Predicting saturation-excess runoff distribution with a lumped hillslope model: SWAT-HS

2017 ◽  
Vol 31 (12) ◽  
pp. 2226-2243 ◽  
Author(s):  
Linh Hoang ◽  
Elliot M. Schneiderman ◽  
Karen E.B. Moore ◽  
Rajith Mukundan ◽  
Emmet M. Owens ◽  
...  
Keyword(s):  
Saturation Excess

scholarly journals Sensitivity of point scale surface runoff predictions to rainfall resolution

2007 ◽  
Vol 11 (2) ◽  
pp. 965-982 ◽  
Author(s):  
A. J. Hearman ◽  
C. Hinz
Keyword(s):  
High Resolution ◽  
Western Australia ◽  
Surface Runoff ◽  
Rainfall Data ◽  
Soil Water Storage ◽  
Point Scale ◽  
Deep Drainage ◽  
Model Predictions ◽  
Infiltration Excess ◽  
Saturation Excess

Abstract. This paper investigates the effects of using non-linear, high resolution rainfall, compared to time averaged rainfall on the triggering of hydrologic thresholds and therefore model predictions of infiltration excess and saturation excess runoff at the point scale. The bounded random cascade model, parameterized to three locations in Western Australia, was used to scale rainfall intensities at various time resolutions ranging from 1.875 min to 2 h. A one dimensional, conceptual rainfall partitioning model was used that instantaneously partitioned water into infiltration excess, infiltration, storage, deep drainage, saturation excess and surface runoff, where the fluxes into and out of the soil store were controlled by thresholds. The results of the numerical modelling were scaled by relating soil infiltration properties to soil draining properties, and in turn, relating these to average storm intensities. For all soil types, we related maximum infiltration capacities to average storm intensities (k*) and were able to show where model predictions of infiltration excess were most sensitive to rainfall resolution (ln k*=0.4) and where using time averaged rainfall data can lead to an under prediction of infiltration excess and an over prediction of the amount of water entering the soil (ln k*>2) for all three rainfall locations tested. For soils susceptible to both infiltration excess and saturation excess, total runoff sensitivity was scaled by relating drainage coefficients to average storm intensities (g*) and parameter ranges where predicted runoff was dominated by infiltration excess or saturation excess depending on the resolution of rainfall data were determined (ln g*<2). Infiltration excess predicted from high resolution rainfall was short and intense, whereas saturation excess produced from low resolution rainfall was more constant and less intense. This has important implications for the accuracy of current hydrological models that use time averaged rainfall under these soil and rainfall conditions and predictions of larger scale phenomena such as hillslope runoff and runon. It offers insight into how rainfall resolution can affect predicted amounts of water entering the soil and thus soil water storage and drainage, possibly changing our understanding of the ecological functioning of the system or predictions of agri-chemical leaching. The application of this sensitivity analysis to different rainfall regions in Western Australia showed that locations in the tropics with higher intensity rainfalls are more likely to have differences in infiltration excess predictions with different rainfall resolutions and that a general understanding of the prevailing rainfall conditions and the soil's infiltration capacity can help in deciding whether high rainfall resolutions (below 1 h) are required for accurate surface runoff predictions.

scholarly journals Spatial Combination Modeling Framework of Saturation-Excess and Infiltration-Excess Runoff for Semihumid Watersheds

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Pengnian Huang ◽  
Zhijia Li ◽  
Cheng Yao ◽  
Qiaoling Li ◽  
Meichun Yan
Keyword(s):  
Difficult Problem ◽  
State Variables ◽  
Runoff Generation ◽  
Modeling Framework ◽  
Hydrological Simulation ◽  
Infiltration Excess ◽  
Generation Mechanisms ◽  
Event Based ◽  
Parameter Values ◽  
Saturation Excess

There exist two types of direct runoff generation mechanisms in semihumid watersheds: saturation-excess mechanism and infiltration-excess mechanism. It has always been a difficult problem for event hydrological simulation to distinguish the two types of runoff processes. Based on the concept of dominant runoff processes, combined with GIS and RS techniques, this paper proposed an event-based spatial combination modeling framework and built two spatial combination models (SCMs) accordingly. The CN parameter and topographic index, both of which are widely used in hydrological researches, are adopted by the SCM to divide the entire watershed into infiltration-excess dominated (IED) areas and saturation-excess dominated (SED) areas. Dongwan watershed was taken as an example to test the performances of infiltration-excess model, saturation-excess model, and SCM, respectively. The results of parameter optimization showed that the parameter values and state variables of SCM are much more realistic than those of infiltration-excess model and saturation-excess model. The more accurate the divisions of infiltration-excess and saturation-excess dominated areas, the more realistic the SCM parameter values. The simulation results showed that the performance of SCM was improved in both calibration and validation periods. The framework is useful for flood forecasting in semihumid watersheds.

scholarly journals Saturation excess overland flow accelerates the spread of a generalist soil-borne pathogen

2020 ◽  
Author(s):  
Jean Wilkening ◽  
Enrique Cardillo ◽  
Enrique Abad ◽  
Sally Thompson
Keyword(s):  
Overland Flow ◽  
Saturation Excess

scholarly journals Seasonal variation of 24D export through surface runoff from pasture

2006 ◽  
Vol 59 ◽  
pp. 255-260 ◽  
Author(s):  
K. M?ller ◽  
R. Stenger ◽  
A. Rahman
Keyword(s):  
Seasonal Variation ◽  
Soil Water ◽  
Surface Runoff ◽  
Rainfall Simulator ◽  
Water Conditions ◽  
Infiltration Excess ◽  
Soil Water Conditions ◽  
Saturation Excess

One day after the herbicide 24D was applied to 1050 m2 of a pastoral hillslope in Waikato runoff was generated with a sprinklertype rainfall simulator and 24D transport in surface runoff was measured The runoff coefficients differed significantly between an autumn (47) and a spring (19) event in spite of similar preevent soil water conditions Saturation excess with a variable contributing area had earlier been identified as the main runoff generating process for the autumn event In contrast infiltration excess possibly induced by treading effects and hydrophobicity are proposed as runoff causing processes for the spring event The eventaveraged 24D concentration in runoff was higher in autumn (049 mg/litre) than in spring (024 mg/litre) Correspondingly the exported 24D loss in autumn totalled 75 g/ha which equals 7 of the applied mass compared to only 14 g/ha (or 1) during the spring event

scholarly journals A Saturation Excess Erosion Model

2011 ◽  
Author(s):  
Tammo S Steenhuis ◽  
Seifu Admassu Tilahun
Keyword(s):  
Erosion Model ◽  
Saturation Excess

How geomorphology shapes groundwater transit times at the hillslope scale?

2021 ◽  
Author(s):  
Jean-Raynald De Dreuzy ◽  
Alexandre Gauvain ◽  
Sarah Leray ◽  
Jean Marçais ◽  
Clément Roques ◽  
...  
Keyword(s):  
Transit Time ◽  
Coefficient Of Variation ◽  
Average Distance ◽  
Environmental Tracers ◽  
Analytical Approximations ◽  
Overland Flows ◽  
Transit Times ◽  
The Mean ◽  
Constant Slope ◽  
Saturation Excess

&lt;p&gt;We investigate how geomorphological structures shape Transit Time Distributions (TTDs) in shallow aquifers. We show that the TTD is determined by integrated features of the groundwater structure and of the repartition of seepage in convergent/divergent hillslopes of constant slope. More specifically, the coefficient of variation of the TTD (standard deviation divided by the mean) scales linearly with the mean distance of the groundwater volume to the river. The extent and structure of seepage modify the groundwater contribution to the transit time distribution and increase its variability.&lt;/p&gt;&lt;p&gt;Extensive 3D simulations were performed to determine the TTDs synthetic convergent, straight and divergent hillslope models of constant slope. The recharge was applied uniformly on top of the aquifer and transferred to the receiving stream through steady-state groundwater flows, return flows and saturation excess overland flows. Without seepage, TTDs evolve from uniform- to power law-like- distributions depending on the average distance of the groundwater volume to the river. Remarkably, the coefficient of variation of the TTDs scales linearly with the groundwater volume to the river at any hillslope convergent/divergent rate in agreement with a theoretical prediction based on three analytical approximations. With seepage, the TTD progressively displays three separate modes corresponding (1) to the rapid saturation excess overland flows, (2) to the intermediary circulations ending up in seepage area and (3) to the slower circulations going from a recharge upstream the seepage zone to a discharge in the river. The coefficient of variation additionally depends on the extent of the seepage area.&lt;/p&gt;&lt;p&gt;Applied to a natural hillslope in the crystalline basement of Normandy (France), the same synthetic analysis demonstrates that the coefficient of variation is not only determined by the extent of the seepage zone but also by its structure in relation to the geomorphological local and global organizations. These results suggest the possibility to assess the variability of transit times by combining geomorphological analysis, surface soil saturation observations and environmental tracers.&lt;/p&gt;

scholarly journals Revisiting SWAT as a Saturation-Excess Runoff Model

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1427 ◽  
Author(s):  
Tammo S. Steenhuis ◽  
Elliot M. Schneiderman ◽  
Rajith Mukundan ◽  
Linh Hoang ◽  
Mamaru Moges ◽  
...  
Keyword(s):  
Overland Flow ◽  
Assessment Tool ◽  
Root Zone ◽  
Curve Number ◽  
Mountainous Regions ◽  
Hydrologic Response Units ◽  
Impermeable Layer ◽  
The Right ◽  
Town Brook Watershed ◽  
Saturation Excess

The Soil Water Assessment Tool (SWAT) is employed throughout the world to simulate watershed processes. A limitation of this model is that locations of saturation excess overland flow in hilly and mountainous regions with an impermeable layer at shallow depth cannot be simulated realistically. The objective of this research is to overcome this limitation with minor changes in the original SWAT code. The new approach is called SWAT-with-impervious-layers (SWAT-wil). Adaptations consisted of redefining the hillslope length, restricting downward percolation from the root zone, and redefining hydrologic response units (HRUs) such that they are associated with the landscape position. Finally, input parameters were chosen such that overland flow from variable saturated areas (VSAs) corresponds to the variable source interpretation of the Soil Conservation Service (SCS) curve number runoff equation. We tested the model for the Town Brook watershed in the Catskill Mountains. The results showed that the discharge calculated with SWAT-wil agreed with observed outflow and results simulated with the original SWAT and SWAT-hillslope (SWAT-HS) models that had a surface aquifer that transferred water between groups of HRUs. The locations of the periodically saturated runoff areas were predicted by SWAT-wil at the right locations. Current users can utilize the SWAT-wil approach for catchments where VSA hydrology predominates.

A statistically based runoff-yield model coupling infiltration excess and saturation excess mechanisms

2011 ◽  
Vol 26 (19) ◽  
pp. 2856-2865 ◽  
Author(s):  
Zhongmin Liang ◽  
Jun Wang ◽  
Binquan Li ◽  
Zhongbo Yu
Keyword(s):  
Model Coupling ◽  
Yield Model ◽  
Infiltration Excess ◽  
Saturation Excess
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