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Separation of surface flow from subsurface flow in catchments using runoff coefficient

Ardekani A. Afshar, Sabzevari T., Haghighi A. Torabi, Petroselli A.

Acta Geophysica

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2021

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Vol. 69, no. 6

2363--2376

EN

Separating surface flow (SF) from subsurface flow (SSF) based on direct runoff measurements in river gauges is an important issue in hydrology. In this study, we developed a simple and practical method, based on runoff coefficient (RC), for separating SF from SSF. RC depends mainly on soil texture, land use and land cover, but we also considered the effect of slope and rainfall intensity. We assessed our RC-based method for three different soil types by comparing the value obtained with laboratory rainfall simulator data. The correlation coefficient between observed and calculated data exceeded 0.93 and 0.63 when estimating SF and SSF, respectively. The method was then used to separate SF and SSF in two catchments (Heng-Chi and San-Hsia) in Northern Taiwan, and the results were compared with those produced by the geomorphological instantaneous unit hydrograph (GIUH) model. Test revealed that, if RC is calculated accurately, the proposed method can satisfactorily separate SF from SSF at catchment scale.

2

Symulowany efekt hydrogeochemiczny mieszania wód kopalnianych oraz powierzchniowych z rejonu Trzebini

Klojzy-Karczmarczyk B.

Przegląd Górniczy

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2012

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T. 68, nr 3

132--136

PL

W eksploatacji górniczej zachodzi konieczność odwadniania wyrobisk oraz zrzut wód dołowych, często do cieków powierzchniowych. Analizie poddano kierunki zmian chemizmu przykładowych wód powierzchniowych z rejonu Trzebini o zróżnicowanej mineralizacji (rzeka Chechło), w wyniku zrzutu wód dołowych kopalni rud cynku i ołowiu, przy założeniu zmiennej temperatury cieku powierzchniowego uzależnionej od pory roku. Symulację efektu mieszania roztworów wodnych prowadzono w stosunku objętościowym 1:1, z wykorzystaniem obliczeń programem PHREEQC. W analizowanym przypadku, typ hydrogeochemiczny roztworów wynikowych ulega zmianie w kierunku dominacji jonów, charakterystycznych dla wód kopalnianych o podwyższonej mineralizacji. Najbardziej istotne zmiany chemizmu wód obserwowane są w przypadku potencjalnego mieszania wód kopalnianych z wodami powierzchniowymi o niskiej mineralizacji i jednocześnie przy największej różnicy temperatur roztworów wejściowych.

EN

In mine exploitation there occurs the necessity of mine workings drainage and underground water discharge, frequently into surface flows. To analysis were subjected the directions of changes of the chemism of taken by way of example surface waters from the Trzebinia region with differentiated mineralization (Chechło river), as a result of underground water discharge from the zinc and lead ore mine, under the assumption of changeable temperature of the surface flow dependent on the season of the year. The simulation of the effect of water solution mixing was conducted in the volumetric relation 1:1, using calculations by means of the PHREEQC program. In the analyzed case, the hydrogeochemical type of result solutions is subject to change towards the domination of ions, characteristic for mine waters with increased mineralization. The most essential changes of the water chemism are observed in the case of potential mixing of underground waters with surface waters of low mineralization and simultaneously under the highest difference of temperatures of input solutions.

3

Water erosion and supply of material for fluvial transport under episodic surface flow conditions in the semi-arid zone on Boa Vista (Cabo Verde)

Gierszewski P., Rodzik J.

Landform Analysis

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2003

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Vol. 4

49--58

EN

This paper presents the effects of the natural conditions of the semi-arid zone on the tem-poral and spatial variability of production and supply of material for fluvial transport under conditions of episodic surface flow. Based on measurements of water runoff, concentration of suspension and dissolved material in the course of a one-hour rainfall, it has been determined that the catchments under study have a considerable resistance to the effects of water erosion. Some protection is supplied by the ablation pavement, which reduces rainsplash and slopewash and prevents flow concentration. Consid-erably more erosion has been noted on unpaved roads concentrating water flow even on plateaux and gently inclined slopes. Obviously the potential for leaching rock material in short-duration flow is limited. Large proportions of the dissolved material carried away from the catchments are salts of marine and aeolian provenance. The high intensity of erosional processes in the early phase of runoff is evidence of the role of physical weathering between rainfalls, which supplies the material for fluvial transport.