ABSTRACTS / RESUMES - Comitato Glaciologico Italiano

NANCY L. JACKSON 1 & KARL F. NORDSTROM 2
Evolution of the developed shoreline of New Jersey, USA
1 Center for Policy Studies, New Jersey Institute of Technology,
Newark, NJ, USA, 07102
2 Karl F. Nordstrom, Institute of Marine and Coastal Sciences,
New Brunswick, NJ, USA, 08903
This study examines the effects of human actions on the
physical evolution of the shoreline of New Jersey, USA.
The objectives are to: 1) explain the changing physical attributes
of coastal landscapes over large spatial scales (tens
of kilometers), and long temporal scales (decades); 2) determine
if there is a clearly identifiable pattern of evolution
for coastal segments modified by human action; and 3) determine
whether coastal storms or human actions are the
dominant agents of landform evolution.
Geomorphic changes are examined by comparing the dimensions,
configurations, topography, surface cover and
mobility of representative coastal barrier systems prior to
major human occupancy with conditions on subsequent
maps and aerial photos that represent stages in evolution
from natural to human-altered systems. Geomorphic settings
at the end of discrete time periods are constructed
and linked to public and private investment decisions, policy
decisions, changes in land use practices, and growth
patterns in communities identified in public documents
and historical narratives. Classification of geomorphic assemblages
during discrete time periods is accomplished through
multivariate analysis of variables measured from aerial
photographs, bathymetric maps and shoreline change
maps at each of the three representative study reaches in
the state. Assessment of storms includes both the shortterm
effects of storms and the long-term effects of restoration
efforts as well as the susceptibility of the human-restored
landscape to change in subsequent storms. Variables
include dune width, height, volume, and crestline location;
flood levels and debris lines; grain-size characteristics of
deposits; depth of overwash sediments and bulldozed sediments;
volume of sediment removed from streets, yards
and driveways; internal structure (by trenching) and surface
characteristics (natural and exotic vegetation, pavement)
of landforms.
Results indicate a sequence of human alterations, including:
1) construction of the first buildings on the upland
portions of the barrier islands at inlets and at locations
where railway lines from the mainland first made contact
with the barriers; 2) appearance of new isolated communities,
with subsequent growth outward from these locations
(both alongshore on the upland portion of the barriers and
bayward onto the marsh surface); 3) grading of dunes to a
flatter form to facilitate construction of buildings and
roads; 4) filling of the marsh behind the upland on barrier
islands; and 5) dredging of channels into the backbarrier
marsh to accommodate boats. The sequence of development
observed at the locations that developed early was
followed at later time periods on other shoreline segments.
Analysis of storms indicates that these events can have li-
mited effect in re-establishing a natural coastal resource
base of lasting significance because reconstruction of coastallandscapes
by human action may be more rapid than
natural restoration, decreasing the likelihood for geomorphic
features to develop based on natural processes.
ALAN M. JACOBS 1, ANN G. HARRIS 2 & IKRAM U. KHAWAJA 2
Using topographic indicators to prevent environmental
damage from mine subsidence
1 Center for Environmental Studies,
University Plaza, Youngstown, Ohio 44555, U.S.A.
2 Department of Geology Youngstown State University,
University Plaza, Youngstown, Ohio 44555, U.S.A.
Natural landforms over glaciated and non-glaciated, upper
Carboniferous (Pennsylvanian) terrain have been altered
by both strip and underground coal mining in the
northern Appalachian plateaus. Alteration of the landscape
can adversely affect the environment for both strip and
underground coal mining, but changes from underground
mining produce environmental effects that are, in many cases,
not anticipated or even recognized by non-geomorphologists.
As a result, environmental hazards are not
slated for remediation, reclamation, or proper design of
structures or infra-structure to be built above the minedout
areas. This is especially true of land above room-andpillar
mining (as contrasted with longwall mining), where
room and pillar collapse has been delayed decades after
mining takes place.
Subsidence can be subtle in the Appalachian plateaus,
especially if the mining depth is greater than 30 meters and
where the coal seams are commonly only one to two meters
thick. Cases where a stream has changed its course
and where a rider on horseback was swallowed up, as was
reported in Virginia for gypsum mining of beds 50 meters
thick, get immediate media attention. Nevertheless, unsensational
topographic effects from subsidence over minedout
coal have significant environmental consequences.
Subtle topographic effects include the development of 10to
150 centimeter troughs and closed depressions and increased
fracturing in the near-surface bedrock.
These subtle topographic changes produce damage to
buildings and highways, leakage of mine drainage (of low
pH) to surface streams and ground-water aquifers, triggering
of landslides, rupturing of sewage and pipelines, rupturing
of underground and aboveground storage tanks,
draining of wetlands, and disturbance of wildlife habitats.
The geomorphic processes that exacerbate the subsidence
effects include piping of surface runoff into cracks and
troughs, slope instability, increased erosion, increased rates
of physical weathering, and increased rates of chemical
weathering in areas of acid-mine drainage.
Field techniques that identify topographic changes from
mine subsidence include air-photo interpretation, contour
mapping, and mapping of changes in vegetation patterns,
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