Integrated Hydrology Model Research Articles

Comparison of IHM and MIKE SHE Model Performance for Modeling Hydrologic Dynamics in Shallow Water Table Settings

Modeling hydrologic dynamics behavior in shallow water table settings provides unique challenges for integrated hydrologic models. The Integrated Hydrologic Model (IHM), a comprehensive distributed‐parameter model, was developed based on deterministic and physically based soil and vegetative properties. In the paper, the IHM was compared with the popular MIKE SHE model in the study of a shallow water table site in west‐central Florida. The theoretical basis and integration pathways of IHM are discussed. The models were compared in terms of their performance in predicting streamflow and water table depth. Performance was evaluated using the coefficient of determination (R2) and the Nash–Sutcliffe efficiency (Ens). The P factor and R factor were used as uncertainty statistics, comparing observed data with the 95% prediction band. Both models performed reasonably well and reliably in predicting monthly water table depth and streamflow, with acceptable R2 values (0.49–0.86) and Ens values (0.41–0.78) over a 3‐yr period. Overall, MIKE SHE was the more robust model, producing slightly better streamflow predictions than IHM. However, there was no major difference in the ability of the models to predict depth of the water table, using existing parameter sets. The generalized likelihood uncertainty estimation (GLUE) was used to quantify parameter sensitivity and the uncertainty of predictions made by the IHM and MIKE SHE models. A sensitivity analysis (SA) was conducted in the form of Sobol's method with first‐ and second‐order sensitivity indices, based on the Ens values for the two models. Pair‐wise correlations between parameters as well as uncertainties associated with equifinality in model parameter estimation were also explored. It is concluded that both models performed adequately after calibration, and parameter identification in both was subject to considerable uncertainties.

Effects of Land Use and Climate Change on Groundwater and Ecosystems at the Middle Reaches of the Tarim River Using the MIKE SHE Integrated Hydrological Model

The Tarim basin is a unique ecosystem. The water from the Tarim River supports both wildlife and humans. To analyze the effects of both land use and climate changes on groundwater, a research site was established at Yingibazar, which is a river oasis along the middle section of the Tarim River. A hydrological survey was performed to assess the general water cycle in this area with special emphasis on groundwater replenishment as well as the impact of agricultural irrigation on the riparian natural vegetation with respect to salt transport and depth of groundwater. Although high-resolution input data is scarce for this region, simulation of water cycle processes was performed using the hydrological model MIKE SHE (DHI). The results of the calibrated model show that natural flooding is the major contributor to groundwater recharge. There is also a close interaction between irrigated agricultural areas and the adjacent natural vegetation for groundwater levels and salinity up to 300 m away from the fields. Furthermore, the source of water used for irrigation (i.e., river and/or groundwater) has a high impact on groundwater levels and salt transportation efficiency. The ongoing expansion of agricultural areas is rapidly destroying natural vegetation, floodplains, and their natural flow paths. Our results show that more unstable annual Tarim floods will occur in the future under the background of climate change. Therefore, integrated hydrological simulations were also performed for 2050 and 2100 using MIKE SHE. The results confirm that after the glaciers melt in the Tian Shan Mountains, serious aquifer depletion and environmental degradation will occur in the area, causing great difficulties for the local people.

Impact of earthquake-induced-landslides on hydrologic response of a steep mountainous catchment: a case study of the Wenchuan earthquake zone

Earthquake-induced-landslides will change the underlying surface conditions (topography, vegetation cover rate, etc.), which consequently may influence the hydrologic response and then change the flash flood risk. The Jianpinggou catchment, located in the Wenchuan earthquake (occurred in Sichuan, China, 2008) affected area, is selected as the study area. The distribution of the landslides is obtained from the remote sensing image data. The changes of topography are obtained from the comparisons among digital elevation models (DEMs) during different periods. A physical-based model, the integrated hydrology model (InHM), is used to simulate the hydrologic response before and after the landslide. The influence of the underlying surface conditions is then discussed based on the simulation results. The results reveal that landslides cause significant effects on the hydrologic response, and the impact is proportional to the proportion of surface flow in the total runoff. The effect of landslides on the runoff is insignificant at the outlet, but obvious in the local area. The larger the rainfall, the more visible the impact, and the impact of landslides will increase rapidly at the threshold of the runoff (the total rainfall of 235 mm in 6 h in the study area), but there is a limit with the further enlarged rainfall. The improved understanding of the impact of landslides on the hydrologic response provides valuable theoretical support for storm flood forecasting.

Automating data-model workflows at a level 12 HUC scale: Watershed modeling in a distributed computing environment

The prototype discussed in this article retrieves Essential Terrestrial Variable (ETV) web services and uses data-model workflows to transform ETV data for hydrological models in a distributed computing environment. The ETV workflow is a service layer to 100's of terabytes of national datasets bundled for fast data access in support of watershed modeling using the United States Geological Survey (USGS) Hydrological Unit Code (HUC) level-12 scale. The ETV data has been proposed as the Essential Terrestrial Data necessary to construct watershed models anywhere in the continental USA (Leonard and Duffy, 2013). Here, we present the hardware and software system designs to support the ETV, data-model, and model workflows using High Performance Computing (HPC) and service-oriented architecture.This infrastructure design is an important contribution to both how and where the workflows operate. We describe details of how these workflow services operate in a distributed manner for modeling CONUS HUC-12 catchments using the Penn State Integrated Hydrological Model (PIHM) as an example. The prototype is evaluated by generating data-model workflows for every CONUS HUC-12 and creating a repository of workflow provenance for every HUC-12 (∼100 km2) for use by researchers as a strategy to begin a new hydrological model study. The concept of provenance for data-model workflows developed here assures reproducibility of model simulations (e.g. reanalysis) from ETV datasets without storing model results which we have shown will require many petabytes of storage.

Surface–groundwater interactions in hard rocks in Sardon Catchment of western Spain: An integrated modeling approach

Summary The structural and hydrological complexity of hard rock systems (HRSs) affects dynamics of surface–groundwater interactions. These complexities are not well described or understood by hydrogeologists because simplified analyses typically are used to study HRSs. A transient, integrated hydrologic model (IHM) GSFLOW (Groundwater and Surface water FLOW) was calibrated and post-audited using 18 years of daily groundwater head and stream discharge data to evaluate the surface–groundwater interactions in semi-arid, ∼80 km 2 granitic Sardon hilly catchment in Spain characterized by shallow water table conditions, relatively low storage, dense drainage networks and frequent, high intensity rainfall. The following hydrological observations for the Sardon Catchment, and more generally for HRSs were made: (i) significant bi-directional vertical flows occur between surface water and groundwater throughout the HRSs; (ii) relatively large groundwater recharge represents 16% of precipitation ( P , 562 mm . y −1 ) and large groundwater exfiltration (∼11% of P ) results in short groundwater flow paths due to a dense network of streams, low permeability and hilly topographic relief; deep, long groundwater flow paths constitute a smaller component of the water budget (∼1% of P ); quite high groundwater evapotranspiration (∼5% of P and ∼7% of total evapotranspiration); low permeability and shallow soils are the main reasons for relatively large components of Hortonian flow and interflow (15% and 11% of P , respectively); (iii) the majority of drainage from the catchment leaves as surface water; (iv) declining 18 years trend (4.44 mm . y −1 ) of groundwater storage; and (v) large spatio-temporal variability of water fluxes. This IHM study of HRSs provides greater understanding of these relatively unknown hydrologic systems that are widespread throughout the world and are important for water resources in many regions.

Certification Tests of MODFLOW Implementation in the Integrated Hydrologic Model

AbstractMODFLOW is a three-dimensional finite-difference groundwater flow model. IHM (integrated hydrologic model) is a recent integrated model developed to simulate the interaction between surface water and groundwater, which formally couples HSPF and MODFLOW. The purpose of this research was to define a set of comparisons between IHM-MODFLOW96 (IHM-MF96) and standard MODFLOW96 (MF96) to certify that IHM-MF96 is acceptable to use with the IHM. The certification tests were necessary to determine whether model runs with modifications to the source code of MF-96, contained in the source code of IHM-MF96, would alter the head or flux results when compared to model runs with the standard source code. The tests were conducted over a range of problem sets, which are anticipated to cover the range of hydrogeologic conditions and anticipated applications for which IHM will be used in westcentral Florida. The tests results showed the MF96 implementation in IHM appears to produce virtually the same results as the s...

A physics-based hydro-geomorphologic simulation utilizing cluster parallel computing

To conduct a large-scale hydrologic-response and landform evolution simulation at high resolution, a complex physics-based numerical model, the Integrated Hydrology Model (InHM), was revised utilizing cluster parallel computing. The parallelized InHM (ParInHM) divides the simulated area into multiple catchments based on geomorphologic features, and generates boundary-value problems for each catchment to construct simulation tasks, which are then dispatched to different computers to start the simulation. Landform evolution is considered during simulating and implemention in one framework. The dynamical Longest-Processing-Time (LPT) first scheduling algorithm is applied to job management. In addition, a pause-integrate- divide-resume routine method is used to ensure the hydrologic validity during the simulation period. The routine repeats until the entire simulation period is finished. ParInHM has been tested in a computer cluster that uses 16 processors for the calculation, to simulate 100 years’ hydrologic-response and soil erosion for the 117-km2 Kaho’olawe Island in the Hawaiian Islands under two different mesh resolutions. The efficiency of ParInHM was evaluated by comparing the performance of the cluster system utilizing different numbers of processors, as well as the performance of non-parallelized system without domain decomposition. The results of this study show that it is feasible to conduct a regional-scale hydrologic-response and sediment transport simulation at high resolution without demanding significant computing resources.

Hydrologic-response simulations for the North Fork of Caspar Creek: second-growth, clear-cut, new-growth, and cumulative watershed effect scenarios

This study demonstrates that comprehensive hydrologic-response simulation can be a useful tool for studying cumulative watershed effects. The simulations reported here were conducted with the Integrated Hydrology Model (InHM). The location of the 473 ha study site is the North Fork of the Caspar Creek Experimental Watershed, near Fort Bragg, California. Existing information from a long-term monitoring programme and new soil-hydraulic property measurements made for this study were used to parameterize InHM. Long-term continuous wet-season simulations were conducted for the North Fork catchments and main stem for second-growth, clear-cut and new-growth scenarios. The simulation results show that the increases and decreases, respectively, for throughfall and potential evapotranspiration related to clear-cutting had quantifiable impacts on the simulated hydrologic response at both the catchment and watershed scales. Model performance was best for the new-growth simulation scenarios. To improve upon the simulations reported here would require additional soil-hydraulic property information from across the study area. Although principally focused on the integrated hydrologic response, the effort reported here demonstrates the potential for characterizing distributed responses with physics-based simulation. The search for a comprehensive understanding of hydrologic response will require both data-intensive discovery and concept-development simulation, from both integrated and distributed perspectives. Copyright © 2013 John Wiley & Sons, Ltd.

Physically-based approach to analyze rainfall-triggered landslide using hydraulic gradient as slide direction

An infinite slope stability numerical model driven by the comprehensive physically-based integrated hydrology model (InHM) is presented. In this approach, the failure plane is assumed to be parallel to the hydraulic gradient instead of the slope surface. The method helps with irregularities in complex terrain since depressions and flat areas are allowed in the model. The present model has been tested for two synthetic single slopes and a small catchment in the Mettman Ridge study area in Oregon, United States, to estimate the shallow landslide susceptibility. The results show that the present approach can reduce the simulation error of hydrological factors caused by the rolling topography and depressions, and is capable of estimating spatial-temporal variations for landslide susceptibilities at simple slopes as well as at catchment scale, providing a valuable tool for the prediction of shallow landslides.

Discretization approach in integrated Hydrologic Model for surface and groundwater interaction

The commonly used discretization approaches for distributed hydrological models can be broadly categorized into four types, based on the nature of the discrete components: Regular Mesh, Triangular Irregular Networks (TINs), Representative Elementary Watershed (REWs) and Hydrologic Response Units (HRUs). In this paper, a new discretization approach for landforms that have similar hydrologic properties is developed and discussed here for the Integrated Hydrologic Model (IHM), a combining simulation of surface and groundwater processes, accounting for the interaction between the systems. The approach used in the IHM is to disaggregate basin parameters into discrete landforms that have similar hydrologic properties. These landforms may be impervious areas, related areas, areas with high or low clay or organic fractions, areas with significantly different depths-to-water-table, and areas with different types of land cover or different land uses. Incorporating discrete landforms within basins allows significant distributed parameter analysis, but requires an efficient computational structure. The IHM integration represents a new approach interpreting fluxes across the model interface and storages near the interface for transfer to the appropriate model component, accounting for the disparate discretization while rigidly maintaining mass conservation. The discretization approaches employed in IHM will provide some ideas and insights which are helpful to those researchers who have been working on the integrated models for surface-groundwater interaction.

A synthetic hydrologic‐response dataset

AbstractSynthetic data have long been employed in hydrology for model development and testing. The objective of this study was to generate a synthetic dataset of hydrologic response with higher spatial and temporal resolution than could presently be obtained in the field, spanning a longer period than the typical duration of monitoring campaigns in experimental catchments. The synthetic dataset was generated for a rangeland catchment with the Integrated Hydrology Model (InHM), and is presented for future use by the community. The InHM boundary‐value problem is based upon the previously reported hypothetical reality of Tarrawarra‐like hydrologic response. Whereas the emphasis in developing the hypothetical reality was on parameterising InHM to reproduce observations from the Tarrawarra catchment, the emphasis in generating the synthetic dataset is on developing an internally valid hydrologic‐response dataset that extends well beyond the period of observations at Tarrawarra. The synthetic dataset spans 11 years of continuous forcing and response data (e.g. integrated response, distributed fluxes, state variable dynamics). The dataset should be useful for a wide range of problems including evaluation of simple rainfall runoff modelling techniques, design of measurement networks, development of data‐assimilation algorithms, and studies on information theory. The dataset is available at: ftp://pangea.stanford.edu/pub/loague/. Copyright © 2011 John Wiley & Sons, Ltd.

Hydrologic‐response‐driven sediment transport at a regional scale, process‐based simulation

AbstractAssessing hydrologically driven erosion at regional scales from a process‐based perspective presents a significant challenge. Most regional‐scale erosion assessments are based upon a simple steady‐state hydrology foundation. For this study, the sediment transport version of the physics‐based Integrated Hydrology Model (InHM), excited by synthetically generated rainfall, was employed to assess long‐term hydrologically driven erosion for a regional‐scale island boundary‐value problem. The spatiotemporal dynamics of runoff generation, erosion, and deposition are illustrated through saturation, water depth, velocity, and sediment concentration results. The simulations demonstrate that process‐based assessment for concept development is both feasible and tractable at regional spatial and human time scales. Copyright © 2011 John Wiley & Sons, Ltd.

Numerical modeling of shallow water table behavior with Lisse effect

Air entrapment is an important consideration in environments with shallow water tables and sandy soil, like the condition of highly conductive sandy soils and flat topography in Florida, USA. It causes water table rises in soils, which are significantly faster and higher than those in soils without air entrapment. Two numerical models, Integrated Hydrologic Model (IHM) and HYDRUS-1D (a single-phase, one-dimensional Richards’ equation model) were tested at an area of west central Florida to help further understanding the shallow water table behavior during a long term air entrapment. This investigation employed field data with two modeling approaches to quantify the variation of air pressurization values. It was found that the air pressurization effect was responsible at time up to 40 cm of water table rise being recorded by the observation well for these two models. The values of air pressurization calculated from IHM and HYDRUS-1D match the previously published values. Results also indicated that the two numerical models did not consider air entrapment effect (as the predictive parameters remain uncertain) and thus results of depth to water table from these models did not compare to the observations for these selected periods. Incorporating air entrapment in prediction models is critical to reproduce shallow water table observations.

Modeling Evapotranspiration of Two Land Covers Using Integrated Hydrologic Model

Modeling evapotranspiration (ET) distribution in shallow water table environments is of great importance for understanding and reproducing other hydrologic fluxes such as runoff and recharge. Unfortunately, ET distribution can be the most difficult hydrologic process to analyze. The partitioning of ET into upper zone ET, lower zone ET, and groundwater ET is complex because it depends on land cover and subsurface characteristics. One comprehensive distributed parameter model, integrated hydrologic model (IHM), builds on an improved understanding and characterization of ET partitioning between surface storages, vadose zone storage, and saturated groundwater storage. It provides a smooth transition to satisfy ET demand between the vadose zone and the deeper saturated groundwater. In this paper, the IHM was used to analyze ET contribution from different regions of the vadose zone and saturated zone. Rigorous testing was done on two distinct land covers, grass land and forest land, at a study site in West-Cent...

Using simulated hydrologic response to revisit the 1973 Lerida Court landslide

Hydrologically driven mass wasting in the form of landslides on steep slopes is a worldwide occurrence. High-profile events in, for example, Brazil, Chile, the Philippines, Puerto Rico, and Venezuela during the last three decades all clearly illustrate, based upon significant losses of life and property, that hydrologically driven slope instability in developed (urban) areas can be a major geologic/environmental hazard. The focus of this study is the 1973 hydrologically driven Lerida Court landslide in Portola Valley, CA, USA. Physics-based hydrologic-response simulation, with the comprehensive Integrated Hydrology Model, was employed to forensically estimate the spatiotemporal pore pressure distributions for the Lerida Court site. Slope stability, driven by the simulated pore pressure dynamics, was estimated for the Lerida Court site with the infinite slope/Factor of Safety approach. The pore pressure dynamics for the Lerida Court site were reasonably captured by the hydrologic-response simulation. The estimated time of slope failure for the Lerida Court site compares well with field observations. A recommendation is made that hydrologically driven slope stability estimates including variably saturated subsurface flow be standard protocol for development sites in steep urban settings.

First‐order exchange coefficient coupling for simulating surface water–groundwater interactions: parameter sensitivity and consistency with a physics‐based approach

AbstractDistributed hydrologic models capable of simulating fully‐coupled surface water and groundwater flow are increasingly used to examine problems in the hydrologic sciences. Several techniques are currently available to couple the surface and subsurface; the two most frequently employed approaches are first‐order exchange coefficients (a.k.a., the surface conductance method) and enforced continuity of pressure and flux at the surface‐subsurface boundary condition. The effort reported here examines the parameter sensitivity of simulated hydrologic response for the first‐order exchange coefficients at a well‐characterized field site using the fully coupled Integrated Hydrology Model (InHM). This investigation demonstrates that the first‐order exchange coefficients can be selected such that the simulated hydrologic response is insensitive to the parameter choice, while simulation time is considerably reduced. Alternatively, the ability to choose a first‐order exchange coefficient that intentionally decouples the surface and subsurface facilitates concept‐development simulations to examine real‐world situations where the surface‐subsurface exchange is impaired. While the parameters comprising the first‐order exchange coefficient cannot be directly estimated or measured, the insensitivity of the simulated flow system to these parameters (when chosen appropriately) combined with the ability to mimic actual physical processes suggests that the first‐order exchange coefficient approach can be consistent with a physics‐based framework. Copyright © 2009 John Wiley & Sons, Ltd.

Modelling vadose zone moisture dynamics in shallow water table settings with the Integrated Hydrologic Model: field-scale testing and application

Reproducing the moisture retention behaviour of the vadose zone in shallow water table settings, especially for the near-surface water table aquifer of the Florida coastal plain, provides unique challenges for integrated hydrological models. A comprehensive distributed parameter model, the Integrated Hydrologic Model (IHM), is developed based on deterministic and physically based soil and vegetative properties. The theory and vertical behaviour of IHM is examined through comparisons with data collected at a study site in west-central Florida. The objectives of this exploration are to test a model of the vertical processes controlling water table behaviour, and to also investigate model parameter effects and offer recommendations for improvements and parameterization for regional model application. Rigorous testing is performed to better understand the robustness and/or the limitations of the methodology of the IHM for vadose zones. Simulation results indicate that IHM is capable of providing reasonable predictions of infiltration, depth to water table (DTWT) elevation response, evapotranspiration (ET) distributions from the upper, lower soil and water table while incorporating field-scale variability of soil and land cover properties.

A hypothetical reality of Tarrawarra‐like hydrologic response

AbstractThe objective of this work was to develop a hypothetical reality of hydrologic response to be used as an error‐free synthetic dataset in a larger ongoing study. The hypothetical reality was generated via rigorous simulation of a real system with a comprehensive physics‐based model. The simulation was conducted with the Integrated Hydrology Model (InHM); the system is the Tarrawarra catchment located in southeastern Australia. Parameterization of the Tarrawarra boundary‐value problem was based on the best available information, which, for example includes rainfall, discharge, and soil‐water content data for the last six months of 1996. The InHM‐simulated near‐surface hydrologic response for the Tarrawarra boundary‐value problem compares well (albeit not perfectly) with both the integrated and distributed observations from the catchment. The Tarrawarra‐like hypothetical reality of wet season hydrologic response generated in this study is rich enough to be employed as an error‐free synthetic dataset for quantitatively evaluating the capabilities/limitations of competing (underlying) modelling techniques. Copyright © 2009 John Wiley & Sons, Ltd.

A dam problem: simulated upstream impacts for a Searsville‐like watershed

AbstractThe integrated hydrology model (InHM), a physics‐based hydrologic‐response model with sediment‐transport capabilities, was used to simulate upstream impacts from dam construction/removal for a generalized approximation of the Searsville watershed in Portola Valley, California. Four 10‐year simulation scenarios (pre‐dam, early dam, current and post‐dam) were considered. Each scenario was simulated using the same sequence of synthetically generated rainfall and evapotranspiration. For each scenario the boundary‐value problem was constructed based on the available watershed information (e.g. topography, soils, geology, reservoir bathymetry and land use). The results from the simulations are presented in terms of the temporal and spatial characteristics of hydrologic response and sediment transport. The commonalities/differences between the four Searsville‐like watershed scenarios are discussed. The effort demonstrates that heuristic physics‐based simulation can be a useful tool for the characterization of dam‐related impacts at the watershed scale. Copyright © 2008 John Wiley & Sons, Ltd.

Physics‐based continuous simulation of long‐term near‐surface hydrologic response for the Coos Bay experimental catchment

The study reported here employed the physics‐based Integrated Hydrology Model (InHM) to conduct continuous hydrologic‐response simulation from 1990 through 1996 for the Coos Bay experimental catchment. The uniqueness of the boundary‐value problem used to simulate three sprinkling experiments was assessed, via model performance evaluation against observed piezometric and discharge data, for 33 events extracted from the continuous record. The InHM simulations could not adequately reproduce the distributed observed pore water pressures, suggesting that detailed characterization of the locations and connectivities of bedrock fractures is critical for future efforts designed to simulate distributed hydrologic response at the field scale for locations where bedrock fracture flow is important. The simulations presented here suggest the potential for interaction between the deeper water table and near‐surface hydrologic response. The results reported herein suggest that while uniqueness can be reasonably achieved with respect to the integrated response (i.e., discharge), the integrated response uniqueness is no guarantee that the distributed response (i.e., pressure head) is either unique or well simulated.