LOTE work at Old Hall Marshes

Blog by Kieren Alexander -  RSPB Site Manager, Old Hall Marshes Reserve

Last Summer and Autumn was a time of high activity at Old Hall, as the next round of LIFE on the Edge works was completed.

Like in previous years, the focus of the work was on reprofiling footdrains to benefit breeding waders by improving edge and then using this claimed material to rebuild and repair some historical but damaged crossing points. The latter for the purposes of allowing us finer and greater water control and greater compartmentalisation of the marshes. 

However, this time we also completed the installation of a new tilting weir with eel pass, this is an important update to the site’s infrastructure. It replaces an old, leaky and somewhat difficult to use wooden dropboard sluice with a new purpose built easier to use at all water levels sluice. The important part of this is the ability to use the sluice at all water levels, in the event of a saline incursion our ability to remove water from the marshes will be critical. This weir with its safe access route will enable us to do this. The other improvement reducing the amount of freshwater that was being lost through the old dropboard, freshwater is critical to the health of the marshes and is one of the things we can’t control.
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Although it may sound odd to have an eel pass on this, the borrowdyke where the weir is placed is hardly a main river, as eel numbers have dwindled freshwater marshes near the sea have become increasingly important as refuges for this species and is now home to a good number of eels. This eel pass will allow the eels that call Old Hall home to complete their natural lifecycle. It will ease passage into the marshes and then when the time comes allow them to leave the Marshes and return to the Sargasso sea to spawn, it what must be one of the most incredible migrations of any animal. 

New tilting weir with eel pass by RSPB

​During the works we were reminded of some of the pressures that are increasingly prevalent to highly valuable and designed sites, this time in the case of a wildfire which ripped through around 10ha of scrub on the marshes. Incidents like this remind us of why we need to start the careful adaptation of our protected sites and change the way we work. 

Aerial view of the wildfire by Ocker engineering

​Later this year, we will be concluding our LIFE on the Edge work at Old Hall, with the installation of some new solar pumps but before that we have the breeding season to navigate, although we may not have received the water we would have wished for this winter (we seem to have been stuck in a dry high pressure system for months), the key fields are more or less where they need to be and before long lapwing will laying eggs and raising young across the marshes.