Wednesday 3rd January 2018

Lower Marsh Ride on 3rd January 2018 – submerged under 1m of water

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A series of deep depressions with associated high winds and rain, interspersed with brief quiet periods and heavy frosts have prevented any ringing at South Milton since the middle of December. However there have been benefits.

Storm Eleanor piled up an exceptionally high sandbar at the seaward end of the reserve and this barrier, coupled with high spring tides and a lot of water flowing from the catchment, has raised the water level in the reedbed and ditches. Nick Townsend and I visited today, to determine which areas of reedbed would be accessible for cutting next weekend, and we were able to make measurements of water depths and flows along the length of the reserve. The weight of entrained water subsequently breached the sandbar and it partially reformed over the next two days. Nick managed to make additional measurements over this period and we now have a series of observations relating the depth of water at the coastal footbridge to the extent and depth of water in the reedbed and ditches.

We have been working together with Natural England to produce a proposal to install control structures along the main drainage ditch in order to rectify the impacts of previous, over-enthusiastic ditching operations. A historical concern about a risk of flooding at Mill Lane, the eastern boundary of the reserve, has driven past management and we now have conclusive evidence that it is a lack of capacity in the culvert under Mill Lane, rather than the water level in our ditches, which has caused surface water flooding there in the past. The installation of up to three sluices would give us control over water levels in the eastern half of the reserve for the first time and should restore both the water table and gradients along and across the whole reserve with no effect on the flood risk at Mill Lane.

South Milton Stream pre 1991

The widened, deepened and straightened stream in 1994

The same view in December 2017 showing how far the water table has been lowered

Our intention is to raise the water level in the main ditch to something like this (taken on 3rd January 2018)