DOCSLIB.ORG

Flooding Dynamics in a Large Low-Gradient Alluvial Fan, the Okavango Delta, Botswana, from Analysis and Interpretation of a 30-Year Hydrometric Record

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Flooding Dynamics in a Large Low-Gradient Alluvial Fan, the Okavango Delta, Botswana, from Analysis and Interpretation of a 30-Year Hydrometric Record Hydrology and Earth System Sciences, 10, 127–137, 2006 www.copernicus.org/EGU/hess/hess/10/127/ Hydrology and SRef-ID: 1607-7938/hess/2006-10-127 Earth System European Geosciences Union Sciences Flooding dynamics in a large low-gradient alluvial fan, the Okavango Delta, Botswana, from analysis and interpretation of a 30-year hydrometric record P. Wolski and M. Murray-Hudson Harry Oppenheimer Okavango Research Centre, Maun, Botswana Received: 11 August 2005 – Published in Hydrology and Earth System Sciences Discussions: 6 September 2005 Revised: 29 November 2005 – Accepted: 3 January 2006 – Published: 21 February 2006 Abstract. The Okavango Delta is a flood-pulsed wetland, tem, and the flood frequency distribution itself can change, which supports a large tourism industry and the subsistence compared to that at upstream locations (Wolff and Burges, of the local population through the provision of ecosystem 1994). The ecological role of the channel-floodplain interac- services. In order to obtain insight into the influence of var- tion is expressed by the flood pulse concept (Junk et al., 1989; ious environmental factors on flood propagation and distri- Middleton, 1999). According to this concept, floodplain wet- bution in this system, an analysis was undertaken of a 30- lands and riparian ecosystems adjust to, and are maintained, year record of hydrometric data (discharges and water lev- by the pulsing of water, sediment and nutrients that occurs els) from one of the Delta distributaries. The analysis re- during over-bank flow conditions. Odum (1994) addition- vealed that water levels and discharges at any given channel ally identifies flood pulsing at various spatial and temporal site in this distributary are influenced by a complex interplay scales as an energy subsidy to wetland ecosystems, explain- of flood wave and local rainfall inputs, modified by channel- ing in part the high ecological productivity associated with floodplain interactions, in-channel sedimentation and techni- such systems. cal interventions, both at the given site and upstream. Ad- In the past, river management has been focused on control- ditionally, cyclical variation of channel vegetation due to in- ling rivers rather than managing them in sympathy with their termittent nutrient loading, possibly sustained by nutrient re- natural variability. This has often resulted in a considerable cycling, may play a role. It is shown that short and long- reduction in floodplain wetlands and loss of biodiversity and term flood dynamics are mainly due to variation in floodplain ecosystem services (Tockner and Stanford, 2002). More re- flows. As a consequence, discharge data collected within the cently, however, recognition of the role of flood pulsing and main channels of distributaries do not adequately represent the hydrological role of floodplains has led to the tendency to flooding dynamics in the system. The paper contributes to rehabilitate regulated rivers through the re-establishment of the understanding of seasonal and long-term flood pulsing natural channel-floodplain links, and their hydrological and and their variation in low gradient systems of channels and geomorphological dynamics. This recognition has also re- floodplains. sulted in a trend towards trying to maintain the natural dy- namics in undisturbed systems, in order to maintain ecosys- tem services such as effective flood mitigation (Middleton, 1 Introduction 1999). Flood dynamics in a channel-floodplain system can change due to exogenic processes such as climate change, The dynamics of flood propagation and inundation in a endogenic processes such as geomorphological evolution of channel-floodplain system constitute an important hydrolog- river channels and floodplains, and anthropogenic processes ical and ecological variable. Hydrologically, the interactions such as channelization, regulation, water diversion. Not all of channels with floodplains cause considerable variation in change is undesirable, however. Continuous and episodic al- flood levels, storage and conveyance capacity of the system. luvial processes such as the natural evolution of river chan- As a result, the flood wave is modified – often flattened and nels and flood-induced shifting of floodplain morphology delayed – while passing through a channel-floodplain sys- are recognized as important drivers of floodplain ecology. They cause habitat rejuvenation and thus maintain high habi- Correspondence to: P. Wolski tat diversity (Ellery and McCarthy, 1994; Hauer and Lo- ([email protected]) rang, 2004; Richards et al., 2002; van der Nat et al., 2003). © 2006 Author(s). This work is licensed under a Creative Commons License. 128 P. Wolski and M. Murray-Hudson: Flooding dynamics in Okavango Delta These processes can also maintain floodplain communities ural resources of which support an economically important at an early stage of succession, resulting in high productivity tourism industry and the subsistence livelihoods of the lo- (Odum, 1994). Thus, for the effective management of river cal population. In the last three decades a general decline corridors and floodplain wetlands, a thorough understanding of flooding extent occurred, with some parts of the system of the natural dynamics of channel-floodplain systems and of being affected more than others. So far, the system has not endogenic and exogenic changes occurring in these systems been subject to major human interventions, but technical al- is needed. terations such as channel clearing are being considered. Such The dynamics of floodplain flows and water levels and proposals are prompted by drying up of floodplains and de- their change are often difficult to ascertain. Hydrological ob- velopment of vegetation blockages in channels in the vicinity servation networks are generally focused on the in-channel of settlements and safari camps. Such actions are, due to their situation rather than the overbank one. Off-channel flows capacity to alter the natural hydrological and geomorpholog- can be measured directly with a current meter or by dye ical dynamics of the system, potentially harmful to the Delta techniques (e.g. Stern et al., 2001). Indirectly, they can be ecosystem functioning, and their technical results may not obtained by the slope-area method involving hydraulic cal- be sustainable. Understanding of the processes causing flood culations based on post-event high flood mark surveys or on decline and flooding shifts is thus essential for effective man- water levels measured with new airborne or space radar tech- agement of the natural resources associated with the Delta in niques (Alsdorf et al., 2000). Such measurements, however, general, and for making informed decisions about any pro- are usually campaign-based, not continuous, and thus are not posed technical interventions in particular. suitable for longer term change analyses. Usually, overbank In this paper we systematize and analyse hydrometric data flood discharges are obtained by comparison with continu- from channels in the eastern part of the Okavango Delta, ous measurements at upstream/downstream stations where where hydrological responses differ widely, suggesting that the total discharge is measurable (e.g. Wyzga, 1999) or by several processes are acting simultaneously to produce the extrapolation of a known in-bank stage-discharge curve to observed flooding conditions. We describe the processes overbank conditions (e.g. Chen and Chiu, 2004). However, causing the observed hydrological responses, and thus im- these techniques are not suitable in systems where there is prove the understanding of the hydrological functioning of lateral differentiation of flood dynamics, such as low gradi- the Okavango Delta system. In a broader context, using the ent rivers and river deltas. Such environments are character- example of the Okavango Delta we illustrate issues of flood- ized by very complex and variable water regimes, because a ing dynamics and change in the channel-floodplain network large proportion of total flow can occur as off-channel flow. of a low gradient broad system, as influenced by a combina- This may lead to the splitting of the flood wave into indepen- tion of endogenic and exogenic processes, and as modified dent flow paths of different dynamics. Additionally, the re- by hydraulic relationships between channels and floodplains. lationship between channel and floodplain flows varies with flood level, between systems, and within a system, depend- ing on the hydraulic connectivity of floodplains, and the na- 2 Study site ture of the channel-floodplain link. For example, in some systems floodplains carry increasingly more water with in- The main features of the Okavango Delta have been creased flood levels. Floodplain flow in such systems is es- described in detail elsewhere in the literature (e.g. sentially parallel to that of channel, and floodplain storage is Gieske, 1997; Gumbricht et al., 2004; McCarthy et al., 1998). much smaller than the flow volume. In other systems, flood- In brief, the Delta is a large alluvial fan with a mean surface plain storage effects dominate during larger floods, with little gradient of approximately 1:3700, in which water and sedi- floodplain flow in the longitudinal direction. Flow in these ment from the inflowing Okavango river are spread across a “storage” floodplains is mostly perpendicular to the channel convex conical surface through a complex system of chan- direction: away from the channel during the rising flood, nels and floodplains (Fig. 1). The upper part of the Delta, the increasing floodplain storage, and in towards the channel,
Load more

Recommended publications
  • (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.
    [Show full text]
  • Alluvial Fans in the Death Valley Region California and Nevada
    Alluvial Fans in the Death Valley Region California and Nevada GEOLOGICAL SURVEY PROFESSIONAL PAPER 466 Alluvial Fans in the Death Valley Region California and Nevada By CHARLES S. DENNY GEOLOGICAL SURVEY PROFESSIONAL PAPER 466 A survey and interpretation of some aspects of desert geomorphology UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1965 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director The U.S. Geological Survey Library has cataloged this publications as follows: Denny, Charles Storrow, 1911- Alluvial fans in the Death Valley region, California and Nevada. Washington, U.S. Govt. Print. Off., 1964. iv, 61 p. illus., maps (5 fold. col. in pocket) diagrs., profiles, tables. 30 cm. (U.S. Geological Survey. Professional Paper 466) Bibliography: p. 59. 1. Physical geography California Death Valley region. 2. Physi­ cal geography Nevada Death Valley region. 3. Sedimentation and deposition. 4. Alluvium. I. Title. II. Title: Death Valley region. (Series) For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C., 20402 CONTENTS Page Page Abstract.. _ ________________ 1 Shadow Mountain fan Continued Introduction. ______________ 2 Origin of the Shadow Mountain fan. 21 Method of study________ 2 Fan east of Alkali Flat- ___-__---.__-_- 25 Definitions and symbols. 6 Fans surrounding hills near Devils Hole_ 25 Geography _________________ 6 Bat Mountain fan___-____-___--___-__ 25 Shadow Mountain fan..______ 7 Fans east of Greenwater Range___ ______ 30 Geology.______________ 9 Fans in Greenwater Valley..-----_____. 32 Death Valley fans.__________--___-__- 32 Geomorpholo gy ______ 9 Characteristics of fans.._______-___-__- 38 Modern washes____.
    [Show full text]
  • Geomorphic Classification of Rivers
    9.36 Geomorphic Classification of Rivers JM Buffington, U.S. Forest Service, Boise, ID, USA DR Montgomery, University of Washington, Seattle, WA, USA Published by Elsevier Inc. 9.36.1 Introduction 730 9.36.2 Purpose of Classification 730 9.36.3 Types of Channel Classification 731 9.36.3.1 Stream Order 731 9.36.3.2 Process Domains 732 9.36.3.3 Channel Pattern 732 9.36.3.4 Channel–Floodplain Interactions 735 9.36.3.5 Bed Material and Mobility 737 9.36.3.6 Channel Units 739 9.36.3.7 Hierarchical Classifications 739 9.36.3.8 Statistical Classifications 745 9.36.4 Use and Compatibility of Channel Classifications 745 9.36.5 The Rise and Fall of Classifications: Why Are Some Channel Classifications More Used Than Others? 747 9.36.6 Future Needs and Directions 753 9.36.6.1 Standardization and Sample Size 753 9.36.6.2 Remote Sensing 754 9.36.7 Conclusion 755 Acknowledgements 756 References 756 Appendix 762 9.36.1 Introduction 9.36.2 Purpose of Classification Over the last several decades, environmental legislation and a A basic tenet in geomorphology is that ‘form implies process.’As growing awareness of historical human disturbance to rivers such, numerous geomorphic classifications have been de- worldwide (Schumm, 1977; Collins et al., 2003; Surian and veloped for landscapes (Davis, 1899), hillslopes (Varnes, 1958), Rinaldi, 2003; Nilsson et al., 2005; Chin, 2006; Walter and and rivers (Section 9.36.3). The form–process paradigm is a Merritts, 2008) have fostered unprecedented collaboration potentially powerful tool for conducting quantitative geo- among scientists, land managers, and stakeholders to better morphic investigations.
    [Show full text]
  • Characterization of Fuel Before and After a Single Prescribed Fire in an Appalachian Hardwood Forest • Elizabeth Bucks, Mary A
    Characterization of Fuel before and after a Single Prescribed Fire in an Appalachian Hardwood Forest • Elizabeth bucks, Mary A. Arthur, Jessi E. Lyons, and David L. Loftis Improved understanding of how fuel loads and prescribed fire interact in Appalachian hardwood forests can help managers evaluate the impacts of increased use of prescribed fire in the region. The objective of this study was to characterize fuel loads before and after a single late-winter/early spring prescribed fire and after autumn leaf fall. A repeated measures split-plot design was used to examine dead and down fuels by treatment, sampling time, and landscape position. Preburn mean fuel moss was 40.5 Mg/ha with the duff (Oea) comprising the largest component (19.5 Mg/ha; 48%), followed by large (more than 7.6 cm in diameter) downed lags (9.6 Mg/ha; 24%). Fuel mass was similar across landscape positions; however, duff depth was greater on subxeric compared with intermediate and submesic landscape positions. Burning reduced litter mass (0i; P < 0.00]) and duff depth (P = 0.01). Changes in woody fuels (1-, 10-, 100-, and 1,000-hour) and duff mass were not statistically significant. Post—leaf fall fuel masses did not differ from preburn masses. Thus, a single prescribed burn did not accomplish significant fuel reduction. However, significant declines in duff depth and fuel bed continuity may limit the spread of fire beyond leaf fall and increase potential for soil erosion. This study contributes to the dialogue regarding the use of fire in the Appalachian forest region and impacts on fuel loads.
    [Show full text]
  • 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.
    [Show full text]
  • Fan-Deltas and Braid Deltas: Varieties of Coarse-Grained Deltas
    Fan-deltas and braid deltas: Varieties of coarse-grained deltas John g. Mcpherson \ ,,,.,„ , , GANAPATHY SHANMUGAM > Mob" Research and Development Corporation, Dallas Research Laboratory, P.O. Box 819047 RICHARD J. MOIOLA J Dallas, Texas 75381 ABSTRACT delta sediments; they lack a muddy matrix; ening of the definition of fan-delta to the point of they display size grading and bar migration; confusion over its meaning and sedimentologic Two types of coarse-grained deltas are they commonly have a sheet geometry with implications. The term "fan-delta" is widely recognized: fan-deltas and braid deltas. Fan- high lateral continuity (tens to hundreds of used to describe depositional settings embracing deltas are gravel-rich deltas formed where an square kilometres); and they exhibit moderate a range of coarse-grained delta types other than alluvial fan is deposited directly into a stand- to high porosity and permeability. Valuable that of the fan-delta originally described by ing body of water from an adjacent highland. paleogeographic and tectonic information Holmes (1965). Many descriptions in the litera- They occupy a space between the highland concerning the proximity of highlands and ture of ancient fan-delta sequences contain no (usually a fault-bounded margin) and the major fault zones may be misinterpreted or evidence of the required presence of an alluvial standing body of water. In contrast, braid lost if these two coarse-grained deltaic sys- fan; instead they consist of deltaic deposits com- deltas (here introduced) are gravel-rich deltas tems are not differentiated. prising multilateral channel conglomerates and that form where a braided fluvial system pro- sandstones deposited from braided fluvial dis- grades into a standing body of water.
    [Show full text]
  • Hydrogeomorphic Processes and Torrent Control Works on a Large Alluvial Fan in the Eastern Italian Alps
    Nat. Hazards Earth Syst. Sci., 10, 547–558, 2010 www.nat-hazards-earth-syst-sci.net/10/547/2010/ Natural Hazards © Author(s) 2010. This work is distributed under and Earth the Creative Commons Attribution 3.0 License. System Sciences Hydrogeomorphic processes and torrent control works on a large alluvial fan in the eastern Italian Alps L. Marchi1, M. Cavalli1, and V. D’Agostino2 1Consiglio Nazionale delle Ricerche – Istituto di Ricerca per la Protezione Idrogeologica (CNR IRPI), Padova, Italy 2Dipartimento Territorio e Sistemi Agroforestali, Universita` di Padova, Legnaro (Padova), Italy Received: 17 November 2009 – Revised: 26 February 2010 – Accepted: 8 March 2010 – Published: 23 March 2010 Abstract. Alluvial fans are often present at the outlet of 1 Introduction small drainage basins in alpine valleys; their formation is due to sediment transport associated with flash floods and Alluvial fans at the outlet of small, high-gradient drainage debris flows. Alluvial fans are preferred sites for human set- basins are a common feature of alpine valleys. Although de- tlements and are frequently crossed by transport routes. In bris flows commonly dominate the formation and develop- order to reduce the risk for economic activities located on or ment of these alluvial fans, also bedload and hyperconcen- near the fan and prevent loss of lives due to floods and de- trated flows contribute to the transfer of sediment from the bris flows, torrent control works have been extensively car- drainage basin to the alluvial fan and its distribution on the ried out on many alpine alluvial fans. Hazard management fan surface. These flow processes result in major risk when on alluvial fans in alpine regions is dependent upon reliable they encroach settlements and transport routes, which are of- procedures to evaluate variations in the frequency and sever- ten present on the alluvial fans of the European Alps.
    [Show full text]
  • 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.
    [Show full text]
  • 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).
    [Show full text]
  • Moving Water Shapes Land
    KEY CONCEPT Moving water shapes land. BEFORE, you learned NOW, you will learn •Erosion is the movement of • How moving water shapes rock and soil Earth’s surface • Gravity causes mass movements • How water moving under- of rock and soil ground forms caves and other features VOCABULARY EXPLORE Divides drainage basin p. 579 How do divides work? divide p. 579 floodplain p. 580 PROCEDURE MATERIALS alluvial fan p. 581 •sheet of paper 1 Fold the sheet of paper in thirds and tape delta p. 581 • tape it as shown to make a “ridge.” sinkhole p. 583 •paper clips 2 Drop the paper clips one at a time directly on top of the ridge from a height of about 30 cm. Observe what happens and record your observations. WHAT DO YOU THINK? How might the paper clips be similar to water falling on a ridge? Streams shape Earth’s surface. If you look at a river or stream, you may be able to notice something about the land around it. The land is higher than the river. If a river is running through a steep valley, you can easily see that the river is the low point. But even in very flat places, the land is sloping down to the river, which is itself running downhill in a low path through the land. NOTE-TAKING STRATEGY Running water is the major force shaping the landscape over most A main idea and detail of Earth. From the broad, flat land around the lower Mississippi River notes chart would be a good strategy to use for to the steep mountain valleys of the Himalayas, water running downhill taking notes about streams changes the land.
    [Show full text]
  • Impacts of a Flood Pulsing Hydrology on Plants and Invertebrates in Riparian Wetlands
    IMPACTS OF A FLOOD PULSING HYDROLOGY ON PLANTS AND INVERTEBRATES IN RIPARIAN WETLANDS A dissertation submitted to Kent State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy by Maureen K. Drinkard August 2012 Dissertation written by Maureen K. Drinkard B.S., Kent State University, 2003 Ph.D., Kent State University, 2012 Approved by ___Ferenc de Szalay_, Chair, Doctoral Dissertation Committee ___Mark Kershner_______, Members, Doctoral Dissertation Committee _____Oscar Rocha________, ____Mandy Munro-Stasiuk_, Accepted by _____James Blank______, Chair, Department of Biological Sciences ______Raymond Craig___, Dean, College of Arts and Sciences ii TABLE OF CONTENTS LIST OF FIGURES ............................................................................................................... vi LIST OF TABLES ................................................................................................................. vii ACKNOWLEDGEMENTS .................................................................................................... x CHAPTER I. INTRODUCTION ................................................................................................ 1 Dissertation Goals ............................................................................................. 1 Definition of the Flood Pulse Concept .............................................................. 2 Ecological and economic importance ............................................................... 3 Impacts of environmental
    [Show full text]
  • The Burdiehouse Burn Valley Park
    The Burdiehouse Burn Valley Park Local Nature Reserve Management Plan 2008 – 2018 Revised in 2010 D:\Ranger\My Documents\BBVP\Burdiehouse Burn Valley Park Management Plan 2008\green flag Management plan.doc 1 INDEX PAGE Introduction .................................................................................................................................... 3 SECTION ONE –Site description........................................................................................................... 3 Site maps I, II, III and IV…………………………………………………………………………………………...6-9 1.1 Management plan framework........................................................................................................... 10 SECTION TWO – Our vision ................................................................................................................ 11 SECTION THREE – Aims ..................................................................................................................... 12 3.1 Aims and links with Green Flag criteria ............................................................................................ 12 SECTION FOUR – Surveys .................................................................................................................. 13 4.1 Introduction .................................................................................................................................. 13 4.2 Historical links .................................................................................................................................
    [Show full text]