The impact of forest cover on Rainfall - Runoff relation - study in the Jevany creek basin

Tijana Ristov

Master's thesis

Abstract:

Present changes in land cover caused by climate change affect the rainfall-runoff relation. Jevanský catchment is one of the areas which has been noticed to be affected by climate change. The decrease of the Norway spruce forests stands is happening all around the Czech Republic and is also present in this catchment. Apart from economical and biodiversity questions, a question regarding rainfall-runoff relation can be raised. MIKE 11 is a software that allows utilization of the Unit Hydrograph Model (UHM), a rainfall-runoff model, which was calibrated for the Jevanský catchment based on historic rainfall episodes and then used for simulation of various scenarios. As a part of this thesis, 5 scenarios were designed. The first one being the current land cover of the catchment, and the other 4 representing different forest cover shares. The land use of the catchment for each scenario was represented by different CN values. All of them undergone simulations by using design precipitation data for return periods of 10, 50, and 100 years. The scenario where all current forest cover was removed showed the greatest maximum runoff values and accumulated runoff values. The runoff amount was greater for 36.29 %, 33.64 %, and 32.31 %, for 10, 50, and 100 years return periods, respectively, compared to the current land use situation in the Jevanský basin. The absence of the forest cover for this scenario also caused the fastest hydrograph peak occurrence. Broadleaved forests showed lower retention abilities than coniferous by producing greater peak values and runoff amounts. Runoff accumulation was greater (9.84-11.36 %) in the scenario where broadleaved forests were the only forest type in the catchment.

Keywords

Runoff, Jevanský creek, rainfall, land cover, coniferous forests, broadleaved forests, MIKE 11, UHM, SCS, CN

Language used: English

Date on which the thesis was submitted / produced: 20. 4. 2021

Thesis defence

• Supervisor: doc. Ing. Evžen Zeman, CSc.

Czech University of Life Sciences Prague

Faculty of Environmental Sciences

Master programme / field:
Forestry Engineering / Forestry, Water and Landscape Management