Coastal Erosion and Control
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Coastal Erosion - Orrin H
COASTAL ZONES AND ESTUARIES – Coastal Erosion - Orrin H. Pilkey, William J. Neal, David M. Bush COASTAL EROSION Orrin H. Pilkey Program for the Study of Developed Shorelines, Division of Earth and Ocean Sciences, Duke University, Durham, NC, U.S.A. William J. Neal Department of Geology, Grand Valley State University, Allendale, MI, USA. David M. Bush Department of Geosciences, State University of West Georgia, Carrollton, GA, USA. Keywords: erosion, shoreline retreat, sea level rise, barrier islands, beach, coastal management, shoreline armoring, seawalls, sand supply Contents 1. Introduction 2. Causes of Erosion 2.1. Sea Level Rise 2.2. Sand Supply 2.3. Shoreline Engineering 2.4. Wave Energy and Storm Frequency 3. "Special" Cases 4. Solutions to Coastal Erosion 5. The Future Glossary Bibliography Biographical Sketches Summary Almost all of the world’s shorelines are retreating in a landward direction—a process called shoreline erosion. Sea level rise and the reduction of sand supply to the shoreline by damming of rivers, armoring of shorelines and the dredging of navigation channels are among the major causes of shoreline retreat. As sea levels continue to rise, sometimesUNESCO enhanced by subsidence caused – byEOLSS oil and water extraction, global erosion rates should increase in coming decades. Three response alternatives are available to "solve" the erosionSAMPLE problem. These are cons tructionCHAPTERS of seawalls and other engineering structures, beach nourishment and relocation or abandonment of buildings. No matter what path is chosen, response to the erosion problem is costly. 1. Introduction Coastal erosion is a major problem for developed shorelines everywhere in the world. Such erosion is regarded as a coastal hazard and is a common focus of local and national coastal management. -
Coastal Flood Defences - Groynes
Coastal Flood Defences - Groynes Coastal flood defences are key to protecting our coasts against flooding, which is when normally dry, low lying flat land is inundated by sea water. Hard engineering methods are forms of coastal flood defences which mitigate the risk of flooding and coastal erosion and the consequential effects. Hard Engineering Hard engineering methods are often used as a temporary measure to protect against coastal flooding as they are costly and only last for a relatively short amount of time before they require maintenance. However, they are very effective at protecting the coastline in the short-term as they are immediately effective as opposed to some longer term soft engineering methods. But they are often intrusive and can cause issues elsewhere at other areas along the coastline. Groynes are low lying wood or concrete structures which are situated out to sea from the shore. They are designed to trap sediment, dissipate wave energy and restrict the transfer of sediment away from the beach through long shore drift. Longshore drift is caused when prevailing winds blow waves across the shore at an angle which carries sediment along the beach.Groynes prevent this process and therefore, slow the process of erosion at the shore. They can also be permeable or impermeable, permeable groynes allow some sediment to pass through and some longshore drift to take place. However, impermeable groynes are solid and prevent the transfer of any sediment. Advantages and Disadvantages +Groynes are easy to construct. +They have long term durability and are low maintenance. +They reduce the need for the beach to be maintained through beach nourishment and the recycling of sand. -
Coastal Processes and Causes of Shoreline Erosion and Accretion Causes of Shoreline Erosion and Accretion
Coastal Processes and Causes of Shoreline Erosion and Accretion and Accretion Erosion Causes of Shoreline Heather Weitzner, Great Lakes Coastal Processes and Hazards Specialist Photo by Brittney Rogers, New York Sea Grant York Photo by Brittney Rogers, New New York Sea Grant Waves breaking on the eastern Lake Ontario shore. Wayne County Cooperative Extension A shoreline is a dynamic environment that evolves under the effects of both natural 1581 Route 88 North and human influences. Many areas along New York’s shorelines are naturally subject Newark, NY 14513-9739 315.331.8415 to erosion. Although human actions can impact the erosion process, natural coastal processes, such as wind, waves or ice movement are constantly eroding and/or building www.nyseagrant.org up the shoreline. This constant change may seem alarming, but erosion and accretion (build up of sediment) are natural phenomena experienced by the shoreline in a sort of give and take relationship. This relationship is of particular interest due to its impact on human uses and development of the shore. This fact sheet aims to introduce these processes and causes of erosion and accretion that affect New York’s shorelines. Waves New York’s Sea Grant Extension Program Wind-driven waves are a primary source of coastal erosion along the Great provides Equal Program and Lakes shorelines. Factors affecting wave height, period and length include: Equal Employment Opportunities in 1. Fetch: the distance the wind blows over open water association with Cornell Cooperative 2. Length of time the wind blows Extension, U.S. Department 3. Speed of the wind of Agriculture and 4. -
Management of Coastal Erosion by Creating Large-Scale and Small-Scale Sediment Cells
COASTAL EROSION CONTROL BASED ON THE CONCEPT OF SEDIMENT CELLS by L. C. van Rijn, www.leovanrijn-sediment.com, March 2013 1. Introduction Nearly all coastal states have to deal with the problem of coastal erosion. Coastal erosion and accretion has always existed and these processes have contributed to the shaping of the present coastlines. However, coastal erosion now is largely intensified due to human activities. Presently, the total coastal area (including houses and buildings) lost in Europe due to marine erosion is estimated to be about 15 km2 per year. The annual cost of mitigation measures is estimated to be about 3 billion euros per year (EUROSION Study, European Commission, 2004), which is not acceptable. Although engineering projects are aimed at solving the erosion problems, it has long been known that these projects can also contribute to creating problems at other nearby locations (side effects). Dramatic examples of side effects are presented by Douglas et al. (The amount of sand removed from America’s beaches by engineering works, Coastal Sediments, 2003), who state that about 1 billion m3 (109 m3) of sand are removed from the beaches of America by engineering works during the past century. The EUROSION study (2004) recommends to deal with coastal erosion by restoring the overall sediment balance on the scale of coastal cells, which are defined as coastal compartments containing the complete cycle of erosion, deposition, sediment sources and sinks and the transport paths involved. Each cell should have sufficient sediment reservoirs (sources of sediment) in the form of buffer zones between the land and the sea and sediment stocks in the nearshore and offshore coastal zones to compensate by natural or artificial processes (nourishment) for sea level rise effects and human-induced erosional effects leading to an overall favourable sediment status. -
GEOTEXTILE TUBE and GABION ARMOURED SEAWALL for COASTAL PROTECTION an ALTERNATIVE by S Sherlin Prem Nishold1, Ranganathan Sundaravadivelu 2*, Nilanjan Saha3
PIANC-World Congress Panama City, Panama 2018 GEOTEXTILE TUBE AND GABION ARMOURED SEAWALL FOR COASTAL PROTECTION AN ALTERNATIVE by S Sherlin Prem Nishold1, Ranganathan Sundaravadivelu 2*, Nilanjan Saha3 ABSTRACT The present study deals with a site-specific innovative solution executed in the northeast coastline of Odisha in India. The retarded embankment which had been maintained yearly by traditional means of ‘bullah piling’ and sandbags, proved ineffective and got washed away for a stretch of 350 meters in 2011. About the site condition, it is required to design an efficient coastal protection system prevailing to a low soil bearing capacity and continuously exposed to tides and waves. The erosion of existing embankment at Pentha ( Odisha ) has necessitated the construction of a retarded embankment. Conventional hard engineered materials for coastal protection are more expensive since they are not readily available near to the site. Moreover, they have not been found suitable for prevailing in in-situ marine environment and soil condition. Geosynthetics are innovative solutions for coastal erosion and protection are cheap, quickly installable when compared to other materials and methods. Therefore, a geotextile tube seawall was designed and built for a length of 505 m as soft coastal protection structure. A scaled model (1:10) study of geotextile tube configurations with and without gabion box structure is examined for the better understanding of hydrodynamic characteristics for such configurations. The scaled model in the mentioned configuration was constructed using woven geotextile fabric as geo tubes. The gabion box was made up of eco-friendly polypropylene tar-coated rope and consists of small rubble stones which increase the porosity when compared to the conventional monolithic rubble mound. -
GEOG 101 PLACE NAME LIST for EXAM THREE
GEOG 101 PLACE NAME LIST for EXAM THREE Each exam will have a place name location map section based on the list below, plus countries and political units. Consult the appropriate maps in the atlas and textbook to locate these places. The atlas has a detailed INDEX. Exam III will focus on place names from Asia and Oceania. This section of the exam will be in the form of a matching question. You will match the names to numbers on a map. ________________________________________________________________________________ I. CONTINENTS Australia Asia ________________________________________________________________________________ II. OCEANS Pacific Indian Arctic ________________________________________________________________________________ III. ASIA Seas/Gulfs/Bays/Lakes: Caspian Sea Sea of Japan Arabian Sea South China Sea Red Sea Aral Sea Lake Baikal East China Sea Bering Sea Persian Gulf Bay of Bengal Sea of Okhotsk ________________________________________________________________________________ Islands: New Guinea Taiwan Sri Lanka Singapore Maldives Sakhalin Sumatra Borneo Java Honshu Philippines Luzon Mindanao Cyprus Hokkaido ________________________________________________________________________________ Straits/Canals: Str. of Malacca Bosporas Dardanelles Suez Canal Str. of Hormuz ________________________________________________________________________________ Rivers: Huang Yangtze Tigris Euphrates Amur Ob Mekong Indus Ganges Brahmaputra Lena _______________________________________________________________________________ Mountains, Plateaus, -
Shore Protection by Offshore Breakwaters
l§lHydraulics Research Wallingford SHORE PROTECTION BY OFFSHORE BREAKWATERS A H Brampton Ph .D J V Smallman Ph.D Report No SR 8 July 1985 Registered Office: Hydraulics Research Limited, Wallingford, Oxfordshire OX 10 8BA. Telephone: 0491 35381. Telex: 848552 Thi s report describes work carri ed out wi thin the research programme Commission B for the Ministry of Agriculture, Fisheri es and Food . The study was carri ed ou t in the Coas tal Processes Sect ion of the Mari time Engineering Department of Hydraulics Research . The departmental nominated officer is Mr A Alli son . The Company's nominated project officer is Dr S W Huntington. The report is publi s hed on behalf of MAFF but any op inions expressed are not necessarily those of the Ministry . C Crown copyri ght 19 85 ABSTRACT This report reviews the information available for the design and use of offshore breakwaters in shore protection. As an introduction to the subject the physical processes occurring in the lee of an offshore breakwater are described with reference to natural examples. This is followed by a survey of case histories, and mathematical and physical modelling techniques for offshore breakwaters. Some of the methods which are available for the design of a breakwater system are reviewed. Possible future developments in the design process are described, and the areas in which further research on the effects of offshore breakwaters is required are highlighted. CONTENTS Page EXECUTIVE SUMMARY 1 INTRODUCTION 1 2 OFFSHORE BREAKWATERS - THE PHYSICAL PROCESSES 2 2.1 Natural Examples 2 2.2 Physical processes 4 3 LITERATURE STUDY 6 3.1 Review of case histories 6 3.2 Physical model studies 10 3 .3 Ma thematical model studies 16 4 DESIGN METHODS FOR AN OFFSHORE BREAKWATER SYSTEM 19 4.1 Developing the initial design 19 4.2 Methods for improving the breakwa ter design 22 5 FUTURE DEVELOPMENT 26 6 CONCLUS IONS AND RECOMMENDATIONS 28 7 ACKNOWLEDGE MENTS 29 8 REFERENCES 30 FIGURES PLATES EXECUTIVE SUMMARY 1. -
Safe Boating Through the St. Lucie Inlet
Information: Florida Fish & Wildlife Commission 850-488-4676 SAFE BOATING US Coast Guard - Ft. Pierce 772-461-7606 THROUGH THE ST. LUCIE INLET US Coast Guard Auxiliary 772-465-8128 US Army Corps of Engineers 772-221-3349 St. Lucie Inlet Coastal 772-225-2300 Weather Station HERE ARE SOME THINGS TO REMEMBER: • Listen to the most recent weather forecast for the times you plan to go out AND come back in the inlet. • Look in the Tide Tables or local newspapers for the times St. Lucie Inlet of predicted high and low tides for the day you plan to go out. Remember the outgoing (ebb) tital current at low Newcomers tide is the worst time to make a passage through the St. Lucie Inlet. If you are a boater new to this area, it is highly • Safe boating practices are even more important in inlets. recommended that you make your first passage of Check your boat before you head out. Life preservers the St. Lucie Inlet as an observer. An experienced should be worn when going through inlets. boater with local knowledge at the helm can point • Expect the unexpected. Watch the clouds to anticipate out various hazards and conditions to avoid. This is severe weather such as thunderstorms. Be on the lookout for shifting shoals and changing channels. especially important if you have no prior experience • Engine failure is common in small boats in rough seas. with any ocean inlets. The extra roughness agitates gasoline and settled dirt or water in the fuel system, which can cause engine failure Notes on Navigation at Night at a crtical time. -
Our Ocean Backyard –– Santa Cruz Sentinel Columns by Gary Griggs, Director, Institute of Marine Sciences, UC Santa Cruz
Our Ocean Backyard –– Santa Cruz Sentinel columns by Gary Griggs, Director, Institute of Marine Sciences, UC Santa Cruz. #45 January 2, 2010 Why Monterey Submarine Canyon? Monterey Submarine Canyon forms a deep gash beneath the waters of Monterey Bay. At the risk of beating submarine canyons to death, I’m going to try to wrap up this discussion with some final thoughts on why we have one of the world’s largest submarine canyons in our backyard. Monterey Submarine Canyon has been known for over a century, and as with other offshore drainage systems, there has been considerable speculation over the years as to why we have this huge chasm cutting across the seafloor. Most submarine canyons align with river systems, but Elkhorn Slough hardly provides an adequate onshore source for such a massive feature. We do know that prior to 1910 the Salinas River discharged six miles north of its present mouth into Elkhorn Slough, closer to the head of Monterey Submarine Canyons. But even the Salinas River is not of the scale we would expect for an offshore feature as large as the Grand Canyon. Over 50 years ago, two geologists discovered the presence of a deep buried inland canyon beneath the Santa Cruz Mountains from oil company drill holes. This combined with other geological and geophysical observations strongly suggested that this canyon was eroded by an ancient river drainage system that played a critical role in the initial formation of the Monterey Submarine Canyon. This buried canyon, named Pajaro Gorge by some, was the route that the drainage from California’s vast Central Valley followed to the ocean for million of years. -
Wetland Loss in the Lower Galveston Bay Watershed
Galveston Bay Wetland Permit and Mitigation Assessment Lisa Gonzalez Dr. Erin Kinney Dr. John Jacob Marissa Llosa Transportation Stream & Wetland Mitigation Peer Exchange – June 5-6, 2018 Galveston Bay Watershed ~24,000 square miles ~Half of Texas’ population of 28M TXDOT Districts Beaumont Houston Population Growth 213 % 59 % 65 % * 119 % * 54 % 239 % 106 % 89 % % Change in Population 1990 to 2017 Data Source: U.S. Census, *Texas Demographic Center Population Projection Regional Habitat H-GAC Eco-Logical Map; Wetland Mitigation Opportunities white paper, 2014 Regional Land Cover Change; 1996-2010 • Growth in impervious (107K acres) & developed (254K acres) areas • Wetland net change -54K acres NLDC, NOAA C-CAP Coastal Bottomlands and Blue Elbow Mitigation Banks Mitigation Bank Mitigation Bank HUC8 ORMII Permits ORMII Permits Galveston Bay Mitigation Banks TCWP Ground-truth Wetland Mitigation Assessment • 17 sites: 4 permit mitigation sites not accessible, leaving 13 permits for site review (8 PRM, 5 MB). • Assessment criteria based on three-fold definition of a wetland (Tiner, 1989): – Hydrophytic vegetation (partially or completely submerged in water), – Evidence of hydrology, – Soil indicators consistent with wetland hydrology. • Conservative assessment: – Success: “reasonably wet” with recognizable wetland plants and hydric soils. – Failure: substandard compensatory mitigation site with a lack of any evidence for wetland mitigation TCWP Ground-truth Wetland Mitigation Assessment • Minimum 5% of the total mitigation site inventoried. • Plots (10 m x 10 m) representatively within the tract. • Plant species presence and percent cover assessed. • Cover of various biotic and abiotic surface materials collected in each plot. • Comprehensive list of species compiled. • Pictures of the site and the sample plot taken along with any notable site features. -
1 the Influence of Groyne Fields and Other Hard Defences on the Shoreline Configuration
1 The Influence of Groyne Fields and Other Hard Defences on the Shoreline Configuration 2 of Soft Cliff Coastlines 3 4 Sally Brown1*, Max Barton1, Robert J Nicholls1 5 6 1. Faculty of Engineering and the Environment, University of Southampton, 7 University Road, Highfield, Southampton, UK. S017 1BJ. 8 9 * Sally Brown ([email protected], Telephone: +44(0)2380 594796). 10 11 Abstract: Building defences, such as groynes, on eroding soft cliff coastlines alters the 12 sediment budget, changing the shoreline configuration adjacent to defences. On the 13 down-drift side, the coastline is set-back. This is often believed to be caused by increased 14 erosion via the ‘terminal groyne effect’, resulting in rapid land loss. This paper examines 15 whether the terminal groyne effect always occurs down-drift post defence construction 16 (i.e. whether or not the retreat rate increases down-drift) through case study analysis. 17 18 Nine cases were analysed at Holderness and Christchurch Bay, England. Seven out of 19 nine sites experienced an increase in down-drift retreat rates. For the two remaining sites, 20 retreat rates remained constant after construction, probably as a sediment deficit already 21 existed prior to construction or as sediment movement was restricted further down-drift. 22 For these two sites, a set-back still evolved, leading to the erroneous perception that a 23 terminal groyne effect had developed. Additionally, seven of the nine sites developed a 24 set back up-drift of the initial groyne, leading to the defended sections of coast acting as 1 25 a hard headland, inhabiting long-shore drift. -
Integrated Coastal Management Act: National Estuarine Management
26 No.35296 GOVERNMENT GAZETTE, 4 MAY 2012 DEPARTMENT OF ENVIRONMENTAL AFFAIRS No. 336 4 May 2012 NATIONAL ENVIRONMENTAL MANAGEMENT INTEGRA TED COASTAL MANAGEMENT ACT, 2008 (ACT NO. 24 OF 2008) INVITATION TO COMMENT ON THE DRAFT NATIONAL ESTUARINE MANAGEMENT PROTOCOL I, Bomo Edith Edna Molewa, the Minister of Water and Environmental Affairs, hereby in terms of section 33 (2) read with section 53 of the Integrated Coastal Management Act, 2008 (Act No. 24 of 2008) publish for comment the draft National Estuarine Management Protocol. Interested persons and organizations are invited to submit written commen~ on the draft National Estuarine Management Protocol as follows: Written comments may be submitted to the Department by no later than 16h00 on 04 June 2012, by mail, hand, e-mail or telefax transmission. Please note that comments received after the closing date may not be considered. 1.1.1 By mail 1.1.2 By hand 1.1.3 By E-mail Subject: Draft National Subject: Draft National Estuarine Subject: Draft NatiQ!]al Eswarine Estuarine Management Protocol Management Protocol Management Protocol The Deputy Director -General The Deputy Director-General; [email protected] .za Department of Environmental Department of Environmental Affairs: Telephonic enquiries Affairs: Oceans & Coasts; P.O Oceans & Coasts; East Pier 2; East Pier Mr Ayanda Matoti: +27 21 819 2476 Box 52126; V& A Waterfront, Road; V&A Waterfront CAPE TOWN, 8002 CAPETOWN The draft protocol is also available for download from the Departmenfs webs"e, www.environment.gov.za BOMO EDITH EDNA MOLEWA MINISTER OF WATER AND ENVIRONMENTAL AFFAIRS STAATSKOERANT, 4 MEl 2012 No.