3- How did human activity alter the marsh?

At the beginning of the 19th century a pattern of drainage channels began to be constructed across the west of the marsh to lead the main streams to a single outlet to the sea via a sluice, which would open to allow fresh water out, but would close against the tide to avoid salt water entering.  These developments were called the “New Works” the remains of which can be seen in Resource 14. This drainage system regulated water levels so that the coastal grazing marsh could be reclaimed to create “improved low intensity agricultural systems, primarily the grazing of livestock (predominantly cattle with some horses and sheep) with limited areas of arable cropping (barley and wheat), a managed reed bed for thatching and a small plot of Christmas trees” (National Rivers Authority et al 1992).  A report by DEFRA and the Environment Agency (2001 p 8) documents that in the 1930 s Porlock Marsh was recorded as having  “exceptionally good grazing land”.   Detailed maps drawn up in the 1930s recorded the names and extent of each of the reclaimed pasture and arable fields across Porlock Marsh as can be seen in the examples in Resource 15, Resource 16 and Resource 17. The image in Resource 18 dating from the 1950s shows stooked sheaves of wheat in an arable field whilst the photographs in Resource 19 and Resource 20 from the 1960s illustrate the harvesting of reeds to be sold for thatching.  The photograph in Resource 21 shows how streams entering Porlock Bay were widened, deepened and canalised in order to more effectively channel their water across the marsh to the New Works sluice and then onwards to the sea.  The 1984 photograph in Resource 22 is a view westwards across central Porlock Bay showing the pebble ridge with its steep and high crest and the freshwater grazing marsh and reclaimed fields  behind the barrier drained by the sluice at New Works (mid distance).  The 1956 photograph in Resource 23 shows several of the inner marsh fields ploughed and reseeded.  It should be noted here however that although the tidal sluice gate system (New Works) did allow for sufficient freshwater drainage to allow pasture development for livestock it was never efficient enough to fully drain the back barrier area. As a result a small mere and reed fen was able to establish itself behind the ridge (see also  Resource 24) would subsequently provide the interest for the original SSSI biological designation.

Consolidate Your thinking 

Orientate the photograph in Resource 23 with the Ordnance Survey map in Resource 4. Most of the agricultural land behind the pebble ridge in the photograph is lying between the South West Coast Path on the map and the area of the pebble ridge known as Bossington Beach.   Now look at the picture of Porlock Bay in Resource 8 and the satellite image in Resource 25. What has happened to most of this reclaimed agricultural land?  What evidence is there in the picture and the Google Earth image to explain what has occurred?

Resource 26 shows two Ordnance Survey maps of Porlock Bay – one from 1931 and the other from 2008.  Describe how the landscape of Porlock Marsh changed during the period of time between the two maps.  What do you feel to be the most significant change?  Can you explain what might have caused this change?

Go to Question 4  -  Why has the pebble and shingle ridge at Porlock Bay become progressively more vulnerable to breaching?