It rises at Ashley Head spring in Crondall and flows north to meet the Whitewater at Bramshill.

[6] Beyond this, it threads its way through Coxmoor Farm, under the Basingstoke Canal and across Peatmoor Copse, where it is joined by another small stream, to reach the main channel of the Hart.

[9] Pilcot farm is on the left bank, and then the river passes often tree-lined through fields west of Fleet, where ditches add to it.

The channel splits into two to pass under the South West Main Line embankment, fields being drained up to about the M3 motorway.

A lake was constructed in 1871, to the north-east of the hall, but this had become overgrown with vegetation by the 1980s, and a weir and bypass channel were built, so that the river could be diverted around it to allow it to be dredged.

[11] Teulon also built a bridge over the river, with two segmental brick arches and wrought iron gates.

Its original 2,500 acres (1,000 ha) of land was enclosed by Thomas Foxley in 1347 as a deer park, and he later built the house.

Diplomat, Edward, Lord Zouche of Harringworth, bought it in 1605, and built a mansion between 1605 and 1612, incorporating part of the house.

[13] Within the park is a grade I listed bridge crossing the river, built in the early 19th century in Jacobean style, with two red-brick arches and stone dressing.

A mill in Dogmersfield was mentioned in the Domesday Book, compiled in 1086, but it was probably a little further downstream at a building known as Pilcot and more recently, Catherine of Aragon.

Components of determination include biological status (the quantity and varieties of invertebrates, angiosperms and fish).

Reasons for the quality being less than good include: discharge from sewage treatment works; runoff from agricultural land; physical barriers such as weirs and impounding of the water which prevent the free migration of fish and other species; runoff from roads; and leaching from landfill sites.