A History of No. 6 tank (part two)
Map of No. 6 tank as of Summer/Winter 1994.
To keep the Manchester Ship Canal navigable to large craft, vast quantities of sludge and silt are dredged up by specialist craft more or less continuously. The dredgings are transported along the canal to a Pumping Station bordering the canal and then pumped through huge pipes into vast sludge deposit grounds. These are the famous “Frodsham Sludge Pools” and they now occupy over half of the flat reclaimed area of pasture and arable land known as Frodsham Marsh.
Since about 1941, these sludge pools have been well-known as a superb habitat for birds. Numbers 1, 2, 3, 4, and 5 Sludge Pools have each in turn, both during the construction phase and then during the subsequent years of infilling, proved ideal to the requirements of a remarkable variety of migrant, wintering and breeding wetland species.
(Above image is of No 6 tank soon after the first excavation work commenced and without the retaining embankments in place. This area is buried under 23 years worth of sludge/silt and currently several feet of water. Presently the area is situated below the viewing area on the south bank of No 5 tank.)
During the last three years, a new sludge deposit ground has been referred to by local birders as “Frodsham Marsh New Workings/Frodsham New Tank Excavations/Frodsham Marsh No6 tank Sludge Pools”. Top soil is scraped out of the marsh to create a 15 metre high bank surrounding the whole area to be later filled with sludge. The scrapings create shallow freshwater pools and these soon acquire muddy margins, reed fringes and a healthy supply of invertebrates.
The whole area rapidly becomes a veritable paradise for birds and birdwatchers. Once sludge starts to be pumped into the tank, the habitat starts to deteriorate. It is expected that pumping into No6 Sludge Pool will commence in 1995. Frodsham Marsh bird recorder Bill Morton has drawn a detailed map showing the “inside” of the new workings as they were in Summer/November 1994 – before any pumping operations started and as most birders will nostalgically remember the site in years to come.
If you visit the area please remember that you are private land and managed by the Manchester Ship Canal Company and that you must respect any reasonable request from their representatives. Also note that the pools are often shot over by wildfowlers between September and February, usually at dusk. However there are public rights of way across the marsh for bona fide naturalists there should be no real problems of access.
Here are some of the highlights from Frodsham Marsh New Workings in its ‘glory years’ of 1992 – 93 – 94.
1992 – Temminck’s Stint 14th – 17th May.
1993 – at least five different Little Egret between 10th August and 22nd September, adult Spoonbill 12th – 15th July and again 24th – 29th and 6th – 7 th August, peak Garganey count of 16 on 7th September, two Quails calling in late May/early June, juvenile Spotted Crake 31st August to 10th September, three Black-winged Stilts 25th April and again 14th may to 7th June with failed breeding attempt, Temminck’s Stint 8th – 12th May.
1994 – adult Spoonbill 23rd June – 2nd July, eight Ruddy Shelducks 31st August, 13 Garganey in August, Osprey 1st October and 600 Black-tailed Godwit (Unusual high number in the early 1900’s) 9th August.
Ted wrote this article called ‘Frodsham Marsh New Workings 1992 – 94’ for North West Region Bird Report 1994. The glory years he talks about above were in reality still to come, the period after 1994 saw a tremendous increase in activity with some incredible birds and birding.
All images and illustration by WSM except for photo 1,2 & 6 by Tom Edmondson.
To be continued…