THE RIVERS TRUST RESTORING NORFOLK’S RIVERS THE A WATER FRAMEWORK DIRECTIVE LOCAL CATCHMENT PLAN

DEVELOPED IN PARTNERSHIP WITH

WITH SUPPORT FROM

THE RIVER A WATER FRAMEWORK DIRECTIVE LOCAL CATCHMENT PLAN | PAGE 1 CONTENTS INTRODUCTION Introduction 3 The Water Framework Directive 3 This plan has been produced by Norfolk Rivers Trust in The plan begins by providing an audit of the current state consultation with the Environment Agency, landowners, of the catchment. Information gathered is then used to River statistics 3 and interested local people. The plan provides an outline identify ecological pressures in the catchment. In the for improvement of the ecological status of the Hun, final stages of the plan, solutions to these pressures are THE CATCHMENT guided by the Water Framework Directive. Delivery of the identified, costed and prioritised. actions outlined in the plan will lead to improvements in The community 4 the wildlife and amenity value of the river. Why restore rivers? 4 Overview of restorations options 5 A geological and human history of the catchment 6 Wildlife surrounding the Hun 8 Wildlife profiles 10 THE WATER FRAMEWORK DIRECTIVE The Hun from source to mouth 11 From source in Park – Bridge 11 The Water Framework Directive (WFD) was introduced fail to meet good status. In England, the Environment in 2000 and commits European Union member states Agency are responsible for WFD delivery. Most streams A149 Road Bridge start of Holme Nature Reserve 14 to improving the physical and ecological quality of their are assessed by the Environment Agency in detailed Holme Nature Reserve 16 streams, rivers and lakes. Each member state is required Waterbody Reports, however, because the Hun is so to bring its water bodies to good status by 2015. Where small it has not been formally assessed. Therefore, this is not possible, good status must be achieved by this report draws on ad hoc data from some existing THE PROBLEMS AND SOLUTIONS 2021 or 2027, depending on the severity of the barrier monitoring and field observations. It forms a first step in to good status. A majority of the UK’s rivers currently understanding the River Hun. River structure 18 Connectivity between the river and the surrounding landscape 18 Fish passage 18 Water quality 19 Ecosystem 19 Invasive species 20 RIVER STATISTICS Trees and woody debris 21

AN ACTION PLAN Approximate river length: 6 km

A149 Road Bridge to outfall start of Holme Nature Reserve 22 Protected areas: SSSI (for Esker in Hunstanton Park; Holme Dunes Nature Reserve and Redwell Nature Reserve), Nature reserves and coast are also designated as: SAC, SPA and Holme Nature Reserve 23 Ramsar sites. Costs and timeline 24 Designations: Bathing Waters Directive

Author: Olly van Biervliet of Norfolk Rivers Trust

This plan has Philip Amies Helen Blower THANKS been enriched by Andrew Brown Rory Sanderson contributions from many different people Gary Hibberd Charles Rangeley Wilson and organisations. Norfolk Rivers Trust Michael Meakin John Dobson would like to thank Tim Holt-Wilson Jonah Tosney all those involved for their help: Lorraine Marks

THE RIVER HUN A WATER FRAMEWORK DIRECTIVE LOCAL CATCHMENT PLAN | PAGE 3 SECTION 1 THE CATCHMENT OVERVIEW OF RESTORATIONS OPTIONS Summary of possible restoration options on the . These proposals will greatly enhance the value, The Hun is a very small (6 km) which carries Nevertheless, the river habitat has been degraded water quality and wildlife value of the river. It is stressed its waters from its source in Hunstanton Park to its by centuries of modification and could benefit from that these are subject to landowner consent and are only mouth in Holme Nature Reserve. Wildlife abounds in the conservation work. outline ideas at this stage. surrounding area with a profusion of birdlife in particular.

THE COMMUNITY

It is part of the Norfolk Rivers Trust’s mission to gain the The River Hun has a rural catchment, containing the active participation of the community to restore their river. towns and villages of Hunstanton, Holme next to the sea Stakeholders help us to set objectives, keep us informed and Thornham within the catchment. So far, we have about issues on the ground such as pollution, and been very pleased with the enthusiasm and participation actively volunteer to make many more worthwhile projects of several locals in the process of planning future possible. conservation work, and would be very happy to hear from anyone who has an interest in conservation around the River Hun

WHY RESTORE RIVERS?

Britain’s rivers generally fail to reach “good” ecological absorb and process pollutants. This enhances water quality. This is both a problem in itself and a sentinel of quality within limits, however, very polluted rivers have less trouble. wildlife and in turn a reduced capacity to provide such benefits. This leads to a downward spiral. Wildlife itself A well-functioning river system is an inseparable has an intrinsic value and is enjoyed by groups such as combination of good water quality, distinctive physical fishermen, ramblers and bird watchers. processes and diverse wildlife. These factors interact to provide benefits. A naturally functioning river has a If any of the three pillars of the river system are damaged floodplain with sufficient capacity to absorb inundation (water quality, physical processes, ecosystem), then the and to act as a store for silt carried by high flows. The river value of the entire interconnected system is reduced. channel is also self-scouring. This reduces flood risk and Arguably, we also have a responsibility to repair our the need for expensive management. Headwater forests damaged natural heritage for future generations. Thus, reduce surges of water into the system by increasing ecological restoration aims to enhance the functioning, as drainage and removal of water. Moreover, the vegetation, well as the intrinsic value of our beautiful rivers. microbes and invertebrates in the river corridor also

PAGE 4 | THE RIVER HUN A WATER FRAMEWORK DIRECTIVE LOCAL CATCHMENT PLAN THE RIVER HUN A WATER FRAMEWORK DIRECTIVE LOCAL CATCHMENT PLAN | PAGE 5 Some 7,400 years ago sea level started to rise, eventually The open fields were productive and supported a relative A GEOLOGICAL AND flooding the area which is now The Wash, and which had dense human population. The Doomsday population for been an area of woodland. Fluctuations of sea level are the Hunstanton area is amongst the highest in England. HUMAN HISTORY OF THE preserved in sequences of peat and marine clay found exposed on the modern beach at Holme. During the late 1700s and early 1800s a series of CATCHMENT enclosure awards reorganised this landscape with many The coastal plain was several kilometres wide during the of the commons disappearing. Sheep were still the basis Neolithic to Bronze Age (roughly 6000 to 4000 years of fertility but crops such as turnips and rape used with The landscape surrounding the Hun has been formed by ago). Freshwater reeds and alder woods developed clover rotations replaced the commons and fallow. powerful processes acting in the deep past. Overall the from saltmarshes forming peat which was subsequently landscape can be divided into a coastal plain, a slope covered by marine clays as the sea covered the area. In the 1630s Sir Nicholas Le Strange and the Dutch (scarp) and a plateau dissected by now dry valleys caused These fluctuating conditions have preserved a rich series engineer Van Haesdonck built a series of sea banks from by past erosion by streams (during the Ice Age). The scarp of wooden artefacts including the well-known Sea Henge Thornham through Holme to Hunstanton which enabled was a sea cliff in earlier periods before the most recent at Holme. an area of marsh to be drained. A sluice excluded tidal ice age. inflow totally from the river upstream to Hunstanton Hall. During this period, human settlements existed on the The river was canalised from Hunstanton Hall to the At Hunstanton Cliffs, the geological sequence is exposed. higher ground and woodland was cleared over much of sluice and drainage ditches constructed in the river valley The basal Carstone is a sandstone with pebble beds. A the area. By the Iron Age (some 2,500 years ago) the marshes. These sea banks enabled drainage of some red chalk (Hunstanton Formation) is overlain by younger coastline was similar to today, and it is likely that woodland 60 acres. white chalks (Photo 1). had been almost completely cleared. Grazing by livestock on steep chalk and nutrient poor Holme was enclosed in 1820 which had limited impact During the Pleistocene period, 2.6 million to 11,700 years glacial sands formed an extensive series of downs and on the coastal common and the river downstream of the ago, there were some 8 ice ages, with this region either on heaths which developed into common land. The chalk sluice. In 1860 a large part of Hunstanton and Holme the edge of the ice sheet or covered by deep sheets of ice rich till and the gentler slopes with deeper soils eventually Common was enclosed, an embankment was created which extended far to the south. Each ice age has eroded developed into open field systems. from the older 1630 wall west of Thornham Staithe road the deposits of earlier ice ages leaving a partial picture. towards the north joining the dunes near the east of The Poorer soils could be farmed with the addition of lime Broadwater (a former tidal creek). Hunstanton Park contains another fascinating relic of (hence chalk pits) which could make some of the easily glacial times. This is a landform called an esker. An esker Photo 1. Philip Amies Copyright . Hunstanton cliffs. ploughed light soils of the glacial sands available for arable The river was diverted to flow south of the old course at is formed by the sands and gravels derived from the farming for a few years before nutrient levels dropped and Beach Road, Holme, and was canalised in Holme parish bed of an ice-age river running through the heart of a grassland would be re-established. Such areas, known as and the surrounding land drained. The resulting Polder Photo 2. Hunstanton Park Esker (SSSI). The meandering form of the river can still be Brecks, have been recorded at Ringstead. The basis of grasslands remained grassland until the 1960s when discerned in the winding form of the esker. glacier. When the glacier finally melted, the gravels were deposited. Hunstanton Park Esker is about 1.5km long farming was the transfer of nutrients from the commons some arable cultivation developed. The area has now running from just north of Ringstead Down to Hunstanton (coastal saltmarsh and dunes and the heaths and downs) reverted to cattle grazed grassland. The lower Hun was Hall (Photo 2). to the cultivated arable fields. This was enabled by sheep substantially deepened during World War 2 in order to act being grazed by day on the commons (and open field as a barrier to enemy assault using tanks. fallow) being penned at night in a fenced enclosure in the arable field which was fertilised by their dung this is called More recently, The and The Norfolk sheepfold. Ornithological Association have created a number of pools Photo 2. Hunstanton Park Esker (SSSI). The meandering form of the river can still be discerned in the winding and reedbeds by re-flooding old creeks. These are fed by form of the esker. Some enclosure occurred by agreement in the Medieval springs found at Redwell and Holme Marsh, otherwise period during which Hunstanton Hall and park developed, surface water depends on rainfall. The hard work of these evidence such as moats and documents of other conservation groups has helped to reinstate a vibrant medieval manors exists, forming a complex pattern of wildlife community in the area. landownership and manorial rights. Contribution: Philip Amies, with thanks from Norfolk Rivers Trust

Painting of barge being unloaded near Hunstanton, Peter de Wint ©, early nineteenth century

PAGE 6 | THE RIVER HUN A WATER FRAMEWORK DIRECTIVE LOCAL CATCHMENT PLAN THE RIVER HUN A WATER FRAMEWORK DIRECTIVE LOCAL CATCHMENT PLAN | PAGE 7 WILDLIFE SURROUNDING THE HUN

The grazing marshes around the mouth of the Hun are a Moreover, a colourful array of dragon flies and damsel Photo 5. Bittern, One of Britain’s haven for a variety of wildlife. Birds, amphibians, mammals flies beguile visitors to the marshes. These include ruddy most endangered animals, the and invertebrates thrive in this highly productive area. darter, common darter, emperor dragonfly, banded Bittern is a secretive bird inhabiting demoiselle, emerald damselfly, common and azure reed beds. It quietly stalks eats Iconic species such as bittern and marsh harrier inhabit damselfly. Lunar hornet moth (lava feeding in willow fish, amphibians and insects during Holme Marsh. Ducks such as mallard, gadwall, shoveller, trunks) and hornet moth (lava feeding in poplars) are found most of the year, but the male has shelduck, tufted duck, and pochard also breed in the in the river valley, these impressive moths are good mimics an incredible, booming call during marshes. Breeding waders include oystercatcher, lapwing, of hornets. There are also a number of scarce plants are the spring. avocet and redshank. Large flocks of pink-footed geese, found including marsh orchids and a variety of wetland brent geese, wigeon, teal, curlew are present in the winter. species. Photograph: © Philip Ames

Photograph: © Philip Ames Photograph: © Jack Perks

Photo 3. Pink footed geese Photo 4. Banded demoiselle

Otter are starting to be recorded more frequently, kingfishers winter in the area (up to 6) and water Photograph: © Philip Ames vole are found in good numbers along the river and in marsh ditches. Barbastelle bat has been recorded using the river valley by Keith Fox. This is a rare species which uses long linear feeding habitats such as coastal grassland or river valleys flying considerable distances (8 – 14 miles). Natterjack toads enrich the soundscape, calling loudly at dusk from the marsh.

In summary, the marshes surrounding the lower Hun represent a thriving ecosystem, which gives pleasure to innumerable local people and visitors.

Contribution: Philip Ames, with thanks from Norfolk Rivers Trust

Photo 6. Spoonbill, “Watching a flock of spoonbills feeding on a shoal of sticklebacks is impressive. The flock moves in a rough line sweeping their bills and constantly catching and swallowing small fish eating hundreds of them. At times it gets really frantic and they catch a fish on almost every sweep.”

PAGE 8 | THE RIVER HUN A WATER FRAMEWORK DIRECTIVE LOCAL CATCHMENT PLAN THE RIVER HUN A WATER FRAMEWORK DIRECTIVE LOCAL CATCHMENT PLAN | PAGE 9 WILDLIFE PROFILES THE HUN FROM SOURCE TO MOUTH

Wildlife profile: From source in Hunstanton Park – point of first flows moves up the course with increasing The Eurasian Otter, groundwater levels. Flows are augmented by side- A149 Road Bridge channels during wet periods. The surrounding land is Lutra lutra This section of the River Hun is predominantly a seasonally estate park land which is grazed by sheep. The stream running stream with permanent flow only originating just runs through several shallow ponds and eventually into The otter is a predatory mammal which uses its above the A149 road bridge. Such streams, where flow the moat of Hunstanton Hall. Some ponds which are excellent swimming ability and specialised teeth to feed is seasonal, are called winterbournes. This section has ephemeral, have very clear water, but the moat and more on a variety of prey such as fish but also amphibians a natural form, defined only by a gentle undulation and permanent ponds have black, bacterial waters. The and occasionally birds. They have even been shown no clear channel. It is not a useful concept to think of surroundings are grazed parkland. Below the hall the river to be capable of eating toads despite their poisoned a winterbourne as having one particular source all the is channelized and deepened as it flows through a damp skins. They corral the amphibians into groups before time. Rather, as one reaches the uppermost sections, the meadow, and past a lake towards the road bridge. proceeding to skin them and eat the nutritious innards. Otters hold territories against the same sex, and this stops their numbers building up into high densities, especially when food is scarce. This beautiful and reclusive animal is wide ranging and can be seen around ponds, lakes, rivers and marine habitats. Text, Mark Rylands, Photograph: © Jack Perks

Wildlife profile: River plants

Aquatic plants exert important influences on the lowland river environment. Their sinuous fronds create a large surface area for colonisation by algae, bacteria and invertebrates which in turn process nutrients and organic matter within the river. Their physical role in the stream is also vital. They narrow the channel in places and cause water to accelerate, as well as holding water up in other places. This allows differential scour and deposition of sediment, which helps river channels to remove and store sediment. Together with trees, they are nature’s architects of channel structure, helping rivers which have been artificially straightened to recover to a more meandering form. Their delicate greens and subtle white flowers are also one of the wonders of the British countryside.

River Hun with upper section highlighted. Light blue shows the winterborne (ephemeral) section of the river and dark green represents the permanent section.

Photo 9. The uppermost source along the winterborne section or the river forms a pond, and can feed the stream through the depression in the foreground when levels are high.

PAGE 10 | THE RIVER HUN A WATER FRAMEWORK DIRECTIVE LOCAL CATCHMENT PLAN THE RIVER HUN A WATER FRAMEWORK DIRECTIVE LOCAL CATCHMENT PLAN | PAGE 11 Photo 10. Subtle depression in the ground where the ephemeral section of the stream flows when the water table is high. Photo 12. Crystal clear water entering the Hun from an ephemeral groundwater-fed pond during higher water levels and joining the main river course.

Photo 11. Dystrophic permanent pond.

Photo 13. River enters moat at manor house at Hunstanton Park. Photo 14. River in deepened and vegetated channel below the moat.

PAGE 12 | THE RIVER HUN A WATER FRAMEWORK DIRECTIVE LOCAL CATCHMENT PLAN THE RIVER HUN A WATER FRAMEWORK DIRECTIVE LOCAL CATCHMENT PLAN | PAGE 13 A149 Road Bridge start of Holme an arable field to the East, and a golf course to the West. The river is very deepened and has a straight-sided banks Nature Reserve at this point with a featureless silty substrate. Below the road bridge several springs contribute to a The majority of this section flows through an artificial substantial increase in flow. A majority of water in the Hun landscape because it is a tidal area which has been arises from the clear flows of the springs which are located reclaimed from the sea. Historically the river would have near Waterworks Road, as shown in Photo 17. A ditch flowed through tidal creaks in freshwater and salt water running adjacent to the golf course, which also functions marshland, and the consequent a lack of gradient has as a storm drain brings more water. The surrounding land important implications for any restoration options. use in this section is comprised of rough grassland, and

Lower section of River Hun highlighted.

Photo 16. There is a diversity of vegetation and Photo 17. Flows of clear, high quality water originating flows in this slightly “wilder” section of the river. from springs close to Waterworks Road.

Photograph: © Philip Ames

Photo 18. A representative picture of the silty and canalised lower Hun.

Photo 19. A representative picture of the silty and Photo 15. Below A149 road bridge. canalised lower Hun

PAGE 14 | THE RIVER HUN A WATER FRAMEWORK DIRECTIVE LOCAL CATCHMENT PLAN THE RIVER HUN A WATER FRAMEWORK DIRECTIVE LOCAL CATCHMENT PLAN | PAGE 15 Holme Nature Reserve Holme Dunes Nature Reserve and Redwell Marsh The fringes are bordered by reeds, thus providing some Nature Reserves are Sites of Special Scientific Interest, ecological value as refuges for invertebrates and birds. designated for the quality of the habitat which they The tidal outfall is through a sluice, and the Hun then flows provide for birds. The Hun runs in a straight line through through tidal creaks to the sea. the reserves and remains deepened and channelized.

Photo 22. The Hun just upstream of the tidal sluice. Photo 23. Tidal sluice at Hun outfall in to salt marshes.

Photo 20. Old creaks and scrapes represent excellent bird habitat

Photo 21. Broadwater, a lake which was probably a tidal meander of the river in the past. Photo 24. Tidal section of River Hun.

PAGE 16 | THE RIVER HUN A WATER FRAMEWORK DIRECTIVE LOCAL CATCHMENT PLAN THE RIVER HUN A WATER FRAMEWORK DIRECTIVE LOCAL CATCHMENT PLAN | PAGE 17 SECTION 2 THE PROBLEMS WATER QUALITY

Limited point-samples of the Hun’s water quality suggest tidal sluice, but not at concentrations which are damaging AND SOLUTIONS that it is relatively low in nutrients and good in quality. Ad to freshwater wildlife. Nevertheless, more water quality hoc samples taken between September 2013 and March data is needed to determine seasonal fluxes in nutrients, 2014 indicate that levels of salinity do increase close to the and to determine to what extent saline ingression occurs.

The natural state of the river Hun is best understood by marshland which would have backed up from the salt imagining the landscape without the tidal wall. The stream marshes which themselves would have been much further would flow from its gentle beginnings as a diffuse area of inland. The ecological value of this area would have been steadily-moving wetted ground, and would be gradually great, providing extensive breeding habitat for birds and met by more springs. It would rapidly have met freshwater nursery areas for young fish.

RIVER STRUCTURE

The upper part of the river is unusual in that the Due to the heavily deepened and engineered nature of winterbourne section probably resembles a natural form. the channel, and its low gradient, it would be of dubious All too often upper sections of winterbourne rivers have value to increase the sinuosity of the channel overall. been converted to ditches, and it is good to see this This is because sustaining functioning river meanders sensitive management of the river throughout most of requires a certain slope which enables the river water to Hunstanton Park. have sufficient energy. However, the over-capacity of the channel means that there might be scope for the stream Currently, the area below the confluence with the waters to gain some sinuosity within the channel. This could be from Waterworks Road is totally straightened and artificial. encouraged by the addition of stable woody debris which In the lower river, there is a 1.3 km section of river which would constrict the river flow in some places and create is absolutely straight. Little is known about the biological pools in others. This variety of different habitats, and community of the river, due to a lack of monitoring of the shelter provided by the woody material itself would key groups such as water plants, fish and invertebrates. increase the biological richness of the stream. Therefore, Figure 1. Salinity changes as distance from tidal sluice increases. Sea water has a concentration However, it appears likely that these communities are very tree planting now would provide woody material which of around 35,000 mg/l CHECK , CHECK of chloride, and concentrations in the low hundreds are impoverished as a consequence of the poor habitat. would be very valuable in the future. These ideas are not thought to be damaging to wildlife such as plants or invertebrates. expanded in the Action Plan section.

CONNECTIVITY BETWEEN THE RIVER AND THE SURROUNDING LANDSCAPE

The extensive wetlands which would have occupied this not found.). Within the nature reserve, some channel ECOSYSTEM area clearly cannot be re-instated due to the residential structure work could be possible, and raising of the water and agricultural land uses in the area. However, there levels could also locally re-wet some of the creaks, thus could be scope to create wet platforms (“2 stage further extending marginal habitat (see Action Plan section Very little is known about the aquatic ecosystem in the channels”) bordering the channel which would increase for details). River Hun due to a lack of biological surveys. Generalist the marginal habitat available (see Error! Reference source aquatic vegetation such as water starwort (Callitriche sp), sedge species (Carex sp.) and fool’s watercress (Apium nodiflorum) were have been observed during walkovers. More specialist chalk stream vegetation may be excluded due to siltation. Anecdotal reports suggest that vegetation FISH PASSAGE undergoes a major seasonal dieback below the golf course. Water quality monitoring has been undertaken to determine whether saline intrusion could be the cause, but In terms of barriers to fish passage, the tidal sluice this does not seem to be the case (see previous section). could represent some barrier to fish passage, however the significance of this has not been quantified. The lower river represents poor habitat for most aquatic A flounder was observed close to species due to the lack of cover such as that provided by Redwell Nature reserve, demonstrating trees, and variation in substrate and flow velocities. that the structure is passable in some circumstances.

Photograph: © Wikicommons / Peter van der Sluijs

PAGE 18 | THE RIVER HUN A WATER FRAMEWORK DIRECTIVE LOCAL CATCHMENT PLAN THE RIVER HUN A WATER FRAMEWORK DIRECTIVE LOCAL CATCHMENT PLAN | PAGE 19 INVASIVE SPECIES Photograph: © Mike Sutton-Croft TREES AND WOODY DEBRIS

Invasive species have not been observed in or around Over the past two decades the importance of trees to the Hun as part of river walkovers. However, Himalayan rivers has been shown by a growing body of research. balsam and giant hogweed have been found in the They are a habitat in their own right, act as nutrient adjacent catchment. Norfolk Rivers Trust always modulators and architects of channel structure. The roots appreciate it when people can report the presence of of trees act as hard points which deflect flow and cause invasive species, and can often mobilise volunteer groups pools to develop and meander bends to initiate. Fallen or relevant authorities to deal with the problem. Moreover, trees are equally important as deflectors of flow and to the link below can be used to report invasive species and stabilise banks which they fall onto, as shown in Photo 25. trigger the local authority into action: Moreover, the shade which they provide will help to keep rivers cool in the face of climate change.

Tree planting could be of great benefit to the habitat quality of the River Hun for both aquatic and riparian wildlife. However, trees need to be placed strategically in sections of river which do not impact ground nesting birds within the nature reserves.

Himalayan Balsam (Impatiens glandulifera).

Giant hogweed

Photograph: © Wikipedia: Fritz Geller-Grimm

Photo 25. In naturally-functioning river systems, research has shown that trees play a vital role in structuring the river channel. A. Tree acting to cause formation of a vegetated island on the floodplain, South Island, New Zealand. B. Trees protect near bank from powerful flows, Powys, Wales. C. Tree acts enhances in-channel habitat, Coldwell Brook, Oxfordshire. D. Tree has fallen along the river bank and has stabilised the bank, with a branch then developing into a new tree (Powys, Wales). Photograph: © Olaf Booy

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Within the nature reserve there could be some scope in Figure 4. This may be excessive, so some physical re-flooding of historic creaks. Features such as Hun Pool reduction in the height of the beds of the creaks may be and Broadwater Pool are the old tidal meanders of the required, which will allow water to flow into lower areas. Actions for the River Hun should take into account local people’s views, current land usage, and aim River Hun itself and are clearly seen on Figure 4. It has Depending on the eventual increase in levels suggested, to enhance the ecological potential of the river. been suggested by managers of the nature reserve that other creaks may also be re-wetted as a result, for re-wetting some historic creaks by raising water levels instance those show in Figure 4 and 5. A hydrological In the future, the River Hun could be a river with varied marginal habitat, supporting a range of birds, small mammals and using a sluice would be desirable for bird habitat and modelling exercise would be needed to determine if this invertebrates. The stream channel itself could also have increased natural sinuosity with a patchwork of shade, and different could be achieved using an existing sluice. From an initial was appropriate to the area. A more ambitious plan put water velocities provided by marginal trees and in-channel woody debris. This would improve the nursery and breeding assessment, it appears that water levels in the lower river forward in a report by UEA in the early 1990’s suggested habitat for fish and invertebrates. Thus, a degree of the river’s natural function could be restored without compromising would need to be raised by around 50 cm to increase the more extensive channel morphology work, but this plan other land uses in the area. To provide this, actions should focus on the river below the confluence with waters from the wetted area effectively in the creaks investigated, shown could to cost prohibitive. Waterworks Road.

A149 ROAD BRIDGE TO OUTFALL START OF HOLME NATURE RESERVE

The section of river below the additional flows from the such as alders (Alnus sp) and willows (Sallix sp) in areas springs at Waterworks Road would benefit from tree more distant from the nature reserves. Closer to the nature planting, which would provide woody debris in the long reserves plants of a more bushy nature such as blackthorn term. Trees should be positioned strategically to avoid could be planted, or emergent water plants allowed to providing perches for predatory birds which could impact colonise the platforms. Error! Reference source not found. ground nesting birds in the nature reserves. This could summarises the current state of the lower Hun and shows be achieved in synchrony with channel modification by how planting and some channel morphology work could production of a two stage channel which would provide greatly improve the value to wildlife and, arguably, the low-level platforms for the planting of water-loving trees aesthetic value of the river.

Figure 2. Schematic showing: A. The siltation and poor habitat caused by the current form of the river channel. B. Potential improvements to the straightened river channel which would improve habitat diversity and wildlife value in the long term. Nearer the nature Figure 3. Elevation analysis of River Hun in Holme Nature Reserve to assess the feasibility of re-wetting historic tidal reserve, lowered platforms creaks to improve bird habitat. Green areas are of higher elevation and increasingly dark blue areas are lower. Cross could be planted with sections are taken left-right looking downstream as is standard practice. The area pictured is about 290 metres upstream reeds instead of trees. of the tidal sluice. Because the creaks under examination historically originated from the Broadwater side it can be seen that they are in fact of greatest elevation closer to the river and reduce in elevation as they approach Broadwater. As a result once water has reached the creaks from the river system it will easily flow to fill the rest of the creak system. Bunds to protect Broadwater from filling from the river would need to be checked. To fill the creaks as they stand, a 50-60 cm increase in water levels and removal of what appears to be a bund at the top of the creak system would be required. It may be that this increase in water levels would be excessive. In this case, some physical work to lower the bed of the first section of the creaks would to allow the water to flow into the rest of the system. This will mean that less of an increase in water levels would be needed.

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In the case of most rivers there would be a Water Measures to maintain public access between Old Within the nature reserve there could be some scope in Figure 4. This may be excessive, so some physical Framework Directive target set, and the Hun’s progress Hunstanton and Holme Nature reserve is usually the role re-flooding of historic creaks. Features such as Hun Pool reduction in the height of the beds of the creaks may be would be judged against relatively rigorous biological of the local authorities. However, if this is not possible, and Broadwater Pool are the old tidal meanders of the required, which will allow water to flow into lower areas. physical and chemical standards. Due to its small size maintenance could be undertaken by volunteer groups, River Hun itself and are clearly seen on Figure 4. It has Depending on the eventual increase in levels suggested, and consequent low profile, the Hun is not given a status and this could commence when it is required as plants been suggested by managers of the nature reserve that other creaks may also be re-wetted as a result, for or objective under the Water Framework Directive. This begin to grow in the spring. re-wetting some historic creaks by raising water levels instance those show in Figure 4 and 5. A hydrological means that this catchment plan has particular significance using a sluice would be desirable for bird habitat and modelling exercise would be needed to determine if this as a step in determining what objectives should be set. In the longer term, tree planting and channel morphology could be achieved using an existing sluice. From an initial was appropriate to the area. A more ambitious plan put work could be undertaken where landowner permission assessment, it appears that water levels in the lower river forward in a report by UEA in the early 1990’s suggested As a result of centuries of modification, the lower sections can be gained. Investigating the possibility of raising water would need to be raised by around 50 cm to increase the more extensive channel morphology work, but this plan of the river could benefit from measures which would levels in Holme Nature Reserve could be undertaken when wetted area effectively in the creaks investigated, shown could to cost prohibitive. increase the habitat quality, which is currently extremely funding is available to undertake hydrological modelling. poor. Increased cover, and a variety of in channel habitat in particular will need to be addressed.

Overall, the order of priorities for the river are as follows:

1. To improve stream habitat diversity for aquatic wildlife in the lower section of the river.

2. To maintain public access along the middle section of the river.

3. To investigate the possibility of raising water levels in Holme Nature reserve, with the aim of enhancing habitat for birds within the reserve.

Action Number of kilometres / Predicted cost Achievable timeline Responsibility / sites capability Tree planting 190 trees £ 900 Ongoing to 2027 Volunteers/ (less with volunteer help) Norfolk Rivers Trust/ / EA Channel morphology 2 km £ 38, 000 Ongoing to 2027 Norfolk Rivers work Trust/ EA Improvements to public 1.4 km Ongoing Volunteers with footpath support of NRT Hydrological modelling 1 site £ 8, 000 When desirable to NWT/ support to determine viability of NWT from NRT raising water levels in Holme Nature Reserve

FURTHER INFORMATION

Figure 4. Elevation analysis of another area in the River Hun in Holme Nature Reserve. Green areas are of higher elevation and increasingly dark blue areas are lower. Cross sections are taken looking downstream as is standard practice. They show that river Hun is lower in elevation than the historic of the creaks by 0.2 – 0.5 metres.

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THE NORFOLK RIVERS TRUST RESTORING NORFOLK’S RIVERS

The Norfolk Rivers Trust www.norfolkriverstrust.org Stody Hall Barns, Stody, Near Holt, Norfolk NR24 2ED