Developing Guidelines for Two-Dimensional Model Review and Acceptance

Two independent modelers ran two hydraulic models, SRH-2D and HEC-RAS 2D. The models were applied to the Lakina River (MP 44 McCarthy Road) and to Quartz Creek (MP 0.7 Quartz Creek Road), which approximately represent straight and bend flow conditions, respectively. We compared the results, including water depth, depth averaged velocity, and bed shear stress, from the two models for both modelers. We found that the extent and density of survey data were insufficient for Quartz Creek. Neither model was calibrated due to the lack of basic field data (i.e., discharge, water surface elevation, and sediment characteristics). Consequently, we were unable to draw any conclusion about the accuracy of the models. Concerning the time step and the equations used (simplified or full) to solve the momentum equation in the HEC-RAS 2D model, we found that the minimum time step allowed by the model must be used if the diffusion wave equation is used in the simulations. A greater time step can be used if the full momentum equation is used in the simulations. We developed a set of guidelines for reviewing model results, and developed and provided a two-day training workshop on the two models for ADOT&PF hydraulic engineers

Monitoring Winter Flow Conditions on the Ivishak River, Alaska

The Sagavanirktok River, a braided river on the Alaska North Slope, flows adjacent to the trans-Alaska pipeline for approximately 100 miles south of Prudhoe Bay. During an unprecedented flooding event in mid-May 2015, the pipeline was exposed in an area located approximately 20 miles south of Prudhoe Bay. The Ivishak River is a main tributary of the Sagavanirktok River, but little is known about its water flow characteristics and contribution to the Sagavanirktok River, especially in winter and during spring breakup. To gather this information, we installed water level sensors on two main tributaries of the Ivishak River (Upper Ivishak and Saviukviayak rivers), early in winter season 2016–2017, in open-water channels that showed promise as locations for long-term gauging stations. Our ultimate goal was to find a location for permanent deployment of water level sensors. By February, the first sites chosen were ice covered, so two additional sensors, one on each river, were deployed in different locations. Some of the sensors were lost (i.e., carried away by the current or buried under a thick layer of sediments). Water level data gathered from the sensors showed a maximum change of 1.07 m. Winter discharge measurements indicate a 44% reduction between February and April 2017. A summer discharge measurement shows a 430% increase from winter to summer

Bibliography of Published Reports and Articles Related to Hydrological Research on the Sagavanirktok River

Researchers from the Water and Environmental Research Center (WERC), University of Alaska Fairbanks (UAF), are conducting a study of sediment transport conditions along the Sagavanirktok River. This document, as part of the study, provides a compilation of published literature related to the Sagavanirktok River (or adjacent watersheds with similar characteristics) including previous or ongoing hydrological and sedimentological research in the Sagavanirktok River basin. The literature referenced includes research on climate change, hydrology, sedimentology, permafrost and soils, meteorology, field data, satellite or aerial imagery, geophysics, modeling, water quality, and geochemistry in the Sagavanirktok River basin.Alaska Department of Transportation and Public Facilitie

Study to Compare the Performance of Two Designs to Prevent River Bend Erosion in Arctic Environments

INE/AUTC 10.0

Sagavanirktok River Particle Size Distributions

Acknowledgments........................................................................................................................... ii Disclaimer ....................................................................................................................................... ii List of Figures ........................................................................................................................................................ iii List of Tables .......................................................................................................................................................... iii introduction ............................................................................................................................................................ 1 Methods .................................................................................................................................................................... 1 Results .......................................................................................................................................................................

Depositional turbidity currents in diapiric minibasins on the continental slope: Formulation and theory

The northern continental slope of the Gulf of Mexico is riddled with numerous subsiding diapiric minibasins bounded by ridges, many but not all of which are connected by channels created by turbidity currents. The region is economically relevant in that many of these diapiric minibasins constitute focal points for the deposition of sand. Some of these sandy deposits in turn serve as excellent reservoirs for hydrocarbons. A better understanding of the "fill and spill" process by which minibasins fill with mud and sand as the intervening ridges are dissected by canyons may serve to aid in the location of such reservoirs. In the present paper a theory is developed to describe sediment deposition in minibasins. The theory relies on the hypotheses that the turbidity currents in question are sustained for at least about one hour. Two key and heretofore unrecognized aspects of the "fill and spill" process are revealed: (1) the formation of an internal hydraulic jump as a turbidity current spills into a confined basin, and (2) the detrainment of water across a settling interface forming at the top of the ponded turbidity current downstream of the hydraulic jump. It is shown that sufficiently strong detrainment can consume the flow, so that they is no outflow of either water or sediment even with continuous inflow. As the basin fills with sediment, however, overspill is eventually realized. The theory is developed into a numerical model, tested against experiments and applied at field scale in a companion paper

The Effects of Surface Debris Diversion Devices on River Hydrodynamic Conditions and Implications for In-Stream Hydrokinetic Development

Floating objects designed to divert woody debris—known as debris diversion devices—can protect hydrokinetic turbines deployed in rivers; they also change the hydrodynamic conditions of a river, at least locally. Modifications associated with velocity adjustments in both magnitude and direction would be expected. Thus, one could assume that extra macro-turbulent levels would be found immediately behind a device and downstream of that location. This article presents a set of cross-sectional and longitudinal velocity measurements carried out to quantify these effects. Results show important changes in the velocity components. In addition, significant changes in the vorticity field, calculated along cross-sectional profiles, demonstrate the role of a submerged chain used to maintain the debris diversion device in place. More importantly, findings suggest that hydrokinetic turbines should not be installed in a river’s central area behind a debris diversion device, due to the additional turbulence created by the submerged chain

Hydrologic Modeling of Three Sub-Basins in the Kenai River Watershed, Alaska, USA

Streams in the Kenai River watershed are characterized by a fish-rich environment. The commercial fishing industry and recreational users compete for the fish in these streams, and resource managers strive to balance both groups’ needs while maintaining the sustainability of the resource. The ability to estimate future river conditions could help preserve the resource and a strong economy on the Kenai Peninsula. This research used the U.S. Army Corps of Engineers Hydrological Modeling System, which transforms rainfall to river discharge. The main goal was to define a set of parameters that were calibrated using an event-based condition of concurrent rainfall and discharge data. The model was calibrated and validated in three sub-basins located in different environmental settings (i.e., lowlands, mid, and high elevation)

Initial Quantification of Suspended Sediment Loads for Three Alaska North Slope Rivers

This study provides an initial assessment of suspended sediment transport in three rivers on the Alaska North Slope. From 2011 to 2013, the Anaktuvuk (69°27′51.00′′ N, 151°10′07.00′′ W), Chandler (69°17′0.30′′ N, 151°24′16.14′′ W), and Itkillik (68°51′59.46′′ N, 150°2′24.00′′ W) Rivers were monitored for a variety of hydrologic, meteorologic, and sedimentologic characteristics. Watershed response to summer precipitation events was examined for each river. Bed sediment grain-size distribution was calculated using a photographic grid technique. Mean sediment diameters were 27.1 and 41.5 mm (Samples A and B) for the Chandler, 35.8 mm for the Anaktuvuk, and 65.0 mm for the Itkillik. Suspended sediment rating curves were developed for each river. Suspended sediment discharge was analyzed. In 2011 and 2013, most of the total annual suspended sediment transport occurred during spring melt and widespread rainfall events, respectively. The results show that each river reacts differently to environmental inputs such as rain and basin characteristics