Hydrology
The region through which the river flows is underlaid by an extensive water-bearing porous rock structure called the Magnesian Limestone aquifer, which is near the surface in the west and dips downwards to the east. Magnesian Limestone is so called because it contains quantities of the mineral Dolomite, which is rich in Magnesium. The Triassic Sherwood Sandstone aquifer is another porous rock layer which covers this to the east, and is the major geological component of the area. Further east, they are both covered by a layer of Mercia Mudstone. Where these aquifers reach the surface, they often supply water to the river system, but can also take water from it. This is affected by the extraction of groundwater, particularly for public water supply, and by fracturing of the aquifers as a result of subsidence caused by deep coal mining.
The Ryton draws its water from the Anston Brook, the Pudding Dyke, the Bondhay Dyke, and to a lesser extent the Broadbridge Dyke. Prior to the construction of the Chesterfield Canal in the 1770s, the flow of the Broadbridge Dyke was much greater, but water from its catchment area was diverted to form the reservoirs at Pebley and Harthill, which supply the canal. Overflow from the reservoirs reaches the Ryton by the Pudding Dyke, but the river also supplies water to the canal via the Brancliffe feeder and the Kilton feeder. The natural water sources are supplemented by the outflows from Dinnington and Anston Sewage Treatment Works into the Anston Brook, which together provide about 7 Ml/d (megalitres per day), while Kilton Treatment Works supplies about 12.8 Ml/d. At Manton, excess flow from the canal tops up the river, and water pumped from Manton Colliery formerly performed the same function. With the closure of the mine, a new borehole was constructed in 2004, and water is pumped from the Sherwood Sandstone aquifer into the river. The borehole is operated by Severn Trent Water.
In order to monitor flows on the river, the Environment Agency maintain gauging stations, one to the east of Worksop and a second to the east of Blyth. They also have one on Oldcotes dyke, just below Blyth Old Bridge. The catchment area above the Worksop gauging station is 29.7 square miles (77 km2) and the mean flow is 8.55 million gallons (38.88 Megalitres) per day. The catchment receives 25.8 inches (655 mm) of rainfall in an average year. Oldcoates Dyke contributes 12.92 million gallons (58.75 Ml) per day, and the flow at the Blyth gauging station amounts to 28.89 million gallons (131.3 Ml) per day, derived from a catchment area of 89 square miles (231 km2). This station has been operational since 1984. Previously, there was a gauging station a little further downstream at Serlby Park, but this was decommissioned in 1978, as the flow readings in the summer were not reliable. Data from the Blyth station is transmitted to the pumping station at West Stockwith, where it is used to control discharges from the River Idle into the River Trent.
Read more about this topic: River Ryton