134
C.I.S. Pater
conservation designations that are applied here have local, national and international
importance.
The enclosure and draining of the upper saltmarsh has produced a soil
medium that is highly fertile and following centuries of landclaim by the construction
of embankments, a protective barrier around the Wash from Gibraltar Point
(Lincolnshire) to Wolferton Creek (Norfolk) has been created. To landward of these
defences the terrestrial environment is one of high yield, intensive agriculture
including the largest area of grade one agricultural land in the UK. However, land
drainage has led to peat shrinkage with the relative height of the farmland now three
metres below the level of the mean high water spring tide (WEMP, 1996). Storm
driven tidal inundation therefore presents a serious risk in this area and maintenance
of the flood defences is paramount.
Concerning other commercial activities in the Wash, the main ports of the
embayment Boston and King’s Lynn, handle between them four million tons of trade
annually (WEMP, 1996). It is a result of this freighter traffic through the Wash that
the pilots frequently conduct surveys in the approach routes to Boston and King’s
Lynn. This information is in turn supplied to the Hydrographic Office for use in chart
updates. These often surveyed locations are referred to on the charts as the
‘Approaches to Boston’ and the ‘Approaches to King’s Lynn’.
Research Objectives
The primary objective of this research is to demonstrate the discrepancy between
Digital Terrain Models produced within a Geographical Information System (GIS) and
the representation of topography on a conventional Hydrographic Office chart.
Bathymetric data sets have also been procured from the Port of Boston from which the
resultant DTMs demonstrate the high level of resolution possible in a qualitative
investigation of morphological change. Other issues for examination include:
compatibility between the available data sets
spatial and temporal extent of the available data sets
suitability of analysis within a GIS
the value of GIS to Shoreline Management Plans
The primary bathymetric data source for this exercise has been the 1993 edition of the
Hydrographic Office (HO) chart 1200 (The Wash Ports). To demonstrate the variable
level of subtidal and intertidal data intensity across the embayment, soundings from
June 1994 and December 1996 have been supplied by the Hydrographer of the Port of
Boston. This data represents part of the Port’s routine survey work conducted in the
‘Approaches to Boston’; particular interest concerns the growth of channels, deeper
than Chart Datum, to the north east of the Welland Cut (at the centre of Fig. 2).
Access to the lower shore area in the Wash is difficult and the Environment Agency
intertidal surveying strategy is reviewed. Attention is directed at the practicalities of
C.I.S. Pater
conservation designations that are applied here have local, national and international
importance.
The enclosure and draining of the upper saltmarsh has produced a soil
medium that is highly fertile and following centuries of landclaim by the construction
of embankments, a protective barrier around the Wash from Gibraltar Point
(Lincolnshire) to Wolferton Creek (Norfolk) has been created. To landward of these
defences the terrestrial environment is one of high yield, intensive agriculture
including the largest area of grade one agricultural land in the UK. However, land
drainage has led to peat shrinkage with the relative height of the farmland now three
metres below the level of the mean high water spring tide (WEMP, 1996). Storm
driven tidal inundation therefore presents a serious risk in this area and maintenance
of the flood defences is paramount.
Concerning other commercial activities in the Wash, the main ports of the
embayment Boston and King’s Lynn, handle between them four million tons of trade
annually (WEMP, 1996). It is a result of this freighter traffic through the Wash that
the pilots frequently conduct surveys in the approach routes to Boston and King’s
Lynn. This information is in turn supplied to the Hydrographic Office for use in chart
updates. These often surveyed locations are referred to on the charts as the
‘Approaches to Boston’ and the ‘Approaches to King’s Lynn’.
Research Objectives
The primary objective of this research is to demonstrate the discrepancy between
Digital Terrain Models produced within a Geographical Information System (GIS) and
the representation of topography on a conventional Hydrographic Office chart.
Bathymetric data sets have also been procured from the Port of Boston from which the
resultant DTMs demonstrate the high level of resolution possible in a qualitative
investigation of morphological change. Other issues for examination include:
compatibility between the available data sets
spatial and temporal extent of the available data sets
suitability of analysis within a GIS
the value of GIS to Shoreline Management Plans
The primary bathymetric data source for this exercise has been the 1993 edition of the
Hydrographic Office (HO) chart 1200 (The Wash Ports). To demonstrate the variable
level of subtidal and intertidal data intensity across the embayment, soundings from
June 1994 and December 1996 have been supplied by the Hydrographer of the Port of
Boston. This data represents part of the Port’s routine survey work conducted in the
‘Approaches to Boston’; particular interest concerns the growth of channels, deeper
than Chart Datum, to the north east of the Welland Cut (at the centre of Fig. 2).
Access to the lower shore area in the Wash is difficult and the Environment Agency
intertidal surveying strategy is reviewed. Attention is directed at the practicalities of