Sediment Transport During Flood Event
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(P 117-140) Flood Pulse.Qxp
117 THE FLOOD PULSE CONCEPT: NEW ASPECTS, APPROACHES AND APPLICATIONS - AN UPDATE Junk W.J. Wantzen K.M. Max-Planck-Institute for Limnology, Working Group Tropical Ecology, P.O. Box 165, 24302 Plön, Germany E-mail: [email protected] ABSTRACT The flood pulse concept (FPC), published in 1989, was based on the scientific experience of the authors and published data worldwide. Since then, knowledge on floodplains has increased considerably, creating a large database for testing the predictions of the concept. The FPC has proved to be an integrative approach for studying highly diverse and complex ecological processes in river-floodplain systems; however, the concept has been modified, extended and restricted by several authors. Major advances have been achieved through detailed studies on the effects of hydrology and hydrochemistry, climate, paleoclimate, biogeography, biodi- versity and landscape ecology and also through wetland restoration and sustainable management of flood- plains in different latitudes and continents. Discussions on floodplain ecology and management are greatly influenced by data obtained on flow pulses and connectivity, the Riverine Productivity Model and the Multiple Use Concept. This paper summarizes the predictions of the FPC, evaluates their value in the light of recent data and new concepts and discusses further developments in floodplain theory. 118 The flood pulse concept: New aspects, INTRODUCTION plain, where production and degradation of organic matter also takes place. Rivers and floodplain wetlands are among the most threatened ecosystems. For example, 77 percent These characteristics are reflected for lakes in of the water discharge of the 139 largest river systems the “Seentypenlehre” (Lake typology), elaborated by in North America and Europe is affected by fragmen- Thienemann and Naumann between 1915 and 1935 tation of the river channels by dams and river regula- (e.g. -
Seasonal Flooding Affects Habitat and Landscape Dynamics of a Gravel
Seasonal flooding affects habitat and landscape dynamics of a gravel-bed river floodplain Katelyn P. Driscoll1,2,5 and F. Richard Hauer1,3,4,6 1Systems Ecology Graduate Program, University of Montana, Missoula, Montana 59812 USA 2Rocky Mountain Research Station, Albuquerque, New Mexico 87102 USA 3Flathead Lake Biological Station, University of Montana, Polson, Montana 59806 USA 4Montana Institute on Ecosystems, University of Montana, Missoula, Montana 59812 USA Abstract: Floodplains are comprised of aquatic and terrestrial habitats that are reshaped frequently by hydrologic processes that operate at multiple spatial and temporal scales. It is well established that hydrologic and geomorphic dynamics are the primary drivers of habitat change in river floodplains over extended time periods. However, the effect of fluctuating discharge on floodplain habitat structure during seasonal flooding is less well understood. We collected ultra-high resolution digital multispectral imagery of a gravel-bed river floodplain in western Montana on 6 dates during a typical seasonal flood pulse and used it to quantify changes in habitat abundance and diversity as- sociated with annual flooding. We observed significant changes in areal abundance of many habitat types, such as riffles, runs, shallow shorelines, and overbank flow. However, the relative abundance of some habitats, such as back- waters, springbrooks, pools, and ponds, changed very little. We also examined habitat transition patterns through- out the flood pulse. Few habitat transitions occurred in the main channel, which was dominated by riffle and run habitat. In contrast, in the near-channel, scoured habitats of the floodplain were dominated by cobble bars at low flows but transitioned to isolated flood channels at moderate discharge. -
River Dynamics 101 - Fact Sheet River Management Program Vermont Agency of Natural Resources
River Dynamics 101 - Fact Sheet River Management Program Vermont Agency of Natural Resources Overview In the discussion of river, or fluvial systems, and the strategies that may be used in the management of fluvial systems, it is important to have a basic understanding of the fundamental principals of how river systems work. This fact sheet will illustrate how sediment moves in the river, and the general response of the fluvial system when changes are imposed on or occur in the watershed, river channel, and the sediment supply. The Working River The complex river network that is an integral component of Vermont’s landscape is created as water flows from higher to lower elevations. There is an inherent supply of potential energy in the river systems created by the change in elevation between the beginning and ending points of the river or within any discrete stream reach. This potential energy is expressed in a variety of ways as the river moves through and shapes the landscape, developing a complex fluvial network, with a variety of channel and valley forms and associated aquatic and riparian habitats. Excess energy is dissipated in many ways: contact with vegetation along the banks, in turbulence at steps and riffles in the river profiles, in erosion at meander bends, in irregularities, or roughness of the channel bed and banks, and in sediment, ice and debris transport (Kondolf, 2002). Sediment Production, Transport, and Storage in the Working River Sediment production is influenced by many factors, including soil type, vegetation type and coverage, land use, climate, and weathering/erosion rates. -
Documentation and Analysis of Flash Flood Prone Streams and Subwatershed Basins in Pulaski County, Virginia
DOCUMENTATION AND ANALYSIS OF FLASH FLOOD PRONE STREAMS AND SUBWATERSHED BASINS IN PULASKI COUNTY, VIRGINIA Prepared by Anthony Phillips Department of Geography Virginia Polytechnic Institute & State University Report Distributed August 10, 2009 Prepared for National Oceanic and Atmospheric Administration - National Weather Service Blacksburg, Virginia & Office of the Emergency Manager Pulaski County, Virginia The research on which this report is based was financed by Virginia Tech through the McNair Scholars Summer Research Program. ABSTRACT Flash flooding is the number one weather-related killer in the United States. With so many deaths related to this type of severe weather, additional detailed information about local streams and creeks could help forecasters issue more accurate and precise warnings, which could help save lives. Using GIS software, streams within twenty-five feet of a roadway in Pulaski County, Virginia were identified and selected to be surveyed. Field work at each survey point involved taking measurements to determine the required stream level rise necessary to cause flooding along any nearby roadway(s). Additionally, digital pictures were taken to document the environment upstream and downstream at each survey point. This information has been color- coded, mapped, and overlaid in Google Earth for quick access on computers at the National Weather Service Office in Blacksburg, Virginia. It has also been compiled into an operational handbook and DVD for use at the NWS. iii ACKNOWLEDGMENTS The author would like to thank -
Flash Flood PREPAREDNESS
Flash Flood PREPAREDNESS Flash floods occur within a few minutes or Before a flood occurs. hours of excessive rainfall, a dam or levee failure or a sudden release of water held by an Find out if you live in a flood prone area. ice jam. Flash floods can roll boulders, tear out You can check with your local building trees, destroy buildings and bridges. Flash department to see the flood maps for your floods can also trigger catastrophic mudslides. municipality. Flash floods are the #1 weather related killer If you are in a flood zone - purchase in the United States. sufficient flood insurance. Flood losses are not covered under normal National Weather Service . homeowner’s insurance. Staying current with forecasts from the Learn how your community would alert you National Weather Service can be an important if a flood was occurring or predicted. part of flood preparedness. Individuals can purchase a NOAA weather radio to directly Pre-assemble flood-fighting supplies like hear the forecasts, advisories, watches and/or plastic sheeting, lumber, sandbags. warnings. Some NOAA weather radios can alarm when there is a serious/dangerous Have check valves installed in building weather condition. These radios are available sewer traps to prevent flood waters from at many stores. backing up in sewer drains. The following terms may be used by the As a last resort have large corks or National Weather service: stoppers to plug showers, tubs or basins from water rising up through the pipes. A Flash Flood or Flood Watch means that flash flooding or flooding is possible within the Maintain a disaster supply kit at home. -
Field Studies and 3D Modelling of Morphodynamics in a Meandering River Reach Dominated by Tides and Suspended Load
fluids Article Field Studies and 3D Modelling of Morphodynamics in a Meandering River Reach Dominated by Tides and Suspended Load Qiancheng Xie 1,* , James Yang 2,3 and T. Staffan Lundström 1 1 Division of Fluid and Experimental Mechanics, Luleå University of Technology, 97187 Luleå, Sweden; [email protected] 2 Vattenfall AB, Research and Development, Hydraulic Laboratory, 81426 Älvkarleby, Sweden; [email protected] 3 Resources, Energy and Infrastructure, Royal Institute of Technology, 10044 Stockholm, Sweden * Correspondence: [email protected]; Tel.: +4672-2870-381 Received: 9 December 2018; Accepted: 20 January 2019; Published: 22 January 2019 Abstract: Meandering is a common feature in natural alluvial streams. This study deals with alluvial behaviors of a meander reach subjected to both fresh-water flow and strong tides from the coast. Field measurements are carried out to obtain flow and sediment data. Approximately 95% of the sediment in the river is suspended load of silt and clay. The results indicate that, due to the tidal currents, the flow velocity and sediment concentration are always out of phase with each other. The cross-sectional asymmetry and bi-directional flow result in higher sediment concentration along inner banks than along outer banks of the main stream. For a given location, the near-bed concentration is 2−5 times the surface value. Based on Froude number, a sediment carrying capacity formula is derived for the flood and ebb tides. The tidal flow stirs the sediment and modifies its concentration and transport. A 3D hydrodynamic model of flow and suspended sediment transport is established to compute the flow patterns and morphology changes. -
Variable Hydrologic and Geomorphic Responses to Intentional Levee Breaches Along the Lower Cosumnes River, California
Received: 21 April 2016 Revised: 29 March 2017 Accepted: 30 March 2017 DOI: 10.1002/rra.3159 RESEARCH ARTICLE Not all breaks are equal: Variable hydrologic and geomorphic responses to intentional levee breaches along the lower Cosumnes River, California A. L. Nichols1 | J. H. Viers1,2 1 Center for Watershed Sciences, University of California, Davis, California, USA Abstract 2 School of Engineering, University of The transport of water and sediment from rivers to adjacent floodplains helps generate complex California, Merced, California, USA floodplain, wetland, and riparian ecosystems. However, riverside levees restrict lateral connectiv- Correspondence ity of water and sediment during flood pulses, making the re‐introduction of floodplain hydrogeo- A. L. Nichols, Center for Watershed Sciences, morphic processes through intentional levee breaching and removal an emerging floodplain University of California, Davis, California, USA. restoration practice. Repeated topographic observations from levee breach sites along the lower Email: [email protected] Cosumnes River (USA) indicated that breach architecture influences floodplain and channel hydrogeomorphic processes. Where narrow breaches (<75 m) open onto graded floodplains, Funding information California Department of Fish and Wildlife archetypal crevasse splays developed along a single dominant flowpath, with floodplain erosion (CDFW) Ecosystem Restoration Program in near‐bank areas and lobate splay deposition in distal floodplain regions. Narrow breaches (ERP), Grant/Award Number: E1120001; The opening into excavated floodplain channels promoted both transverse advection and turbulent Nature Concervancy (TNC); Consumnes River Preserve diffusion of sediment into the floodplain channel, facilitating near‐bank deposition and potential breach closure. Wide breaches (>250 m) enabled multiple modes of water and sediment transport onto graded floodplains. -
Bedload Transport and Large Organic Debris in Steep Mountain Streams in Forested Watersheds on the Olympic Penisula, Washington
77 TFW-SH7-94-001 Bedload Transport and Large Organic Debris in Steep Mountain Streams in Forested Watersheds on the Olympic Penisula, Washington Final Report By Matthew O’Connor and R. Dennis Harr October 1994 BEDLOAD TRANSPORT AND LARGE ORGANIC DEBRIS IN STEEP MOUNTAIN STREAMS IN FORESTED WATERSHEDS ON THE OLYMPIC PENINSULA, WASHINGTON FINAL REPORT Submitted by Matthew O’Connor College of Forest Resources, AR-10 University of Washington Seattle, WA 98195 and R. Dennis Harr Research Hydrologist USDA Forest Service Pacific Northwest Research Station and Professor, College of Forest Resources University of Washington Seattle, WA 98195 to Timber/Fish/Wildlife Sediment, Hydrology and Mass Wasting Steering Committee and State of Washington Department of Natural Resources October 31, 1994 TABLE OF CONTENTS LIST OF FIGURES iv LIST OF TABLES vi ACKNOWLEDGEMENTS vii OVERVIEW 1 INTRODUCTION 2 BACKGROUND 3 Sediment Routing in Low-Order Channels 3 Timber/Fish/Wildlife Literature Review of Sediment Dynamics in Low-order Streams 5 Conceptual Model of Bedload Routing 6 Effects of Timber Harvest on LOD Accumulation Rates 8 MONITORING SEDIMENT TRANSPORT IN LOW-ORDER CHANNELS 11 Monitoring Objectives 11 Field Sites for Monitoring Program 12 BEDLOAD TRANSPORT MODEL 16 Model Overview 16 Stochastic Model Outputs from Predictive Relationships 17 24-Hour Precipitation 17 Synthesis of Frequency of Threshold 24-Hour Precipitation 18 Peak Discharge as a Function of 24-Hour Precipitation 21 Excess Unit Stream Power as a Function of Peak Discharge 28 Mean Scour -
Severe Weather Safety Guide Flash Flooding
What causes River Flooding? Stay informed! • Persistent storms over the same area for long Listen to NOAA Weather Radio, local radio or Severe periods of time. television for the latest weather and river forecasts. • Combined rainfall and snowmelt • Ice jams Weather • Releases from man made lakes • Excessive rain from tropical systems making Safety landfall. How does the NWS issue To check out the latest river forecast information Guide and current stages on our area rivers, visit: Flood/Flash Flood Warnings? http://weather.gov/pah/ahps Flash Check out the National Weather Service Paducah website for the latest information at Flooding weather.gov/paducah Call for the latest forecast from the National Weather Service’s Weather Information Now number: Paducah, KY: 270-744-6331 Evansville, IN: 812-425-5549 National Weather Service forecasters rely on a A reference guide from your network of almost 10,000 gages to monitor the National Oceanic & Atmospheric Administration height of rivers and streams across the Nation. National Weather Service National Weather Service This gage data is only one of many different 8250 Kentucky Highway 3520 Paducah, Kentucky sources for data. Forecasters use data from the Doppler Radar, surface weather observations, West Paducah, KY 42086 snow melt/cover information and many other 270-744-6440 different data sources in order to monitor the threat for flooding. FLOODS KILL MORE PEOPLE FACT: Almost half of all flash flood Flooding PER YEAR THAN ANY OTHER fatalities occur in vehicles. WEATHER PHENOMENAN. fatalities occur in vehicles. Safety • As little as 6 inches of water may cause you to lose What are Flash Floods ? control of your vehicle. -
Biogeochemical and Metabolic Responses to the Flood Pulse in a Semi-Arid Floodplain
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by DigitalCommons@USU 1 Running Head: Semi-arid floodplain response to flood pulse 2 3 4 5 6 Biogeochemical and Metabolic Responses 7 to the Flood Pulse in a Semi-Arid Floodplain 8 9 10 11 with 7 Figures and 3 Tables 12 13 14 15 H. M. Valett1, M.A. Baker2, J.A. Morrice3, C.S. Crawford, 16 M.C. Molles, Jr., C.N. Dahm, D.L. Moyer4, J.R. Thibault, and Lisa M. Ellis 17 18 19 20 21 22 Department of Biology 23 University of New Mexico 24 Albuquerque, New Mexico 87131 USA 25 26 27 28 29 30 31 present addresses: 32 33 1Department of Biology 2Department of Biology 3U.S. EPA 34 Virginia Tech Utah State University Mid-Continent Ecology Division 35 Blacksburg, Virginia 24061 USA Logan, Utah 84322 USA Duluth, Minnesota 55804 USA 36 540-231-2065, 540-231-9307 fax 37 [email protected] 38 4Water Resources Division 39 United States Geological Survey 40 Richmond, Virginia 23228 USA 41 1 1 Abstract: Flood pulse inundation of riparian forests alters rates of nutrient retention and 2 organic matter processing in the aquatic ecosystems formed in the forest interior. Along the 3 Middle Rio Grande (New Mexico, USA), impoundment and levee construction have created 4 riparian forests that differ in their inter-flood intervals (IFIs) because some floodplains are 5 still regularly inundated by the flood pulse (i.e., connected), while other floodplains remain 6 isolated from flooding (i.e., disconnected). -
Stream Erosion
STREAM EROSION Erosion is an ongoing process on all bodies of water, especially moving water. Both natural and human- caused factors affect the amount of erosion a stream may experience. Natural factors include the gradient (or steepness) of the streambed since that affects the speed of the flow of water. Rainfall and snowmelt affect the amount of water in a stream as well as the speed of the flow. Human factors include run-off from farm fields and parking lots and water releases from dams that increase the amount of water flowing in streams. Removal of trees and shrubs from stream banks and deadfall from within the stream makes them more susceptible to erosion and increases stream flow. When there is too much erosion in a stream or on lands that drain into a stream, there is an increase in silting, a serious problem that affects our drinking water and the plants and creatures that live there. Serious problems are also caused by flash floods, when a river or stream is carrying a far greater than normal amount of water. Flash floods damage streams because they tear up stream banks and bottoms and move silt downstream and into lakes and ponds and slow spots in a stream. Causes of flash floods can be natural, human-made or a combination of both. Our experiments will examine three variables that affect water flow in a stream and test for their effect on erosion: slope (gradient) of the streambed, total amount of water flowing in a streambed (discharge), and pulses (spikes) in water. -
Classifying Rivers - Three Stages of River Development
Classifying Rivers - Three Stages of River Development River Characteristics - Sediment Transport - River Velocity - Terminology The illustrations below represent the 3 general classifications into which rivers are placed according to specific characteristics. These categories are: Youthful, Mature and Old Age. A Rejuvenated River, one with a gradient that is raised by the earth's movement, can be an old age river that returns to a Youthful State, and which repeats the cycle of stages once again. A brief overview of each stage of river development begins after the images. A list of pertinent vocabulary appears at the bottom of this document. You may wish to consult it so that you will be aware of terminology used in the descriptive text that follows. Characteristics found in the 3 Stages of River Development: L. Immoor 2006 Geoteach.com 1 Youthful River: Perhaps the most dynamic of all rivers is a Youthful River. Rafters seeking an exciting ride will surely gravitate towards a young river for their recreational thrills. Characteristically youthful rivers are found at higher elevations, in mountainous areas, where the slope of the land is steeper. Water that flows over such a landscape will flow very fast. Youthful rivers can be a tributary of a larger and older river, hundreds of miles away and, in fact, they may be close to the headwaters (the beginning) of that larger river. Upon observation of a Youthful River, here is what one might see: 1. The river flowing down a steep gradient (slope). 2. The channel is deeper than it is wide and V-shaped due to downcutting rather than lateral (side-to-side) erosion.