The stream rises on heath land to the north of Camberley and descends in a south-westerly direction, passing through the grounds of the Royal Military Academy Sandhurst.

[9] Below the tanks, the remaining two channels continue downwards, passing over weirs and under Dawnay Road, to be joined by several drains, supplied by nearby springs.

Below the pool, the stream used to follow a course to the south-west, to reach the Lower Lake, as the county boundary still does,[1] but in the late 1960s the Academy was expanding, and a new range known as the East Buildings was constructed, with a parade ground on its northern side.

To accommodate them, a new course was built for the stream that follows the northern and western edges of the rectangle of land on which the East Buildings stand.

It consists of a series of small ponds and weirs,[10] and at the south-western corner of the rectangle, the Wish Stream enters the Lower Lake.

[1] The outflow from the Lower Lake is crossed by Yorktown Bridge, and is punctuated by a series of weirs as it continues its descent to the Blackwater.

As the channels leave the grounds of the Academy, they enter culverts which have allowed a superstore to be built over them, and emerge on the other side as a single stream.

[11] In 1800, the land through which the Wish Stream ran was part of the estate of William Pitt, but an agreement was reached in 1801 that the government would buy 450 acres (180 ha) on which to build a college for the training of military personnel.

The project was not without its difficulties, as the Royal Staff Corps who were carrying out the work asked for protection from the cadets at the Academy, who were using the wheeling planks as rafts on the unfinished Lake.

[22] The upper Wish Stream is part of the Broadmoor to Bagshot Heaths and Woods Site of Special Scientific Interest (SSSI).

Nine species of sphagnum moss grow in Wishmoor Bottom, of which two are particularly notable, and it is also noted for the presence of hare's-tail cotton-grass, crested buckler-fern and marsh fern.

[23] Natural England is working with Defence Estates and the Royal Military Academy Sandhurst conservation group to improve the heathland, from "unfavourable recovering" to "favourable" status.

This has involved the felling of large numbers of trees, to allow the heath vegetation to regenerate, and surveys of nesting birds indicate that the three species mentioned has increased significantly since the project began.

The Bathing Lake holds good numbers of wild brown trout, which use the gravel beds of the Wish Stream to spawn.

[27] When the Wish Stream was diverted around the East Buildings, the new ponds were made of concrete, but were lined with chalk and gravel to manage the acidity.

[29] As part of their responsibility under the Water Framework Directive, the Environment Agency assessed the ecological status of the Wish Stream in 2009 and 2010, and the barriers to migration of fish.

They found that the section above the Bathing Pool was largely unmanaged, with woody debris providing cover for the trout, and gravels suitable for spawning.

However, there was one section where the river ran through a concrete pipe, which forms part of the cadet obstacle course, where the water was fast-running but very shallow.

[31] The outflow from the Lower Lake is a large stepped weir structure, with the water then running through a shallow concrete culvert, both of which are impassable to fish.