Wyniki wyszukiwania - BazTech

1

The development of ephemeral gullies in cultivated areas of Wiśnicz Foothills, Poland

Święchowicz J.

Landform Analysis

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2011

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Vol. 17

209-214

EN

Ephemeral gullies most frequently form and develop on cultivated slopes in natural drainage lines or they are associated with man-made agricultural activities like field borders, furrows, tractor traces and cart roads. The paper presents the results of ephemeral gullies studies carried out in hydrological years 1998-2009 on cultivated slopes in the Wiśnicz Foothills. Ephemeral gullies usually form and develop during single rain or several subsequent rains of high erosivity (of several hundred MJ mm ha-1 h -1) on long cultivated slopes, particularly at the beginning of vegetation period, when most slopes are devoid of vegetation cover or plants are in the inicial stage of growth.

2

Morphological characteristics of ephemeral gullies in Sicily, south Italy

Capra A., Di Stefano C., Ferro V., Scicolone B.

Landform Analysis

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2011

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Vol. 17

27-32

EN

Ephemeral gullies (EGs) are channels of different sizes refilled by tillage equipment normally used on farms. In this paper, the data-set collected from 1995 to 2007 in a wheat--ultivated area in Raddusa (Sicily, Italy), having a surface of almost 80 ha, were used to analyze the morphological characteristics of EGs. The measurements show an high temporal variability in EG characteristics. The EG measurements and the rill erosion measurements carried out in 15 plots located in the experimental "Sparacia" area (Sicily), demonstrated that a morphological similarity condition exists between rills and ephemeral gullies. The occurrence of step-pool structures in an EG occurring in the observation period in the same place allows to conclude that, in the considered environment, an ephemeral channel, such an EG, similarly to a stream, tends to reach a step-pool morphology as the structure that maximises its stability.

3

Evolution of rill networks on soil - mantled experimental landscapes driven by rainfall and baselevel adjustments

Gordon L. M., Bennett S. J., Wells R. R.

Landform Analysis

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2011

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Vol. 17

57-63

EN

Experiments were conducted using a soil-mantled flume subjected to simulated rain and downstream baselevel lowering to quantify the evolution of rill networks. Results show that: (1) headcuts formed by baselevel lowering were the primary drivers of rill incision and network development, and the communication of this wave of degradation occurred very quickly through the landscape, (2) rill networks extended upstream by headcut erosion, where channels bifurcated and filled the available space, (3) rill incision, channel development, and peaks in sediment efflux occurred episodically, linked directly to the downstream baselevel adjustments, and (4) sediment discharge and rill drainage density approached asymptotic values with time following baselevel adjustments despite continuous application of rainfall. These findings have important implications for the prediction of soil loss, rill network development, and landscape evolution where headcut erosion can occur.

4

Zmiany erozyjne dna koryta Sanu z uwzględnieniem czynników antropogenicznych

Łapuszek M.

Gospodarka Wodna

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2011

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Nr 1

22-26

PL

Zaprezentowano wyniki obliczeń zmian położenia dna koryta Sanu zachodzących na przestrzeni dziesięcioleci (analizowano 10 profili). Wyniki obliczeń zweryfikowano na podstawie analizy zmienności przekro-jów poprzecznych koryta. Występowanie intensywnej erozji dna Sanu powiązano z działaniem o charakterze antropogenicznym na koryto cieku.

EN

The article presents the results of calculations of the San riverbed location changes during the last several dozen years (10 water level profiles were analysed). The results of calculations were verified on the basis of the analysis of the riverbed cross section changeability. Occurrence of intensive erosion of the San riverbed bottom was connected with the anthropogenic activity's impact on the riverbed.