scholarly journals Analysis of the runoff response of an alpine catchment at different scales

2007 ◽  
Vol 11 (4) ◽  
pp. 1441-1454 ◽  
Author(s):  
B. Zillgens ◽  
B. Merz ◽  
R. Kirnbauer ◽  
N. Tilch

Abstract. To understand how hydrological processes are related across different spatial scales, 201 rainfall runoff events were examined in three nested catchments of the upper river Saalach in the Austrian Alps. The Saalach basin is a nested catchment covering different spatial scales, from the micro-scale (Limberg, 0.07 km²), to the small-catchment scale (Rammern, 15.5 km²), and the meso-scale (Viehhofen, 150 km²). At these three scales two different event types could clearly be identified, depending on rainfall characteristics and initial baseflow level: (1) a unimodal event type with a quick rising and falling hydrograph, responding to short duration rainfall, and (2) a bimodal event type with a double peak hydrograph at the micro-scale and substantially increased flow values at the larger basins Rammern and Viehhofen, responding to long duration rainfall events. In all cases where a bimodal event was identified at the microscale, the hydrographs at the larger scales exhibited significantly attenuated recession behavior, quantified by recession constants. At all scales, the bimodal events are associated with considerably higher runoff volumes than the unimodal events. From the investigations at the headwater Limberg we came to the conclusion that the higher amount of runoff of bimodal events is due to the mobilization of subsurface flow processes. The analysis shows that the occurrence of the two event types is consistent over three orders of magnitude in area. This link between the scales means that the runoff behavior of the headwater may be used as an indicator of the runoff behavior of much larger areas.

2005 ◽  
Vol 2 (5) ◽  
pp. 1923-1960 ◽  
Author(s):  
B. Zillgens ◽  
B. Merz ◽  
R. Kirnbauer ◽  
N. Tilch

Abstract. To understand how hydrological processes are related across different spatial scales, 201 rainfall runoff events were examined in three nested catchments of the upper river Saalach in the Austrian Alps. The Saalach basin is a nested catchment covering different spatial scales, from the micro-scale (Limberg, 0.07 km2), to the small-catchment scale (Rammern, 15.5 km2), and the meso-scale (Viehhofen, 150 km2). At these three scales two different event types could clearly be identified, depending on rainfall characteristics and initial baseflow level: (1) a unimodal event type with a quick rising and falling hydrograph, responding to short duration rainfall, and (2) a bimodal event type with a double peak hydrograph at the micro-scale and substantially increased flow values at the larger basins Rammern and Viehhofen, responding to long duration rainfall events. In all cases where a bimodal event was identified at the microscale, the hydrographs at the larger scales exhibited significantly attenuated recession behavior, quantified by recession constants. At all scales, the bimodal events are associated with considerably higher runoff volumes than the unimodal events. From the investigations at the headwater Limberg we came to the conclusion that the higher amount of runoff of bimodal events is due to the mobilization of subsurface flow processes. The analysis shows that the occurrence of the two event types is consistent over three orders of magnitude in area. This link between the scales means that the runoff behavior of the headwater may be used as an indicator of the runoff behavior of much larger areas.


1997 ◽  
Vol 36 (8-9) ◽  
pp. 51-56
Author(s):  
F. Calomino ◽  
P. Veltri ◽  
P. Piro ◽  
J. Niemczynowicz

In Urban Hydrology, a basic question is whether or not the common methods involving the use of design storms bring to the the some results obtained by those methods that make use of real storms. In general, one can say that different design storms give good results when used with the appropriate model, or, conversely, that good results can be achieved through careful model calibration. On the basis of 51 rainfall-runoff recordings obtained from the experimental catchment of Luzzi (Cosenza, Italy), the frequency distribution of the observed peak discharges was initially computed. Then the runoff events were simulated using Wallrus, a well known simulation model, taking as input the observed precipitations. The frequency distribution of the simulated peak discharges was compared to that of the observed ones, with the aim of calibrating the model on a statistical basis. After that, the rainfall events were analysed, obtaining the frequency distributions of the observed intensities over several durations and developing IDF curves of given frequencies and, then, the Chicago design storms. The plotting positions of the peak discharges simulated by this way show a good agreement with the distribution of both the observed peak discharges and the peak discharges simulated through the real storms.


Author(s):  
L. Hejduk ◽  
A. Hejduk ◽  
K. Banasik

Abstract. One of the widely used methods for predicting flood runoff depth from ungauged catchments is the curve number (CN) method, developed by Soil Conservation Service (SCS) of US Department of Agriculture. The CN parameter can be computed directly from recorded rainfall depths and direct runoff volumes in case of existing data. In presented investigations, the CN parameter has been computed for snowmelt-runoff events based on snowmelt and rainfall measurements. All required data has been gathered for a small agricultural catchment (A = 23.4 km2) of Zagożdżonka river, located in Central Poland. The CN number received from 28 snowmelt-runoff events has been compared with CN computed from rainfall-runoff events for the same catchment. The CN parameter, estimated empirically varies from 64.0 to 94.8. The relation between CN and snowmelt depth was investigated in a similar procedure to relation between CN and rainfall depth.


2021 ◽  
Author(s):  
Chen Xu ◽  
Zaohong Liu ◽  
Guanjun Cai ◽  
Jian Zhan

Abstract Due to substrate layers with different substrate configurations, extensive green roofs (EGRs) exhibit different rainfall runoff retention and pollution interception effects. In the rainfall runoff scouring process, nutrient leaching often occurs in the substrate layer, which becomes a pollution source for rainwater runoff. In this study, six EGR devices with different substrate layer configurations were fabricated. Then, the cumulative leaching quantity (CLQ) and total leaching rate (TLR) of NH4+, TN and TP in the outflow of nine different depth simulated rainfall events under local rainfall characteristics were evaluated and recorded. Furthermore, the impact of different substrate configurations on the pollution interception effects of EGRs for rainfall runoff was studied. Results show that a mixed adsorption substrate in the EGR substrate layer has a more significant rainfall runoff pollution interception capacity than a single adsorption substrate. PVL and PVGL, as EGRs with layered configuration substrate layers, exhibited good NH4+-N interception capacity. The CLQ and TLR of NH4+-N for PVL and PVGL were -114.613 mg and -63.43%, -121.364 mg and -67.16%, respectively. Further, the addition of biochar as a modifier significantly slowed down the substrate layer TP leaching effect and improved the interception effect of NH4+-N and TN. Moreover, although polyacrylamide addition in the substrate layer aggravated the nitrogen leaching phenomenon in the EGRs outflow, but the granular structure substrate layer constructed by it exhibited a significantly inhibited TP leaching effect.


2019 ◽  
Vol 23 (7) ◽  
pp. 2863-2875 ◽  
Author(s):  
Sungmin O ◽  
Ulrich Foelsche

Abstract. Hydrology and remote-sensing communities have made use of dense rain-gauge networks for studying rainfall uncertainty and variability. However, in most regions, these dense networks are only available at small spatial scales (e.g., within remote-sensing subpixel areas) and over short periods of time. Just a few studies have applied a similar approach, i.e., employing dense gauge networks to catchment-scale areas, which limits the verification of their results in other regions. Using 10-year rainfall measurements from a network of 150 rain gauges, WegenerNet (WEGN), we assess the spatial uncertainty in observed heavy rainfall events. The WEGN network is located in southeastern Austria over an area of 20 km × 15 km with moderate orography. First, the spatial variability in rainfall in the region was characterized using a correlogram at daily and sub-daily scales. Differences in the spatial structure of rainfall events between warm and cold seasons are apparent, and we selected heavy rainfall events, the upper 10 % of wettest days during the warm season, for further analyses because of their high potential for causing hazards. Secondly, we investigated the uncertainty in estimating mean areal rainfall arising from a limited gauge density. The average number of gauges required to obtain areal rainfall with errors less than a certain threshold (≤20 % normalized root-mean-square error – RMSE – is considered here) tends to increase, roughly following a power law as the timescale decreases, while the errors can be significantly reduced by establishing regularly distributed gauges. Lastly, the impact of spatial aggregation on extreme rainfall was examined, using gridded rainfall data with various horizontal grid spacings. The spatial-scale dependence was clearly observed at high intensity thresholds and high temporal resolutions; e.g., the 5 min extreme intensity increases by 44 % for the 99.9th and by 25 % for the 99th percentile, with increasing horizontal resolution from 0.1 to 0.01∘. Quantitative uncertainty information from this study can guide both data users and producers to estimate uncertainty in their own observational datasets, consequently leading to the sensible use of the data in relevant applications. Our findings could be transferred to midlatitude regions with moderate topography, but only to a limited extent, given that regional factors that can affect rainfall type and process are not explicitly considered in the study.


Author(s):  
Beata Karabová ◽  
Anna E. Sikorska ◽  
Kazimierz Banasik ◽  
Silvia Kohnová

Abstract Parameters determination of a conceptual rainfall-runoff model for a small catchment in Carpathians. One of the most important tasks in hydrology is to simulate and forecast hydrologic processes and variables. To achieve this, various linear and nonlinear hydrologic models were developed. One of the most commonly applied rainfall-runoff models is the Nash’s model of the Instantaneous Unit Hydrograph (IUH) (Nash, 1957) used jointly with the CN-NRCS method. Within this paper, the Nash’s model was applied to a small forested basin (Vištucký Creek, Slovakia) to reconstruct rainfall-runoff events based on the recorded precipitation. The Vištucký Creek catchment, located in the Little Carpathians, is a part of the flood protection management of regional sites in the Little Carpathians. Therefore, the object of this paper is, first, to determine the parameters of a conceptual rainfall-runoff model for the Vištucký creek catchment, second, to analyse how the selected characteristics of the model depend on the rainfall characteristics, and third, to compare obtained results with a similar study of Sikorska and Banasik (2010). The computer programme developed at the Dept. of Water Engineering (WULS-SGGW) was used to obtain the rainfall-runoff characteristics based on the Nash´s model. The derived characteristics were parameters of the Nash’s model (N, k, lag time) and rainfall-runoff characteristics (sum of total and effective precipitation, rainfall duration, runoff coefficient, time to IUH peak, value of IUH peak, goodness of fit). A relatively small effective precipitation from the rainfall events was derived. For the purpose of the analysis, a correlation between the lag time (and k parameter) and the sum of the total and effective precipitation was used. The use of the conceptual rainfall-runoff model (Nash´s model) for the small catchment in Carpathians was proved to give satisfactory results. The rainfall characteristics derived in this study are comparable to the results obtained by Spál et. al (2011), who used the same catchment in their analysis. Interestingly, our analysis indicated that there is a correlation between the rainfall duration and the lag time, what is opposite to the compared results of Sikorska and Banasik (2010).


2021 ◽  
Vol 15 ◽  
Author(s):  
Ronald H. Stevens ◽  
Trysha L. Galloway

Neurodynamic organizations are information-based abstractions, expressed in bits, of the structure of long duration EEG amplitude levels. Neurodynamic information (NI, the variable of neurodynamic organization) is thought to continually accumulate as EEG amplitudes cycle through periods of persistent activation and deactivation in response to the activities and uncertainties of teamwork. Here we show that (1) Neurodynamic information levels were a better predictor of uncertainty and novice and expert behaviors than were the EEG power levels from which NI was derived. (2) Spatial and temporal parsing of team NI from experienced submarine navigation and healthcare teams showed that it was composed of discrete peaks with durations up to 20–60 s, and identified the involvement of activated delta waves when precise motor control was needed. (3) The relationship between NI and EEG power was complex varying by brain regions, EEG frequencies, and global vs. local brain interactions. The presence of an organizational system of information that parallels the amplitude of EEG rhythms is important as it provides a greatly reduced data dimension while retaining the essential system features, i.e., linkages to higher scale behaviors that span temporal and spatial scales of teamwork. In this way the combinatorial explosion of EEG rhythmic variables at micro levels become compressed into an intermediate system of information and organization which links to macro-scale team and team member behaviors. These studies provide an avenue for understanding how complex organizations arise from the dynamics of underlying micro-scale variables. The study also has practical implications for how micro-scale variables might be better represented, both conceptually and in terms of parsimony, for training machines to recognize human behaviors that span scales of teams.


2007 ◽  
Vol 22 (7) ◽  
pp. 861-876 ◽  
Author(s):  
S. K. Mishra ◽  
R. P. Pandey ◽  
M. K. Jain ◽  
Vijay P. Singh

Water ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 105
Author(s):  
Argelia E. Rascón-Ramos ◽  
Martín Martínez-Salvador ◽  
Gabriel Sosa-Pérez ◽  
Federico Villarreal-Guerrero ◽  
Alfredo Pinedo-Alvarez ◽  
...  

Understanding soil moisture behavior in semi-dry forests is essential for evaluating the impact of forest management on water availability. The objective of the study was to analyze soil moisture based in storm observations in three micro-catchments (0.19, 0.20, and 0.27 ha) with similar tree densities, and subject to different thinning intensities in a semi-dry forest in Chihuahua, Mexico. Vegetation, soil characteristics, precipitation, and volumetric water content were measured before thinning (2018), and after 0%, 40%, and 80% thinning for each micro-catchment (2019). Soil moisture was low and relatively similar among the three micro-catchments in 2018 (mean = 8.5%), and only large rainfall events (>30 mm) increased soil moisture significantly (29–52%). After thinning, soil moisture was higher and significantly different among the micro-catchments only during small rainfall events (<10 mm), while a difference was not noted during large events. The difference before–after during small rainfall events was not significant for the control (0% thinning); whereas 40% and 80% thinning increased soil moisture significantly by 40% and 53%, respectively. Knowledge of the response of soil moisture as a result of thinning and rainfall characteristics has important implications, especially for evaluating the impact of forest management on water availability.


2021 ◽  
Author(s):  
Marcelle Martins Vargas ◽  
Samuel Beskow ◽  
Carlos Rogério de Mello ◽  
Maíra Martim de Moura ◽  
Maria Cândida Moitinho Nunes ◽  
...  

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