The river rises in Normanshill Wood, to the north-west of Ravenshead and flows eastwards, passing under the A60 road, and to the south of Portland Training College.

[3] To the north of the second lake is Fountain Dale moat, which is known to have existed in 1251, when there was a hunting lodge on the 52-by-38-yard (48 by 35 m) island, from which tolls were collected by the forester Raffe Clerc.

[6] The main lake covers an area of 4.0 acres (1.62 ha) and is a private fishery, stocked with bream, carp, pike, roach and tench.

[7] It forms part of the Rainworth Lakes Site of Special Scientific Interest (SSSI), which covers an area of 36.2 acres (14.6 ha) and has been designated because of the variety of plant species which grow in the open water and adjacent marsh.

Although separated from the river by the A614 road, the complex has over 1000 villas, together with bars, shops and cafes, and is of sufficient size that it maintains its own private sewage treatment works, the outflow from which swells the flow of Gallow Hole Dyke before it joins Rainworth Water.

[10] The river then reaches the southern boundary of the country park at Rufford Abbey, where Gallow Hall Dyke joins it from the east.

Because the volume of water it contains exceeds 880 thousand cubic feet (25,000 m3), it has been subject to the conditions of the Reservoir (Safety Provisions) Act 1930.

This has required significant engineering works to be carried out, which have been complicated by the presence of a listed mill building in the vicinity, and the fact that the site is a public amenity.

In 1974, the dam had to be raised and sealed, the overflow works were reconstructed, and a retaining wall was built on the upstream side of the mill building.

Water running over the wall ran down a gentle slope, formed of interlocking hollow concrete blocks filled with earth and grassed over.

[22] Continuing subsidence meant that the dam freeboard was reduced to a height below that required by the reservoir safety legislation, and any work carried out could not make flooding above the lake worse, as this had previously resulted in a High Court action.

[25] With the water level permanently lowered, some work was required at the southern end of the lake to rewater the dry sections.

The bottom of the lake consists of a layer of black sediment, thought to have come from the nearby colliery, which provides an impervious lining, with sand and gravel below that.

[27] In November 1992, high rainfall meant that water ran over the main spillway, and there was serious disruption of the downstream concrete blockwork and grass.

[28] Rainworth Water LNR was once part of Rufford Colliery, which created the spoil heaps that form a bowl around the watercourse.

The spoil heaps were restored after the colliery closure and the planting of thousands of broadleaved trees and other woodland species have stabilised the ground.

The Water itself is a wetland habitat consisting of artificial pools, shallows and meanders that appear natural and support dragonflies and damselflies.

[29] The streams drain areas where the underlying rock consists of Bunter pebble beds from the Triassic period, and the sandstone results in the water being base poor and hence slightly acidic.

[16] Much of the river channel has been straightened over the years, to ensure that large quantities of water can be removed from the area during wet periods or flooding incidents.

[34] The ecological status of the river system in 2013 failed because of the presence of pollutants, notably Triclosan in Rainworth Water and copper in Gallow Hole Dyke.

These issues are exacerbated by low flows, run-off of surface water from roads which cross the catchment, diffuse pollution from agriculture and urban areas, and the discharges from sewage treatment works.

[35] The work undertaken on assessing the catchment resulted in proposals for eleven schemes which will produce benefits to the river system.

[36] Typical of such schemes is an area of wetland at Thieves Wood that would allow run-off from the A60 to deposit silt, and chemical contaminants to be removed before the water enters the main river.

Like most rivers in the UK, the chemical status changed from good to fail in 2019, due to the presence of polybrominated diphenyl ethers (PBDE) and mercury compounds, neither of which had previously been included in the assessment.