Evaluation of monitoring on Modrava catchments

Abstract

In this paper is presented the comparison of the selected hydrometeorological data from two experimental micro-scale catchments Modrava 1 (0.1 km2) and Modrava 2 (0.17 km2) in upper parts of Bohemian Forest. These catchments differ mainly in the vegetation cover - a dead forest with very young trees (Modrava 1) and primary forest clearings with 10 to 15-year old young forest (Modrava 2). For comparison were used the data monitored close to the catchments outlets during the hydrological year 2007. Average hourly rainfall and runoff data were analysed. During the winter season, snow water equivalents were measured and the maximum value was added to the rainfall amount measured during the vegetation season for the estimation of total year precipitation on each catchment. The data of the air temperature and water conductivity measured in hourly time intervals were also compared. For the estimation of differences between the monitored data sets the cumulative values of the characteristics observed during whole year were computed. It follows from the comparison of the time series that the time rainfall distribution was similar during the year on both catchments with a higher total year precipitation and hour intensities on the catchment Modrava 2. The time distribution and total runoff depth were similar on both catchments. On Modrava 1 a faster recession of hydrographs could be seen which might relate to a lower retention capacity. The value of the water conductivity on the catchment Modrava 1 depended more on the changes of the runoff depth. The maximal values occurred during the peak discharges or in time of hydrographs rising. This fact can be the result of a lower stability of the soil profile in the catchment with dead forest cover.