[1][2] Highland Water is a Geological Conservation Review site[3] and Ober Water is a Nature Conservation Review site, Grade I.

[4] Parts of the site are in The New Forest and Solent and Southampton Water Ramsar sites,[5][6] and in The New Forest Special Protection Area.

[7] This site covers the river and its tributaries Highland Water, Ober Water and Mill Lawn Brook, and no other system in England shows such a rapid succession of plant communities in such a short stretch of river.

Ober Water has a very unusual and diverse flora and several rare and protected species of dragonfly.

Highland Water is important for illustrating fluvial processes in rivers in southern England which have not been subject to modification.