A Site of Special Scientific Interest (SSSI)
A Site of Special Scientific Interest (SSSI) is a formal conservative designation. Usually it describes an area that is of particular interest to science and to the rare species of fauna and flora it contains. There may also be important geological features that may lie in its boundaries.
In England, Sites of Scientific Interest (SSSIs) are designated by Natural England, which is responsible for protecting England’s natural environment. Designation as a SSSI gives legal protection to the most important wildlife and geological sites.
There are 200 chalk streams known globally – 85% of which can be found in Southern and Eastern England.
The River Test is a chalk stream in Hampshire, England. It has a total length of 40 miles (64km) and it flows through downland from its source near Ashe to its estuary at Southampton, where it converges with the River Itchen to form Southampton Water. The whole river has been designated a SSSI.
This chalk stream has one of the richest fauna and flora of any lowland river in England. More than 100 species of flowering plant have been recorded along its banks and 232 invertebrate taxa in the river. It is also important for wetland birds, with breeding species including kingfishers, grey wagtails and little grebes. Also found here are Great Egrets and the rare Barbastelle bat.
Kimbridge Estate covers the middle of the River Test, with approximately 7 miles of fishable bank of the River Test flowing through it. All works carried out on the Estate are scrutinised by Natural England and the Environment Agency to ensure that the work will improve the SSSI.
Kimbridge Trout farm was originally built in 1974 to supply trout for stocking and the table. Once the first farm was built, three others soon followed elsewhere on the Estate. Meadow Farm had two sites and along with Cottage Farm were fed from the River Test. Garden Farm was supplied from the River Dun.
Meadow farm consisted of 29 fry tanks, 24 circular growing on tanks, 8 concrete ponds and 7 earth ponds. Cottage Farm had 8 earth ponds and Garden Farm 3 circular tanks and 6 earth ponds.
As you can imagine there was a very high production rate of Trout when these sites were running at their maximum.
In 2001 the new owner decided not to continue commercial fish farming. Three of the farms ceased to operate; Cottage Farm is now a nature habitat, Garden Farm has been developed into a wildlife pond and one of Meadow Farms sites dramatically transformed into two lakes used for Fly Fishing Lessons and to encourage a whole host of wildlife. The remaining farm has its own hatchery and is much smaller in size, around 1.7 hectares.
The Hatchery has been producing fry for the Estate since 2005 and is fed from a metred borehole. Eggs and milt are from our own Brood stock. The fry leave the Hatchery at the end of March and are grown on to a suitable size for stocking in the outside ponds. The fish will be around two and a half years of age when they are released into the river.
Throughout the year monthly checks are undertaken by the Environment Agency. Water quality entering and exiting the farm is monitored. The inlet screens also conform to the Eel regulations and S14 of The Salmon and Freshwater Fisheries Act.
Water Wheel renovation
Two hatches that control water levels near Mill Cottage were given a new lease of life in 2000. Both had become overgrown from ivy and creepers, also the water wheel had seized up. After clearing metal work from the right-hand hatch, the water wheel to the left had new boards fitted and after some grease was applied, started to turn for the first time in years. The old eel rack behind the hatches was also removed to allow a better passage for migratory Trout and Salmon.
The Cottage Stream is a small carrier from the river Test. In 2001 the Estate worked closely with the Environment agency to improve the river as a better habitat for spawning Salmon. Overhanging Alder trees were felled to let more light in for weed growth and the brush wood from these trees placed behind chestnut stakes to help narrow the river, this increased water flows over the original gravel bed. Over a short period of time, the brushwood collected silt; Watercress and Reeds grew over this very quickly.
2003 was a big year for projects on the Estate, 16 fry tanks were removed, and, in their place, a new water feature and stream created. Seven large earth ponds on Meadow Farm were turned into the two large casting lakes and the old Bailey Bridge at Mill Cottage collapsed and had to be replaced.
Once one half of the Meadow Farm was no longer in use, it was decided to create a more visual and wildlife friendly area. Seven large earth ponds that were surrounded by metal sheet piles, concrete slabs, numerous amounts of pipework and tall metal posts had to be removed. Using a Dragline and other mechanical equipment, two new lakes were formed along with a new outlet stream, this stream replaced old settlement ponds for the fish farm.
Bailey Bridge Removal
Crossing the River Test just above Mill Cottage was a second world war Bailey Bridge. The sides were original, but the floor had been concreted. Over time the weight of the concrete and rusting supports caused the bridge to buckle in its centre. It was replaced with a steel framed bridge with wooden flooring. We still refer to it as the Bailey Bridge, some names just can’t be changed.
The concrete base was cut into sections using a high-powered water jet, then lifted out using a crane.
A concrete spillway that took excess water from the river Dun into the river Test was replaced with a more environmentally friendly design.
The old spillway had a cracked concrete base and too high a fall for any migratory fish to pass up and over easily
The new spillway was constructed from permanent turf reinforced matting, a more suitable gradient for migratory fish and water entry into the Test was formed
The living weir in use
The conveyor belt used for transporting gravel and sand from the excavating site to the loading area was dismantled. A new gravel path is now in its place. Quite often of an early morning or evening Roe Deer can be seen using this path.
A small stream, running through a wooded area that flows from one of Kimbridge`s main rivers to the other, had been neglected for a few years. The whole length of the stream had silted up due to poor flows; this was mainly due to the small hatch controlling the flow being in disrepair.
The stream was narrowed using willow posts and willow shoots, the shoots were woven between the posts to form a narrow and natural bank edge. The hatch was also repaired, with better control of the water, the silt was soon displaced and the natural gravel bed exposed. Since the work has been finished, lots of juvenile Wild Trout can been seen using this stream as a refuge from the main rivers, no Redds have been spotted unfortunately yet. This stream is now a refuge for several small fish.
Garden farm was the next disused Fish Farm to be transformed. This site had 3 circular metal ponds and six large earth ponds fed from the River Dun. The surrounding sheet piles, pipe work and concrete pads were removed by an excavator and taken away. The ground on this site was different to the Meadow Farm; whereas Meadow Farm was Peat, Garden Farm was gravel. As the new pond was formed, extra dug gravel was stock piled to one side to be used on a later river restoration project.
A small stream was also created to run along one side of the ponds edge. Both the pond and stream provide a much better habitat than the old fish farm for numerous wildlife.
Sitting on the benches you can look across to the pond, which happened to be one of the last big projects that Peter undertook. In 2015 a memorial patio was laid for Peter Wilkins. Peter had managed Kimbridge since early 2000`s, however he had been on and off the Estate since a small boy helping his dad on the Sunday gang. The Sunday gang were a group of locals who used to help the Estate catch up with small jobs throughout the year.
Kimbridge Estate and the National Trust undertook a project to renovate the existing Bittern Grove weir on the River Dun. The project had four main objectives; to maintain the water levels upstream of the weir, to fill in the scoured-out pool below the weir to the original bed level, to narrow below the weir to the original bank line and to stabilise the existing weir.
The old weir had collapsed, and overtime had scoured a deep hole below the weir and caused the downstream banks to erode and widen. The sheet Pilling at both sides was removed
First, the bank edges above and below the weir were narrowed using locally won gravel. This was placed and compacted with a 360 excavator until the required line was met.
After the edges were finished, coir matting to help new vegetation to grow was placed. The deep scour below the weir was filled with heavy gravel, then gabion stone placed over this to stabilise the new surface. Gravel was then added onto this to bind it all together.
Three sheet piles in the centre of the weir were pushed down to the riverbed to create a fish pass.
River Dun Weir Removal and River Restoration Works
Work carried out on the River Dun at Kimbridge began in July 2015. This work followed the successful project on the weir shared with the National Trust which was finished in 2014.
The Environment Agency consented for the work to be carried out. This was funded entirely by Kimbridge, as is all the restoration work carried out on the estate, and the contractors were Brian Parsons and Matt Foord.
Several objectives aimed to be achieved by the finished work were.
To remove two weirs from the bottom stretch of the Dun
To fill the pool at the top weir to the original bed level
To create a gentle glide from a new confluence with the Test to the site of the top weir
To create a passage for Sea Trout and Salmon
To secure and re sculpture the existing banks
To remove silt from the bed and replace with gravel
A new glide was excavated downstream of the bottom weir and a bed of heavy Rip Rap laid create a firm anchor. The length of the new glide is 40 metres and the crest is set at the original bed level; a fall of 0.45 metres will meet the River Test. Gabion stone was then placed in between the Rip Rap and 20mm gravel added, this covered the Rip Rap and stone to form a more natural looking bottom. Gravel excavated from a previous project adjacent to the Dun was used for this purpose
Rock nets filled with Gabion Stone formed the new edges of the glide, these were then wrapped with coir mesh. The new glide was opened up during the July weed cut, the Dun could still flow over the bottom weir but now had a second confluence with the Test. This stayed in place until November when work could resume.
In November the bottom weir was removed and backfilled with heavy Rip Rap, gravel and material excavated from the new glide
Upstream from this point to the middle weir the river was narrowed using rock nets and pre-planted coir rolls. Gravel and soil placed behind the rock nets completed the new bank, 20mm gravel was then added to form riffles and pools along this stretch of water.
While this work was in progress coir mesh and an oil arresting boom had been placed at the end of the new confluence as a silt control system.
Most winters the River Dun has brief periods of very high flood water. There was concern that by narrowing and adding gravel to the Dun its banks would be breached during high water. However, during these high-water spells flood water flowed over a spillway further upstream and the new lower end flood water stayed within the banks.
With this work completed, the last weir could be removed. The concrete structure was removed with a pneumatic breaker and all materials taken off site. Once the weir was removed, the hatch pool was filled with heavy Rip Rap, Gabion Stone and then 20mm gravel.
A new glide from the works completed below this weir to the top of where the removed weir once sat was formed. Downstream from this new glide the edges were secured with more rock nets and coir mesh.
The project finished in March 2016 and by April weed had already established itself with no pre- planting of any sorts. Water Crows-foot, Water Parsnip and Starwort grew, no trees were removed from the far bank. Lots of small wild fish could also be seen darting along the gravel bottom. The flow along the whole stretch had increased quite considerably too.
Invertebrate samples taken along this stretch recorded larger numbers than samples taken upstream of the works.
The new confluence meets the river Test better than the old confluence and has a better passage for migratory fish.
3000 tonnes of gravel and 100 tonnes of heavy stone was used.
In 2018 Salmon Parr were found on the Dun for the first time, this is almost certainly due to removing the two weirs.
During the spring a project was undertaken to improve a stretch of the Test just below the Bailey bridge at Mill Cottage. An area of dead water had formed over several years and had become quite stagnant, especially in the summer months when the water levels were low. The existing bank was also a very poor habitat for Water Voles, concrete filled sandbags formed a wall which was impossible to burrow. The area also collected lot of cut weed and debris; it could look unsightly at times during weed cuts.
The planned work involved creating a new bank edge with pre-planted coir rolls and back filling behind with locally won gravel. The gravel was then covered with soil and sown with grass seed and wildflowers.
Once established this will be a much improved SSSI area.
Long before the works were started, the Environment Agency were contacted to grant us permission with a permit to undertake the work. Lots of detailed information had to be submitted with an application form.
Permission was granted and the work started on the 15th March.
Approximately 150 tonnes of gravel backfilled behind the coir rolls. The gravel had to be classed as ‘locally won gravel’ by the Environment Agency. This meant the material we used had to come from the Estate and not brought in from elsewhere. Our material was from an old gravel pit, this was removed and formed a wildlife pond there.