Monitoring and validating the temporal dynamics of interday streamflow from two upland head micro-watersheds with different vegetative conditions during dry periods of the growing season in the Bohemian Massif, Czech Republic

Abstract

At present, dynamic land use, climate change, and growing needs for fresh water are increasing the demand on the ecosystem effects of forest vegetation. Mountainous areas are at the forefront of scientific interest in European forest ecology and forest hydrology. Although uplands cover a significant area of the Czech Republic and other countries and are often covered with forest formations, they do not receive an appropriate amount of attention. Therefore, two experimental upland head micro-watersheds in the Bohemian Massif were selected for study because they display similar natural conditions, but different vegetative conditions (forest versus meadow). During the 2011 growing season, short-term streamflow measurements were carried out at the discharge profiles of both catchments and were evaluated in relation to climatic data (rainfall and temperature). The basic premise was that the streamflow in a forested catchment must exhibit different temporal dynamics compared to that in treeless areas and that these differences can be attributed to the effects of woody vegetation. These conclusions were drawn from measurements performed during dry periods lasting several days. A decreasing streamflow trend during the day part of the day (0900-1900 hours) was observed in both localities. The decrease reached approx. 44 % of the initial morning streamflow (0.24 dm(3) s(-1) day(-1)) in the treeless catchment and approx. 20 % (0.19 dm(3) s(-1) day(-1)) in the forested catchment. At night (1900-0900 hours), the streamflow in the forested catchment increased back to its initial level, whereas the streamflow in the treeless catchment stagnated or slowly decreased. We attribute these differences to the ecosystem effects of woody vegetation and its capacity to control water loss during the day. This type of vegetation can also function as a water source for the hydrographic network during the night.

Diurnal dynamics of streamflow in an upland forested micro‐watershed during short precipitation‐free periods is altered by tree sap flow

“…It may be therefore possible that the daily amplitude is mostly dependent on the vegetation in the catchment. Moreover, results from a close treeless catchment (Deutscher and Kupec, ) showed amplitudes approaching 40%, pointing out regulatory role of the forests on the dynamics of water discharge.…”

“…The comparison of streamflow during short precipitation‐free periods of the growing seasons in 2 years 2011 (Deutscher and Kupec, ) and 2012 indicated that the year 2011 was wetter than 2012. In 2011, the mean observed streamflow reached 0.8 l s −1 versus 0.4 l s −1 in 2012.…”

“…In Central Europe, similarly to the Czech Republic, the research was primarily focused on the hydrologically important alpine regions, and relatively, little work was carried out in the lower altitudes with less MAP (although some exceptions exist, i.e. Gribovszki et al , ; Szilagyi et al , – both in Sopron Hills, Hungary, MAP 750 mm; Carey et al – the ‘North Watch’ catchments, Krycklan, Sweden, MAP 651 mm; Mátyás and Sun, – forest steppe, Hungary, MAP 560 mm; Lamačová et al – GEOMON network catchments, Czech Republic, MAP 400–1554 mm; Deutscher and Kupec, – KFC, MAP 610 mm).…”

Impact of evapotranspiration on diurnal discharge fluctuation determined by the Fourier series model in dry periods

“…They show harmonic evapotranspiration rates that have orders of magnitude, which are smaller than the levels assessed on typical catchments (Kirchner 2006(Kirchner , 2009Langhammer & Vilimek 2008;Deutscher & Kupec 2014). The problem is thus clearly delimited.…”

Diel discharge variations in dormant and growing seasons in a headwater catchment suggest potential sources of an evapotranspiration signal

“…Diel fluctuations in streamflow magnitude on days without precipitation input have been identified in catchments around the world, starting as early as the 1930's (for example: Deutscher & Kupec, ; Godwin, ). Several catchment processes can lead to such variations in discharge.…”