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48 results on '"Douglass, Scott L."'

1. Highways in the coastal environment

Author

Douglass, Scott L.

Subjects
Handbooks and manuals., Highway engineering -- Handbooks, manuals, etc. -- Environmental aspects -- United States, Road drainage -- Handbooks, manuals, etc. -- United States, Hydraulic engineering -- Handbooks, manuals, etc. -- United States, Coastal engineering -- Handbooks, manuals, etc. -- United States, Roads -- Handbooks, manuals, etc. -- Environmental aspects -- United States, Coastal engineering., Highway engineering -- Environmental aspects., Hydraulic engineering., Road drainage.
Published
2020

5. Prediction of wind waves in a shallow estuary

Author

Chen, Qin, Zhao, Haihong, Hu, Kelin, and Douglass, Scott L.

Subjects
Wave propagation -- Research, Estuaries -- Research, Engineering and manufacturing industries, Science and technology
Abstract

In comparison with wave modeling on an open coast, the complex geometry and bathymetry of estuaries, the unsteady conditions associated with estuarine circulation generated by tides and winds, and the relatively inadequate field data present a unique challenge. This study utilizes an unsteady, curvilinear spectral wave model that has the flexibility to resolve large geometric and bathymetric gradients and allows for consideration of unsteady forcing and currents to predict wind waves in Mobile Bay, Alabama. First, a laboratory data set on wave transformation over a circular shoal is chosen to test the curvilinear wave model. Excellent agreement is found between the numerical results and the laboratory measurements with a directional wave input and fine spatial resolution. Second, a three-dimensional circulation model is used to predict the varying current field and water levels that serve as the input to the wave model. The predictions of the wave model under unsteady forcing and ambient currents are then compared with the existing field measurement of wind waves in Mobile Bay. Numerical experiments are carried out to examine the effects of estuarine circulation and grid resolution on the model result. The study shows that the technique of linking a spectral wave model to a hydrodynamic model on curvilinear grids is an effective tool for wave prediction in estuaries. CE Database subject headings: Water circulation; Estuaries; Wave generation; Wind waves; Numerical models; Water levels.

Published
2005

6. Review and comparison of methods for estimating irregular wave overtopping rates

Author

Douglass, Scott L., Coastal Engineering Research Center (U.S.), Waterways Experiment Station (U.S.), United States. Army. Corps of Engineers, MBLWHOI Library, Douglass, Scott L., Coastal Engineering Research Center (U.S.), Waterways Experiment Station (U.S.), and United States. Army. Corps of Engineers

Subjects
Hydrodynamics, Ocean waves, Offshore structures

8. Estimating landward migration of nearshore constructed sand mounds

Author

Douglass, Scott L.

Subjects
Ocean waves -- Research, Soil erosion -- Research, Engineering and manufacturing industries, Science and technology
Abstract

A model for the migration of submerged mounds constructed offshore of the day-to-day surf zone but within the depths disturbed by waves during storm events is developed. The model considers net shoreward sand transport due to the velocity asymmetry of finite-amplitude waves, and is based on Bagnold's bed-load - sand transport equation with Stokes' second-order wave theory. Conservation of sand considerations lead to an equation that indicates mounds will behave according to a nonlinear convection-diffusion model. The 'convection coefficient -like parameter, which is based on the wave and sand-transport models only, is proposed as an estimate of the migration rate for submerged mounds. The expected value of mound movement in different depths can be estimated with site-specific wave-climate data. The full sediment-transport equations successfully simulate the migration of a mound at Silver Strand State Park, California, in 1989. The expected value of the mound-movement parameter gives results that agree reasonably well with measured migration rates both at Silver Strand and offshore of Mobile, Alabama.

Published
1995

9. Estimating extreme values of run-up on beaches

Author

Douglass, Scott L.

Subjects
Hydrodynamics -- Research, Coastal engineering -- Research, Engineering and manufacturing industries, Science and technology
Abstract

Run-up effects on beaches have little correlation with run-up effects on structures. Run-up defines the zone of wave action and can be used to set coastal setback lines, design man-made beaches, model beach and dune erosion, set management policies regarding creation of dune fields and predict flooding due to overtopping. In defining the extreme values of run-up on beaches, the beach slope term should be omitted from the calculation.

Published
1992

15. Coast Guards

Author

Webb, Bret M., primary, Douglass, Scott L., additional, Dixon, Caren R., additional, and Buhring, Beau, additional

Published
2011
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17. Preliminary Evaluation of Critical Wave Energy Thresholds at Natural and Created Coastal Wetlands

Author

ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS, Shafer, Deborah J., Roland, Rebecca, Douglass, Scott L., ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS, Shafer, Deborah J., Roland, Rebecca, and Douglass, Scott L.

Abstract

This technical note presents an evaluation of the wave climate at eight natural and created coastal wetland sites in an effort to identify the existence of critical wave energy thresholds for long-term marsh stability. This information could be used to help determine the minimum degree of protective structures necessary for successful establishment of created or restored coastal wetlands. Davis and Streever (1999) noted that some structures designed to protect dredged material wetlands may be overbuilt. If adequate protection could be provided by smaller, lower elevation structures, increased wetland functionality could be achieved at a considerable cost savings.

Published
2003

20. Estimating Runup on Beaches: A Review of the State of the Art

Author

Douglass, Scott L. and University of South Alabama. Department of Civil Engineering.

Subjects
Mathematical models, Shore protection, Beaches, Numerical models, Coastal changes, Shorelines, Ingenieurwissenschaften (620), Ocean waves, Coastal engineering, Wave runup
Abstract

Source: https://erdc-library.erdc.dren.mil/jspui/ The literature on estimating extreme values of runup on beaches is reviewed. The few available models for estimating beach runup agree with each other and the available data. However, the models are of limited engineering usefulness. Also, the available data are significantly limited. The use of Hunt's Equation to scale beach run up should be carefully examined. Future research on beach run up is recommended and the importance of the engineering applications of such research is outlined. The extreme beach runup data set of R. A. Holman is published in Appendix B.

Published
1990

27. Impact of Near-Bottom Currents on Dredged Material Mounds Near Mobile Bay.

Author

ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS, Douglass, Scott L., Resio, Donald T., Hands, Edward B., ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS, Douglass, Scott L., Resio, Donald T., and Hands, Edward B.

Abstract

The Corps' Dredging Research Program (DRP) and the U.S. Army Engineer District, Mobile (CESAM) have continued monitoring dredged material deposits (berms) and environmental factors at the NBDP site. Repeated bathymetric surveys have documented gradual loss of material from the crests of two shallower sand berms. For 4 years, these berms remained as distinct forms, but migrated persistently north northwest, toward the coast. Surface wave buoys and bottom-mounted gauges recorded wave and current forces over this 4-year period. Instrument stations were maintained offshore, just seaward, and on top of the berms. This is the first report using measured waves and currents to investigate how large berms move. Several fundamental berm movement mechanisms are proposed and evaluated against the Alabama field measurements. The collected data are sufficient to reject some concepts of sediment movement that were previously relied on. The data suggest that two other proposed mechanisms are important. These findings help focus work on new mechanisms to better understand and predict long-term, large-scale sediment movement in open coastal environments.

Published
1995

32. Prediction of Storm Surges and Wind Waves on Coastal Highways in Hurricane-Prone Areas.

Author

Qin Chen, Lixia Wang, Haihong Zhao, and Douglass, Scott L.

Subjects
STORM surges, FLOODS, ROADS, HYDROLOGIC models, WATER waves, SPATIO-temporal variation, HURRICANE protection, HAZARD mitigation, HURRICANE Georges, 1998
Abstract

A recent study reveals that more than 60,000 miles (>96,500 km) of coastal roadways are in the 100-year floodplain in the United States and vulnerable to the attacks of water surges and storm waves generated by hurricanes. Mitigating the effects of coastal flooding requires accurate predictions of the destructive hydrodynamic forces. This study demonstrates a methodology for integrating state-of-the-art storm surge and wave prediction models as an effective tool for engineering design of coastal infrastructure and facilitation of hurricane emergency management. The methodology has the capability of resolving complex geometry and topography typical of coastal road flooding. The surge model incorporates moving shoreline conditions associated with flooding and allows for nonlinear interactions among astronomical tide, storm surge, and wave setup. The wave model takes into account the unsteadiness of wind forcing, currents, and water levels. A historical hurricane event is simulated for the landfall of Hurricane Georges (1998) on the north coast of the Gulf of Mexico. Good agreement between the modeled and measured surge hydrographs in Mobile Bay, Alabama, has been found. The advanced surge model (ADCIRC), coupled with the wave model, successfully simulates the inundation and measured high water marks along two highways adjacent to the bay. The third- generation wind wave model (SWAN) coupled with the hydrodynamic model reveals the temporal and spatial variability of wave heights and wave periods in the Mobile Bay estuary and on the flooded highways. Numerical experiments were carried out to examine the response of the estuary to various forcing agents, including the offshore surge hydrograph, local wind forcing, and wave thrust. [ABSTRACT FROM AUTHOR]

Published
2007
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34. Prediction of Wind Waves in a Shallow Estuary.

Author

Qin Chen, Haihong Zhao, Hu, Kelin, and Douglass, Scott L.

Subjects
ESTUARIES, WATER levels, COASTS, RIVERS, COASTAL ecology
Abstract

In comparison with wave modeling on an open coast, the complex geometry and bathymetry of estuaries, the unsteady conditions associated with estuarine circulation generated by tides and winds, and the relatively inadequate field data present a unique challenge. This study utilizes an unsteady, curvilinear spectral wave model that has the flexibility to resolve large geometric and bathymetric gradients and allows for consideration of unsteady forcing and currents to predict wind waves in Mobile Bay, Alabama. First, a laboratory data set on wave transformation over a circular shoal is chosen to test the curvilinear wave model. Excellent agreement is found between the numerical results and the laboratory measurements with a directional wave input and fine spatial resolution. Second, a three-dimensional circulation model is used to predict the varying current field and water levels that serve as the input to the wave model. The predictions of the wave model under unsteady forcing and ambient currents are then compared with the existing field measurement of wind waves in Mobile Bay. Numerical experiments are carried out to examine the effects of estuarine circulation and grid resolution on the model result. The study shows that the technique of linking a spectral wave model to a hydrodynamic model on curvilinear grids is an effective tool for wave prediction in estuaries. [ABSTRACT FROM AUTHOR]

Published
2005
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35. Sand‐Bypassing Simulation Using Synthetic Longshore Transport Data

Author

Weggel, J. Richard, Douglass, Scott L., and Tunnell, John E.

Abstract

Longshore‐sand transport rates in the vicinity of Indian River Inlet, Delaware are calculated from the Corps of Engineers' Wave Information Study (WIS) wave hindcast data. The longshore transport rate data are divided into two populations, northward and southward transport, and each described statistically with a log‐normal probability distribution. Monthly values for the mean and variance of each of the two log‐normal distributions are then established and a scheme to synthetically generate daily longshore transport rates is developed using the probability distributions and information on how frequently transport was either northward or southward. The synthetic data are used to simulate the operation of a sand bypassing system proposed for Indian River Inlet. Various pumping rates and operating constraints are investigated. For example, the total volume of sand that could be bypassed when system operation was limited to weekdays and the system was shut down during January and February, and again in July and August, has been determined. The effect of varying the system's storage capacity (the potential quantity of sand within reach of the system's intake) is also studied.

Published
1988

36. Review and Comparison of Methods for Estimating Irregular Wave Overtopping Rates

Author

Douglass, Scott L.

Subjects
Irregular waves, Coastal structures, Wave overtopping, Coastal flooding, Ingenieurwissenschaften (620), Hydrodynamics, Ocean waves, Seawalls, Offshore structures, Overtopping, Wave runup
Abstract

Source: https://erdc-library.erdc.dren.mil/jspui/ Methods for estimating the volume rate of wave overtopping by irregular seas are reviewed. Four methods are discussed in detail: Shore Protection Manual (SPM 1984), Goda (1971), Battjes (1974), and Owen (1980). Each method is discussed adequately for engineering use, and an example using each method is given. The assumptions made in each method's derivation and the importance of these assumptions are discussed also. Since the four methods were derived for different situations, the methods' ranges of applicability are summarized. The different methods yield results which can vary by more than an order-of-magnitude. For vertical seawalls, the SPM method estimates more overtopping than Goda's method except in very shallow water. For steeply sloped structures, the SPM method estimates less overtopping than Owen's method. For mildly sloped structures, the SPM method estimates less overtopping than Battjes' method except for very low relative freeboards. Published irregular-wave overtopping data are briefly reviewed and shown to be inadequate for evaluating the available methods. Until better data are available, estimates from these methods should be considered to be within a factor-of-three , and more conservatively, an order-of-magnitude of the actual overtopping rate.

Published
1986

37. Coastal Response to Navigation Structures at Murrells Inlet, South Carolina

Author

Douglass, Scott L.

Subjects
Murrells Inlet (S.C.), Ingenieurwissenschaften (620), Offshore structures, Hydrodynamics, Sediment transport, Coast changes, South Carolina, Murrells Inlet (S.C.)
Abstract

Source: https://erdc-library.erdc.dren.mil/jspui/ Coastal response to navigation structures at Murrells Inlet, S. C., is documented herein. Data, which result from a postconstruction monitoring program, consist of beach, inlet, and jetty surveys, aerial photography, visual wave observations, wave buoy results, hindcast wave results, and site inspection trips. These data were collected during the period 1978-1982, approximately 5 years after jetty construction began. Beach change and wave data col.lected indicate that net longshore sand transport at the inlet has not been strongly to the south as previously assumed. The variability of longshore sand transport rate in time and space appears to be very important to coastal response to the jetties. Longshore transport rates are calculated from visual wave observations for 1979-1982. The direction of net transport was northward at all four wave data locations in 1979 and was toward the inlet from both sides during 1980-1982. The only wave data south of the inlet was close enough to be strongly affected by the jetties; therefore, a local reversal in net transport direction could have occurred south of the inlet during 1980-1982. Analysis of hindcast wave data for 1956-1975 indicates that the major southerly growth of the tip of Garden City in the early 1960's may have been in response to an unusually strong period of southerly sand transport. Possible modifications to the navigation project are suggested for further consideration and analysis. Improvements in the Murrells Inlet monitoring data collection program are recommended in light of the conclusions reached in this report.

Published
1987

38. Coastal Response to Navigation Structures at Murrells Inlet, South Carolina. Appendixes C thru H.

Author

COASTAL ENGINEERING RESEARCH CENTER VICKSBURG MS, Douglass,Scott L., COASTAL ENGINEERING RESEARCH CENTER VICKSBURG MS, and Douglass,Scott L.

Abstract

Appendix C: Summaries of Littoral Environment Observations (LEO) with Longshore Sand Transport Analysis, 1979 to 1982 -- Leo data collected as part of the Murrells Inlet monitoring program are summarized. Monthly and yearly statistics are presented for the following four LEO stations: (a) Sta 48271, Surfside Holiday Inn, S. C. (Tables C1-C5); (b) Sta 48270, Kingfisher Pier, S. C. (Tables C6-C10); (c) Sta 48272, Gulf Stream, S. C. (Tables C11-15); (d) Sta 48254, Huntington Beach, S. C. (Tables C16-C20)., See also Main Report and Appendixes A and B, AD-A179 044.

Published
1987

39. Coastal Response to Navigation Structures at Murrells Inlet, South Carolina. Main Text and Appendixes A and B.

Author

COASTAL ENGINEERING RESEARCH CENTER VICKSBURG MS, Douglass,Scott L., COASTAL ENGINEERING RESEARCH CENTER VICKSBURG MS, and Douglass,Scott L.

Abstract

Coastal response to navigation structures at Murrells Inlet, S. C., is documented herein. Data, which results from a postconstruction monitoring program, consist of beach, inlet, and jetty surveys, aerial photography, visual wave observations, wave buoy results, hindcast wave results, and site inspection trips. These data were collected during the period 1978-1982, approximately 5 years after jetty construction began. Beach change and wave data collected indicate that net longshore sand transport at the inlet has not been strongly to the south as previously assumed. The variability of longshore sand transport rate in time and space appears to be very important to coastal response to the jetties. Longshore transport rates are calculated from visual wave observations for 1979-1982. The direction of net transport was northward at all four wave data locations in 1979 and was toward the inlet from both sides during 1980-1982. The only wave data south of the inlet was close enough to be strongly affected by the jetties; therefore, a local reversal in net transport direction could have occurred south of the inlet during 1980-1982. Analysis of hindcast wave data for 1956-1975 indicates that the major southerly growth of the tip of Garden City in the early 1960's may have been in response to an unusually strong period of southerly sand transport. Possible modifications to the navigation project are suggested for further consideration and analysis. Improvements in the Murrells Inlet monitoring data collection program are recommended in light of the conclusions reached in this report. (Author), See also Appendixes C thru H, AD-A179 045.

Published
1987

40. Review and Comparison of Methods for Estimating Irregular Wave Overtopping Rates.

Author

COASTAL ENGINEERING RESEARCH CENTER VICKSBURG MS, Douglass,Scott L, COASTAL ENGINEERING RESEARCH CENTER VICKSBURG MS, and Douglass,Scott L

Abstract

Methods for estimating the volume rate of wave overtopping by irregular seas are reviewed. Four methods are discussed in detail: Shore Protection Manual (SPM 1984), Goda (1971), Battjes (1974), and Owen (1980). Each method is discussed adequately for engineering use, and an example using each method is given. The assumptions made in each method's derivation and the importance of these assumptions are discussed also. Since the four methods were derived for different situations, the methods' ranges of applicability are summarized. The different methods yield results which can vary by more than an order-of-magnitude. For vertical seawalls, the SPM method estimates more overtopping than Goda's method except in very shallow water. For steeply sloped structures, the SPM method estimates less overtopping than Owen's method. For mildly structures, the SPM method estimates less overtopping than Battjes' method except for very low relative freeboards. Published irregular-wave overtopping data are briefly reviewed and shown to be inadequate for evaluating the available methods. Until better data are available, estimates from these methods should be considered to be within a factor-of-three, and more conservatively, an order-of-magnitude of the actural overtopping rate.

Published
1986

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