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Dehtare

The catchment Dehtáře is situated in the south-west Bohemo-Moravian Highland (Czech Republic), at 49°28´ N – 15° 12´ E, close to Pelhřimov town, within the Želivka river basin. Dehtáře has an area of 59.6 ha, with tile drained areas occupying 19 ha (~32%). The catchment area is mainly agricultural land (89.3%). Minor forested areas (3.3%) lie at its north-western and northern borders. Grassland (20.3%) covers the southern part of the catchment, as well as the adjacent lowest lying south-western area, which is tile-drained. The remaining area (69%) is arable land, which is exploited mainly for cereals production, see Fig. 3. The catchment geomorphology belongs to the erosion-accumulation relief type. The altitude ranges between 497.0 and 549.8 m. The local climate is classified as moderately warm. The average annual total precipitation is 660 mm and the average air temperature is 7.0°C.

There is no permanent open water channel within the catchment. The catchment hydrogeology is characterized by shallow aquifers (with groundwater table in the discharge zone lying at 0.2–1.5 m), occurring in Quaternary deposits, in the weathered zone of the bedrock and in its fissures and faults. The bedrock is a partially migmatized paragneiss. Quaternary deposits are slope sands and bottom loams, reaching a thickness of 1–2 m. The bottom loams usually act as aquitards and have their own phreatic groundwater table, partially recharged from the atmosphere, so that the water from below mixes in them with the water from above. The dominant soil types are Haplic Cambisols in the recharge and transient zones. These soils are light, shallow and stony (the thickness of the soil profile being only 30 cm in some parts) sandy loams and loamy sands. Haplic Stagnosols, Haplic Gleysols, Fibric Histosols and Stagnic Cambisols are typical for the discharge and the discharge/transient zones. Medium-deep sandy loams dominate in the lower parts of the slopes, while deep loams are most typical for the catchment bottom. Tile drainage (still fully functioning) was laid in 1977 in the western, lower part of the catchment. The average slope of the drained land is about 5%. The spacing of lateral drains is 13 or 20 m.

Dehtáře experimental catchment was established for the research of linkages between land use and management in various geomorphological zones and water quantity and quality dynamics. For this purpose, several sites have been monitored (since 2003) – water levels (discharges) – continuously by UV probes and dataloggers – in drainage shafts and boreholes. For water quality, manual samples are withdrawn in a 14 day step. Beside this, in the catchment outlet, one automatic sampler (MORAVA type) is placed to take the samples in rainfal-runoff event., in minutes-hours-days sampling step. Moreover, the research also focuses on crop response to water and nutrient stress induced by different soil conditions. There are two fully equipped automatic meteorologial stations within the catchment.

Obr. 3 – Povodí Dehtáře