CHAPTER 13
A GIS Application for the Study of Beach Morphodynamics
L. P. Humphries and C. N. Ligdas
ABSTRACT: This research is a continuation of work conducted at the University of
Sunderland since 1990 on the impacts of the accumulation of millions of tonnes of
colliery spoil on the beaches. Regular surveys of the beaches were undertaken from
1991 spanning a period of about 5 years during which all mining activity ceased on the
Durham coast. During mining operations the accumulation of spoil on the beaches
affected both the geomorphology and the geochemistry of the beaches. It may also
have masked the impact that deep mining of multiple coal seams under the coasts had
on the beaches. Once tipping ceased, it was expected that spoil would erode rapidly
and that the pattern of erosion would show changes parallel to the shoreline. This was
the case on some of the beaches but on others, notably the Dawdon blast beach,
anomalies appeared showing localised patches of changes at orientations at variance
with the expected pattern. Dawdon Blast beach has been extensively undermined and
it is possible that some of these patterns may have been produced by structural changes
in the bedrock caused by subsidence. To test this hypothesis, a Geographical
Information System (GIS) was used to study changes of the beach surface over the
years immediately superseding the cessation of mining, focusing on 3 study areas
(Dawdon, Easington and Horden) which present different undermining conditions. It
was found that the spatial pattern of significant elevation changes in the Dawdon beach
is considerably different from that observed in Easington and Horden. The possible
relationship to coastal colliery panels was further tested by obtaining the strain,
subsidence and surface heights along the transect from the centre of the worked panels
lying east and west of the beach area in Dawdon. The implications for coastal
management on this coastline are that areas directly undermined may be suffering
subsidence impacts causing increased levels of erosion of beach material. This is an
important factor of local significance in assessing coast vulnerability and risk of cliff
173
D.R. Green and S.D. King (eds.), Coastal and Marine Geo-Information Systems, 173–189.
© 2003 Kluwer Academic Publishers. Printed in the Netherlands.
A GIS Application for the Study of Beach Morphodynamics
L. P. Humphries and C. N. Ligdas
ABSTRACT: This research is a continuation of work conducted at the University of
Sunderland since 1990 on the impacts of the accumulation of millions of tonnes of
colliery spoil on the beaches. Regular surveys of the beaches were undertaken from
1991 spanning a period of about 5 years during which all mining activity ceased on the
Durham coast. During mining operations the accumulation of spoil on the beaches
affected both the geomorphology and the geochemistry of the beaches. It may also
have masked the impact that deep mining of multiple coal seams under the coasts had
on the beaches. Once tipping ceased, it was expected that spoil would erode rapidly
and that the pattern of erosion would show changes parallel to the shoreline. This was
the case on some of the beaches but on others, notably the Dawdon blast beach,
anomalies appeared showing localised patches of changes at orientations at variance
with the expected pattern. Dawdon Blast beach has been extensively undermined and
it is possible that some of these patterns may have been produced by structural changes
in the bedrock caused by subsidence. To test this hypothesis, a Geographical
Information System (GIS) was used to study changes of the beach surface over the
years immediately superseding the cessation of mining, focusing on 3 study areas
(Dawdon, Easington and Horden) which present different undermining conditions. It
was found that the spatial pattern of significant elevation changes in the Dawdon beach
is considerably different from that observed in Easington and Horden. The possible
relationship to coastal colliery panels was further tested by obtaining the strain,
subsidence and surface heights along the transect from the centre of the worked panels
lying east and west of the beach area in Dawdon. The implications for coastal
management on this coastline are that areas directly undermined may be suffering
subsidence impacts causing increased levels of erosion of beach material. This is an
important factor of local significance in assessing coast vulnerability and risk of cliff
173
D.R. Green and S.D. King (eds.), Coastal and Marine Geo-Information Systems, 173–189.
© 2003 Kluwer Academic Publishers. Printed in the Netherlands.