Cheriton Stream Enhancement - EA Partnership Project

The Cheriton Stream is widely recognised as the primary headwater of the River Itchen in Hampshire. This section of river was one of the country’s first ever Wild Fishery Protection Zones, where no stocking is permitted by the Environment Agency. It is crucial therefore, that habitat quality is good enough to support a healthy and vibrant wild trout population. Unfortunately, historic channel modifications, coupled with excessive grazing pressures, has left a wide, uniform and very shallow river channel. 

Following a successful project delivered by the WTT further downstream last year, the Environment Agency have funded a further phase of work at the very top of the Tichborne fishery. This fishery is managed by the Tichborne Fly Fishers and volunteers from the club, led by WTT Conservation Officer Andy Thomas, have been busy improving a 100m section of channel to create enhanced habitat for all the life stages of brown trout, as well as providing improved cover for native white clawed crayfish.

1 Cheriton Stream Before
A typical section of heavily modified river, where the banks are made up from hard chalk and the channel is flat and shallow, with precious little cover for fish.

The enhancements focused on creating a low, soft margin where aquatic plants and marginal chalkstream herbs will flourish, providing improved cover for fish and refuge areas for the adult phases of river flies and crayfish in a new, complex margin. A key element of the project was to also create improved holding habitat for adult trout and enhanced spawning habitat. This was achieved by tracking in with a small excavator to create a series of pool and run” features. The pools were created adjacent to sites where there was at least some existing tree cover. This was further enhanced by hinging” or lowering the trees to create the all-important low-level cover which fish need to feel comfortable and reduce predation pressures. 

The first task was to dig a naturalistic pool habitat right under the new cover and install a large natural flow deflector made up of either one large, or several smaller tree trunks secured to the river bed with driven chestnut clefts. 

2 Cheriton Digger
A shallow excavation is made to loosen the bed materials to free them up for redistribution.
3 Cheriton Flow Deflector
Next a large flow deflector is dug into the opposite bank to flume the flow into the newly created pool habitat

In creating the ideal lie for an adult trout, the work also enables a valuable ramp of loose gravels to be formed at the pool tail, providing new and improved opportunities for gravel spawners.

4 Cheriton Pool Tail
A new pool tail, ideal for trout spawning.
5 Cheriton Soft Bank
The high, hard bank has gone, to be replaced with a low-level soft bank ideal for colonisation by chalkstream plants and providing cover for native crayfish and small trout. In addition the channel cross section has been squeezed to promote a lively riffle, ideal for trout parr habitat