Hydrological analysis of runoff generation in a forested mountain catchment using a nested multi-tracer approach

2021 ◽  
Author(s):  
Lisa Rommel ◽  
Thomas Wöhling
Keyword(s):  
Stable Isotopes ◽  
Spatial Scales ◽  
Forecast Model ◽  
Runoff Generation ◽  
Soil Horizons ◽  
Flow Paths ◽  
Field Campaign ◽  
Runoff Formation ◽  
Source Areas ◽  
Nested Approach

<p>Rising concentrations of dissolved organic carbon (DOC) in inland waters are observed and investigated intensely in the last decades. The development of adaptive measures requires the forecasting of DOC-exports from catchments. Since DOC is exported from river catchments along hydrological pathways it is evident that the investigation of runoff generation, retention and travel times along flow paths are important to quantify DOC-loads and to develop a forecast model.</p><p>To gain comprehensive insights in runoff formation and DOC export in a small forested catchment in the Bavarian Forest National Park we apply a nested multi-tracer approach, combining experimental and analytical methods with the aim to develop a hydrological forecast model which is able to reproduce the dominant mobilization- and export processes of DOC in forested mountain catchments. The use of multiple tracers combines different approaches to determine source areas, flow paths and retention times of runoff water in catchments. Stable isotopes (d2H, d18O) are suitable as natural tracers to estimate contributions from precipitation to stream discharge. With the additional use of geochemical tracers (e.g. DOC, SiO2) contributions from groundwater and the organic and mineral soil horizons can be estimated. Combined with a nested approach these analyses can be conducted on different spatial scales, enabling the development of scalable prognostic models of runoff formation in catchments.</p><p>To complement the limited information from historic data sets we instrumented two hill transects to observe lateral contributions from hill slopes and to investigate potential preferential flow paths. Water samples from stream-, soil-, ground- and precipitation water were collected during two flood events and analysed for stable isotopes and chemical compositions. To support the nested approach, the sampling sites were chosen at strategical sites within the catchment, including the instrumented hill transects and the stream network from the creek to the catchment outlet.</p><p>Preliminary results of stable isotope analysis show, that after dry periods nearly no event water seems to contribute to runoff formation, whereas after wet periods the proportions can be up to 40 %. A strongly delayed reaction of the groundwater was observed which suggests that deep groundwater is not contributing to stream flow, but a possible mobilization of pre-event water in the riparian zone was observed as a response to precipitation events.</p><p>A likely major source of DOC is in the organic soil horizons due to storage and degradation of organic material. This is supported by higher DOC-concentrations in the soil water from these horizons. In how far residence times, precipitation intensities and flow paths activation from different source areas influence concentration peaks of DOC in the stream will be analysed in the next steps.</p><p>The results of the recent field campaign help to identify the dominant processes of runoff generation and DOC mobilization on different temporal and spatial scales and for different antecedent system states. The data and insights gained from the field campaign will be used to develop and calibrate process models for hypothesis testing and further analyses to eventually develop a forecast model for DOC mobilization.</p>

scholarly journals Depth–Sequential Investigation of Major Ions, δ18o, δ2h and δ13C in Fractured Aquifers of the St. Lawrence Lowlands (Quebec, Canada) Using Passive Samplers

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1806
Author(s):  
Guillaume Meyzonnat ◽  
Florent Barbecot ◽  
José Corcho Alvarado ◽  
Daniele Luigi Pinti ◽  
Jean-Marc Lauzon ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Major Ions ◽  
Anthropogenic Activities ◽  
Carbon Sources ◽  
Passive Samplers ◽  
Flow Paths ◽  
Aquifer Heterogeneity ◽  
Fractured Aquifers ◽  
Fractured Carbonate ◽  
Observation Wells

General and isotopic geochemistry of groundwater is an essential tool to decipher hydrogeological contexts and flow paths. Different hydrogeochemical patterns may result from the inherent physical aquifer heterogeneity, which may go unnoticed without detailed investigations gathered from multilevel or multiple observation wells. An alternative to overcome the frequent unavailability of multiple wellbores at sites is to perform a detailed investigation on the single wellbore available. In this perspective, the aim of this study is to use passive samplers to sequentially collect groundwater at depths in long–screened wellbores. Such investigation is carried out for major ions and stable isotopes compositions (δ2H, δ18O, δ13C) at ten sites in the context of fractured carbonate aquifers of the St. Lawrence Lowlands (Quebec, Canada). The information gathered from the calco–carbonic system, major ions and stable isotopes report poorly stratified and evolved groundwater bodies. Contribution of water impacted by anthropogenic activities, such as road salts pollution and carbon sources from C4 vegetation, when they occur, are even observed at the greatest depths. Such observations suggest quick flow paths and efficient mixing conditions, which leads to significant contributions of contemporary groundwater bodies in the fractured aquifers investigated down to depths of about 100 m. Although physical aquifer investigation reported few and heterogeneously distributed fractures per wellbore, hydrogeochemical findings point to at overall well interconnected fracture networks in the aquifer and high vulnerability of groundwater, even at significant depths.

scholarly journals A Comprehensive Review of Low Impact Development Models for Research, Conceptual, Preliminary and Detailed Design Applications

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1541 ◽  
Author(s):  
Sahereh Kaykhosravi ◽  
Usman Khan ◽  
Amaneh Jadidi
Keyword(s):  
Spatial Data ◽  
Spatial Scales ◽  
Low Impact Development ◽  
Model Development ◽  
Point Of View ◽  
Tree Canopy ◽  
Balance Model ◽  
Runoff Generation ◽  
Development Models ◽  
Model Features

This review compares and evaluates eleven Low Impact Development (LID) models on the basis of: (i) general model features including the model application, the temporal resolution, the spatial data visualization, the method of placing LID within catchments; (ii) hydrological modelling aspects including: the type of inbuilt LIDs, water balance model, runoff generation and infiltration; and (iii) hydraulic modelling methods with a focus on the flow routing method. Results show that despite the recent updates of existing LID models, several important features are still missing and need improvement. These features include the ability to model: multi-layer subsurface media, tree canopy and processes associated with vegetation, different spatial scales, snowmelt and runoff calculations. This review provides in-depth insight into existing LID models from a hydrological and hydraulic point of view, which will facilitate in selecting the best-suited model. Recommendations on further studies and LID model development are also presented.

scholarly journals Dye staining and excavation of a lateral preferential flow network

2009 ◽  
Vol 13 (6) ◽  
pp. 935-944 ◽  
Author(s):  
A. E. Anderson ◽  
M. Weiler ◽  
Y. Alila ◽  
R. O. Hudson
Keyword(s):  
Slope Stability ◽  
Solute Transport ◽  
Preferential Flow ◽  
Runoff Generation ◽  
Flow Paths ◽  
Soil Matrix ◽  
Preferential Flow Paths ◽  
Dye Staining ◽  
Hillslope Scale ◽  
Surrounding Soil

Abstract. Preferential flow paths have been found to be important for runoff generation, solute transport, and slope stability in many areas around the world. Although many studies have identified the particular characteristics of individual features and measured the runoff generation and solute transport within hillslopes, very few studies have determined how individual features are hydraulically connected at a hillslope scale. In this study, we used dye staining and excavation to determine the morphology and spatial pattern of a preferential flow network over a large scale (30 m). We explore the feasibility of extending small-scale dye staining techniques to the hillslope scale. We determine the lateral preferential flow paths that are active during the steady-state flow conditions and their interaction with the surrounding soil matrix. We also calculate the velocities of the flow through each cross-section of the hillslope and compare them to hillslope scale applied tracer measurements. Finally, we investigate the relationship between the contributing area and the characteristics of the preferential flow paths. The experiment revealed that larger contributing areas coincided with highly developed and hydraulically connected preferential flow paths that had flow with little interaction with the surrounding soil matrix. We found evidence of subsurface erosion and deposition of soil and organic material laterally and vertically within the soil. These results are important because they add to the understanding of the runoff generation, solute transport, and slope stability of preferential flow-dominated hillslopes.

Linking of 2D and Pipe hydraulic models at fine spatial scales

2007 ◽  
Vol 2 (2) ◽  
Author(s):  
R.S. Carr ◽  
G.P. Smith
Keyword(s):  
Overland Flow ◽  
Spatial Scales ◽  
Urban Environments ◽  
Flow Paths ◽  
Urban Flood ◽  
Hydraulic Models ◽  
Small Complex ◽  
Modelling Techniques ◽  
Flood Risk Mapping ◽  
Fine Resolution

Linking of two-dimensional overland flow hydraulic models with one-dimensional storm water pipe models at very fine resolution is becoming a standard approach for urban flood investigations. This paper describes the application of such an approach to a variety of small, complex urbanised catchments in Australia and New Zealand. A benefit of this approach is that previously hidden information in terms of secondary flow paths and cross-flows become apparent, an outcome that is not possible with traditional 1D modelling tools. Generation of flood risk mapping is much simpler through the use of direct GIS interfaces to the model result files, making the modelling and presentation process much more transparent. The paper will describe the application of the models, the calibration approach and some specialised modelling techniques when working at such fine spatial resolution in urban environments.

scholarly journals Assimilation of stratospheric and mesospheric temperatures from MLS and SABER into a global NWP model

2008 ◽  
Vol 8 (3) ◽  
pp. 8455-8490 ◽  
Author(s):  
K. W. Hoppel ◽  
N. L. Baker ◽  
L. Coy ◽  
S. D. Eckermann ◽  
J. P. McCormack ◽  
...  
Keyword(s):  
High Altitude ◽  
Spatial Scales ◽  
Three Dimensional ◽  
Forecast Model ◽  
Temperature Structure ◽  
Deep Circulation ◽  
Zonal Winds ◽  
Mesospheric Temperature ◽  
Standard Deviations ◽  
Nwp Model

Abstract. The forecast model and three-dimensional variational data assimilation components of the Navy Operational Global Atmospheric Prediction System (NOGAPS) have each been extended into the upper stratosphere and mesosphere to form an Advanced Level Physics High Altitude (ALPHA) version of NOGAPS extending to ~100 km. This NOGAPS-ALPHA NWP prototype is used to assimilate stratospheric and mesospheric temperature data from the Microwave Limb Sounder (MLS) and the Sounding of the Atmosphere using Broadband Radiometry (SABER) instruments. A 60-day analysis period in January and February, 2006, was chosen that includes a well documented stratospheric sudden warming. SABER temperatures indicate that the SSW caused the polar winter stratopause at ~40 km to disappear, then reform at ~80 km altitude and slowly descend during February. The NOGAPS-ALPHA analysis reproduces this observed stratospheric and mesospheric temperature structure, as well as realistic evolution of zonal winds, residual velocities, and Eliassen-Palm fluxes that aid interpretation of the vertically deep circulation and eddy flux anomalies that developed in response to this wave-breaking event. The observation minus forecast (O-F) standard deviations for MLS and SABER are ~2 K in the mid-stratosphere and increase monotonically to about 6 K in the upper mesosphere. Increasing O-F standard deviations in the mesosphere are expected due to increasing instrument error and increasing geophysical variance at small spatial scales in the forecast model. In the mid/high latitude winter regions, 10-day forecast skill is improved throughout the upper stratosphere and mesosphere when the model is initialized using the high-altitude analysis based on assimilation of both SABER and MLS data.

scholarly journals Evaluation of coupled ANN-GA model to prioritize flood source areas in ungauged watersheds

2020 ◽  
Vol 51 (3) ◽  
pp. 423-442
Author(s):  
Naser Dehghanian ◽  
S. Saeid Mousavi Nadoushani ◽  
Bahram Saghafian ◽  
Morteza Rayati Damavandi
Keyword(s):  
Flood Control ◽  
Mean Squared Error ◽  
Absolute Error ◽  
Ann Model ◽  
Runoff Generation ◽  
Source Areas ◽  
Walnut Gulch ◽  
Artificial Neural Network Ann ◽  
Semi Arid ◽  
Flood Source

Abstract An important step in flood control planning is identification of flood source areas (FSAs). This study presents a methodology for identifying FSAs. Unit flood response (UFR) approach has been proposed to quantify FSAs at subwatershed and/or cell scale. In this study, a distributed ModClark model linked with Muskingum flow routing was used for hydrological simulations. Furthermore, a fuzzy hybrid clustering method was adopted to identify hydrological homogenous regions (HHRs) resulting in clusters involving the most effective variables in runoff generation as selected through factor analysis (FA). The selected variables along with 50-year rainfall were entered into an artificial neural network (ANN) model optimized via genetic algorithm (GA) to predict flood index (FI) at cell scale. The case studies were two semi-arid watersheds, Tangrah in northeastern Iran and Walnut Gulch Experimental Watershed in Arizona. The results revealed that the predicted values of FI via ANN-GA were slightly different from those derived via UFR in terms of mean squared error (MSE), mean absolute error (MAE), and relative error (RE). Also, the prioritized FSAs via ANN-GA were almost similar to those of UFR. The proposed methodology may be applicable in prioritization of HHRs with respect to flood generation in ungauged semi-arid watersheds.

Extending the forecast model: Predicting Western Lake Erie harmful algal blooms at multiple spatial scales

2019 ◽  
Vol 45 (3) ◽  
pp. 587-595 ◽  
Author(s):  
Nathan F. Manning ◽  
Yu-Chen Wang ◽  
Colleen M. Long ◽  
Isabella Bertani ◽  
Michael J. Sayers ◽  
...  
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Lake Erie ◽  
Spatial Scales ◽  
Forecast Model ◽  
Multiple Spatial Scales ◽  
Western Lake ◽  
Western Lake Erie

scholarly journals Identification of runoff formation with two dyes in a mid-latitude mountain headwater

2017 ◽  
Vol 21 (6) ◽  
pp. 3025-3040 ◽  
Author(s):  
Lukáš Vlček ◽  
Kristýna Falátková ◽  
Philipp Schneider
Keyword(s):  
Pipe Flow ◽  
Preferential Flow ◽  
Subsurface Flow ◽  
Peat Bog ◽  
Catchment Scale ◽  
Tree Roots ◽  
Flow Paths ◽  
Runoff Formation ◽  
Shallow Subsurface ◽  
Preferential Flow Paths

Abstract. Subsurface flow in peat bog areas and its role in the hydrologic cycle has garnered increased attention as water scarcity and floods have increased due to a changing climate. In order to further probe the mechanisms in peat bog areas and contextualize them at the catchment scale, this experimental study identifies runoff formation at two opposite hillslopes in a peaty mountain headwater; a slope with organic peat soils and a shallow phreatic zone (0.5 m below surface), and a slope with mineral Podzol soils and no detectable groundwater (> 2 m below surface). Similarities and differences in infiltration, percolation and preferential flow paths between both hillslopes could be identified by sprinkling experiments with Brilliant Blue and Fluorescein sodium. To our knowledge, this is the first time these two dyes have been compared in their ability to stain preferential flow paths in soils. Dye-stained soil profiles within and downstream of the sprinkling areas were excavated parallel (lateral profiles) and perpendicular (frontal profiles) to the slopes' gradients. That way preferential flow patterns in the soil could be clearly identified. The results show that biomat flow, shallow subsurface flow in the organic topsoil layer, occurred at both hillslopes; however, at the peat bog hillslope it was significantly more prominent. The dye solutions infiltrated into the soil and continued either as lateral subsurface pipe flow in the case of the peat bog, or percolated vertically towards the bedrock in the case of the Podzol. This study provides evidence that subsurface pipe flow, lateral preferential flow along decomposed tree roots or logs in the unsaturated zone, is a major runoff formation process at the peat bog hillslope and in the adjacent riparian zone.

scholarly journals Characterisation of stable isotopes to identify residence times and runoff components in two meso-scale catchments in the Abay/Upper Blue Nile basin, Ethiopia

2014 ◽  
Vol 18 (6) ◽  
pp. 2415-2431 ◽  
Author(s):  
S. Tekleab ◽  
J. Wenninger ◽  
S. Uhlenbrook
Keyword(s):  
Stable Isotopes ◽  
Stable Isotope ◽  
Isotopic Composition ◽  
Residence Times ◽  
Nile Basin ◽  
Blue Nile ◽  
Source Areas ◽  
Blue Nile Basin ◽  
Mean Residence Times ◽  
Meso Scale

Abstract. Measurements of the stable isotopes oxygen-18 (18O) and deuterium (2H) were carried out in two meso-scale catchments, Chemoga (358 km2) and Jedeb (296 km2) south of Lake Tana, Abay/Upper Blue Nile basin, Ethiopia. The region is of paramount importance for the water resources in the Nile basin, as more than 70% of total Nile water flow originates from the Ethiopian highlands. Stable isotope compositions in precipitation, spring water and streamflow were analysed (i) to characterise the spatial and temporal variations of water fluxes; (ii) to estimate the mean residence time of water using a sine wave regression approach; and (iii) to identify runoff components using classical two-component hydrograph separations on a seasonal timescale. The results show that the isotopic composition of precipitation exhibits marked seasonal variations, which suggests different sources of moisture generation for the rainfall in the study area. The Atlantic–Indian Ocean, Congo basin, Upper White Nile and the Sudd swamps are the potential moisture source areas during the main rainy (summer) season, while the Indian–Arabian and Mediterranean Sea moisture source areas during little rain (spring) and dry (winter) seasons. The spatial variation in the isotopic composition is influenced by the amount effect as depicted by moderate coefficients of determination on a monthly timescale (R2 varies from 0.38 to 0.68) and weak regression coefficients (R2 varies from 0.18 to 0.58) for the altitude and temperature effects. A mean altitude effect accounting for −0.12‰/100 m for 18O and −0.58‰/100 m for 2H was discernible in precipitation isotope composition. Results from the hydrograph separation on a seasonal timescale indicate the dominance of event water, with an average of 71 and 64% of the total runoff during the wet season in the Chemoga and Jedeb catchments, respectively. Moreover, the stable isotope compositions of streamflow samples were damped compared to the input function of precipitation for both catchments. This damping was used to estimate mean residence times of stream water of 4.1 and 6.0 months at the Chemoga and Jedeb catchment outlets, respectively. Short mean residence times and high fractions of event water components recommend catchment management measures aiming at reduction of overland flow/soil erosion and increasing of soil water retention and recharge to enable sustainable development in these agriculturally dominated catchments.

scholarly journals E-DATA: A Comprehensive Field Campaign to Investigate Evaporation Enhanced by Advection in the Hyper-Arid Altiplano

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 745 ◽  
Author(s):  
Francisco Suárez ◽  
Felipe Lobos ◽  
Alberto de la Fuente ◽  
Jordi Vilà-Guerau de Arellano ◽  
Ana Prieto ◽  
...  
Keyword(s):  
Large Scale ◽  
Spatial Scales ◽  
Open Water ◽  
Water Evaporation ◽  
Distributed Temperature Sensing ◽  
Field Campaign ◽  
Spatial And Temporal Scales ◽  
Airborne Measurements ◽  
Dry Air ◽  
Evaporation Dynamics

In the endorheic basins of the Altiplano, water is crucial for sustaining unique ecological habitats. Here, the wetlands act as highly localized evaporative environments, and little is known about the processes that control evaporation. Understanding evaporation in the Altiplano is challenging because these environments are immersed in a complex topography surrounded by desert and are affected by atmospheric circulations at various spatial scales. Also, these environments may be subject to evaporation enhancement events as the result of dry air advection. To better characterize evaporation processes in the Altiplano, the novel Evaporation caused by Dry Air Transport over the Atacama Desert (E-DATA) field campaign was designed and tested at the Salar del Huasco, Chile. The E-DATA combines surface and airborne measurements to understand the evaporation dynamics over heterogeneous surfaces, with the main emphasis on the open water evaporation. The weather and research forecasting model was used for planning the instruments installation strategy to understand how large-scale air flow affects evaporation. Instrumentation deployed included: meteorological stations, eddy covariance systems, scintillometers, radiosondes and an unmanned aerial vehicle, and fiber-optic distributed temperature sensing. Additional water quality and CO2 fluxes measurements were carried out to identify the link between meteorological conditions and the biochemical dynamics of Salar del Huasco. Our first results show that, in the study site, evaporation is driven by processes occurring at multiple spatial and temporal scales and that, even in the case of available water and energy, evaporation is triggered by mechanical turbulence induced by wind.

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