William H. McAnally

Analysis of Hydrological Processes Applying the HSPF Model in Selected Watersheds in Alabama, Mississippi, and Puerto Rico

The goal of this study was to evaluate the Hydrological Simulation Program – FORTRAN (HSPF) to gain more insight in the underlying causes and mechanisms of hydrological processes in an upland basin in Alabama and Mississippi (1,856-km2 Luxapallila Creek), a humid subtropical watershed in coastal Alabama (140-km2 Fish River), and a steep-slope tropical catchment in Puerto Rico (99-km2 Rio Caonillas). For each watershed model, rainfall, potential evapotranspiration, and streamflow time series from January 1999 to December 2000 were used to calibrate model parameters and 2001 time series were applied to verify model results. In each study area, actual evapotranspiration was the main mechanism of water loss followed by river discharge. Annual baseflow values ranged from 58% of total discharge in Luxapallila Creek basin to 84% of total discharge in Fish River watershed. In Luxapallila Creek and Fish River, interflow was the primary mechanism of direct runoff; however, surface runoff was the main process of direct runoff in Rio Caonillas. The HSPF model was successfully adapted to model daily streamflow processes in Luxapallila Creek basin and Rio Caonillas catchment with coefficient of determination and Nash and Sutcliffe coefficient values between 0.61 and 0.71 for the entire period; however, the Fish River watershed model performance was poor. The poor performance is likely due to the lack of rainfall time series available within the watershed boundaries. In general, this study showed the robustness of the HSPF model in extreme environments (small catchments vs. large basins, flat vs. hilly areas, low vs. moderate/high runoff potential, tropical marine vs. humid subtropical climates).

In-stream hydrokinetic power: Review and appraisal

AbstractThe objective of this paper is to provide a review of in-stream hydrokinetic power, which is defined as electric power generated by devices capturing the energy of naturally flowing water—stream, tidal, or open ocean flows—without impounding the water. North America has significant in-stream energy resources, and hydrokinetic electric power technologies to harness those resources have the potential to make a significant contribution to U.S. electricity needs by adding as much as 120  TWh/year from rivers alone to the present hydroelectric power generation capacity. Additionally, tidal and ocean current resources in the U.S. respectively contain 438  TWh/year and 163  TWh/year of extractable power. Among their attractive features, in-stream hydrokinetic operations do not contribute to greenhouse gas emissions or other air pollution and have less visual impact than wind turbines. Since these systems do no utilize dams the way traditional hydropower systems typically do, their impact on the environme...

IMPACTS OF LAND USE CHARACTERIZATION IN MODELING HYDROLOGY AND SEDIMENTS FOR THE LUXAPALLILA CREEK WATERSHED, ALABAMA AND MISSISSIPPI

The Hydrological Simulation Program - Fortran (HSPF), interfaced with the Better Assessment Science Integrating Point and Nonpoint (BASINS), was used to evaluate the impact of land use (as characterized by different land use/land cover (LU/LC) datasets) on hydrology and sediment components of the Luxapallila Creek watershed. The 1,770 km2 watershed is located in Alabama and Mississippi. Simulation of the watershed processes were tested at the hillslope and at the watershed outlet for the period between 1985 and 2003. Three LU/LC databases were used: the Geographic Information Retrieval and Analysis System (GIRAS), the Moderate Resolution Imaging Spectroradiometer land cover product (MODIS MOD12Q1), and the National Land Cover Dataset (NLCD). The two main land use categories revealed by the three LU/LC databases were forest and agricultural lands. Whereas forest cover mechanisms were the main source of water loss in hydrology simulation, agricultural land was the main source of sediment export in sediment modeling. Land use datasets of coarser spatial resolution (MODIS and GIRAS) produced larger HSPF estimations for sediment fraction values than land use datasets identifying smaller percentages of those agricultural land cover classes (NLCD). Differences in agricultural land characterization among the land use datasets showed that sediment predictions were more sensitive than streamflow predictions to the scale and resolution of land use datasets. Choosing the right land use dataset will impact the modeling of sediments and, potentially, other water quality constituents that are related with agricultural activities.

A Comparison of Bayesian Methods for Uncertainty Analysis in Hydraulic and Hydrodynamic Modeling

We evaluate and compare the performance of Bayesian Monte Carlo (BMC), Markov chain Monte Carlo (MCMC), and the Generalized Likelihood Uncertainty Estimation (GLUE) for uncertainty analysis in hydraulic and hydrodynamic modeling (HHM) studies. The methods are evaluated in a synthetic 1D wave routing exercise based on the diffusion wave model, and in a multidimensional hydrodynamic study based on the Environmental Fluid Dynamics Code to simulate estuarine circulation processes in Weeks Bay, Alabama. Results show that BMC and MCMC provide similar estimates of uncertainty. The posterior parameter densities computed by both methods are highly consistent, as well as the calibrated parameter estimates and uncertainty bounds. Although some studies suggest that MCMC is more efficient than BMC, our results did not show a clear difference between the performance of the two methods. This seems to be due to the low number of model parameters typically involved in HHM studies, and the use of the same likelihood function. In fact, for these studies, the implementation of BMC results simpler and provides similar results to MCMC. The results of GLUE are, on the other hand, less consistent to the results of BMC and MCMC in both applications. The posterior probability densities tend to be flat and similar to the uniform priors, which can result in calibrated parameter estimates centered in the parametric space.

A Hydrological Model of the Mobile River Watershed, Southeastern USA

A hydrological model of the Mobile Bay watershed located in the northern Gulf of Mexico, (Alabama, USA) is presented. The modeling of hydrological processes is performed using the Hydrological Simulation Program Fortran (HSPF). The project region was divided into two sectors for simplifying the modeling task: an upland watershed (that included streams not draining directly to the Mobile Estuary), and several watersheds of selected streams that drain directly to the Mobile estuary (namely: Fish River, Magnolia River, and Chickasaw Creek). The Better Assessment Science Integrating Point & Nonpoint Sources (BASINS) GIS system was used to perform most of the geospatial operations, although ArcGis and ArcInfo were also used to complement geospatial processing that was not available in BASINS.

Estimation and Propagation of Parameter Uncertainty in Lumped Hydrological Models: A Case Study of HSPF Model Applied to Luxapallila Creek Watershed in Southeast USA

Estimation and Propagation of Parameter Uncertainty in Lumped Hydrological Models: A Case Study of HSPF Model Applied to Luxapallila Creek Watershed in Southeast USA Explicit quantification of the uncertainty associated to the predictions of a hydrologic model is a necessary activity to objectively evaluate and report the limitations of the model caused by different sources of error. The current state of the practice of hydrologic modeling indicates that parametric uncertainty is considered as one of the most important sources of uncertainty. Some of the most relevant problems remaining in the practice include the identification of the principal parameters affecting model predictions and quantification of parameter ranges. This study evaluated stochastically one of the most popular deterministic watershed water quality models for decision making in USA.

Effects of Land-Use Changes on Saint Louis Bay Watershed Modeling

Abstract Saint Louis Bay Watershed is a coastal watershed located in southern Mississippi, which composes two basins: Jordan River Basin and Wolf River Basin. Two land use/land cover (LULC) datasets: the Geographic Information Retrieval and Analysis System (GIRAS) and the National Land Cover Data (NLCD) are applied on these two basins to simulate the hydrologic and water quality parameters by using the Hydrological Simulation Program - FORTRAN (HSPF) and the Better Assessment Science Integrating Point and Nonpoint Sources (BASINS). The difference of GIRAS dataset and NLCD dataset for the Saint Louis Bay represents the LULC change from 1977 to 1992. The area percentages of Forest Land and Urban or Built-up Land decrease for both these two basins. However, the area percentages of Wetlands and Barren Land increase. The Rate of Soil Erosion has a great increase in the area changing from other LULC classifications to Barren Land. As a result of the loss of vegetation and the aggravation of soil erosion, the Total Outflows of Sediments has a great increase, which deteriorates the water quality. However, other hydrologic and water quality parameters including Streamflow, Water Temperature, and Dissolved Oxygen, in contrast, result in insignificant changes.

Designing open water disposal for dredged muddy sediments

Abstract Open water disposal of muddy sediments in the estuarine environment is practiced to minimize dredging costs and to preserve contained disposal site capacity. Open water sites are usually either dispersive or retentive. Dispersive sites are used in the expectation that disposed sediments will not remain there, but will be transported out of the site, leaving room for additional disposal. Retentive sites are designed to ensure that disposed sediments mostly remain within the site. Choice of one of these approaches depends on the site character, sediment character, and disposal quantities. Design of disposal management plans for both site types is accomplished by use of field observations, laboratory tests, and numerical modeling. Three disposal site studies illustrate the methods used. At the Alcatraz site in San Francisco Bay, a dispersive condition is maintained by use of constraints on dredged mud characteristics that were developed from laboratory tests on erosion rates and from numerical modeling of the dump process. Field experiments were designed to evaluate the management procedure. In Corpus Christi Bay a numerical model was used to determine how much disposed sediment returns to the navigation channel, and to devise a location for disposal that will minimize that return. In Puget Sound a model has been used to ensure that most of the disposed material remains in the site. New techniques, including a piped disposal through 60 m of water, were investigated.

Using hydrodynamic modeling for estimating flooding and water depths in grand bay, alabama

This paper presents a methodology for using hydrodynamic modeling to estimate inundation areas and water depths during a hurricane event. The Environmental Fluid Dynamic Code (EFDC) is used in this research. EFDC is one of the most commonly applied models to Gulf of Mexico estuaries. The event with which the hydrodynamic model was tested was hurricane Ivan. This hurricane made landfall at the Alabama Gulf Coast in September 16, 2004. Hurricane Ivan was the most severe hurricane to hit eastern Alabama. Results show that the EFDC model is able to generate instances of flooded areas before, during and after a hurricane event (Ivan hurricane). The model also estimated water depths and water surface elevation values consistent to measured data reported in the literature, and comparable to model-estimated data from a meso-scale Slosh model for the region (also reported in the literature).

Hydrology and Sediment Modeling Using BASINS/HSPF in a Tropical Island Watershed

The Hydrological Simulation Program - FORTRAN (HSPF) in interface with Better Assessment Science Integrating Point and Nonpoint Sources (BASINS) v.3.0 was used to study hydrology, soil erosion, and sediment transport of the Rio Caonillas watershed in Puerto Rico. The HSPF model has been used widely since 1980; however, little is known about the models performance in tropical island watersheds that have extreme environmental conditions, such as rainfall intensity more than 25 mm h-1 and average soil slope of 38%. Three years (1999-2001) of continuous meteorological, flow, and suspended sediments data were used for model evaluation. The study found that the groundwater recession rate coefficient (AGWRC) was the most sensitive model parameter for both streamflow and sediment transport modeling. The calibrated model explained more than 85% of the monthly variability of streamflows and 70% of the monthly variability of suspended sediment concentrations. Agricultural and barren areas yielded the highest soil losses, contributing 55% and 20% of annual soil erosion, respectively. These results demonstrate that HSPF is capable of simulating hydrology and suspended sediment in the river for tropical island watersheds, principally for analysis on a monthly basis.