scholarly journals MODELLING THE IMPACTS OF WILDFIRE ON SURFACE RUNOFF IN THE UPPER UBERABINHA RIVER WATERSHED USING HEC-HMS

2017 ◽  
pp. 88-98
Author(s):  
Jean Maikon Santos Oliveira ◽  
Marcio Ricardo Salla
Keyword(s):  
Debris Flow ◽  
Surface Runoff ◽  
Overland Flow ◽  
Peak Flow ◽  
Daily Basis ◽  
Hydrological Processes ◽  
Watershed Model ◽  
Wet Season ◽  
River Watershed ◽  
Discharge Volume

Fire significantly affects hydrological processes in the watershed because it changes land cover and it creates a double layer of hydrophobic soil covered with ash, increasing the surface runoff and the production of debris flow in the basin. Assessing the impacts of fire on overland flow requires the use of modeling softwares capable of simulating post-fire discharge. Because a total of 760 wildfires were detected in the Upper Uberabinha River subbasin in the last nine years, it is of dire importance to understand the consequential impacts of fire on hydrological processes in this basin. In this study, the HEC-HMS model was used to evaluate post-fire discharge in the Upper Uberabinha River watershed. Model was previously calibrated and validated using two representative storms observed in the wet season. After calibration, the 5-, 10-, 25-, 50-, 100-, and 200-year storms were simulated in scenarios with increasing burn severity. The calibrated model performed well in the prediction of discharge values at a daily basis (0% difference in peak timing; 0% difference in peak flow; 31.8% BIAS). Peak flow and discharge volume increased and peak timing shifted to the left as severity of burn increased. The highest increment in peak discharge was 74.7% for the 10-year storm, whereas overall discharge volume raised in up to 31.9% for the 50-year storm, both after simulation in the most fire-impacted scenario. The results reveal that fire highly affects hydrological characteristics, e.g. peak timing and flow and discharge volume, in the Upper Uberabinha River watershed. The authors suggest further investigations concerning the impacts of wildfire on other processes, such as the production of debris flow in the basin.

scholarly journals Augmentation and Use of WRF-Hydro to Simulate Overland Flow- and Streamflow-Generated Debris Flow Hazards in Burn Scars

2021 ◽  
Author(s):  
Chuxuan Li ◽  
Alexander L. Handwerger ◽  
Jiali Wang ◽  
Wei Yu ◽  
Xiang Li ◽  
...  
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Hydrological Modeling ◽  
Overland Flow ◽  
New Physics ◽  
Reanalysis Data ◽  
Peak Discharge ◽  
Burn Scar ◽  
Big Sur ◽  
Discharge Volume

Abstract. In steep wildfire-burned terrains, intense rainfall can produce large volumes of runoff that can trigger highly destructive debris flows. The ability to accurately characterize and forecast debris-flow hazards in burned terrains, however, remains limited. Here, we augment the Weather Research and Forecasting Hydrological modeling system (WRF-Hydro) to simulate both overland and channelized flows and assess postfire debris-flow hazards over a regional domain. We perform hindcast simulations using high-resolution weather radar-derived precipitation and reanalysis data to drive non-burned baseline and burn scar sensitivity experiments. Our simulations focus on January 2021 when an atmospheric river triggered numerous debris flows within a wildfire burn scar in Big Sur – one of which destroyed California’s famous Highway 1. Compared to the baseline, our burn scar simulation yields dramatic increases in total and peak discharge, and shorter lags between rainfall onset and peak discharge. At Rat Creek, where Highway 1 was destroyed, discharge volume increases eight-fold and peak discharge triples relative to the baseline. For all catchments within the burn scar, we find that the median catchment-area normalized discharge volume increases nine-fold after incorporating burn scar characteristics, while the 95th percentile volume increases 13-fold. Catchments with anomalously high hazard levels correspond well with post-event debris flow observations. Our results demonstrate that WRF-Hydro provides a compelling new physics-based tool to investigate and potentially forecast postfire hydrologic hazards at regional scales.

Modelling of Solute Transfer to Surface Runoff

1992 ◽  
Vol 26 (7-8) ◽  
pp. 1851-1856 ◽  
Author(s):  
J. L. Lai ◽  
K. S. L. Lo
Keyword(s):  
Potassium Chloride ◽  
Surface Runoff ◽  
Laboratory Experiments ◽  
Overland Flow ◽  
Chloride Concentration ◽  
Runoff Water ◽  
Mixing Depth ◽  
Change Rate ◽  
Solute Transfer ◽  
The Media

A mixing-based model for describing solute transfer to overland flow was developed. This model included a time-dependent mixing depth of the top layer and a complete-mixed surface runoff zone. In a series of laboratory experiments, runoff was passed at various velocities and depths over a medium bed. The media were saturated with uniform concentration of potassium chloride solution. Runoff water was sampled at the beginning and end of the flume and the potassium chloride concentration analyzed. Using this model, dimensionless ultimate mixing depth and dimensionless change rate of mixing depth from experimental data were investigated and implemented. The results showed that the Reynolds number and relative roughness are two important factors.

Susceptibility Assessments and Validations of Debris-Flow Events in Meizoseismal Areas: Case Study in China’s Longxi River Watershed

2020 ◽  
Vol 21 (1) ◽  
pp. 05019005 ◽  
Author(s):  
Saier Wu ◽  
Jian Chen ◽  
Chong Xu ◽  
Wendy Zhou ◽  
Leihua Yao ◽  
...  
Keyword(s):  
Debris Flow ◽  
River Watershed

scholarly journals Role of Runoff–Infiltration Partitioning and Resolved Overland Flow on Land–Atmosphere Feedbacks: A Case Study with the WRF-Hydro Coupled Modeling System for West Africa

2016 ◽  
Vol 17 (5) ◽  
pp. 1489-1516 ◽  
Author(s):  
Joel Arnault ◽  
Sven Wagner ◽  
Thomas Rummler ◽  
Benjamin Fersch ◽  
Jan Bliefernicht ◽  
...  
Keyword(s):  
West Africa ◽  
Overland Flow ◽  
River Flow ◽  
Efficiency Coefficient ◽  
Wet Season ◽  
Coupled Modeling ◽  
Study Region ◽  
Outer Domain ◽  
Terrestrial Water

Abstract The analysis of land–atmosphere feedbacks requires detailed representation of land processes in atmospheric models. The focus here is on runoff–infiltration partitioning and resolved overland flow. In the standard version of WRF, runoff–infiltration partitioning is described as a purely vertical process. In WRF-Hydro, runoff is enhanced with lateral water flows. The study region is the Sissili catchment (12 800 km2) in West Africa, and the study period is from March 2003 to February 2004. The WRF setup here includes an outer and inner domain at 10- and 2-km resolution covering the West Africa and Sissili regions, respectively. In this WRF-Hydro setup, the inner domain is coupled with a subgrid at 500-m resolution to compute overland and river flow. Model results are compared with TRMM precipitation, model tree ensemble (MTE) evapotranspiration, Climate Change Initiative (CCI) soil moisture, CRU temperature, and streamflow observation. The role of runoff–infiltration partitioning and resolved overland flow on land–atmosphere feedbacks is addressed with a sensitivity analysis of WRF results to the runoff–infiltration partitioning parameter and a comparison between WRF and WRF-Hydro results, respectively. In the outer domain, precipitation is sensitive to runoff–infiltration partitioning at the scale of the Sissili area (~100 × 100 km2), but not of area A (500 × 2500 km2). In the inner domain, where precipitation patterns are mainly prescribed by lateral boundary conditions, sensitivity is small, but additionally resolved overland flow here clearly increases infiltration and evapotranspiration at the beginning of the wet season when soils are still dry. The WRF-Hydro setup presented here shows potential for joint atmospheric and terrestrial water balance studies and reproduces observed daily discharge with a Nash–Sutcliffe model efficiency coefficient of 0.43.

Post Wildfire Debris Flow and Flood Analysis of the September 2020 Badger Fire in the Trapper Creek and Rock Creek Watersheds, Idaho, USA.

2021 ◽  
Author(s):  
Stephen Turnbull ◽  
Nawa Pradhan ◽  
Ian Floyd
Keyword(s):  
Debris Flow ◽  
Finite Volume ◽  
Overland Flow ◽  
Frozen Ground ◽  
Channel Network ◽  
Hydrologic Analysis ◽  
Flood Analysis ◽  
Model Equations ◽  
Volume Method ◽  
Parameter Values

<p>There are several different infiltration, overland flow routing, and channel routing schemes that can be used in conjunction with recommended hydrodynamic and infiltration parameter values, which are found within the literature, to provide critical flooding assessments for stakeholders and decision makers.  We focus on post wildfire debris flow and flood analysis in two tributaries of the Snake River in Idaho, Trapper Creek and Rock Creek.  The Badger Fire started on September 12, 2020 in the Sawtooth National Forest in Idaho, USA, and burned sub-alpine fir, lodgepole pine, juniper, mountain brush and grass communities, in the upper part of both the Trapper Creek and Rock Creek watersheds.  Trapper Creek has a U.S. Geological Gaging station, and there are two snow gaging sites available.   The biggest concern for flooding and debris flow is the result of a wintertime rain-on-snow event, which resulted in the largest storm in the gaging record period.    </p><p>To estimate runoff in ungaged stream locations, existing process-based hydrodynamic models can be applied in a distributed form to solve the governing equations for mass, momentum and energy in a spatially explicit way. The purpose of this study is to predict potentially inundated land areas as a result of a rain-on-snow event, using the data in the gages basin to provide flood analysis information for both the gaged (Trapper Creek) and ungaged watershed (Rock Creek).  Rain-on-snow events are rainfall events that occur on the snowpack and frozen ground, resulting in a larger magnitude and volume of streamflow.  To predict these flows, Gridded Surface Subsurface Hydrologic Analysis (GSSHA) watershed models are prepared and calibrated to simulate rain-on-snow events in both watersheds.  The runoff generated from a two dimensional overland flow grid is transferred over land with a finite volume numerical method into a one dimensional channel network.  The channel network also uses a finite volume method.    The consistency in the identified range of the parametric values and their physical applicability make GSSHA an ideal candidate for this study, as the model equations provide a methods to evaluate a rain-on-snow event.</p>

scholarly journals The Development of a 1-D Integrated Hydro-Mechanical Model Based on Flume Tests to Unravel Different Hydrological Triggering Processes of Debris Flows

Water ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 950 ◽  
Author(s):  
Theo van Asch ◽  
Bin Yu ◽  
Wei Hu
Keyword(s):  
Debris Flow ◽  
Mechanical Model ◽  
Debris Flows ◽  
Overland Flow ◽  
Slope Angle ◽  
Great Influence ◽  
Flume Experiments ◽  
Triggering Mechanisms ◽  
Bed Material ◽  
Triggering Process

Many studies which try to analyze conditions for debris flow development ignore the type of initiation. Therefore, this paper deals with the following questions: What type of hydro-mechanical triggering mechanisms for debris flows can we distinguish in upstream channels of debris flow prone gullies? Which are the main parameters controlling the type and temporal sequence of these triggering processes, and what is their influence on the meteorological thresholds for debris flow initiation? A series of laboratory experiments were carried out in a flume 8 m long and with a width of 0.3 m to detect the conditions for different types of triggering mechanisms. The flume experiments show a sequence of hydrological processes triggering debris flows, namely erosion and transport by intensive overland flow and by infiltrating water causing failure of channel bed material. On the basis of these experiments, an integrated hydro-mechanical model was developed, which describes Hortonian and saturation overland flow, maximum sediment transport, through flow and failure of bed material. The model was calibrated and validated using process indicator values measured during the experiments in the flume. Virtual model simulations carried out in a schematic hypothetical source area of a catchment show that slope angle and hydraulic conductivity of the bed material determine the type and sequence of these triggering processes. It was also clearly demonstrated that the type of hydrological triggering process and the influencing geometrical and hydro-mechanical parameters may have a great influence on rainfall intensity-duration threshold curves for the start of debris flows.

scholarly journals Physically-based modelling of hydrological processes in a tropical headwater catchment (West Africa) – process representation and multi-criteria validation

2006 ◽  
Vol 10 (6) ◽  
pp. 829-847 ◽  
Author(s):  
S. Giertz ◽  
B. Diekkrüger ◽  
G. Steup
Keyword(s):  
Soil Moisture ◽  
Rainy Season ◽  
Overland Flow ◽  
Soil Layer ◽  
Hydrological Processes ◽  
Runoff Generation ◽  
Field Investigations ◽  
Physically Based ◽  
In The Beginning ◽  
Headwater Catchment

Abstract. The aim of the study was to test the applicability of a physically-based model to simulate the hydrological processes in a headwater catchment in Benin. Field investigations in the catchment have shown that lateral processes such as surface runoff and interflow are most important. Therefore, the 1-D SVAT-model SIMULAT was modified to a semi-distributed hillslope version (SIMULAT-H). Based on a good database, the model was evaluated in a multi-criteria validation using discharge, discharge components and soil moisture data. For the validation of discharge, good results were achieved for dry and wet years. The main differences were observable in the beginning of the rainy season. A comparison of the discharge components determined by hydro-chemical measurements with the simulation revealed that the model simulated the ratio of groundwater fluxes and fast runoff components correctly. For the validation of the discharge components of single events, larger differences were observable, which was partly caused by uncertainties in the precipitation data. The representation of the soil moisture dynamics by the model was good for the top soil layer. For deeper soil horizons, which are characterized by higher gravel content, the differences between simulated and measured soil moisture were larger. A good agreement of simulation results and field investigations was achieved for the runoff generation processes. Interflow is the predominant process on the upper and the middle slopes, while at the bottom of the hillslope groundwater recharge and – during the rainy season – saturated overland flow are important processes.

scholarly journals A theoretical model for the initiation of debris flow in unconsolidated soil under hydrodynamic conditions

2014 ◽  
Vol 2 (6) ◽  
pp. 4487-4524 ◽  
Author(s):  
C.-X. Guo ◽  
J.-W. Zhou ◽  
P. Cui ◽  
M.-H. Hao ◽  
F.-G. Xu
Keyword(s):  
Theoretical Model ◽  
Debris Flow ◽  
Surface Runoff ◽  
Slope Failure ◽  
Fine Particles ◽  
Field Investigation ◽  
Hydrodynamic Theory ◽  
Mechanism Analysis ◽  
Flume Experiments ◽  
Initiation Mechanism

Abstract. Debris flow is one of the catastrophic disasters in an earthquake-stricken area, and remains to be studied in depth. It is imperative to obtain an initiation mechanism and model of the debris flow, especially from unconsolidated soil. With flume experiments and field investigation on the Wenjiagou Gully debris flow induced from unconsolidated soil, it can be found that surface runoff can support the shear force along the slope and lead to soil strength decreasing, with fine particles migrating and forming a local relatively impermeable face. The surface runoff effect is the primary factor for accelerating the unconsolidated slope failure and initiating debris flow. Thus, a new theoretical model for the initiation of debris flow in unconsolidated soil was established by incorporating hydrodynamic theory and soil mechanics. This model was validated by a laboratory test and proved to be better suited for unconsolidated soil failure analysis. In addition, the mechanism analysis and the established model can provide a new direction and deeper understanding of debris flow initiation with unconsolidated soil.

Combining  concentration-discharge hysteresis and reach-scale lateral flow modelling to characterize flood water origin and processes: application to karst catchments

2021 ◽  
Author(s):  
Martin Le Mesnil ◽  
Jean-Baptiste Charlier ◽  
Roger Moussa ◽  
Yvan Caballero
Keyword(s):  
Surface Runoff ◽  
Hysteresis Loops ◽  
Hydrological Processes ◽  
Storm Events ◽  
New Classification ◽  
Catchment Scale ◽  
Saturation State ◽  
Relationship Analysis ◽  
Water Origin

<p>We propose a data-driven approach of concentration-discharge (C-Q) relationship analysis, including a new classification of C-Q hysteresis loop at the catchment scale, combined to a simulation of lateral Q and C at the reach scale. We analyse high-frequency, multiple-site records of Q and electrical conductivity (EC) in karst catchment outlets, in which EC informs on water residence time. At the catchment scale, contributions of pre-event water (PEW) and event water (EW) during storm events are investigated through hysteresis loops analysis, which allows inferring hydrological processes. Our new classification of hysteresis loops is based on loop mean slope and hysteresis index. At the reach scale, lateral Q and EC are simulated using a diffusive wave equation model, providing a more spatialized picture of PEW and EW contributions to streamflow during storm events. The methodology is applied to two catchments (Loue river and Cèze river) in France, including 8 gauging stations with hourly Q and EC time series covering 66 storm events.</p><p>For both catchments, a conceptual model of water origin and hydrological-processes seasonal and spatial variability is drawn. Regarding Loue catchment, summer and fall storm-events are characterized by contribution of PEW through piston-type flows, whereas decreasing EC values in winter and spring storm-events indicate the major contribution of EW through surface runoff and following fast infiltration in karst. EW contribution is increasing towards downstream. Regarding Cèze catchment, higher contributions of EW are observed, indicating that fast infiltration and surface runoff are the dominant processes, associated to a PEW signature in summer and fall. PEW contribution also increases in karstified areas. Intra-site water origin seasonality is mostly related to karst aquifer saturation state, whereas inter-site variability is linked to karst areas extension. These results are encouraging to extend this approach to a variety of sites, notably influenced by important surface water/groundwater interactions, and groundwater flooding.</p>

scholarly journals WetSpa-Urban: An Adapted Version of WetSpa-Python, A Suitable Tool for Detailed Runoff Calculation in Urban Areas

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2460 ◽  
Author(s):  
Nahad Rezazadeh Helmi ◽  
Boud Verbeiren ◽  
Charlotte Wirion ◽  
Ann van Griensven ◽  
Imeshi Weerasinghe ◽  
...  
Keyword(s):  
Open Source ◽  
Surface Runoff ◽  
Urban Areas ◽  
Statistical Investigation ◽  
Hydrological Processes ◽  
Rapid Urbanization ◽  
Storm Water Management Model ◽  
Distributed Process ◽  
Model Efficiency ◽  
Event Based

A tool called WetSpa-Urban was developed to respond to the need for precise runoff estimations in an increasingly urbanized world. WetSpa-Urban links the catchment model WetSpa-Python to the urban drainage model Storm Water Management Model (SWMM). WetSpa-Python is an open-source, fully distributed, process-based model that accurately represents surface hydrological processes but does not simulate hydraulic structures. SWMM is a well-known open-source hydrodynamic tool that calculates pipe flow processes in an accurate manner while runoff is calculated conceptually. Merging these tools along with certain modifications, such as improving the efficiency of surface runoff calculation and simulating flow at the sub-catchment level, makes WetSpa-Urban suitable for event-based and continuous rainfall–runoff modeling for urban areas. WetSpa-Urban was applied to the Watermaelbeek catchment in Brussels, Belgium, which recently experienced rapid urbanization. The model efficiency was evaluated using different statistical methods, such as Nash–Sutcliffe efficiency and model bias. In addition, a statistical investigation, independent of time, was performed by applying the box-cox transformation to the observed and simulated values of the flow peaks. By speeding up the simulation of the hydrological processes, the performance of the surface runoff calculation increased by almost 130%. The evaluation of the simulated 10 minute flow versus the observed flow at the outlet of the catchment for 2015 reached a Nash–Sutcliffe efficiency of 0.86 and a bias equal to 0.06.

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