The catchment is predominantly arable, though requires substantial drainage in the northern areas due to the land being at or below sea level.
Near Markham Moor, the Rivers Maun, Meden and Poulter meet to form the River Idle, which is joined downstream by the River Ryton near Bawtry. At Bawtry, the River Idle turns eastwards to its confluence with the River Trent at West Stockwith. From the sources of the major tributaries to confluence, it collectively flows through Mansfield, Worksop, Retford, Maltby and Bawtry. The river Idle originally drained into the Don at Hatfield Chase but was diverted south to its current path in order to drain Hatfield Chase for creation of agricultural land.
The River Torne rises near Tickhill and flows northeastward, through the heavily drained area of the Isle of Axholme to its confluence with the River Trent at Keadby passing through south Doncaster. The Torne is a distinctively engineered river system. It has been extensively modified, straightened and deepened for drainage to enhance agriculture and flood prevention. This has often been at the expense of wildlife, with limited habitat available for aquatic and marginal flora.
The Idle and Torne catchment consists of two main operational catchments, the River Idle (including 31 classified waterbodies) and the Isle of Axholme (incorporating 12 water bodies including the River Torne). The Idle and Torne flow through vast areas of high-grade, drained agricultural land, historic urban areas, various archaeological and historic industrial sites, including former coal mines, sand and gravel quarry pits, some of which have now been given SSSI status and into the tidal reaches of the river Trent. Whilst access is controlled via sluice gates at West Stockwith and Keadby, the navigational journey of the Idle and Torne river networks is in part undertaken by the European Eel and potentially salmon and brown trout, though improved access is required so they can reach the upper waters.
The Idle and Torne’s, drainage and engineering legacy means we need to find ways to future-proof the catchment against a more volatile water cycle, impacted by our changing climate. As the landscape has been built for drainage, it is more vulnerable to drought and flood-the land will not hold, store or slow the water, communities downstream are left vulnerable. Equally, with limited good quality habitat lying below sea level incoming coastal waters are an increasing concern.
Places such as Isle of Axholme have water conflicts written in their history books. Today, we need to think about how we want to build for peace tomorrow – nature-based solutions and restorative work need to be at the heart of such strategies.
None of the rivers in the Torne and Idle reach ‘Good’ overall status. All water bodies are failing on chemical water quality, and only 4 out 43 reach good ecological status, with none of these in the Torne. Reasons for not achieving good vary, but a mix of pollution from agricultural urban and wastewater sources along with physical modifications are most dominant.
A glimpse on the sewage map for 2021 shows that the River Idle catchment has seen a total of 2271 spills for a total duration of 16039h, with the River Torne receiving 3328 spills over 23,642 hours. Changes to natural flow and water level also present major challenges across the catchment, with large water abstraction pressures for agriculture and public water supply.
Climate change projections by 2050 indicate a decrease in summer rainfall by 34% and increase winter rainfall by 29%, with low river flows expected to be 65% lower, but peak flows 30% higher. This is likely to lead to further water resource problems, with climate change due to reduced rainfall in the summer, when extraction is highest. Heavy rainfall in winter will also exacerbate flooding. This catchment has a long history of flooding, and will need investment to mitigate these bleak future projections.
Invasive species also present growing problems with signal crayfish, Himalayan balsam and Chinese mitten crabs recorded within these rivers.
Despite the negative projections, there remains positive stories to tell within the catchment. Efforts are being made to improve access within the River Idle for eels and other aquatic migrants, invasive species are being targeted and ambitious reintroduction programs are being piloted within the catchment. Some water bodies have maintained good ecological health and water quality despite pressures, and wildlife hotspots (e.g. Idle Valley Nature Reserve) are present. The expansive large rural catchment has great potential for Natural Flood Management projects to help meet the challenges of climate change and increased flood risk.
The Torne and Idle catchments support abundant coarse fish, water birds and mammals, including hosting one of the key sites for beaver re-introduction at the Idle valley Nature Reserve. The Thorne Moor and Hatfield Moor (SPA) are important for presence of breeding Nightjars (European migrant), whilst the Idle Washlands are important feeding and roosting sites for populations of wintering waterfowl. Important fish species present within the Idle and Torne include common carp, pike, barbel, perch, chub and eels.
There are a number of Sites of Special Scientific Interest (SSSIs) in the catchment, including the Idle Washlands SSSI and Sookholme Brook and Hills and Holes SSSI. Special Areas of Conservation (SAC) include Birklands and Bilhaugh, Thorne Moor and Hatfield Moor.
Water voles are one of the fastest declining mammal species in the UK. Pressure from predators such as the introduced American Mink and degrading habitat put this riverbank dwelling species at risk.
Agile, playful and excellent hunters otters feed from fish, crayfish and frogs. Often observed as a pair of eyes poking out of the water, the 7-11kg mammal is quick on land, but is most at home in the water thanks to its webbed hands and feet.
Growing up to 1 meter in length, the pike lies still in aquatic vegetation before it strikes out at fish, frogs, small mammals and, on occasion-small ducks! Clearly, the pike is an apex predator, but its speckled olive skin and swift strikes make it a sight to behold.
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