Identifying Sites for Flood Protection
151
greater volumes of water accumulating on the surface of estuaries, beneath which will
lie the denser salt waters of the sea. The area of accumulation of water will fluctuate
depending on the tidal state and on the prevailing weather conditions over the
preceding 72 hours and on the ability of the river catchment area to delay the return of
precipitation.
Computer Model of the Clyde Estuary
The estuary of the River Clyde displays many of the characteristic land use features
associated with managed estuaries in an industrialised country. It is a small river both
in terms of its length, 170 km, and its drainage basin, approximately 3836 sq. km (Fig.
1). Despite the industrialisation which occurred along its lower reaches from the early
1800s parts of the estuary still retain a considerable natural beauty. There are three
designated Sites of Special Scientific Interest (SSSI), one designated ornithological site
and numerous non-designated habitats of local importance. In recognition of its newly
recognised role as a provider of recreation, tourism and conservation values, the
estuary has been designated a special planning zone by the regional planning authority.
A recurrent planning theme of the 1980s was the concept of the Clyde Corridor, a
development plan that embraced the estuary and its immediate tributaries. In the
1990s, planning emphasis has shifted towards the construction of a so-called Eco-Plan
for the estuary. The scope of the Eco-Plan is wider than its name suggests being
involved not only with environmental considerations but also with transport, derelict
land and sites with commercial development potential.
The preparation of a database formed the vital first stage of the project.
Colour vertical air photographs flown in the summer of 1989 were used for the
preparation of a land use base map. The map was digitised and the data stored as
polygons with attribute data attached in a separate file. The MAPICS mapping package
was used for the preparation of these files. Additional layers of data were digitised, for
example, areas of conservation value as designated by Nature Conservancy Council
(NCC) (Scotland), now Scottish Natural Heritage (SNH). A digital terrain model
(DTM) was also constructed from a raster data set comprising a cell size of 100 metres
x 100 metres.
The main purpose of the DTM was to provide the basis for modelling the
extent of sea level change within the estuary using the IPCC predictions of 1990 and
1992.
The database for the estuary was compiled using a purpose-designed package
called MICROMAPPER. The software permitted entry of data in a spreadsheet format
and its subsequent display as a customised two-dimensional colour map. ASCII format
files were produced for subsequent export to the UNIRAS package. The data set
comprised an area including the estuary and adjacent land on the north and south
banks and covered an area equivalent to 5.5 km on a north-south axis and 17.5 km on
an east west axis. The lowest elevation point was recorded in each 100m x 100m grid
cell. Information was collected from the Ordnance Survey Land Ranger map series,
scale 1:50,000. The data base comprising 9625 points was used to construct both two-
151
greater volumes of water accumulating on the surface of estuaries, beneath which will
lie the denser salt waters of the sea. The area of accumulation of water will fluctuate
depending on the tidal state and on the prevailing weather conditions over the
preceding 72 hours and on the ability of the river catchment area to delay the return of
precipitation.
Computer Model of the Clyde Estuary
The estuary of the River Clyde displays many of the characteristic land use features
associated with managed estuaries in an industrialised country. It is a small river both
in terms of its length, 170 km, and its drainage basin, approximately 3836 sq. km (Fig.
1). Despite the industrialisation which occurred along its lower reaches from the early
1800s parts of the estuary still retain a considerable natural beauty. There are three
designated Sites of Special Scientific Interest (SSSI), one designated ornithological site
and numerous non-designated habitats of local importance. In recognition of its newly
recognised role as a provider of recreation, tourism and conservation values, the
estuary has been designated a special planning zone by the regional planning authority.
A recurrent planning theme of the 1980s was the concept of the Clyde Corridor, a
development plan that embraced the estuary and its immediate tributaries. In the
1990s, planning emphasis has shifted towards the construction of a so-called Eco-Plan
for the estuary. The scope of the Eco-Plan is wider than its name suggests being
involved not only with environmental considerations but also with transport, derelict
land and sites with commercial development potential.
The preparation of a database formed the vital first stage of the project.
Colour vertical air photographs flown in the summer of 1989 were used for the
preparation of a land use base map. The map was digitised and the data stored as
polygons with attribute data attached in a separate file. The MAPICS mapping package
was used for the preparation of these files. Additional layers of data were digitised, for
example, areas of conservation value as designated by Nature Conservancy Council
(NCC) (Scotland), now Scottish Natural Heritage (SNH). A digital terrain model
(DTM) was also constructed from a raster data set comprising a cell size of 100 metres
x 100 metres.
The main purpose of the DTM was to provide the basis for modelling the
extent of sea level change within the estuary using the IPCC predictions of 1990 and
1992.
The database for the estuary was compiled using a purpose-designed package
called MICROMAPPER. The software permitted entry of data in a spreadsheet format
and its subsequent display as a customised two-dimensional colour map. ASCII format
files were produced for subsequent export to the UNIRAS package. The data set
comprised an area including the estuary and adjacent land on the north and south
banks and covered an area equivalent to 5.5 km on a north-south axis and 17.5 km on
an east west axis. The lowest elevation point was recorded in each 100m x 100m grid
cell. Information was collected from the Ordnance Survey Land Ranger map series,
scale 1:50,000. The data base comprising 9625 points was used to construct both two-