A PHYSICALLY-BASED COUPLED HYDROLOGIC MODEL FOR CLEAR CREEK WATERSHED

The role of tillage practices on soil aggregate properties has been mainly addressed at the pedon scale (i.e., soilscape scale) by treating landscape elements as disconnected. However, there is observed heterogeneity in aggregate properties along flowpaths, suggesting that landscape scale hydraulic processes are also important. This study examines this supposition using field, laboratory and modeling analysis to assess aggregate size and stability along flowpaths under different management conditions: (1) tillage-induced abrasion effects on aggregate size were evaluated with the dry mean weight diameter (DMWD); (2) raindrop impact effects were evaluated with small macroaggregate stability (SMAGGSTAB) using rainfall simulators; and (3) these aggregate proxies were studied in the context of connectivity through the excess bed shear stress (δ), quantified using a physically-based landscape model. DMWD and SMAGGSTAB decreased along the flowpaths for all managements, and a negative correspondence between the proxies and δ was observed. δ captured roughness effects on connectivity along the flowpaths: highest connectivity was noted for parallel-ridge-till flowpaths, where δ ranged from 0–8.2 Pa, and lowest connectivity for contour-ridge-till flowpaths, where δ ranged from 0–1.1 Pa. High tillage intensity likely led to an increase in aggregate susceptibility to hydraulic forcing, reflected in the higher gradients of aggregate size and stability trendlines with respect to δ. Finally, a linear relationship between DMWD and SMAGGSTAB was established.

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Improving the representation of the prairie pothole dynamics in land surface models

10.5194/egusphere-egu2020-3713 ◽

2020 ◽

Author(s):

Mohamed I. Ahmed ◽

Amin Elshorbagy ◽

Alain Pietroniro

Keyword(s):

Surface Runoff ◽

Land Surface ◽

Flow Simulation ◽

Hydrologic Model ◽

Surface Model ◽

Prairie Pothole ◽

Runoff Generation ◽

Dem Resolution ◽

Physically Based ◽

Streamflow Simulation

The hydrography of the prairie basins is complicated by the existence of numerous land depressions, known as prairie potholes, which can retain a substantial amount of surface runoff. Consequently, the runoff production in the prairies follows a fill, spill, and merging mechanism, which results in a dynamic contributing area that makes the streamflow simulation challenging. Existing approaches to represent the potholes&#8217; dynamics, in different hydrological models, use either a lumped or a series of reservoirs that contribute flow after exceeding a certain storage threshold. These approaches are simplified and do not represent the actual dynamics of the potholes nor their spatial water extents. Consequently, these approaches may not be useful in capturing the potholes&#8217; complexities and may not be able to accurately simulate the complex prairie streamflow. This study advances towards more accurate and physically-based streamflow simulation in the prairies by implanting a physically-based runoff generation algorithm (Prairie Region Inundation MApping, PRIMA model) within the MESH land surface model, and is referred to as MESH-PRIMA. PRIMA is a recently developed hydrological routing model that can simulate the lateral movement of water over prairie landscape using topographic data provided via DEMs. In MESH-PRIMA, MESH handles the vertical water balance calculations, whereas PRIMA routes the water and determines the amount of water storage and surface runoff. The streamflow simulations of MESH-PRIMA (using different DEM resolution as a topographic input) and MESH with its existing conceptual pothole dynamics algorithm are tested on a number of pothole-dominated watersheds within Saskatchewan, Canada, and compared against observed flows. MESH-PRIMA provides improved streamflow and peak flow simulation, compared to that of MESH with its conceptual pothole algorithm, based on the metrics evaluated for the simulations. MESH-PRIMA shows potential for simulating the actual pothole water extents when compared against water areas obtained from remote sensing data. The use of different DEM resolution changes the resulting pothole water extent, especially for the small potholes as they are not detected in the coarse DEM. MESH-PRIMA can be considered as a hydraulic-hydrologic model that can be used for better understanding and accurate representation of the complex prairie hydrology.

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Physically based modeling of rainfall-triggered landslides: a case study in the Luquillo forest, Puerto Rico

Hydrology and Earth System Sciences ◽

10.5194/hess-17-3371-2013 ◽

2013 ◽

Vol 17 (9) ◽

pp. 3371-3387 ◽

Cited By ~ 40

Author(s):

C. Lepore ◽

E. Arnone ◽

L. V. Noto ◽

G. Sivandran ◽

R. L. Bras

Keyword(s):

Soil Moisture ◽

Soil Column ◽

Hydrologic Model ◽

Richards Equation ◽

Landslide Risk ◽

Modeling Framework ◽

Soil Moisture Dynamics ◽

Physically Based ◽

Spatially Distributed ◽

Moisture Dynamics

Abstract. This paper presents the development of a rainfall-triggered landslide module within an existing physically based spatially distributed ecohydrologic model. The model, tRIBS-VEGGIE (Triangulated Irregular Networks-based Real-time Integrated Basin Simulator and Vegetation Generator for Interactive Evolution), is capable of a sophisticated description of many hydrological processes; in particular, the soil moisture dynamics are resolved at a temporal and spatial resolution required to examine the triggering mechanisms of rainfall-induced landslides. The validity of the tRIBS-VEGGIE model to a tropical environment is shown with an evaluation of its performance against direct observations made within the study area of Luquillo Forest. The newly developed landslide module builds upon the previous version of the tRIBS landslide component. This new module utilizes a numerical solution to the Richards' equation (present in tRIBS-VEGGIE but not in tRIBS), which better represents the time evolution of soil moisture transport through the soil column. Moreover, the new landslide module utilizes an extended formulation of the factor of safety (FS) to correctly quantify the role of matric suction in slope stability and to account for unsaturated conditions in the evaluation of FS. The new modeling framework couples the capabilities of the detailed hydrologic model to describe soil moisture dynamics with the infinite slope model, creating a powerful tool for the assessment of rainfall-triggered landslide risk.

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Integrating Daily CO2 Concentrations in SWAT-VSA to Examine Climate Change Impacts on Hydrology in a Karst Watershed

Transactions of the ASABE ◽

10.13031/trans.13711 ◽

2021 ◽

Vol 64 (4) ◽

pp. 1303-1318

Author(s):

Kpoti M. Gunn ◽

Anthony R. Buda ◽

Heather E. Preisendanz ◽

Raj Cibin ◽

Casey D. Kennedy ◽

...

Keyword(s):

Climate Change ◽

Stomatal Conductance ◽

Water Balance ◽

Hydrologic Model ◽

Future Climate ◽

Atmospheric Co2 ◽

Variable Source ◽

Source Areas ◽

Co2 Concentrations ◽

Creek Watershed

HighlightsWe used SWAT-VSA to assess the effects of climate change with rising CO2 on the water balance of a karst basin.For future climate, SWAT-VSA with rising CO2 yielded 7.1% less ET and 6.3% more runoff than standard SWAT-VSA.Rising CO2 also affected variable source areas, with greater ET declines and runoff increases in the wettest soils.Findings suggest CO2 effects on water balance should be included in future climate change studies with SWAT-VSA.Abstract. Characterizing the effects of climate change on hydrology is important to watershed management. In this study, we used SWAT-VSA to examine the effects of climate change and increasing atmospheric CO2 (CO2) on the water balance of Spring Creek watershed, a mixed land-use karst basin in the Upper Chesapeake Bay watershed. First, we modified the stomatal conductance and leaf area index (LAI) routines of SWAT-VSA’s Penman-Monteith evapotranspiration (ET) procedure and enabled the model to accept daily CO2 data. Using downscaled climate projections from nine global climate models (GCMs), we then compared water balance estimations from baseline SWAT-VSA against two modified versions of SWAT-VSA. One SWAT-VSA version integrated daily CO2 levels (SWAT-VSA_CO2), while another version added flexible stomatal conductance and LAI routines (SWAT-VSA_CO2+Plant) to the dynamic CO2 capacity. Under current climate (1985-2015), the three SWAT-VSA models produced generally similar water balance estimations, with 51% of precipitation lost to ET and the remainder converted to runoff (10%), lateral flow (9%), and percolate (30%). For future climate (2020-2065), water balance simulations diverged between baseline SWAT-VSA and the two modified SWAT-VSA models with CO2. Notably, variable stomatal conductance and LAI routines produced no detectable effects beyond that of CO2. For the 2020-2065 period, baseline SWAT-VSA projected ET increases of 0.7 mm year-1, while SWAT-VSA models with CO2 suggested that annual ET could decline by approximately -0.4 mm year-1 over the same period. As a result, the two CO2-based SWAT-VSA models predicted streamflow increases of almost 1.6 mm year-1 over the 2020-2065 period, which were roughly double the streamflow increases projected by baseline SWAT-VSA. In general, SWAT-VSA models with CO2 effects produced 22.4% more streamflow in 2045-2065 than the SWAT-VSA model without CO2. Results also showed that adding daily CO2 to SWAT-VSA reduced ET in wetter parts of Spring Creek watershed, leading to greater runoff losses from variable source areas compared to baseline SWAT-VSA. Findings from the study highlight the importance of considering increasing atmospheric CO2 concentrations in water balance simulations with SWAT-VSA in order to gain a fuller appreciation of the hydrologic uncertainties with climate change. Keywords: Carbon dioxide, Climate change, Hydrologic model, Water balance, Watershed.

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Identifying uncertainties in simulated streamflow from hydrologic model components for climate change impact assessments

10.5194/hess-2019-328 ◽

2019 ◽

Author(s):

Dongmei Feng ◽

Edward Beighley

Keyword(s):

Climate Change ◽

General Circulation ◽

Bayesian Model Averaging ◽

Hydrologic Model ◽

Process Models ◽

Runoff Generation ◽

Modeling Framework ◽

Total Uncertainty ◽

Physically Based ◽

Model Components

Abstract. Assessing the impacts of climate change on hydrologic systems is critical for developing adaptation and mitigation strategies for water resource management, risk control and ecosystem conservation practices. Such assessments are commonly accomplished using outputs from a hydrologic model forced with future precipitation and temperature projections. The algorithms used in the hydrologic model components (e.g., runoff generation) can introduce significant uncertainties in the simulated hydrologic variables, yet the identification and quantification of such uncertainties is rarely studied. Here, a modeling framework is developed that integrates multiple runoff generation algorithms with a routing model and associated parameter optimizations. This framework is able to identify uncertainties from both hydrologic model components and climate forcings as well as associated parameterization. Three fundamentally different runoff generation approaches: runoff coefficient method (RCM, conceptual), variable infiltration capacity (VIC, physically-based, infiltration excess) and simple-TOPMODEL (STP, physically-based, saturation excess), are coupled with Hillslope River Routing model to simulate streamflow. A case study conducted in Santa Barbara County, California, reveals that the median changes are 1–10 % increases in mean annual discharge (Qm) and 10–40 % increases in annual maximum daily discharge (Qp) and 100-yr flood discharge (Q100). The Bayesian Model Averaging analysis indicates that the probability of increase in streamflow can be up to 85 %. However, the simulated discharge uncertainties are large (i.e., 230 % for Qm and 330 % for Qp and Q100) with general circulation models (GCMs) and emission scenarios accounting for more than half of the total uncertainty. Hydrologic process models contribute 10–30 % of the total uncertainty, while uncertainty due to hydrologic model parameterization is almost negligible (

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Integrating remote sensing-derived evapotranspiration and ground-monitored discharge data for the improvement of hydrological modelling: A case study of the Sekong River Basin

10.22541/au.161294477.77976146/v1 ◽

2021 ◽

Author(s):

Raksmey Ang ◽

S. Shrestha ◽

Salvatore Virdis ◽

Saurav KC

Keyword(s):

Remote Sensing ◽

Model Calibration ◽

Hydrological Model ◽

Hydrologic Model ◽

Physically Based Model ◽

Physically Based ◽

Streamflow Data ◽

The Impact ◽

Streamflow Simulation ◽

Calibration Approach

This study analyses the efficiency of integrating remotely sensed evapotranspiration into the process of hydrological model calibration. A joint calibration approach, employing both remote sensing-derived evapotranspiration and ground-monitored streamflow data was compared with a conventional ground-monitored streamflow calibration approach through physically-based hydrological, Soil and Water Assessment Tool (SWAT) model setups. The efficacy of the two calibration schemes was investigated in two modelling setups: 1) a physically-based model with only the outlet gauge available for calibration, and 2) a physically-based model with multiple gauges available for calibration. Joint calibration was found to enhance the skill of hydrological models in streamflow simulation compared to ground-monitored streamflow-only calibration at the unsaturated zone in the upstream area, where essential information on evapotranspiration is also required. Additionally, the use of remote sensing-derived evapotranspiration can significantly improve high flow compared to low flow simulation. A more consistent model performance improvement, obtained from using remote sensing-derived evapotranspiration data was found at gauged sites not used in the calibration, due to additional information on spatial evapotranspiration in internal locations being enhanced into a process-based model. Eventually, satellite-based evapotranspiration with fine resolution was found to be competent for calibrating and validating the hydrological model for streamflow simulation in the absence of measured streamflow data for model calibration. Furthermore, the impact of using evapotranspiration for hydrologic model calibration tended to be stronger at the upstream and tributary sub-basins than at downstream sub-basins.

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Development of a Distributed Hydrologic Model for a Region with Fragipan Soils to Study Impacts of Climate on Soil Moisture: A Case Study on the Obion River Watershed in West Tennessee

Geosciences ◽

10.3390/geosciences8100364 ◽

2018 ◽

Vol 8 (10) ◽

pp. 364

Author(s):

Seyed Ghaneeizad ◽

Athanasios Papanicolaou ◽

Benjamin Abban ◽

Christopher Wilson ◽

Christos Giannopoulos ◽

...

Keyword(s):

Soil Moisture ◽

Land Surface ◽

Model Performance ◽

Hydrologic Model ◽

Infiltration Capacity ◽

River Watershed ◽

Saturation Zone ◽

Variable Infiltration Capacity Model ◽

Capacity Model ◽

Physically Based

Previous land surface modeling efforts to predict and understand water budgets in the U.S. Southeast for soil water management have struggled to characterize parts of the region due to an extensive presence of fragipan soils for which current calibration approaches are not adept at handling. This study presents a physically based approach for calibrating fragipan-dominated regions based on the “effective” soil moisture capacity concept, which accounts for the dynamic perched saturation zone effects created by the low hydraulic capacities of the fragipan layers. The approach is applied to the Variable Infiltration Capacity model to develop a hydrologic model of the Obion River Watershed (ORW), TN, which has extensive fragipan coverage. Model calibration was performed using observed streamflow data, as well as evapotranspiration and soil moisture data, to ensure correct partitioning of surface and subsurface fluxes. Estimated Nash-Sutcliffe coefficients for the various sub-drainage areas within ORW were all greater than 0.65, indicating good model performance. The model results suggest that ORW has a high responsivity and high resilience. Despite forecasted temperature increases, the simulation results suggest that water budget trends in the ORW are unlikely to change significantly in the near future up to 2050 due to sufficient precipitation amounts.

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Application of a Distributed Hydrologic Model to the November 17, 2004, Flood of Bull Creek Watershed, Austin, Texas

Journal of Hydrologic Engineering ◽

10.1061/(asce)he.1943-5584.0000228 ◽

2010 ◽

Vol 15 (8) ◽

pp. 651-657 ◽

Cited By ~ 34

Author(s):

Hatim O. Sharif ◽

Leon Sparks ◽

Almoutaz A. Hassan ◽

Jon Zeitler ◽

Hongjie Xie

Keyword(s):

Hydrologic Model ◽

Distributed Hydrologic Model ◽

Creek Watershed ◽

Bull Creek

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What drives the decline in groundwater table? A story of Edendale in New Zealand

10.5194/egusphere-egu2020-12050 ◽

2020 ◽

Author(s):

Jing Yang ◽

Channa Rajanayaka ◽

Lawrence Kees

Keyword(s):

New Zealand ◽

Statistical Method ◽

Land Surface ◽

Water Allocation ◽

Hydrologic Model ◽

Groundwater Table ◽

Groundwater Model ◽

Groundwater Abstraction ◽

The Past ◽

Physically Based

The Edendale terrace aquifer in Southland New Zealand has experienced a declining trend of groundwater table over the past two decades. Water abstraction has increased over this time and is associated with farming development, intensification and increased production of local industry. Coincident with an increase of groundwater abstraction is a decrease in annual precipitation. Current granted water allocation is ~55% of the allowable limit of 15% of land surface recharge. Determining the main driver of the declining groundwater table is a first step to improving the sustainability of water use in this area.In this study, we combined a statistical method and physically based modelling method to analyse the main driving force. In the statistical method, the relationship between precipitation, groundwater abstract, and groundwater table over the past two decades have been analysed and the contributions from decreasing precipitation and increasing groundwater abstract were quantified. In the physically based method, a groundwater model (MODFLOW) was coupled with a hydrologic model (TopNet) to simulate the groundwater flow, and scenarios of groundwater abstract and precipitation were assessed using this coupled hydrologic model and groundwater model.The modelling result above is used for sustainable water allocation management by the regional government, and this methodology can be used for groundwater management in other regions with declining groundwater table.

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