1 Tøsbæk/Spånbæk brook, Dybvad. Spawning grounds; current concentrators; weed clearance 2 Pump station, Gjøl. Eel pass 3 3 Lerkenfeld stream, Østrup. Examples from Falls ® riffles; spawning grounds the Danish 4 River Storå, . Completed watercourse Bypass riffle counties 5 Idom stream, Idum. New course Editor: 6 Rind stream, . Hans Ole Hansen New course; ochre removal rehabilitation projects 7 River Gudenå, Langå. Spawning ground All 14 Danish counties and many of the In this chapter, staff from 12 County 8 Lilleå stream, . Falls ® riffles; spawning grounds; municipalities have undertaken a wide Councils describe 24 watercourse bypass riffle; current concentrators variety of different watercourse rehabilita- rehabilitation projects undertaken in 9 Lammebæk brook, Daugård. tion projects over the last decade. These different parts of the country. The Culvert lamellae range from simply laying out large stones, examples provide a good impression of 10 Kvak Møllebæk brook, Skibet. to major projects that remeander water- the variety of solutions and methods Bypass riffle; spawning grounds courses and involve the whole river valley. employed to improve watercourses and 11 River Brede, Løgumkloster. their environment. New course; water table raised; river valley; ochre removal 12 River Brede, Bredebro. Falls ® riffles 13 River at Ejby Mølle, Odense. Falls ® riffles; historical project 24. 14 River Odense at The Seahorse, Odense. 1 Falls ® riffles; spawning grounds; . historical project .2 15 Lindved stream at Hollufgård, Odense. New course; prehistoric landscape; lakes; sand trap 16 Holmehave brook at Borreby Mill, Odense. .3 New course; spawning grounds; historical project 7 4 17 Esrum stream, Lake Esrum. . ..8 Spawning grounds; current 5. Zealand concentrators; channel narrowing 6 17. 18 Græse stream, . . Falls ® riffles; fish ladder .18 19 Store Vejleå stream, . 10 9 New course; removal of paving; .. 19. spawning grounds; current concentrators 20 20 Køge stream, Lellinge. . 21. 14 Sand trap ..13 16 .15 . 23 21 Køge stream, Bjæverskov. . 22 . Riffles; current concentrators 12 11 Funen 22 River Suså at Holløse Mill, Skelby .. Falls ® riffles; historical project 23 Lilleå stream, Kongsted. Reopening culvert/removal of conduits; river valley The geograpical 24 Søbæk brook, Neksø. position of the 24 New course; lakes; sand trap examples described. 21 1 3.1 . Nordjylland County Tøsbæk/Spånbæk

Niels Sloth Jens Berthelsen Hans Heidemann Lassen brook at Dybvad Watercourse system: Voer stream

Introduction to the project Aim of the project shady vegetation. The project outline was In 1976, the Outdoor Council asked passed by the County Council in 1978. Voer stream is a relatively Nordjylland County to participate in large watercourse that flows drawing up a project on ecological Implementation of the project into the Kattegat. Until 1980, watercourse maintenance and re- To undertake the detailed planning of the Tøsbæk/Spånbæk brook, establishment of the fish population in project and coordinate the practical work which is a tributary to Voer the Voer stream watercourse system. The a project group was established com- stream, was a strongly Voer stream system was well suited on prised of a hydraulic engineer and a channelized drainage chan- account of a number of factors: The biologist. In September 1979, the nel with a slight slope of 0.5– water quality had been markedly im- Agricultural Commission approved the 1.5‰ over most of its course. proved, among other reasons because project. Some of the landowners affected Tøsbæk brook was up to 3 major effluent discharges had been appealed the approval decision to the metre wide with uniform stopped, there were no freshwater fish Higher Agricultural Commission, which in weed growth dominated by farms in the system, there were only July 1980 ruled in favour of the project. bur reed. Spånbæk brook minor discharges of untreated urban Restoration work started three months was a 1–2 metre wide harshly sewage, and there were no dams. later and was completed at the end of regulated brook. The water- Moreover, although parts of the main 1993. courses were maintained in course and tributaries were channelized, The restoration work was undertaken accordance with traditional many of the upper parts of the tributaries partly by the County Council’s field practice, i.e. weed clearance were natural with good conditions for the personnel, and partly by a team of young in the whole width of the fauna. unemployed persons as part of a youth watercourse and on the In collaboration with various unemployment project. banks, removal of tree roots government bodies, the County drew up and large stones, and fre- a project outline in 1978 aiming at Impact studies in connection with quent dredging. Because of restoring approx. 3 km of Tøsbæk/ the restoration project the slow flow, the bed of the Spånbæk brook andapprox. 1 km of Voer In 1979, detailed baseline studies were watercourse was comprised stream in order to improve watercourse undertaken encompassing the physical, of fine sediments. quality while maintaining good drainage chemical and biological conditions. In conditions. The measures involved addition, a thorough literature report was included the establishment of current prepared in 1981 based on the current concentrators, gravel banks and pebble international literature on watercourse banks, the establishment of artificial fish ecology and restoration. hiding places, modified and more After restoration work had been environmentally sound maintenance, and completed, thorough studies were made 22 Completed watercourse rehabilitation projects

of sediment deposits. The trees (common The project was one of the first of its alder) have grown up well, and their kind in , and influenced general roots have now stabilized the banks and, discussion and formulation of watercourse together with the very diverse vegetation, restoration measures for incorporation in provide good hiding places for the fish. the new Watercourse Act of 1982. The The current concentrators, hiding places project is currently a good example of and stone beds in Tøsbæk-Spånbæk how much one can achieve using brook are now virtually invisible as it has environmentally sound maintenance changed its course, while most of those undertaken by well-trained personnel. in Spånbæk brook are still visible and With the aid of environmentally sound functional. The spawning grounds have maintenance and the planting of vegeta- sanded over in some places, while others tion it is in many cases possible to achieve are still visible and usable by salmonids. the same physical diversity as with more The density of the latter is still high, as it substantial measures such as current was already shortly after completion of concentrators, artificial hiding places for the original restoration work. fish and pebble beds. of the impact of the various measures. A Environmentally Project data: report was prepared whose main conclusion sound maintenance was that the environmental quality of the of Tøsbæk/Spånbæk Project organizer: Nordjylland County watercourse reaches had been improved brook Contractor: Nordjylland County considerably without their drainage Project commenced: October 1980 capacity having been detrimentally Project completed: December 1983 affected. The density of salmonid fish has Total costs: DKK 332,000 + studies and administration increased 4–5 fold, and both sea trout (incl. VAT) and brown trout have been noticed Financing: Nordjylland County and Dronninglund and spawning on the gravel banks. Sæby Municipalities In addition, the studies have shown that the gravel banks and current Watercourse data (Tøsbæk/Spånbæk brook and Voer stream): concentrators laid out in the watercourse do not have any major effect on dis- Catchment: 23 and 121 km2 charge capacity, and that environmentally Discharge: sound maintenance considerably Max: 2,280 / 12,100 l s-1 improves watercourse quality. This also Min: 79/436 l s-1 applies to the reaches where changed Quality objective: B1 (Salmonid spawning and nursery waters), maintenance practice is the only measure B2 (Salmonid waters) that has been implemented. Neither does Pollutional class: I, II (1991) environmentally sound maintenance have any negative impact on discharge capacity, Restoration data: which even increased in some reaches where the weed is cleared more frequently. Coordinates: 57° 17´ N10° 23´ E In places where the current channel is Current concentrators: 22 narrow, the bed is rinsed clean of Gravel beds: 14 sediment because of the stronger current. Slope: 0.5 – 3.3‰ Fish hiding places: 45 Experience gained Spawning gravel laid out: 14 beds The watercourse is still maintained in an Stones laid out: 10 beds environmentally sound manner, and there Vegetation: 1,500 trees is still a meandering current channel free 23 3.2 2 Nordjylland . County Pump station at Gjøl

Niels Sloth Jens Berthelsen Hans Heidemann Lassen

Watercourse system: Limfjorden fjord

Introduction to the project Aim of the project distribution well. The other half of the The land drainage pump In 1992, Brovst Municipality approached water runs through a pipe from the station at Gjøl drains water Nordjylland County to enquire about the bottom of the distribution well back to to Limfjorden fjord from an possibilities for establishing a fish pass the inner canal. This water flushes any approx. 12 km2 low-lying between Limfjorden fjord and the young eel that have been guided into the catchment area separated watercourses leading to the pump distribution well into the watercourses. from the fjord by a dyke. station. The County agreed to participate The pipe ends in a trap box containing a Water is pumped from in the project because it seemed likely small elver trap. The pumps and the eel approx. 150 km of drainage that the watercourses would provide a pass function during the period April- ditches and an unknown good habitat for eel to grow and thrive. September, when the eel migrate. number of private and It was estimated that it would be As the system was untried, two pilot -2 -1 municipal watercourses possible to grow 9.3 g eel m yr . When systems were established – one on each estimated to a total of the eel migrated to Limfjorden fjord, they side of the canal that leads the water approx. 200 km. could be caught, for example in eel traps. from the pump station out to the fjord. The area has a very good eel population, but the pump Implementation of the project Impact studies in connection with station completely blocks the The project was initiated in autumn 1992. the restoration project passage of eel and other fish. An outline project for an eel pass was The pumps were started for the first time It has not been possible to drawn up and submitted to the Ministry in April 1993. The trap box was emptied construct an eel pass in the of Agriculture and Fisheries, which once-twice weekly in 1993–94. Elvers usual manner because the approved the project. Brovst Municipality that could pass the trap’s 2 mm mesh net water level inside the dyke is also recommended the project for a were not registered. In 1995, the 2 mm lower than outside. three-year trial period, and an agreement mesh net was therefore replaced by a 1 The organic production of was entered into with the dike owners’ mm mesh net. Four eel were caught in the drainage ditches and association on the establishment of the 1993, all of which probably entered by watercourses leading to the pass. chance, while no eel were caught in pump station is high. In most Water from the lower-lying inner 1994. cases the designated water- pump canals is pumped to a distribution The reason for the poor result is -1 course quality objective is B3 well (500 l min ). From there, half of the probably that the guide current was – ciprinid waters, although water flows out to the outer pump canal insufficiently strong and/or that the the designated quality through a pipe filled with loosely difference in salinity in the area was objective in the upper intertwined plastic strips designed to insufficient to enable the eel to find the reaches of a few watercourses facilitate the passage of eel (see diagram). outer pump canal, which ends in a is B1/B2 – salmonid waters. This water serves as a guide current to brackish area with a high-tide sluice. In enable the young eel to move up to the addition, the sluice was closed for most 24 Completed watercourse rehabilitation projects of the time in summer 1994 due to the dry weather, and hence there was no Project data: connection between the fjord and the canal. Project organizer: Nordjylland County Salinity measurements made at regular Contractor: Nordjylland County intervals have revealed a salinity diffe- Project commenced: 1992 rence of 2–4 ‰ between the water Project completed: 1996 pumped from the inner canal and the Total costs: DKK 40,000 (incl. VAT) water in the outer canal. At one point in Financing: Nordjylland County the summer 1994, the water being pumped out was more saline than the Watercourse data: surface water in the outer canal. This was due to density stratification in the inner Coordinates: 57° 04´ N9° 44´ E canals caused by seepage of salt water Catchment: 12 km2 into the bottom of the canals, from Discharge: where the water was drawn by the pump. Max: 1,200 l s-1 A pump inlet was therefore established in Min: 0 l s-1 fresh surface water. Quality objective: B3 (Cyprinid waters) (B1 Salmonid spawning and Experience gained nursery waters; B2 Salmonid waters) Impact studies have revealed that the eel Pollutional class: II–III (II) (1991) pass does not yet function in the manner envisaged. The trial period will be pro- longed and modifications will be made underway. Fish surveys will be undertaken to determine if eel are in fact present in the outer pump canal, or whether it is the eel pass itself that does not work. In addi- tion, the occurrence of eel inside the dike will be investigated. An alternative to the eel pass could be to release eel directly Cross section of the into the watercourses leading to the pump station at pump station. Limfjorden fjord.

Pipe containing loosely intertwined plastic strips

Distribution well

Elevation 0 Inner canal (elevation -2.6)

Outer pump canal Pipe to the inner pump canal

Trap box 25 3.3 . Viborg County 3 Lerkenfeld stream

Rolf Christiansen at Østrup Watercourse system: Lerkenfeld stream

Introduction to the project Lerkenfeld stream arises in Nordjylland County, from where it runs west into Aim of the project Implementation of the project Limfjorden fjord. The stream As part of their general work on the In December 1993, the two weirs were lies in a narrow valley with clearance of obstructions, Viborg and converted to spawning grounds. As there numerous springs in the Nordjylland Counties are in the process was a risk of ochre washout if the meadows alongside the of dismantling the seven weirs in order upstream water level fell, the spawning whole of the stream. The to improve passage to the upstream grounds were laid out as a carpet with an land adjacent to the reach in reaches that are designated as salmonid even slope such that the top of the bank question has been identified spawning waters. was at the same level as the upper edge as potentially ochreous. The Four of the weirs are located of the former weir. reach was channelized at the immediately downstream of bridges The spawning gravel was laid out over end of the 1950s, at which and other constructions. These weirs a length of 35 metres. Downstream of time seven weirs were were evened out in 1994 by laying out the spawning ground a 10-m long cross- established in the stream. stone mixes, chiefly comprised of large- sectional profile was built up using fist- From the agricultural point sized stones. At one of the other sized stones in order to stabilize the of view channelization was concrete weirs the drop in water level spawning grounds. The profile lies unsuccessful since the ripar- was only 25 cm, and the weir was approx. 15 cm lower than the top of the ian areas were only culti- therefore removed without any form of spawning ground. In order to protect the vated for a few years before reinforcement. No erosion of any banks from erosion during the initial being turned back into importance has since been noted in the period after their establishment, meadow again. reach. spawning gravel was also placed along The reach of the stream is When removing two of the seven the sides of the stream along the relatively deep with a uni- weirs a study was made of whether it spawning grounds. form sandy bottom. Further was possible to build stable riffles and Construction costs for the two downstream there is a spawning grounds just by using the spawning grounds amounted to approx. freshwater fish farm with a different gravel sizes that comprise DKK 100,000 (excl. VAT), which is less fish ladder that has to be spawning gravel. At the same time, the than half of what a more traditional open from October to riffles were to be established in such a solution was estimated to cost. February each year. way as to maintain the previous upstream water level. The following Experience gained only concerns the experience gained in From the stabilization point of view it was that study. expected that the two newly established riffles would undergo considerable 26 Completed watercourse rehabilitation projects

rebedding during high discharge periods. One of the weirs in The winter 1993/94 was particularly wet, Lerkenfeld stream Project data: as was also reflected in discharge in the prior to restoration stream. (left). Project organizer: Viborg County After the winter discharge period, A newly established Contractor(s): Viborg County and Agroplan aps Viborg County re-surveyed one of the riffle (right). Project commenced: December 1993 spawning grounds. It transpired that Project completed: December 1993 there had only been a minor amount of Total costs: DKK 120,000 (excl. VAT) erosion on the lower 25 metres of the Financing: Viborg County, Nordjylland County and spawning ground. The upper 10 metres Danish Environmental Protection Agency was the same as when it had been laid out. This is in accordance with the visual Watercourse data: evaluation of current conditions over the spawning ground. Water velocity Catchment: 85 km2 accelerates over the upper part of the Discharge: spawning grounds and does not reach a Mean: 950 l s-1 velocity high enough to erode the gravel Max (10-year): 6,300 l s-1 until some way down along the spawning Min: 520 l s-1 ground. Quality objective: B1 (Salmonid spawning and nursery waters) / In contrast, the gravel that had been B2 (Salmonid waters) laid along the sides of the stream was Pollutional class: II–III (1992) considerably eroded, forming a new spawning ground approx. 5 metres Restoration data:: downstream of the first, and a pool formed between them. Coordinates: 56° 46´ N9° 30´ E Length: 45 m Width: 8 m Slope: 2‰ Discharge capacity: >6,300 l s-1 Spawning gravel laid out: 110 m3 Stones laid out: 60 m3

27 4 3.4 . Ringkjøbing County River Storå at Holstebro

Per Søby Jensen

Watercourse system: River Storå Aim of the project the turbine outlet to guide the fish to the Because the fish ladder functioned so fish pass. Introduction to the project badly, Ringkjøbing County decided to improve passage past the power station. Impact studies in connection with In 1942, a hydroelectric By establishing a bypass riffle past the the restoration project power station was built at station, virtually all fish species should be After the bypass riffle had been con- Holstebro. The river Storå able to pass the obstruction at the power structed a follow-up group was estab- was dammed in order to station, and thereby ensure the fish free lished to regularly assess how it functions provide electricity to the migration to the upper 2/3 of the Storå and decide on any necessary changes in town’s i This hindered the river system. discharge and the shape of the riffle. The free passage of fish to the follow-up group is comprised of repre- upper 2/3 of the Storå river Implementation of the project sentatives of , system. Although a fish The new fish pass was formed as a 655 Ringkjøbing County and the Inland ladder was built when the metre long looped riffle of stones that Fisheries Laboratory under the Ministry of power station was erected evened out a difference in height of just Agriculture and Fisheries. and had subsequently bbuilt, over 5 metres (see diagram). This ensured The follow-up group initiated an it had onlyr worked to a very a sufficiently low current to allow fish of investigation aimed at determining limited extent. all species to pass thehydroelectric power whether and by what species the bypass The hydroelectric power plant. Six resting pools were also estab- riffle was used, and in particular the station dam completely lished in the bypass riffle and spawning extent to which the passage of fish is prevented the passage of the gravel was laid out on some reaches so dependent on discharge in the riffle, as lavaret, a salmonid fish that that it could also serve as a breeding and well as the effectiveness of the spawning migrates into the river Storå Optimal discharge nursery area for the fish. In addition, a gravel laid out in the riffle. in large numbers to spawn. It for fish passes. bar screen was erected downstream of From the results of the investigation it was quite clear that the can be concluded that the bypass riffle is lavaret was unable to pass used by and can be passed by fish of all the old fish ladder. When the 1,000 l s-1 400 l s-1 Discharge Not determined the species that inhabit the Storå river lavaret migrated up the river not decisive system. Moreover, based on the relatively Storå in November-December large catches of a number of species, in an attempt to reach their Perch Gudgeon Bream Rainbow trout among others 4,695 lavaret, it can be spawning grounds, they Pike Roach Dace River lamprey concluded that all fish that wish to could be seen standing in Salmon Eel Sea lamprey migrate upstream are able to find the large shoals just below the Sea Trout Flounder Tench bypass riffle and use it. A precondition, power station. Steelhead Grayling Trout Lavaret though, is that discharge over the riffle is Ruffe varied periodically in accordance with the requirements of the individual species. 28 Completed watercourse rehabilitation projects

Project data:

Project organizer: Ringkjøbing County Contractor: Danish Land Development Service Project commenced: October 1989 Project completed: December 1989 Total costs: DKK 1,300,000 (incl. VAT) Financing: Danish Environmental Protection Agency (DKK 800,000), Ringkjøbing County (DKK 250,000), Holstebro Municipality (DKK 250,000)

Watercourse data: River Storå 2 Road Catchment: 725 km Discharge: Mean: 8,900 l s-1 Hydroelectric -1 Bar- power station Max: 30,600 l s screen -1 Bar Min: 2,500 l s screen Quality objective: Downstream: B1 (Salmonid spawning and nursery waters) Resting pool Upstream: A (Areas of special scientific interest) Power station lake Pollutional class: I–II

Salmon and grayling have successfully Aerial photograph Restoration data: spawned in the spawning grounds laid and sketch map of out in the riffle, albeit that it has not the bypass riffle at Coordinates: 56° 22´ N8° 38´ E been possible to determine the extent. Holstebro hydro- Total length: 655 m electric power Height difference equalized: 5.3 m Experience gained station. Slope at riffle: 10‰ The new operational practice for the riffle Slope at spawning grounds: 4‰ incorporating varied discharge takes into Number of spawning grounds: 3 @ 20 m account both the requirements of the Number of resting pools: 6 individual species as to discharge and the Piped sections under roads: 29 m changes in the migratory patterns of the Bed width at riffle: 2.75 m various species caused by discharge Stone rubble for riffle: 1,025 m3 conditions in the river Storå. Boulders for current shelters: 980 It is clear that the bar screen erected Spawning gravel: 50 m3 downstream of the turbine outlet is of Discharge Oct-May: 1,000 l s-1 (day and night) great significance in enabling sea trout, Discharge June-Sept: 400 l s-1 (day) lavaret, salmon and steelheads to find the 1,000 l s-1 (night) riffle. The distance between the screen bars should not exceed 20 mm. It is noteworthy that high discharge and operation of the floodgate that apparently partly or completely masks the guide current from the riffle do not have any negative effect on the functioning of the pass. 29 3.5 .5 Ringkjøbing County Idom stream at Idum

Per Søby Jensen Aim of the project visible much more rapidly, but the In 1990, it was decided that 280 metres necessary construction work will in most Watercourse system: of the channelized stream reach should cases be relatively expensive. River Storå be restored to its former meandering stream bed, thereby increasing its length Implementation of the project to 570 metres. Determining the path of the former stream Introduction to the project The idea for the project originated in bed was relatively simple since nearly all the County’s landscape department. The the former meanders and wet areas could Virtually the whole of Idom reach was restored to the original stream be identified on aerial photographs of the stream, which is a tributary path so as to fulfil both aesthetic and area as darker patches in the meadows. A of the river Storå, was placed watercourse quality aims. preliminary path of the former stream under a preservation order in As weed clearance and dredging had was thereafter mapped out at a scale of 1985. In this connection the not been undertaken between the closure 1:4,000. With this map in hand, it was uppermost of a series of of the fish farm in 1985 and the start of thereafter relatively easy to find the exact freshwater fish farms was restoration in 1990, the reach had begun course in the stretch of meadow land. By closed down. A reach down- to meander in the excessively wide probing with an iron spear the original stream of the fish farm had watercourse profile. As a result, a well-defined gravel bed of the former previously been channelized meandering current channel had already stream was found, whereafter the “former” to ensure water drainage started to form and the physical condit- and future stream bed could be staked out. from the fish farm. The reach ions were becoming more varied. In a few The material filling the former stream has not been maintained places, the sand sediment had been varied from 0.5–1 metres in depth, and since 1987. flushed away to expose the underlying was chiefly comprised of organic matter gravel. Thus the conditions that good and a little sand lying above the stable watercourse quality demands with respect gravel bed. to undercut banks, deep pools and The excavated material was mainly shallow gravel riffles could probably have spread out on the adjacent fields as a soil been recreated by letting the reach develop improver or otherwise used to close off on its own. Careful consideration was the completely straight channelized reach therefore given as to whether or not to let in the places where it was crossed by the the forces of nature transform the reach remeandered reach. By refraining from towards an expected acceptable result. filling in the whole of the channelized Artificial In the majority of cases such natural reach, several large and small ponds were ponds restoration of channelized watercourse created that are now of benefit to the reaches is to be preferred from the amphibians, animals and birds inhabiting financial point of view. The disadvantage, the area. though, is that the aesthetic value to the landscape of the watercourse meandering Impact studies in connection with Sketch map of the through the whole stream valley would the restoration project remeandered course be lacking for many decades. By excavating The restoration project was followed up of Idom stream. the former meanders the result becomes by electrofishery surveys at three 100 metre 30 Completed watercourse rehabilitation projects

250 Older trout pollution from the fish farm. The positive fish population than those attained in the 200 Fry (0+) development at station 3 is therefore upstream regulated reach by self-restoration. largely attributable to removal of the The total trout population in the restored 150 impact of the pollution as well as to reach is therefore 3–4-fold greater than significant improvement in the physical could be expected had the reach only 100 conditions as a result of self-cleansing been allowed to undergoself-restoration 50 following cessation of maintenance. At to the same degree as at station 3. In the

No. of trout per 100 m station 2, in contrast, the population longer term, however, it can be expected 0 90 91 92 93 88 89 90 91 92 93 90 91 92 93 tended to remain constant during the same that trout density at the restored and the Non-channelized Remeandered Channelized period, this being due to the fact that the self-restored reaches will eventually be restoration process retarded development the same. stations. Station 1 lies downstream of the Total number of for a period as time was needed for plants Restoration of the stream reach has restored reach and has never been trout present at to recolonize the reach and for the gravel thus both helped improve the trout channelized, while station 2 lies in the three 100 metre beds to be flushed free of sediment. population as a result of the better restored reach and station 3 lies upstream reaches of Idom In 1993, however, the trout population physical conditions, and has doubled the and is still channelized (see the figure). It stream during the at station 2 was considerably greater than length and hence area of the reach should be noted that electrofishery in years 1988–93: at station 3; despite the delay, restoration relative to that of the channelized reach 1990 was undertaken immediately prior to Station 1 – a non- created better physical conditions for the prior to restoration. restoration in October, and that the trout channelized population at station 1 has not been downstream reach; Project data: investigated before 1990. Between 1990 station 2 – the and 1991, the number of trout in the 100 remeandered reach; Project organizer: Ringkjøbing County metre reach at station 1 almost doubled, and station 3 – an Contractor: Ringkjøbing County and has since remained constant at upstream still Project commenced: October 1990 around 225 trout, which corresponds to a channelized reach. Project completed: November 1990 density of approx. 1 trout m-2. This level Total costs: DKK 70,000 (excl. VAT) probably represents the trout carrying Financing: Danish Environmental Protection Agency capacity that the stream has in its non- channelized form. Similarly at station 2, Watercourse data: the trout population has increased from 25 trout in the 100 metre reach in 1989 Catchment: 14 km2 to approx. 225 trout in 1993. At station Discharge: 3, the trout population increased from Mean: 180 l s-1 just under 25 trout in 1990 to just under Max: 580 l s-1 150 trout in 1993. Min: 90 l s-1 At all three stations, a satisfactory Quality objective: A (Areas of special scientific interest) / percentage of fry from natural reproduction B1 (Salmonid spawning and nursery waters) and of older trout from several generations Pollutional class: I–II, I has been attained over the 3-year period. Restoration data: Experience gained The difference that is apparent in the Coordinates: 56° 20´ N8° 30´ E development of the trout population at Length: 280 ® ® 568 m station 2 and station 3 from 1990 to 1992 Width: 4 ® 1 m is chiefly attributable to the development Slope: 3 ® 1.5‰ in physical conditions at the two stations. Meanders: 0 ® 15 The reach at station 3 had been harshly Spawning gravel laid out: 0 m3 maintained until the closure of the fish Stones laid out: 20 farm in 1985, and hence until then had Earth excavated: 500 m3 also been marked by the effects of 31 3.6 Ringkjøbing County .6 Rind stream at Herning

Per Søby Jensen

Watercourse system: River Skjern

Introduction to the project Aim of the project ochre was commissioned at the end of At the beginning of the Because of the ochre problems caused by 1992. 1940s, part of Rind stream the upstream lignite beds, an attempt was The ochre is removed using grass south of Herning was made to design a project that in addition trickling basins alongside parts of the channelized in order to to meeting drainage interests and environ- reach, as well as by leading part of the reclaim meadow land for mental considerations, also minimized the water into six shallow basins excavated cultivation. Together with ochre problem. The aim of the project was nearby, the beds of which have been decades of maintenance this therefore to recreate a more natural, sown with special species of grass able to left the stream as a straight meandering watercourse, and to reduce tolerate being flooded for longer periods. channel with uniform banks the problems caused by ochre. The vegetation in the basins promotes that sloped straight down to oxidation of the dissolved iron and retains an almost horizontal bed Implementation of the project the ochre. comprised chiefly of sand and The channelized reach of Rind stream was In connection with the remeandering mud deposits. previously 1,800 metres long. After the work and the establishment of the ochre 3 It was not only the physical reach had been remeandered, it was removal basins, approx. 35,000 m conditions that inhibited the approx. 500 metres longer. This has material was excavated. This was used to species composition and increased the number of hiding places for fill in the former channelized sections of density in the watercourse, fish, and at the same time, new spawning the reach as well as to level out other however, but also the quality grounds have been laid out. parts of the area. Now that the vegeta- of the water. The first part of the project – the actual tion has grown up, it is no longer The reach in question was remeandering work – was completed at apparent that the countryside has been clearly affected by ochre Sketch map of the the beginning of 1992. The ochre removal modified by man. Moreover, the area has from two upstream former remeandered reach part of the project whereby the forces of become an ideal stopover for migratory lignite beds. As a conse- of Rind stream nature are harnessed to clean the water of birds. quence, pH was low and the iron content of the water N exceeded permitted levels.

Sand trap Shallow grass basins

New course Old course 32 Completed watercourse rehabilitation projects

Impact studies in connection with Aerial photograph Three subsequent analyses have revealed idea and implementation was the great the restoration project of the remeandered a degree of treatment averaging 63% for support for the project among the The impact of the project on the iron reach of Rind dissolved iron and 30% for total-iron. landowners. content of Rind stream has been assessed stream. The relatively low degree of ochre regularly since completion of the plant Experience gained treatment attained in relation to through monthly analyses of the inflow The idea for the project originated with dedicated ochre treatment plants, where and outflow water (total iron, dissolved two landowners who came to the county the degree of treatment can reach 80– iron, pH, temperature and oxygen authorities wanting the stream restored 95%, is largely attributable to the small content). Since operation started in 1992, to its former meandering path. In April volume of the basins and poor flow of the plant has continued to reduce the 1991, the County held the first meeting water into them. iron content of the water in reasonably with the landowners in the area, and in In the construction phase dams were close accordance with what was ex- October the same year, the first part of not established in the main course as it pected. The average degree of treatment the project was initiated. The last part of was expected that flow from the stream over the period October 1993 to Septem- the project – the ochre removal basins – to the basins would gradually increase in ber 1994 has been around 43% for was completed in 1992. The main reason step with colonization of the new dissolved iron and 32% for total-iron. for the relatively short interval between vegetation-free meanders with weed. 33 Completed watercourse rehabilitation projects

The water level was therefore expected to Project data: increase, thereby resulting in more frequent flow of water to the basins. The last three Project organizer: Ringkjøbing County series of measurements indicate that the Contractor: Ringkjøbing County increasing distribution of vegetation has Project commenced: October 1991 in fact had a positive influence on the Project completed: February 1992 degree of ochre treatment. Total costs: DKK 910,000 (excl. VAT) For one thing, the water quality has Financing: Ringkjøbing County watercourse restoration funds increased, and for another, the physical (DKK 520,000); conditions have improved considerably, as Danish Environmental Protection Agency ochre funds is apparent in the form of much more (DKK 390,000) varied conditions with fish hiding places, riffles and pools, gravel bed and good Watercourse data: hydraulic conditions.

Remeandered reach: Ochre removal reach: Catchment: 170 km2 52.4 km2 Discharge: Mean: 2,600 l s-1 900 l s-1 Max: 6,700 l s-1 2,500 l s-1 Min: 550 l s-1 200 l s-1 Quality objective: B2 (Salmonid waters) B2 (Salmonid waters) and F (Watercourses affected by ochre) Pollutional class: II–III II–III, affected by ochre

Restoration data:

Coordinates: 56° 06´ N8° 58´ E

Remeandered reach: Ochre removal reach: Length: 1,020 ® 1,340 m 750 ® 950 m Width: 10–12 ® 6–12 m 4 m ® (2–6 m and 2–40 m) Slope: 0.65 ® 0.55‰ 0.8 ® 0.65‰ Meanders: 0 ® 12 0 ® 14 Number of riffles established:7 Spawning gravel laid out: 115 m3 30 m3 Boulders laid out: 100 Earth excavated/incorporated: 15,000 m3 Stone rubble laid out: 40 m3 Earth excavated: 20,000 m3 Number of shallow pools: 6 Watercourse corridors: 1 Sand traps: 1

34 .7 3.7 County River Gudenå at Langå

Ole Helgren

Watercourse system: River Gudenå

Introduction to the project The river Gudenå down- stream of the lakes has been channelized and Aim of the project drawn up in close collaboration with the deepened several times over After several years’ discussion as to local committee of the Danish Society for the last century to facilitate whether salmonids spawned in the main the Conservation of Nature, anglers, local navigation with barges, etc. course of the river Gudenå and whether museums, the Natural History Museum, The last time was in the the physical conditions were suitable, the the municipal authorities, Aarhus and 1930s. Large boulders were decision was made in 1992 to undertake Counties, and affected landowners. blown up, and smaller stones a pilot project comprising the establish- The project involved establishing two and gravel were excavated to ment of an artificial spawning ground spawning grounds. Over an area of ensure a good navigation approx. 2 km upstream of Langå. approx. 1,200 m2 the spawning grounds channel. With the construc- The idea was to re-establish one of the were built up to a height of approx. 1.4 tion of a hydroelectric power former excavated spawning grounds. metres above the existing river bed on a station at Tange in 1921 the However, all such sites proved to coincide base of unsorted stony material covered remaining natural spawning with areas of historical interest (fords, with an at least 40 cm thick layer of grounds in the lower reaches etc.) and it was therefore decided to spawning substrate. The latter is of the river Gudenå establish a spawning ground from scratch comprised of naturally occurring stony disappeared, and the formerly at an otherwise suitable site. material from the area having the so rich salmon populations The final location was chosen from following size distribution: 15% 8–16 died out. among 10 possibilities after numerous mm, 35% 16–32 mm, 35% 32–64 mm investigations of water velocity, profile and 15% 64–120 mm. changes, bottom substratum and benthic The water depth over the spawning fauna. Close examination of the historical grounds is at least 40 cm. Along the aspects also played a decisive role in southern bank of the river there is an at making the final choice. least 5 metre wide and 1 metre deep navigation channel. Numerous large Implementation of the project stones have since been placed in the river The Environmental Division of Aarhus to protect the banks and provide shelter County was given the task of planning from the current. and undertaking the project. In order to The project was undertaken by a ensure that all ideas and viewpoints were contractor during a 14-day period in taken into consideration, the project was autumn 1993. 35 Completed watercourse rehabilitation projects

The physical and hydraulic conditions still fulfil those assumed in the project. Fish were observed spawning at the spawning grounds immediately after completion of construction work in October and for the remainder of the year 1993, and electrofishery in the early summer 1994 led to the catch of the first salmon fry (1 indiv.). Electrofishery and the biological investigations were continued in 1994–95. Experiments involving the laying out of hatching boxes are also planned. In winter 1994–95, the spawning grounds was expanded with an associated shallow-water area designed to provide better hiding places for the fry.

Impact studies in connection with Laying out the the restoration project spawning gravel. Project data: As the project was intended as a source of inspiration for future work on improv- Project organizer: Gudenå Committee ing the environmental quality of the river Contractor: Aarhus County, Environmental Division Gudenå, a number of studies were Project commenced: September 1993 undertaken before and after carrying out Project completed: October 1993 the project: Total costs: DKK 130,000 (incl. VAT) Financing: Gudenå Committee .Pre-, during and post-construction surveys Watercourse data: .Pre- and post-construction measure- ments of discharge Catchment: 1,850 km2 .Pre-construction geotechnical surveys Discharge: of river bed conditions Mean: 22,000 l s-1 .Diver surveys to register aspects of Max: 65,000 l s-1 historical interest Min: 10,000 l s-1 .Pre and post construction investigation Quality objective: B2 (Salmonid waters) of the flora and benthic fauna Pollutional class: II (1993) .Regular electrofishery .Visual registration of fish at the Restoration data: spawning grounds Coordinates: 56° 23´ N 9° 55´ E Experience gained Length: 70 m The accessibility of the selected sites Width: 30 m considerably affects construction costs. In Slope: Average 10‰ the case of the present project, which Discharge capacity: 35,000 l s-1 cost DKK 130,000, road access for the Spawning gravel laid out: 180 m3 delivery of materials was particularly Stones laid out: 90 m3 good. Rubble laid out: 370 m3 36 8 3.8 . Aarhus County Lilleå stream at Hadsten

Ole Helgren Aim of the project The construction of a 12–18 metre wide Watercourse system: Due to repeated flooding of agricultural two-step profile along 4 km stream was River Gudenå land in the 1980s and because the undertaken in 1989 in close cooperation watercourse quality objectives were not with the landowners. The project was fulfilled, the decision was made to do partly paid for by the landowners, who something about the problem. provided the land free of charge, and Introduction to the project The passage of migratory fish was also partly by the Municipalities and the included since approximately half of the County subsidized by the Danish Environ- Lilleå stream, which arises salmonids that migrate up the Gudenå mental Protection Agency. Free passage approx. 20 km west of river system enter Lilleå stream. of fish was ensured by: Aarhus and flows into the The task involved improving the . Replacing the fish ladder at Løjstrup in river Gudenå at Langå, is one stream’s discharge capacity and hence 1988 (cost approx. DKK 200,000) of the river’s main tributaries. drainage safety, while at the same time . Removing the dam at Hadsten Mill and The surrounding landscape enhancing its environmental quality and establishing a riffle in 1989 (cost varies from very hilly to flat ensuring free passage for fish in Lilleå approx. DKK 700,000) plains, although there is a stream and subsequently in the whole of . Removing the dam at Grundfør Mill clearly defined river valley. the Lilleå watercourse system. and establishing a riffle in 1990 (cost Approx. 2/3 of Lilleå stream approx. DKK 450,000) has been channelized over Implementation of the project . Establishing a riffle at Granslev in 1991 the years to meet the needs The complete project was drawn up by a (cost DKK 30,000) of agriculture. As a result of working group involving the landowners, . Establishing a bypass riffle at Voer Mill channelization and marked interest groups, weir owners, municipal in 1992 (cost DKK 130,000) urban and industrial growth, and county authorities. The project took . Removing the dam at Selling Mill and Lilleå stream appeared as a approximately five years to complete and establishing a riffle in 1993 (cost DKK barren watercourse charac- encompassed: 60,000). terized by harsh maintenance and sand migration. Water . Constructing a two-step profile along With the prior agreement of the land- quality was affected by 4 km of the stream owners, interest groups and the authorities, effluent, and discharge was . Replacing a fish ladder each sub-project was administratively very variable, often leading . Removing two dams and constructing processed by the County and subsequently to major flooding. riffles undertaken under contract under the . Constructing a bypass riffle County’s supervision or by the County . Laying out approx. 3,000 m3 stones itself. . Laying out approx. 300 m3 spawning Subsequent to the project, work has gravel been undertaken in the tributaries to . Planting approx. 13,000 trees Lilleå stream whereby one bypass riffle . Drawing up new regulations and has been constructed and two dams switching to environmentally sound removed. In addition, most maintenance maintenance. is now undertaken in an environmentally sound manner. 37 Completed watercourse rehabilitation projects

The course of the project and the The result is a pleasant watercourse methodological manner in which it was with a rich flora and fauna, a green carried out has led to a wide understan- corridor through the stream valley, and ding of the complex problems that often satisfied citizens, landowners, organizations arise when balancing agricultural and and authorities. environmental interests, and has given The course of events and the result rise to a good climate of cooperation have generated considerable goodwill in between the landowners, the organizations the whole catchment area and, among and the authorities. other things, has led other landowners to approach the County with proposals for further improvements to the environment.

Laying out stones in Project data: Impact studies in connection with a two-step profile. the restoration project Project organizer: Aarhus County Studies made prior to the project had Contractor(s): Aarhus County and revealed an impoverished aquatic envi- Danish Land Development Service ronment characterized by few plant Project commenced: 1987 species and a barren sandy bed with a Project completed: 1993 small population of stock fish and only a Total costs: DKK 2,700,000 (incl. VAT) few migratory fish. Moreover, large areas Financing: Danish Environmental Protection Agency of agricultural land were frequently (DKK 350,000), flooded. Following completion of the Hadsten and Municipalities project, sand migration has minimized, (DKK 770,000), and long stretches can now be found diverse landowners (DKK 750,000), having a stony or gravel bed. The species and Aarhus County (DKK 830,000) composition of the weed has changed considerably, and there is currently a Watercourse data: good population of indigenous fish. In addition, migratory fish can now be Catchment: 310 km2 found in nearly the whole of the river Discharge: system. Mean: 2,914 l s-1 Flooding of agricultural land has only Max: 26,000 l s-1 taken place in the spring of 1994, and Min: 720 l s-1 the newly created green corridor has Quality objective: A (Areas of special scientific interest), provided a good habitat for fauna and B1 (Salmonid spawning and nursery waters); flora. B2 (Salmonid waters) Pollutional class: II (Average, 1993) Experience gained The procedure chosen involving a broadly Restoration data: based working group and numerous meetings and public hearings is protracted Coordinates: 56° 19´ N10° 03´ E and resource demanding. However, the Length: 31,200 m subsequent implementation phase is Width: 1–7 ® 1–4 m correspondingly quicker and more problem Slope: 1.1‰ free. Discharge capacity: 26,000 l s-1 The construction work was undertaken Spawning gravel laid out: 300 m3 at times that were favourable for both Stones laid out: 3,000 m3 landowners and the environment. Earth excavated: 35,000 m3

38 3.9 Vejle County .9 Lammebæk brook

Tony Bygballe Jan Nielsen at Daugård Watercourse system: Rohden stream

Introduction to the project Lammebæk brook is a tributary of Rohden stream, Aim of the project At the same time, another culvert which runs through a river The culvert was previously an effective located approx. 500 metres upstream was valley covered with trees. obstruction for migratory fish. Because altered such that there is now free Lammebæk brook falls 40 of the culvert’s 30‰ slope, the water passage to fish along the whole length of metres over a 4 km long level inside was so low and the current the watercourse. reach. It has not been velocity so high that not even strong fish dredged or maintained for like the sea trout were able to swim Impact studies in connection with several years. As a result, it upstream through the culvert. The the restoration project has developed a natural and project aimed to effectively improve the Two weeks after the lamellae had been varied course that alternates possibility for fish to migrate upstream in mounted, sea trout had swum through between small falls, riffles the brook. the culvert and further on up the brook. and deep pools. At Daugård, The fish are now evenly distributed along the brook runs under a main Implementation of the project the whole length of the brook. In 1993, road through a 25 metres The County constructed a simple but there was a fine natural trout population long concrete culvert. effective lamallae-like insert to mount of approx. 2.2 trout m-2. Up to 1994, inside the culvert so as to create refuge 2,000 trout fry were stocked in and resting places for fish attempting to Lammebæk brook each year. However, migrate upstream in the brook. The stocking was ceased after 1994 as the insert is comprised of a wooden plank population is now self-reproducing. with a notch cut on the upper edge of alternate sides, and is fitted to an iron Experience gained bracket having the same form as the Culverts that lead watercourses under culvert. The inserts are mounted on the roads are one of the most common base of the culvert at 2 metre intervals obstructions in smaller Danish water- angled in the direction of the current. courses. If there is insufficient water in The water level at each of these lamellae- the culvert, or if the current is too strong, like inserts was thereby raised at least 30 the culvert forms an effective obstruction cm, andtrout and other fish can now for even the strongest swimmers such a swim through the notches in the sea trout. If the culverts lie deep below lamellae and rest in the basins between the road surface it is often economically them. unfeasible to alter them. Mounting 39 Completed watercourse rehabilitation projects

lamellae in culverts has proved to be a The road culvert very effective means of raising the water before and after Project data: level and reducing current velocity. mounting the Moreover, it is a relatively cheap solution lamellae. Project organizer: Vejle County for a major problem. Contractor: Vejle County Project commenced: October 1992 Project completed: October 1992 Total costs: DKK 18,000 (incl. VAT) Financing: Vejle County

Watercourse data:

Catchment: 5 km2 Discharge: Mean: 75 l s-1 Max: 2,000 l s-1 Min: 25 l s-1 Quality objective: B1 (Salmonid spawning and nursery waters) Pollutional class: I

Restoration data:

Coordinates: 55° 44´ N9° 43´ E Length: 25 m Diameter: 1.25 m Slope: 30‰ Culvert discharge capacity: 6,000 ® 5,000 l s-1 40 3.10 Vejle County .10 Kvak Møllebæk brook

Tonny Bygballe Jan Nielsen at Skibet Watercourse system: River Vejle

Aim of the project down to the river Vejle was undertaken in The aim of the project was to construct a October 1992, and included planting the Introduction to the project bypass riffle around the old watermill adjacent land with common alder. dam in order to restore free passage for Kvak Møllebæk brook is a the brook fauna and at the same time tributary of the river Vejle reduce sand deposition in the millpond. Impact studies in connection with lying approx. 7 km upstream In addition, the channelized and deep- the restoration project of Vejle Fjord. At Kvak Mill, a ened brook downstream of the dam was Subsequent studies have shown that water-driven grain mill built to be remeandered to give it a more many trout were already present in the in the last century, a 4.3 natural course before its outlet into the bypass riffle one month after its comple- metres high dam prevented river Vejle. tion. At that time, trout density was up to the passage of fish. 1 trout m-2. The following year, trout Implementation of the project density in the bypass was 2 trout m-2, the The bypass riffle was constructed in May– trout having started to spawn in the June 1991. Remeandering of the reach bypass itself. There were far more trout in

Bypass riffle at Kvak Watermill. 41 Completed watercourse rehabilitation projects

Project data:

Project organizer: Vejle County Contractor(s): Danish Land Development Service and Vejle County Project commenced: May 1991 Project completed: October 1992 Total costs: DKK 252,000 (excl. VAT) Financing: Vejle County, Danish Environmental Protection Agency and

Watercourse data:

Catchment: 4.8 km2 Discharge: Mean: 72 l s-1 Max: 136 l s-1 Min: 36 l s-1 the bypass than in the upstream and Electrofishery in the Quality objective: B1 (Salmonid spawning and nursery waters) downstream reaches of the brook. remeandered reach Pollutional class: I–II Moreover, studies undertaken during of Kvak Møllebæk the sea trout spawning season have brook. Restoration data: shown that numerous sea trout now migrate upstream of the millpond to Coordinates: 55° 43´ N9° 27´ E spawn in the brook’s upper reaches. Thus many more trout are now present in the Remeandered reach: Bypass riffle: brook than previously, and trout stocking Length: 150 ® 190 m 0 ® 260 m has now been stopped. Furthermore, in Width: 3–4 ® 0.6–3 m 0 ® 0.5–1.3 m the remeandered reach twelve spawning Slope: 0 ® 4–5‰ 0 ® 5–25‰ grounds were laid out and sea trout started to use them just a few days after Discharge capacity: Max 150 l s-1 completion of the project. In 1993, there Meanders: 9 was a fine natural trout population of Spawning gravel laid out: 60 m3 approx. 1 trout m-2. Stones laid out: 70 m3 Earth excavated: 200 m3

42 3.11 Sønderjylland 11 . County River Brede

Bodil Deen Petersen Mogens Bjørn Nielsen at Løgumkloster Watercourse system: River Brede

Introduction to the project At Løgumkloster the river Brede runs in a well-defined and rather narrow river valley, the majority of which Aim of the project reach was converted to a 3,130 metre is permanently grass-covered. There were several reasons for wanting to meandering reach and the river bed was From there the river continues restore this particular reach of the river raised. The weir was removed and two past Bredebro, eventually to Brede. Firstly, to improve environmental long riffles were established instead. run out into the Wadden Sea. conditions in the river, including reducing Spawning grounds and stones were laid The river Brede originally the destructive migration of sand. out, and some of the meanders were followed a very meandering Secondly, to remove the last major weir in reinforced with stones. path, but was channelized in the river Brede, thereby enabling the The meandering course is now almost the mid 1950s. The river has upstream migration of salmonids, identical to that prior to channelization since eroded deep down into especially the rare salmonid, the houting, except alongside Løgumkloster town, the landscape and caused which is once again found in the majority where remeandering was not possible considerable sand migration. of watercourses in southern Jutland because a sewer and houses have since Only in very few parts of the courtesy of a successful breeding pro- been constructed at the former course of river there was an actual gramme. The plan also encompassed the river. gravel-bedded current channel improving the continuity between the In several places the former meanders and spawning grounds river and adjoining meadows by raising were preserved after channelization. They suitable for salmonid fish. In the river bed. were still present as open ponds in the 1990, a large weir at Bredebro Prior to the project, the latter lay up to meadows, but became incorporated in was rendered passable by 1 metre below the level stipulated in the the new meandering watercourse after converting it to a riffle (see Provisional Order governing the restoration. To replace them, two new example 3.12). This was the watercourse. The whole of the river valley ponds were excavated in the former only downstream obstruction is potentially ochreous, and raisingthe channelized reach. During excavation in the river system. river bed and hence the water table in work it transpired that one of the former the river valley was also expected to meanders had been used as a landfill, reduce ochre input to the river. and over 200 tonnes material had therefore to be transported to a control- Implementation of the project led landfill. The project was undertaken in the second The project was completed in May 1992. half of 1991. A 2,680 metre channelized 43 Completed watercourse rehabilitation projects

Impact studies in connection with The river Brede near developed, the banks being steep and Compared with the former channelized the restoration project Løgumkloster having been reinforced with fascines. reach the new reach has a greater The plants and benthic macroinverte- during restoration After restoration, the bank vegetation has number of benthic macroinvertebrate brates in the reach in question were in October 1992. become more diverse and well developed. species and the density of macroinverte- studied prior to restoration (in 1991) and The new meanders The vegetation in the river itself was brates is generally greater now because again after six and eighteen months, have been dug and previously strongly dominated by the river bed has become less uniform respectively (in 1992 and 1993). In the former filamentous leaves of the bur reed than previously. addition, electrofishery is undertaken channelized path (Sparganium Emersum), but after Electrofishery has shown that each year in much of the river Brede in has not yet been restoration, there is a higher frequency of numerous and large sea trout migrate up collaboration with the local angling filled in. more environmentally beneficial species the river Brede, and that the houting is association. such as the water starwort (Callitriche now found far up the river system. It has Prior to restoration, the bank vegeta- platycarpa) and the large-flowered water not yet been shown to spawn in the river, tion in the channelized reach was poorly crowfoot (Batrachium peltatum). though. 44 Completed watercourse rehabilitation projects

Experience gained The project affected a total of 10 private Project data: landowners as well as Løgumkloster Municipality. All the landowners were Project organizer: Sønderjylland County involved in the project at an early point so Contractor: Sønderjylland County that they had the opportunity to influ- Project commenced: July 1991 ence the project. They were regularly kept Project completed: December 1991 informed during the whole course of Total costs: DKK 1,750,000 (excl. VAT) events. Financing: Danish Environmental Protection Agency, In 1994 and 1995, a further 6 km of Løgumkloster Municipality and the river Brede downstream of the above Sønderjylland County mentioned reach was restored in the same manner. This project was under- Watercourse data: taken under the EU Life Programme in connection with similar projects in Catchment: 258 km2 England. The significance of the project Discharge: for the river and river valley is still being Mean: 2,700 l s-1 thoroughly investigated by Sønderjylland Max: 16,000 l s-1 County in collaboration with the National Min: 1,000 l s-1 Environmental Research Institute. It is Quality objective: B2 (Salmonid waters) planned to continue restoration of the Pollutional class: II (1990–91) river Brede both downstream and upstream, as well as to undertake Restoration data: projects in some of its tributaries aimed at reducing loading by ochre. The reme- Coordinates: 55° 04´ N8° 58´ E andering project is the largest of its kind Length: 2,680 ® 3,130 m so far undertaken in Denmark. Width (bed): 6 m Slope: 0.3‰ Discharge capacity: 12,000 l s-1 Meanders: 0 ® 13 Spawning gravel laid out: 300 m3 Stones laid out: 5,750 m3 Earth excavated: 48,200 m3

Pilot studies:

Soil analyses in the river valley Surveyance of the river and river valley Collection of water discharge data for the latest years Plants and macroinvertebrates in the river Information on cables and conduits in the area (electricity, telephone, water, sewage, gas) Information on other restrictions and plans for the area (County Plan, Municipal Plan, zoning restrictions, preservation orders, etc.)

45