Assessing the extent of historical floodplain meadows using GIS

Tuesday, June 7, 2022

We have long been interested in assessing the historical extent of floodplain meadows and have worked with a range of individuals over the years who are researching their local meadows in terms of their historic extent. This work requires in-depth research, exploration of the archives and a good knowledge of the local area and is therefore quite specialised. However last year, we worked with Fjordr Ltd, which had previously undertaken related work on the historic character of watercourses to explore the possibility of using easily accessible GIS maps to identify the extent of floodplain meadows in two pilot catchments.

During their previous project on the Dorset Stour, meadows with distinctive funnel-shaped entrances from droveways were identified in the floodplain, echoing the entrances seen where roads and droveways enter a common to facilitate the movement of livestock. These funnel-shaped meadows generally look quite different to the fields surrounding them, which in turn seem to respect their often sinuous, irregular boundaries, suggesting that the funnel-shaped meadows pre-date the more organised enclosed fields that abut them.

Furthermore, on tithe maps from the 1840s, the funnel-shaped meadows are often sub-divided into multiple strips demarcated by dotted lines that fit within the boundaries of the meadow. The system of dividing up meadow into strips to allocate hay followed by common grazing on the aftermath reflects a practice dating back to the medieval period.

The project focussed on using GIS to draw together map-based evidence to estimate how much of a floodplain in a river catchment was floodplain meadow in the past based on the identification of these funnel shaped meadows; how floodplain meadows were distributed relative to parishes; and to explore whether the amount of floodplain meadow might be related to the size of previous populations.

Looking at seven parishes on the Dorset Stour, the project identified additional floodplain meadows managed as commons, and clarified the extent of those identified previously. The methodology was then applied successfully to eleven parishes on the Windrush, Thames and Cole. In both areas, the methodology confirms the persistence into nineteenth century mapping of a distinctive form of floodplain meadow with clear and quite consistent morphological features. Sufficient of these are shown subdivided into doles in tithe maps in the 1840s to indicate that they were managed as commons by allocating strips to individuals for hay followed by grazing of the aftermath. The need to move animals to and from the floodplain meadows gave rise to their funnel-shaped entrances accessed via droves connecting them to settlements. The importance of these droves and meadows caused them to be maintained while surrounding land was enclosed, though in many cases enclosure and private ownership subsequently encroached upon them.

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Source: Floodplain Meadows Partnership

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