Firsby Reservoirs
The two areas of water at Firsby were created in the 1870s by Doncaster Corporation to act as holding reservoirs for the new main reservoir at Thrybergh. They were connected to Thrybergh Reservoir by two conduits: one of the old sluice gates can still be seen. Only a few years after they were opened it was found that there was severe leakage through both the embankments and the bedrock of the reservoir. Water was then collected upstream of the reservoirs and piped past them down to Thrybergh. After the M18 was opened it was found that there was an increase in pollutants and silt being washed downstream. The silt deposits decreased the size of the ponds and the reservoirs were declared redundant in 1974. In 1980 both Firsby and Thrybergh Reservoirs were purchased by Rotherham Metropolitan Borough Council from the Yorkshire Water Authority.
Firsby is a Local Nature Reserve and is managed primarily as a haven for wildlife and an area of quiet relaxation. There is a nice stroll around the lakes - can be very muddy in winter. The area around the lakes consists of both acidic and neutral grasslands with many species of grasses and herbs. The surrounding hedgerows incorporate mature trees and a wide variety of hedgerow plants can be found there. The ponds are subject to significant seasonal fluctuations.
I understand that, although there is no resident ranger, the site is visited regularly to monitor leakage readings from the reservoirs and generally keep an eye on the place.