady-state conditions. Surface sorting and transporting distributions reflect high sand fractions well after perturbations have ceased. This suggests that brief pulses of fine sediment can increase coarse sediment mobility for prolonged periods. / text

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The thesis is concerned with an appraisal of capacity of channel and design of suitable measures for environmental protection. Solved segment is located in the channel of Český potok in RK 0,000 – 6,366. The channel is flowing through villages of Čelechovice na Hané, Smržice a Držovice in solved segment. Within own solution the locality was divided into three partial sections, which is enabling clearer description of the proposed measures. Flood measures are proposed in several variants for each partial section. Calculations of flow capacity and water surface for the selected N-year flows were performed by using the program of HEC - RAS 4.1.0. Proposed solutions to flood measures are processed in the drawings documentation.

The main aim of the thesis is an appraisal of the stream Oslava which belongs to the Náměšť nad Oslavou region with the focus on flood control of the town. The thesis asseses current state of the stream with respect to the state of riverbed, bulwark of the stream and evaluation of the capacity of the stream channel. Calculation water surface profiles have been made by usage of the 1D mathematical model HEC-RAS for selected N-year flows. The capacity of flows and objects in the given period has been detected. There is also a map of the water runoffs included and possible solutions of how to protect the area surrounding the stream are proposed. The thesis was complemented with hydroecological monitoring of the stream channel - the HEM analysis 2014.

The diploma thesis discusses the current status of watercourse Kyjovka and a proposal for appropriate protection measures of the territory. The selected section starts at river-km 71,338 and ends at river-km 74,443. The selected part of the watercourse runs through the town of Koryčany. This thesis examines the selected section of Kyjovka split into two subsections. That allows for detailed presentation of several proposed appropriate measures to be applied at critical spots in the selected subsections. The calculation of the watercourse model and its capacity with the water level progresses for selected N(y.o.) flow rates were processed in HEC-RAS5.0.1. program. Proposed flood protection measures are incorporated in the drawings.