Property:Lessons learnt
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R
As a strategic catchment plan ecah individual project allows for lessons to be learnt for future projects. Thes einclude amending in channel technqiues to more effective way of bringing gravels to site to more innovative ways of utlising material son site to reduce waste. +
As described, the diverted, perched and impounded pre-existing channel form at this project site (typical of mile after mile of English chalk stream) disables natural fluvial and ecological process, by
a) greatly reducing gradient (and therefore flow velocity) and morphological heterogeneity and
b) by divorcing the stream from the floodplain. Natural processes are a function of natural channel shape and gradient and consist of a two-way relationship between the physical form of the river and the ecological engineering that form enables.
A simple example would be how a restoration of gradient will restore ranunculus, which provides habitat for the blackfly larvae which scrub the water of diatoms: thus a change to the physical shape of the river can improve the water quality along it. In consultation with NE we took the decision to introduce nothing to the site except the changes made to the physical form, allowing the form to shape the habitat and later the plant and animal occupants of that habitat to shape the form. The in-stream plants established within one year of Phase 1 included extensive beds of starwort, berula and ranunculus, but rare marginal plants too, including bog-bean. It is notable too (at the time of writing April 2022) that benthic algae is more or less absent from the substrate of the new channel but prevalent in the side, spring-fed channel, suggesting the new channel will favour rheophillic invertebrates as well as plants. An unexpected impact has been the way in which the Konik ponies interact with the meander planform to improve the biodiversity of the plant communities: they graze (and poach) the point-bars on the inside of the meanders, but not the banks above the undercuts on the outside of the bends (see pictures in accompanying folder). Another impact of note is the way in which a stream returned to its natural level in the floodplain creates a scour line at the margin between the gravel floor of the river bed and the clay-peat banks above. On the outsides of bends this scour line becomes a significant undercut, as the stream nibbles away at the motile gravel and sand but not the cohesive upper layer. These undercuts provide fantastic refuge habitat for larger fish. Early results of NRT monitoring suggest a very healthy fish community, with all the size classes from juvenile 0+ and 1+ to large 5+, whereas in the pre-exiting channel the size range was more restricted to 2+ and 3+. This suggests that the fish have responded well to the increased heterogeneity of habitat in the new channel. Interestingly, the Stage Zero flooded woodland is already populated with bullheads and some juvenile trout. Also of note is how in the Stage Zero area the diversion of flow from the perched leat to the base of the floodplain has resulted in a matrix of flooded channels and backwaters: the river has cleared it’s own pathway along a course from which it was diverted centuries ago.
G
At this site in particular we came across some levels of reticence from the local community to the project, mainly due to the significant changes to the landscape and lack of familiarity around SuDS, as well as a lack of understanding of why they were desperately needed. We overcame this by being very transparent and available, and in taking care of the site and the stream and making obvious improvements to its health and potential as a wildlife habitat. Regular communications in many forms were key. This became the site at which volunteer days were best attended by local residents. In future projects it would be ideal to spend a time in the build-up to the project engaging the community about water quality issues, rather than to do this simultaneously with planning the SuDS.
Water quality issues were far more significant than we had anticipated on commencement of the project, particularly in relation to domestic misconnections. Serious pollutant levels damaged the beginning of our SuDS system as Glenbrook. We also found that although we proved our systems had a beneficial impact on water quality, just downstream of each project were outfalls which would bring in yet more pollutants. Therefore SuDS alone could not demonstrate catchment level water improvements needed under WFD. Small scale SuDS have a place in a suite of wider measures that need to be tackled with more drive, especially pollutant impacts from misconnections and vehicle use.
We experienced some design issues which resulted from a lack of quality data pre-project, for example on flows. It would have been prohibitively expensive for us to get the data needed on this project budget, but it meant that some SuDS elements such as weirs required some costly remediation work. +
R
August 2012 update - Confluence bypass channel is not complete, due to the presence of Japanese Knotweed the project could not be totally completed, a deflector was put in and the channel dug but it is not working. In base of visit in August: the channel is dry. +
T
Based on studies of the first year after opening, colonization of invertebrates mainly appeared to be from species drifting from upstream, rather than (except perhaps to a very small extent) from the other Oslo streams. (Refer to David Arnott's master thesis here)
Benthic algae, the first two years after opening, were a mixture of diatoms (mostly early spring and late fall), green algae and cyanobacteria. The main pond (Tegiverksdammen) had an extensive growth of filamentous green algae (Spirogyra) during the warm summer months, which also flourished after mechanical removal in July. The shallow parts of the upper stream reach also had a high production of benthic cyanobacteria, which broke off and flowed massively into the main pond as brown-black lumps on the surface. Whether these were temporary conditions due to the recent opening of the facility, or simply an effect of low water flows and depths remains to be seen. (Refer here to Karoline Dahl Myrstad's Master's thesis)
Due to maintenance requirements during the first summer after opening, the flow of water was shut down for approximately one month. During this period, the pools and ponds had stationary water, while the riffles dried out. The result of this was a massive increase in phytoplankton biomass in the main pond (Teglverksdammen). Other than that, biodiversity did not change significantly between the first two full years after the facility opened. (Refer here to Susanna Birgitta Diana Burgess's Master's thesis)
Monitoring of water chemistry at the inlet and outlet of the system during the first two summer seasons after opening showed the potential of the facility for some purification of the water, but it was partly dependent on time of year, on whether the water was flowing and on the nutrient concentrations of the water entering the system. +
K
Be opportunistic. The upper stretch of the work has been more successful than the lower reach, probably due to a backwater effect from a pond at the downstream end, and partially due to the reduction of energy through the full reach. Since completion in 2011, no further maintenance work has been required (up to 2014), which is a cost savings for the Agency.
The technique will be used again in future projects. +
Y
Biffaward secured, with potential for greatly increasing the scale of the project through an HLF bid. Part of River Crane Projects: 3 sites: Roxbourne Park, Yeading Brook Fields/Meadows, and Crane Park. Cost total value: £230,500; project length (m): 8000m; main funding org: Biffaward (£148,500) +
B
Both the Ladden and the Bradley Brooks are suffering biologically and physico-chemically due to agricultural run-off. Whilst the improvements made during the course of this project will help to reduce these issues to some extent, the catchment requires a much larger programme of improvements in order to make a measurable difference. +
F
Building on this comprehensive eco-hydrological assessment of the valley, a management plan was produced by the project covering all land within the Doode Bemde perimeter of 500 ha, whether it was owned by the beneficiary or not. This is quite innovative in comparison to the traditional Natuurpunt management plans, which only cover land owned by the NGO. The target set in the management plan is to have 50-60% open land (grassland, swamp, pond) and the rest as succession landscape evolving to ash-alder woods. Land purchase targets changed markedly during the project, as the competent authorities began acquiring land originally earmarked for purchase by the beneficiary. 54.3 ha was bought by Natuurpunt within the LIFE project - mostly former grasslands planted with poplars or overgrown as a result of abandonment, fish ponds and patches of degraded woodland. In parallel there were other land acquisition initiatives: 44.8 ha was expropriated by the competent authorities (AMINAL-Natuur and AMINAL-Water) and leased to Natuurpunt to manage, while a VLM (agri-structural authority) project for nature rehabilitation acquired another 10 ha which was also leased to Natuurpunt to manage. So altogether during the LIFE project over 109 ha came under conservation control. The beneficiary now owns or manages the most important 'depression areas’ in the project area. These are the Doode Bemde, the Dijlebroek-Leigracht area and the Grote Bron, the depression zone with the Langerodevijver. Before the LIFE project Natuurpunt only managed 99 ha (20% of the project area), this has now gone up to 208 ha (42% of the project area), mainly in large coherent blocks. The land purchase and acquisition allowed the competent authority (AMINAL-Water) to block a culvert bringing a drainage ditch (the Leigracht) under the IJsse river. This action, done parallel to LIFE, allowed the retention zone to fulfill its natural function. Since then, the drainage of the alluvial woods has stopped and wintertime flooding of the Dijle valley in the project area has started again. The project itself undertook an extensive list of one-off restoration works. - Whereas 20 ha were foreseen, in total 43 ha poplars have been removed by the LIFE project. On 18 ha of this, stumps were totally removed as well. - Four weekend cottages were demolished. - 4 ha maize field was converted into extensively managed grassland, 7.6 ha of production grassland was restored to Annex I habitat status by appropriate recurring mowing and grazing and shrubby overgrowth removed to restore 3.4 ha of former habitats for the benefit of the species Vertigo moulinsiana. - 4 km fences were installed to expand grazing management: 10 ha of the Doode Bemde is now managed by grazing and 40 ha by hay mowing followed by grazing. This recurring management is done by local farmers. - The banks of the 24 ha Langerode pond were cleared of trees and bushes and graded in order to stimulate reed growth. A small pond was restored in order to act as amphibian habitat and as a nature education site. - 5 ha of degraded woods were taken out of use and poplars ring-barked to provide standing dead wood. 400 metres of ditch draining the Langerode wood was filled in. This work was done by own staff (4 labourers were hired), a local employment initiative for disadvantaged youth and volunteers (regular camps were organised). Equipment was bought for the staff and volunteers using LIFE funds (tractor, trailer, shredder). The beneficiary and its partner, the NGO Vrienden van Heverleebos en Meerdaalwoud, are working closely with local farmers on recurring management – the farmers market the meat from their grazing livestock through a local cooperative, Veeakker cvba, as “nature meat”, thereby getting premium prices. This collaboration is one of the case studies in the LIFE-Focus report “LIFE and agri-environment supporting Natura 2000”. In terms of PR and awareness raising, and to channel the growing recreational use of the area, the following was done: - A folder ‘Welkom in de Doode Bemde’ explaining LIFE and the project, was distributed door-to-door in surrounding villages. - Open door day of May 30 1999, to which 1800 people came. - 6 information panels, a 300 m boardwalk, a hide and two bird observation huts were installed on site. - To create a trail across the site, an old tramway was cleared. The footbridge needed to cross the river was built by the Belgian military (Ecole du Génie) as goodwill gesture. The LIFE project was active in networking. The LIFE-Nature projects Obere Drau (Austria) and Alzette (Luxemburg) visited the site, as well as the Dutch NGO Natuurmonumenten involved in several LIFE projects. The project was presented to an international symposium on water retention (Leiden, 2001)and collaborated with a research project by the University of Cardiff on the role of LIFE in Natura 2000 sites. There were also contacts with the Schelde Convention.
N
By 2005 the area had developed into three distinct zones:
(i) an upper zone, which is rarely inundated and retains terrestrial grassland;
(ii) an intermediate zone, which has been colonised by salt marsh species; and
(iii) a lower zone, which experiences regular inundation and in which terrestrial grassland has been replaced by fine sediments. Nineteen species of waders and wildfowl were recorded using the site during winter 2004/05, the commonest of which were redshank (RSPB, 2005). +
R
Cash flow was an issue as sizable sums required up front – project partner supported cash flow but the project could have been wider-reaching without this problem.
Significant up-front investment is required to carry out initial survey work required to be able to inform land owners / managers about risks involved and allow them to decide if this is something they can accommodate.
Lack of understanding about green engineering techniques means significant engagement is required early on to gain buy-in & permissions.
Scottish Rural Development Programme's Agri-Environment Climate Scheme (AECS) can be a good source of funding to deliver river restoration projects, but involves upfront payments which can subsequently be reclaimed.
Sourcing the tree trunks (250 in total) from a near-by plantation considerably reduced costs. +
Challenges:
*Identify spaces for DDs underground amongst utilities.
*Each defender had to be custom made to match the angle of the various outfall pipes allowing them to integrate with the established system.
*Getting commitment from parties to empty the DDs. +
H
Challenges:
-Access to site with machinery. +
T
Challenges:
Landowner engagement and persuading farmers to lose productive ground or change the way they do things. Tweed Forum is able to overcome such barriers because it has become known as a trusted intermediary. We have no statute and can only do things through good will, persuasion, education and enthusiasm. We can speak the language of and know how to integrate restoration measures without impinging on the farm business and cut through the paperwork and manage the works.
Working at a bigger scale also can prove challenging. For example the re-meandering at the Cringletie and Lake Wood involved 6 different landowners with the river acting as the boundary. Thus, moving the physical entity that acts as the property boundary is more than just a practical problem.
Regulation – For example, re-meandering requires consent from SEPA under the controlled activity regulations, consent from SNH due to it being a designated site, planning permission from the local authority because it is deemed an engineering operation. All of these come with a raft of assessments for impact on flood risk, salmonids, ranunculus, otter etc.
Funding – an ever present challenge. Some of the works are expensive and often there are no bespoke funding streams. +
W
Challenges:
- Very urban nature of the site. Complex flood modelling and design was required.
- Multiple underground utilities which had to be identified and avoided during the works.
- Many and varied stakeholder needs and opinions. +
G
Channel reconfiguration can be effective in mitigating fine sediment flux in headwater streams but the full value of this may take many years to achieve whilst the fluvial system slowly readjusts.
The channel is continuing to adjust to the diversion with evidence of continuing local instability. It is therefore recommended that this approach to reducing the fine sediment flux of upland rivers should not be adopted as standard practice.
However, where significant modifications to upland channels are made, comprehensive in-stream monitoring and geomorphological assessments should be regularly conducted to evaluate the response of the river to the new conditions.
This research has highlighted the importance of ensuring appropriate controls on sediment release during in-stream works and effective installation and maintenance of grade control (drop) structures. If these measures had been rigorously applied the overall goal of reducing fine sediment flux through the fluvial system could have been achieved in a more timely fashion. +
R
Close liaison with permitting and enforcement colleagues is essential to establish suitable restoration sites, and ensure that flood risk is not increased. +
L
Communication:
- Consultation and communication of the vision and the business plan is
key to success.
- Groups of individuals representing a stakeholder interest do not response to
communication events equally. The communication style must be chosen to reflect
differing responses to change and different personalities types
- Professional communications teams should be used to establish methods.
- Use experts within the project team for example an agricultural expert to work with the farming community to assess pros and cons of project for the land owners;
- Detailed records of events and outcomes of consultations should be kept and widely
shared.
- More than one consultation event should be held and tailored to the required outcome.
The event should specify what it is not consulting on as well as what it is.
Techniques used:
- There may be the need to revisit if monitoring results indicate methods have not been
successful in delivering specified outcomes. Partners have a duty of care to landowners
and riparian rights owners to ensure that if a risk based approach has been used and
accepted, future tweaking may be required to achieve the desired outcome.
Localism and Trust:
- Those affected by the project need to trust those carrying out the project. They will still be farming the land in 20 years or fishing the banks. Trust is incredibly important. Local
people should be utilised on the steering group and through the delivery of the project.
Doing too much too quickly:
- Delivering too much too quickly could cause problems for benefits realisation and local trust in the project. River restoration is mostly constrained to seasonal work in channel and on the flood embankments due to ecology, social and working conditions. Establish working window and ensure if work cannot comfortably be completed before the window ends; complete it
next year or when funding is available.
Changing opportunities:
- Constantly review opportunities of outcomes and funding options. New schemes, political
agendas and ways of working rapidly change. Funding may not be available for some
opportunities but working with a wide range of partners enables shared use of skills and
resources.
C
Community engagement
- Early and consistent community engagement is key
- Posters aren’t enough. Leaflets, presence at community events, word of mouth and meeting with councillors are all useful engagement techniques.
- Communicating nuance is difficult. Conversations around flood risk, biodiversity and water quality require care and patience. The importance of using language that is easily understood cannot be understated.
Logistics
- Construction site difficulties/ break ins. Securing the site was difficult with frequent break ins and vandalism.
- Deliveries to parks are difficult, especially here as a tunnel under the railway track restricts the vehicle size.
- Close relations with the council and contractors is key for support. +
D
Complex "post industrial" zones, despite appearing to be greenspace can be complex locations to undertake engineering due to subsurface utilities, contaminants and historic refuse material. However by careful design and management natural river form and function can be achieved providing more resilience for the river and its wildlife. +