Sapperton Valley is one of three adjacent nature reserves near Daneway, a few miles east of Stroud in the middle of the Cotswolds, the others being the ancient trees of Siccaridge Wood and the calcareous grasslands of Daneway Banks. The valley - narrow, steep-sided and thickly wooded on both sides, is formed by the River Frome, here usually just a minor stream a few inches deep, while alongside are the remains of the Thames and Severn Canal, opened in 1789 but disused since the early 20th century. During wetter periods this too holds flowing water but for most of the time it contains only static pools, separated by muddy patches, which, together with wet meadows around the river, form an ideal habitat for riparian plant and animal life, recognised in the creation of the nature reserve, in 1964.
The protected area, a narrow corridor, extends 0.7 miles along the valley floor, bordering the Siccaridge Wood reserve to the north. The tall trees create permanently shady conditions, keeping the valley cool and moist, and in spring and summer the undergrowth grows tall and thick. Beside the plants and animals, the reserve is also notable for the ruined canal, which includes five locks, long since lacking their wooden doors but retaining the sheer brick walls, now moss-covered, tunnel-like and quite photogenic, due to the overhead vegetation and the reflective pools within. Wildflowers in the reserve are comparatively colourful, and varied, including purple loosestrife, great willowherb, meadowsweet, yellow iris, ragged robin, nettle-leaved bellflower, marsh marigold and yellow waterlily.
The future of the reserve is somewhat uncertain since Cotswold Canal Trust have since 1972 been gradually restoring the canal, however there are currently no plans to start work on the Sapperton Valley section, or indeed the partly collapsed 2.2 mile tunnel that starts a few hundred yards east.
Parking for Sapperton Valley Nature Reserve is along the unnamed road past Daneway Inn, just south of the bridge over the River Frome. There are two paths into the valley, either side of the river, one starting at the parking area, the other (the main route) on the far side of the road bridge. The land immediately south of the bridge was once the site of a coal wharf on the canal, next to a large, rectangular-shaped basin lock, but now all is overgrown and covered with trees.
The main part of the reserve starts just beyond the overgrown area close to the bridge and extends southwestwards, incorporating five more locks (Upper, Middle and Lower Siccaridge, Bathurst Meadow and Whitehall Upper), all now similar in appearance, filled with pools, fallen masonry and old tree branches. Between the locks, the canal has a mix of shallow water, swampy woodland, marsh, and patches of reeds and other plants. The River Frome flows close by to the south, the majority through woodland, some parts alongside wet, long grass meadows. The main path crosses to the south side of the canal via a footbridge about half way through the reserve, just below Bathurst Meadow Lock, and links to the south-side path, then both routes meet again at the west edge of the reserve, beside Whitehall Bridge, a brick road bridge over the canal, built in 1784. Also near the footbridge, two trails head north, climbing the steep slopes of Siccaridge Wood. Plants grow in the standing water of the canal, along the old towpath, beside the river, in the meadows and in the slightly drier woodland at either side. Otters can sometimes be seen in the pools; other creatures living or visiting here include dormice, frogs, toads, deer and bats.