You are in [Places] [River Shalbourne]
[This article was sent by Dr Jimmy Whittaker, April 2020.]
Hungerford’s Secret River
If you drive down Smitham Bridge Road, you’ll come to a small bridge over a narrow stream. Looking northwards from this vantage point, you will see another bridge, a footbridge which leads to a children’s playground.
In the early 1960s, I used to fish this stream for brown trout with Paul Richens, a.k.a. Mousey, and Andy Robinson from Moore’s Place. Paul’s family lived in a bungalow close to the stream and his dad Arthur farmed the land which runs parallel to the stream up to the boundary of Beacon Farm. There were only two places that were fishable, and these were the two bends where the current had etched deeper channels. In those days we used small fibre glass rods with Mepps spinners. All the trout we caught were small and were safely returned to the wild. A couple of years later, I found a wider, deeper section on the road to Stype. Once again, this fishing spot only produced small brownies.
This stream today is known as the Shalbourne Brook but historically was called Shalbourne Stream but known as the River Shalbourne by the Environmental Agency.
The Agency has installed a monitoring station at Smitham Bridge Road, just behind the entrance to the Hungerford Industrial Estate. It consists of an electronic gauge which measures water levels every 15 minutes, the purpose of which is to act as part of a flood warning system. Normal levels of the “Shalbourne” are between 0.04 and 0.60m. When the water level exceeds 0.6m minor flooding is possible. However, on 3rd June 2008, it reached 1.08m. Incidentally there is also a monitoring station on the bank of the River Dun behind Cobbler’s lock and since monitoring began, for 90% of the time the levels of the Dun have been between 0.05 and 0.2m with a record level of 0.31m on 1st January 2003.
The Shalbourne Stream is a tributary of the River Dun which in turn is a tributary of the River Kennet. It rises from a spring-fed source in the Upper Greensand and flows for 6 km across the Upper Chalk in a northerly direction through agricultural land towards Hungerford. In simple terms Greensand and Upper Chalk are certain types of limestone strata associated with Southern and Eastern England.
Gauged flows for the Shalbourne between 1997 and 2000 show a mean winter flow of 24 ML/D (million litres per day) and a mean summer flow of 12 ML/D. Both the Shalbourne and the Dun are chalk streams as mentioned above. The Dun flows through Freeman’s Marsh, an SSSI, before joining the Kennet, itself a river SSSI, at Denford. It is abstracted by Berkshire Trout Farm immediately upstream of its confluence with the River Kennet.
The Kennet and Avon Canal was built in the late eighteenth century and its route cut across the Shalbourne Brook a short distance upstream of its confluence with the Dun. If you walk on the canal path from the swing bridge behind the church towards Marsh Lock, you will see the property known as The Orchard with Shalbourne on the left , and the Dun on the right. The Orchard is accessed via Marsh Lane. These two watercourses used to be connected by a brick culvert built under the canal close to the swing bridge behind the church. This connection was later disrupted when the entire flow of the Shalbourne was diverted into the canal at a point about 150m west of the culvert. This was done to provide additional water for navigation on the canal. A fixed crest overspill weir positioned opposite the newly-created confluence enabled surplus canal water to drain into the River Dun via a ditch. The complex interconnections between natural watercourses and the Kennet and Avon Canal in the Hungerford area have been the subject of debate since the canal reopened in 1990. The canal is an important recreational and ecological resource in its own right, but its connection with the Dun leads to silting of gravels and epiphytic growth on aquatic plants.
The 1998 Hungerford Fish Mortality:
On the 4th March 1998 almost seven kilometres of the canal, together with the River Dun and the Berkshire Trout Farm, were polluted by toxins caused by algal growth in the canal. This algal growth in turn stemmed from unusual environmental conditions, resulting in the destruction of 150 tons of fish. At the time, this was the largest fish kill incident that the Environmental Agency had had to deal with. In essence, toxic water from the canal had passed over the overspill into the River Dun, aided by the flow from the Shalbourne. A key recommendation of the technical investigation into the fish kill was the reduction of water transfer from the canal to the Dun, to help ensure future similar incidents would be contained within the canal, thus protecting the natural watercourses of Hungerford’s rivers: the Shalbourne, the Dun and the Kennet. Follow this for more on the 1998 Hungerford Fish Mortality.
The diversion of the River Shalbourne:
The solution to the problem was to divert the River Shalbourne into the original culvert and this was achieved by creating a new channel. This was quite an engineering problem since the canal had to be isolated from both of the rivers. The project was completed on 20th March, 2000. Feedback from partner organisations and the local community has since been very positive. The Hungerford Fishery reported an immediate and dramatic improvement in flow and water clarity of the Dun leading to vigorous growth of plant life.
David Susmann, the original owner of Hungerford Marsh who used to live in Mill Hatch in Bridge Street, was an enthusiastic supporter of the River Shalbourne project and, with English Nature’s consent, agreed to let the discharge side of the culvert run over a part of Hungerford Marsh into the River Dun. In 2015, the Town and Manor of Hungerford purchased the 28 acres of Hungerford Marsh and is now designated as Hungerford Marsh Nature Reserve which is managed by Berks, Bucks and Oxon Wildlife Trust (BBOWT). Although this culvert has improved water quality to a certain extent, the water quality status is still poor due to poor nutrient management, sewerage discharge and land drainage. The culvert itself is still an obstacle to fish migration.
I last fished the Shalbourne Brook in 2006 and caught two small brownies just behind the entrance to the Hungerford Industrial Estate. This excitement was marred by the presence of a couple of discarded shopping trolleys that I removed and dumped in someone else’s skip on the estate.
On a passing note, in a recent conversation with local “countryman” Rod Smith, I have since learnt that very few fish now remain in the Shalbourne due to predation by mink, herons, cormorants and possibly otters.
(All images by Dr Jimmry Whittaker)