Time filter

Source Type

Portland, OR, United States

Leon A.S.,University of Houston | Goodell C.,WEST Consultants Inc.
Environmental Modelling and Software | Year: 2016

The U.S. Army Corps of Engineers' Hydrologic Engineering Center's River Analysis System (HEC-RAS) is a widely used software application for performing one-dimensional and two-dimensional steady and unsteady flow river hydraulics calculations, sediment transport-mobile bed modeling, and water quality analysis. User's of HEC-RAS have often unique applications including the coupling with other software to perform system analysis such as optimization of flooding structures and multi-objective reservoir operation under uncertainty. One state-of-the-art environment for integrating software is MATLAB, which integrates computation, visualization, and programming in an easy-to-use environment. This paper presents a set of MATLAB scripts to write input files, read output files, make plots, execute parallel computations, and perform fully-automated functions of HEC-RAS. Examples of procedures are presented throughout the paper and they are illustrated using a river-reservoir network that involves ten inline structures (e.g., dams) with operation of gates at each of these dams. © 2016 Elsevier Ltd

Teal M.J.,WEST Consultants Inc.
Dams and Reservoirs under Changing Challenges - Proceedings of the International Symposium on Dams and Reservoirs under Changing Challenges - 79 Annual Meeting of ICOLD, Swiss Committee on Dams | Year: 2011

General sedimentation issues of the Upper Missouri River reservoirs are examined, with special attention given to two of the reservoirs that have been studied by the author over the last decade: Lake Sharpe (impounded by Big Bend Dam) and Lewis and Clark Lake (impounded by Gavins Point Dam). Delta build-up has and continues to cause problems in both of these areas. Sediment yield (inflows) to the lakes, including major tributary contributions, was estimated via different methods and numerical sediment transport modeling was performed in which the models were calibrated based on the historical cross section data. Estimates were made of progression of the deltas into the lakes, and future effects on water surface profiles and groundwater elevations around and upstream of the reservoirs. © 2011 Taylor & Francis Group.

Fox J.F.,University of Kentucky | Davis C.M.,WEST Consultants Inc. | Martin D.K.,University of Kentucky
Journal of the American Water Resources Association | Year: 2010

Sediment sources and transported sediments were sampled in a lowland watershed with pronounced fine sediment storage in the streambed. Sediments were analyzed for carbon and nitrogen content and stable nitrogen isotopic composition. Analysis of the data shows that temporarily stored streambed sediments dominate the sediment load during moderate- and low-flow hydrologic events. Modeling of sediment transport and nitrogen elemental and isotopic mass balance was performed for the watershed for a 12-month time period using a continuous, conceptual-based model. The model results show that during moderate- and low-flow hydrologic events, the streambed is slowly downcutting. During very high-flow hydrologic events, deposition is pronounced in the streambed and sediment is replenished to the bed. Nitrogen model results show that elemental and isotopic nitrogen of streambed sediments vary substantially over the simulation period. In this manner, the streambed in a lowland watershed functions as a temporary storage zone that, in turn, can impact the nitrogen elemental and isotopic signature of sediments. The variation could significantly impact estimates of sediment provenance using nitrogen tracer-based methods. Future work should consider both hydrologic and biogeochemical control on the nitrogen isotopic signature of sediments in small lowland watersheds and streams where a significant portion of deposited fines are temporarily stored. © 2010 American Water Resources Association.

Wilson C.G.,University of Iowa | Papanicolaou A.N.T.,University of Iowa | Denn K.D.,University of Iowa | Denn K.D.,WEST Consultants Inc.
Journal of Soils and Sediments | Year: 2012

Purpose: This study was developed to improve understanding of the temporal variability of sediment delivery in a representative, intensively agricultural, headwater system of the U. S. Midwest by identifying the primary sediment source (i. e., uplands or channel banks) to the fine suspended sediment loads of three consecutive runoff events (with the third event being a flash flood) using naturally occurring radionuclides. Materials and methods: Suspended sediment concentrations (Cs) from discrete and continuous sampling techniques agreed well despite differences in operating principles. The total sediment flux (Qs) during each event was quantified over a 24-h period from the initiation of the rainfall using the following: (1) measured Cs and flow discharges (Qw); (2) individual Qw-Qs relationships for each event (herein called individual event relationships); and (3) a cumulative Qw-Qs rating curve. The radionuclide tracers, beryllium-7 (7Be) and excess lead-210 (210Pbxs), were used with a simple two end-member mixing model to differentiate eroded upland surface soils and channel-derived sediments in the suspended loads of each event. Results and discussion: Total load estimates from the measurement-based values and individual event relationships were similar, within 10 %, because they accounted for an observed non-linearity between Cs and Qw (i. e., a clockwise hysteresis) during the events. The sediment rating curve assumed a linear relationship between Cs and Qw and under-estimated the loads of the first two events while over-estimating the load of the flood event. The radionuclide partitioning quantified the proportion of eroded upland soils at 67 % for the first event, which was attributed to a "first flush" of readily available material from past events. For the subsequent and flood-event loads, 34 % and 21 % were respectively derived from the uplands, because less material was readily available for mobilization. Proportions are based on integrated samples for each event and are consistent with individual samples where available. During the flood event, stream bank mass failure was observed and bank erosion estimates from multiple methods compared favorably with the load results. Conclusions: The radionuclide analysis showed decreasing proportions of eroded upland soils in the loads of the three successive events that was supported by observed clockwise hysteresis from source material exhaustion. Decreasing slopes observed in successive hysteresis plots for the events suggested that less material was readily available for mobilization following the first event flushing. The results of this study can assist watershed planners in identifying erosion-prone areas and determining optimal management strategies for sediment control. © 2012 Springer-Verlag.

Goodell C.R.,WEST Consultants Inc.
World Environmental and Water Resources Congress 2014: Water Without Borders - Proceedings of the 2014 World Environmental and Water Resources Congress | Year: 2014

The Columbia River Gorge and the Scablands of Eastern Washington are just two of the incredibly stunning geologic features carved out by the great Missoula Floods of approximately 13,000 to 15,000 years ago. These floods of epic proportions were triggered by the "failure" of a massive glacial ice dam that impounded a lake about the same size as the present-day Great Slave Lake in Canada. The geologic history and the academic quest to identify the Missoula Floods as the cause of these features are discussed in this paper. Modern GIS tools and hydraulic modeling techniques make it possible to simulate the enormous floods that inundated areas from Eastern Montana to the Pacific Ocean. The results of the hydraulic modeling exercise are presented. © 2014 American Society of Civil Engineers.

Discover hidden collaborations