River Blackwater (River Test)

Blackwater
River
River Blackwater east of Testwood Lakes
Country	United Kingdom
Regions	Wiltshire, Hampshire
Source
- location	Redlynch, Wiltshire
- coordinates	50°59′23″N 1°42′44″W / 50.98972°N 1.71222°W / 50.98972; -1.71222
Mouth	Totton
- location	Hampshire
- coordinates	50°55′36″N 1°29′31″W / 50.92667°N 1.49194°W / 50.92667; -1.49194Coordinates: 50°55′36″N 1°29′31″W / 50.92667°N 1.49194°W / 50.92667; -1.49194
Length	45.0 km (28 mi)
Basin	67.5 km2 (26 sq mi)

The River Blackwater is a river in the English counties of Hampshire and Wiltshire. It is a tributary of the River Test.

The river rises just to the east of the Wiltshire village of Redlynch, near Salisbury. It then flows east across the county boundary into Hampshire, where it flows north of the village of Wellow and the hamlet of Wigley. The river turns south, passing under the M27 and past Broadlands Lake and the Testwood Lakes reservoirs, before joining the Test between Totton and Redbridge. The Environment Agency records the length of the main river as 39.4 kilometres (24.5 mi), with an additional 5.6 km (3.5 mi) for the watercourse from Redlynch to the confluence north of Hamptworth.

This River Blackwater should not be confused with the River Blackwater in north-east Hampshire, which is a tributary of the River Loddon and (indirectly) of the River Thames.

Another similarly named waterway in Hampshire is Black Water, a small stream which flows eastwards across the New Forest, passing under Rhinefield Ornamental Drive, before joining Ober Water and Highland Water just north of Brockenhurst to form the Lymington River.