Impact of landscape changes on rainfall-runoff processes and flood risk
The main objectives of the research are following: analysis of processes changing ecosystems in floodplains as a result of extreme floods, identification and classification of critical regions and proposal of methodology of systematic monitoring in these regions.
Methodological tasks deal with basic questions of relations between landscape changes and extreme floods by means of quantitative methods. Among most important issues belongs regionalization of flood risk in the Czech Republic, historical floods assessment, impact of anthropogenic landscape changes on flood course and consequences, retention potential of headwater areas assessment, peat-bog influence on runoff process, processes of succession in the floodplains as a result of extreme floods.
The main focus of the research represents analytical tasks. Key aspects of flood risk and landscape changes are solved in selected experimental catchments. Basins affected by a flood in different time interval are chosen as the basic reference areas. Among most important analytical issues belongs analysis of changes in rainfall-runoff processes in headwater areas, assessment of river network historical changes, analysis of stream regulation, rainfall-runoff modelling in headwater areas, modelling the impact of landscape changes on floods or analysis of land cover quality changes by means of remote sensing methods.
Retention potential of headwater areas and flood plains
In context of catastrophic floods and extreme droughts in recent years there is an urgent need of solving of flood protection issues and measures leading to discharge increase in dry periods, not using just classical engineering methods but also untraditional practices. There is a new strategy focusing on gradual increase of river catchment retention capacity including the realization of measures as runoff retardation and water retention increase in headstream areas.
The main aim of the research could be characterized as an evaluation of retention capacity of headstream areas using modern methodical approaches in context of integrated flood protection and hydrological drought problem solving. Following points should support the main goal of the project:
- Evaluation of hydrological regime in catchments with different physical-geographic factors (relief, land use, snow cover) using modern approaches of hydrological and climatologic monitoring and mathematical modelling tools.
- Identification of critical climate change scenarios in relation to hydrological extremes in headwater areas.
- Proposal of catalogue of measures in the landscape reinforcing water retention potential and testing of their effect by means of mathematical modelling.
- Assessment of peat bogs hydrological function base on hydrological, hydrochemical and geochemical data.
- Analysis of historical changes of land use and river network modifications in respect to the retention potential and flow dynamics.
Snow accumulation and snowmelt processes in mountain areas
Snow is important component of hydrological cycle in the central Europe. Large quantity of water is accumulated in form of snow during winter period and this water flows into rivers in relatively short time during spring period. Therefore, the knowledge of water volume accumulated in the snowpack and its spatial distribution represent the basic information for hydrological forecasting. Our results might contribute to understand the processes of snow accumulation, snow redistribution and snowmelt as a factor of flood and hydrological drought risks. The objectives of our research are:
- to determine main factors governing the variability of snow accumulation and ablation by means of repeated measurements of snow depth and snow water equivalent (SWE) in selected study areas
- to estimate the role of forest, forest clearings and disturbed forest on snow accumulation and more importantly, on the snow ablation process.
- to assess the relation between seasonal snowpack and summer low flows, especially to quantify the length of the memory effect of mountaion catchments in terms of the influence of winter snow conditions on summer low flows
Risk processes in alpine regions
Research of risk processes in alpine areas is focused mainly on monitoring of fluvial processes dynamics in light of potentially threat of inhabitants in the alpine valleys in the selected areas. Attention is paid to two regions. First region is the headwater part of Amazon River and the research is focused on detailed survey of the recession of the present glaciers and long-term snow and the determination of the hydrologic regime of the main Amazon headwaters, considering the accelerated glacier ablation and the long-term snow cover. The second region covers selected alpine areas of Kyrgyzstan. The research is dealing with the protection of inhabitants and infrastructure against floods caused by dam rupture of the glacial lakes moraines. Research is made in selected localities in Tian-Shan Mountains (e.g. Petrova, Adygine and Koltor lakes).
Up-to-date methods for assessment are applied – monitoring (continual hydrologic and climatologic data are transmitted using satellite network), remote sensing and consequent data analysis using geoinformation and statistical methods and mathematical modelling.