On the relationship between hydrographs and chemographs
نویسندگان
چکیده
The spatial representativeness of gauging stations was investigated in two low-mountainous river basins near the city of Trier, southwest Germany. Longitudinal profiles during low and high flow conditions were sampled in order to identify sources of solutes and to characterize the alteration of flood wave properties during its travel downstream. Numerous hydrographs and chemographs of natural flood events were analysed in detail. Additionally, artificial flood events were investigated to study in-channel transport processes. During dry weather conditions the gauging station was only representative for a short river segment upstream, owing to discharge and solute concentrations of sources contiguous to the measurement site. During artificial flood events the kinematic wave velocity was considerably faster than the movement of water body and solutes, refuting the idea of a simple mixing process of individual runoff components. Depending on hydrological boundary conditions, the wave at a specific gauge could be entirely composed of old in-channel water, which notably reduces the spatial representativeness of a sampling site. Natural flood events were characterized by a superimposition of local overland flow, riparian water and the kinematic wave process comprising the downstream conveyance of solutes. Summer floods in particular were marked by a chronological occurrence of distinct individual runoff components originating only from a few contributing areas adjacent to the stream and gauge. Thus, the representativeness of a gauge for processes in the whole basin depends on the distance of the nearest significant source to the station. The consequence of our study is that the assumptions of mixing models are not satisfied in river basins larger than 3 km2. Copyright 2006 John Wiley & Sons, Ltd.
منابع مشابه
Sediment Transport in Unsteady Flow Conditions
Sediment transport under unsteady flow condition is studied experimentally. In the first step, sediment transport under different steady flow conditions was measured and an empirical equation was derived for its calculation. In the next step, two continuous and three stepwise hydrographs were generated in the flume, and their sediment transport rate was measured. The continuous hydrographs were...
متن کاملThe flow hydrograph modeling using GIS and distributed hyrdological model, in Dinvar Watershed, Karkheh, Iran
In this paper, the modeling is based on division of the catchment into a grid mesh. Each cell has a unique response function independent of the functioning of other cells Summation of the flow responses from the cells, result the flow hydrograph from this area basin.A method is presented to simulation the flow hydrograph within a river basin using the hydrological model WetSpa. WetSpa is a GIS-b...
متن کاملStudy of Duckbill Weir with Triangular and Curved Plan Form
Constructing of control structures, like dams, change temporal and spatial unequal distribution of water ,and also play an effective role in reduce or eliminate of damage that caused by floods. So reservoir dam’s effect on floods discharges reduction must be determined. In this study the rain Information and flood hydrographs were used to check the flood routing for previous period of Maroon da...
متن کاملClimate variability, snow, and physiographic controls on storm hydrographs in small forested basins, western Cascades, Oregon
Large floods are often attributed to the melting of snow during a rain event. This study tested how climate variability, snowpack presence, and basin physiography were related to storm hydrograph shape in three small (<1 km2) basins with old-growth forest in western Oregon. Relationships between hydrograph characteristics and precipitation were tested for approximately 800 storms over a nearly ...
متن کاملKarst springs hydrographs as indicators of karst aquifers
By analysing the hydrographs of karst springs it is possible to identify aquifer characteristics and, accordingly, the main features of a karst rock-fissure massif. Consequently, relevant data can be obtained by analysing hydrograph recession curves. This paper presents a detailed analysis and explanation of numerous cases of break points on recession curves via various values of the recession ...
متن کامل