Work has been carried out to re-align, clear and build up a small, Littleton head of water and create two backwaters.

It is not navigable to craft and is rich in plant and insects, particularly reeds, diverse sedges (many of which commonly called bulrushes), pond-skaters, amphibians and lepidoptera (moths and butterflies).

[n 1][2] It then turns southward and splits Littleton (specifically the Queen Mary Reservoir, then a thin nature reserve by Shepperton Studios) from Laleham.

It is the northern limit of diminutive, near-square Shepperton Green — the western third of which was for centuries a southern outcrop (projection) of Littleton, and remains so in the Anglican church system.

Canoeists avoid the river when deep enough to canoe due to short barrages, extreme narrows and culverts.

Water quality is ordinarily clean given improvements in the effluent treatment works along the quite populous Colne valley – for a low-gradient river eutrophication and deposition is moderate to low.

To cross this and meander, the river is in a culvert next to: Birch Green; Shortwood Allotments; and Queen Mary Reservoir.

Public budget work then arose, the River Ash Flood Alleviation Scheme of the Environment Agency.

It was built in about 1870, partly by commission of the Wood family whose Manor House, standing at today's Shepperton Studios, had a costly fire in 1874.

[13] Its central newel (pilaster) as to its outer, upstream side has a coat of arms with three swords, not the family's which was that of a bull, instead that of Middlesex.

[1] The Reserve is linked by a large footbridge and has a variety of wildlife, mixed woodland, wildflower glades, ponds and the river.

Conservation over the years has helped to increase the biodiversity of the area and as well as monitoring and recording the wealth of species; the volunteers continue to enhance the site for the benefit of the wildlife and enjoyment of the public.

[1] The woodland onsite is ecologically important thanks to numerous veteran oaks of type quercus robur which promote a vast array of invertebrates.

[1] In 2016 a project was undertaken alongside the Environment Agency which formed part of the ColnCAN's "Weir today: gone tomorrow" programme.

About 600 metres was restored to provide favourable flow variations and enhanced aquatic and terrestrial habitat for a broad range of species.