Lindley Hanson's List: Coastal Geology

The U.S. Environmental Protection Agency estimates that 80 to 90 percent of the sandy beaches along America's coastlines have been eroding for decades. Individual beaches may lose only a few inches per year; others may lose much more. Of particular concern is the effect climate change, which causes sea level rises and also increases the severity and frequency of harsh storms, has on beach erosion.

6 presentation about erosion problems on Plum Island

PLUM ISLAND — Mother Nature plays her part, of course.

But those who have seen Plum Island's beaches and dunes morph for decades say it isn't just the winds of nor'easters, the waves of the Atlantic Ocean and the natural characteristics of a barrier island that account for the erosion seen in recent years.

Man — or at least some of his inventions — is also to blame, they say.

Many locals say the jetties, groins and dredging — or in recent years, the lack of it — of the Merrimack River have contributed to the massive erosion of certain sections of Plum Island's beaches.

Paul Ivaska, the chairman of Newbury's Beach Committee, said nature's role is clear, but humans also contribute.

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Plum Island Beach Erosion, 2008

January 3, 2009

Plum Island was in the news throughout the 2008 calendar year as a result of accelerated beach erosion on the Island.

The low point of the year was the loss of Gerri Buzzotta’s beach front home on Northern Boulevard on the day before Thanksgiving. Her home was demolished by the Town of Newbury after erosion from recent storms had severely weakened the structural integrity of her home and caused several support beams in it to collapse.

The following raw video feed from Fox25 News in Boston shows just how precarious her home was prior to the order to take it down for safety reasons. The video also shows how close the ocean now is to the Northern Boulevard area of Plum Island, near the Island Center.

Oceans in Motion: Waves and Tides
A brief introduction - by Sharon Gilman, Coastal Carolina University

Waves and Tides Next Frontier for Energy Exploration
Description
Several companies are developing technologies that aim to generate energy from ocean waves. Beckey Bright reports.
Several companies are developing technologies that aim to generate energy from ocean waves. ... More
Channel:The Wall Street Journal
Copyright 2009, Dow Jones & Company, Inc.

Paper No. 115-0
CHARACTERISTIC FEATURES OF ROCK-FRAMED, GLACIATED ESTUARIES: NORTHERN NEW ENGLAND, USA
KELLEY, Joseph T., Dept. Geological Sci, Univ of Maine, 120 Bryand Global Sciences Ctr, Orono, ME 04469-5790, jtkelley@maine.edu and BELKNAP, Daniel F., Department of Geological Sciences, Univ Maine - Orono, 111 Bryand Global Sciences Ctr, Orono, ME 04469-5790

To better site expanding aquaculture facilities, manage essential fish habitats and understand the distribution of historic contaminants, better models of estuarine sedimentary deposits and evolution are needed. Existing models, developed in the Coastal Plain, are of little use in rocky, glaciated regions because of differences in processes and materials. High-resolution seismic reflection profiles and side scan sonar mosaics of 6 estuaries in the western Gulf of Maine allow definition of characteristic features of rock-framed, glaciated estuaries. Bedrock structure defines estuarine shape, which controls the spatial distribution of tidal current velocities. In Cobscook Bay, strong currents associated with a 6 m tidal range are confined by a plunging anticline whose limbs create a series of narrow constrictions. Sediment is scoured out of constrictions and modern mud accumulates only where whirlpools form in sub-bays. In rock-framed, linear estuaries like the Saco, Kennebec and Penobscot, high water velocities in the narrow estuaries restrict fine-grained sediment to shallow coves; most of the estuary bottom is floored by rock, sand and gravel. Numerous deep scour holes with up and downstream bedform fields are common. The narrow, confined upper estuaries allow spring freshets to regularly export sediment seaward. Glacial drainage derangement prevents major rivers from entering most embayments, making glacial bluffs and subtidal outcrops primary sources of sediment. In outer areas of the Cobscook, Somes and Damariscotta estuaries, eroding glacial-marine sediment or till crops out extensively and leads to abrupt changes in sediment size and bathymetry. In

These demonstration applets demonstrate a subset of the sedx package, a collection of Java classes for peforming sediment-transport calculations and associated oceanographic calculations. The applets are intended to allow quick access to commonly used calculations. If you are interested in the underlying Java package, contact Chris Sherwood. To run the applets, you need a Java-aware browser (e.g, Netscape 3.0 or higher) with Java enabled (under Options/Network Preferences/Languages). Read the disclaimer, then just click on an applet in the list below. (Ones that are unlinked are under development but should appear soon. I will take suggestions for others!)

This page (www.coastal.udel.edu/faculty/rad) is a listing of Java applets that might prove of use in coastal engineering. To run these applets, you only need a web browser that supports Java, such as Netscape 3.01/4.0+. Note: if, when you try to run an applet, you only see text and have a message at the top of the page saying "This application requires a Java-enhanced browser to use. Sorry,'' then you don't have Java enabled. To do this with Netscape, find Preferences (perhaps under the Edit menu), and look under Advanced. There should be a button to press to Enable "Java."

ost energy in nearshore waters comes from wind-generated waves and tidal currents. The dispersion of water, pollutants, nutrients, and sediments near the coast and the formation and erosion of sandy beaches are some of the common results of nearshore energy dissipation

Welcome to the Seafriends web site for saving our seas. Become an informed conservationist by learning about our planet, oceans, land and resources, threats and what to do. Tap into our independent analyses and courage to tell the truth. This web site contains well researched scientific information, made easy to understand, while not serving established interests, politics or beliefs. Learn about the world we live in. Learn about the sea and how to save our seas and the many mistakes made. Discover the treasures on this web site. Wake up for the future of your children!

Beach Nourishment: A Guide for Local Government Officials
Barrier Islands: Formation and Evolution
Introduction

Barrier islands are elongate accumulations of sand that are separated from the mainland by open water in the form of estuaries, bays, or lagoons. These primarily sandy islands have become in great demand for both residential and recreational development. Beaches on the seaward side of barrier islands are the principal location for beach nourishment. In order to properly manage these important natural resources it is important to understand the origin, dynamics, and probable future of barrier islands and their associated beaches. The following discussion will examine these complex coastal environments and the nature of the coastal processes that affect the evolution of barrier islands in order to assist decision making in better assessing potential measures to stabilize barrier island beaches.

Although barrier islands are quite extensive along the coasts of the United States, they can only be found along 15 percent of the world's existing coastlines. Most of the Atlantic and Gulf Coasts of the United States are comprised of barrier islands, and there are numerous such islands found along both the southeast and northern coasts of Alaska. The Pacific Coast, extending from Washington to California, is characterized by numerous short barrier spits that are elongate, primarily sand accumulations, generally connected to the mainland at a rocky headland.

Abstract: Recent multi-beam, backscatter, and bottom sediment data
demonstrate that a large sand sheet was formed in the inner shelf by the
reworking of the Merrimack River lowstand delta and braid plain (12 kya)
during the Holocene transgression. Seismic data reveal the presence of
widespread channel cut-and-fill structures landward of the delta suggesting
that much of the sand sheet consists of braided stream deposits. These
features map into several sets of cut-and-fill structures, indicating the
avulsion of the primary river channels, which created the lobes of the
paleo-delta. Truncations of these cut-and-fill structures suggest that the
braid plain deposits were probably reworked during the Holocene
transgression and may have contributed sand to developing barriers that
presently border the Merrimack Embayment.

Abstract : The Essex River Inlet ebb-tidal delta system is a well-formed delta along a barrier island chain in the Merrimack Embayment. Sediments comprising this barrier island chain have been supplied primarily from reworking and onshore transport of the Early Holocene Merrimack River Delta. Southerly longshore currents have resulted in a fining grain-size trend to the south along the barrier chain as well as an increase in spacing of the offshore contours. The Essex River Inlet is anchored next to bedrock, and its ebb-tidal delta exhibits classic delta morphology whose environments respond to storms, tidal currents, wave processes, and sand transport. Distal portions of the delta including swash bars and terminal lobe are dominated by southerly and landward directed wave-generated currents. Wave refraction around the delta results in transport reversal approximately 1.2 km south of the main ebb channel. Intertidal sand bodies are dominated by landward-oriented currents with the exception of the distal channel margin linear bars. Sediment transport trends are dominated by gyres that involve sediment input from longshore currents into the updrift marginal flood channel, seaward sandwave migration through the main ebb channel, and onshore reworking of sediment through wave activity and swash bar migration.

Descriptors : *GEOMORPHOLOGY, *STRATIGRAPHY, *SEDIMENT TRANSPORT, GRAIN SIZE, SAND, TIDAL CURRENTS, CHAINS, REVERSIBLE, BARRIERS, TRANSPORT, STORMS, PATTERNS, RODS, REFRACTION, RIVERS, INLETS, SEDIMENTS, WAVES, CURRENTS, ISLANDS, SHORES, MASSACHUSETTS, OFFSHORE, CONTOURS, MORPHOLOGY, DELTAS, INPUT, DYNAMICS

Subject Categories : PHYSICAL AND DYNAMIC OCEANOGRAPHY
GEOLOGY, GEOCHEMISTRY AND MINERALOGY

Styles of Barrier Evolution as a Function of Proximity to the Updrift Tidal Inlet, Castle Neck, Northern Massachusetts
Dougherty, A. J.; FitzGerald, D. M.; Pendleton, E. A.; Buynevich, I. V.
American Geophysical Union, Spring Meeting 2001, abstract #OS42B-12

Castle Neck is one of five barrier islands located within the mixed energy Merrimack Embayment, MA. The barriers and intervening inlets span a 34 km length of coast. Inlets are situated in drowned river valleys and contain well-developed ebb-tidal deltas. A geophysical (ground penetrating radar, GPR) and coring study of Castle Neck has shown that the barrier is a product of abundant sediment supply, slow sea-level rise, inlet processes, and the presence of drumlin covered bedrock acting as pinning points. Fifteen kilometers of GPR transects and 35 cores have been used to delineate eight barrier and associated facies: reworked drumlins, initial progradation, shoreface accretion, inlet cut & fill structures, marsh deposits, bar migration, spit elongation, and aeolian deposition. The barrier can be separated into three geographic regions having distinctive evolutionary styles: 1) The northern barrier exhibits a highly complex stratigraphy that reflects a dynamic depositional history consisting of an early progradational phase punctuated by frequent erosional events. Seaward units contain multiple channel cut and fill structures, bar welding facies as well as shoreface accretion. These features were created due to migration of the main ebb-channel and onshore movement of swash bars. A paleo-marsh/lagoon appears to have formed as a consequence of cat-eye pond development. 2) The central barrier displays evidence of initial reworking of drumlins with the subsequent accumulation of sand from longshore and offshore sources. Beyond the drumlin associated facies are flat-lying beds formed from sand deposited into a shallow open water bay. The seaward most units are dominated by landward dipping foresets (1 to 2 m in thickness) resulting from the landward migration

Redefining the Model of Barrier Island Formation along a Paraglacial Coast: Plum Island, Massachusetts
CARRUTHERS, Emily A.1, HEIN, Christopher J.1, FITZGERALD, Duncan M.1, STONE, Byron D.2, and ELLISON, Mary S.1, (1) Department of Earth Sciences, Boston University, 675 Commonwealth Ave, Boston, MA 02215, emilyac@bu.edu, (2) U.S. Geological Survey, 1080 Shennecossett Rd, Groton, CT 06340

A geophysical and sedimentological study of Plum Island in northern Massachusetts has refined our understanding barrier formation in northern New England. Previous studies suggest various sources of sediment for building the Plum Island and adjacent barrier system, including erosion of drumlin sediments, sand discharged from the Merrimack River, and the Holocene reworking of lowstand deltaic sediments and braid-plain deposits. Although identifying different sediment sources, all models agree that the island evolved through the process of vertical accretion. Analysis of sediment from vibracores, deep (~36 m) drill auger cores and Geoprobe cores along the barrier show a generally coarsening upward sequence from the fine mud of the Presumpscot formation though fluvial deposits and into the barrier island sequence. Occasionally, impenetrable shallow till is encountered that may represent buried drumlins, onto which Plum Island became pinned during its formation. Sediment core and Ground Penetrating Radar (GPR) data suggest that the barrier lithosome ranges in thickness from 5 to 15 m and is composed of pervasive southerly dipping layers along the southern 2/3 of the island's length. These layers are interpreted as spit (thickness: 4-6 m) and inlet fill sands (thickness: 6 to > 8 m). These southerly dipping layers are frequently underlain by thinner sequences of northerly dipping GPR reflectors that represent the northern recurve of the southerly prograding spit. The predominant southerly dipping reflectors are consistent with dominantly southerly longshore transport system driven by northeast storms. Although previous studies have s

For the past century, the pace and density of development near the ocean has been unprecedented, and much of it is incompatible with the dynamic nature of the shoreline. More than $3 trillion are invested in dwellings, resorts, infrastructure, and other real estate along the Atlantic and Gulf coasts of the United States, and more than 155 million people live in coastal counties. The coastal population is estimated to rise by 3,500 people per day.

Yet, as the devastating hurricane season of 2004 showed, there is a price to be paid for living at sea level and building on sand. Even without extreme storms, the shoreline naturally advances and retreats on scales ranging from seconds to millennia.

As a growing population hugs the coast, understanding the complex processes by which coastlines change has never been more relevant and more important to our well-bein