Property:Lessons learnt
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W
'''Accretion''': In order for the site to support both mudflat invertebrates and saltmarsh plants, it was important that fine marine sediments were imported into the site, as these provide the ideal environment for intertidal flora and fauna. Furthermore such sediment import would ensure that the site would continue to increase in elevation (i.e. accrete) as sea levels rise. Observations from previous managed realignments has shown that sites can accrete relatively rapidly immediately after a breach, but that elevation increases then tend to level off. At Welwick, site elevation monitoring has so far followed a similar trajectory. To date, overall, the site has increased in elevation with the most notable changes occurring in the initial year following the realignment. +
F
'''Accretion''': The recent monitoring reports (Brown et al., 2007; Brown 2008) concluded that in the five years after breaching the sea wall, the Freiston managed realignment site has accreted sediment at similar rates to those of the adjacent salt marsh at the equivalent elevation range. Mean annual accretion rates (after removing a few sites influenced by high deposition of material washed in around the central breach area) ranged between 6 and 10mm per year, and the pattern of natural inter-annual variations inside the realignment matched those outside.
'''Vegetation''': Vegetation establishment and spread have been judged as highly successful, as these have been more rapid than in other (earlier) managed realignment sites. By September 2005, 70% of the area was covered by plants, initially with pioneer species such as glasswort (Salicornia) and and annual sea-blite (Suaeda maritima) dominating. By the second and third year, perennial species such as sea purslane (Halimone portulacoides) and sea aster (Aster tripolium) had become more prevalent (Badley and Allcorn, 2006). It was estimated that the realignment site’s species abundance and community types could be equivalent to those outside the site within a further 5 years. This successful vegetation establishment was attributed mainly to the suitable site elevations and the abundant supply of seeds and tiller fragments from the extensive external salt marsh. Overall, no clear evidence was found to suggest that the realignment site has had any
adverse effects on the adjacent saltmarsh in general (Brown et al., 2007).
'''Invertebrates''': The realignment site lies at an elevation suitable for salt marsh establishment therefore most of the invertebrates found were species associated with the developing salt marsh. The nature of the fauna (seasonal and weather-dependent activity of mobile organisms and large variation in numbers of small species) made it difficult to make comparisons between years, or between the realignment site and the adjacent marsh, from an annual survey. However, most species found outside were recorded in the site and many species have increased in abundance (Brown et al., 2007).
'''Fish''': The annual fish surveys showed that at least 11 species utilised the realignment site during the first four years of its existence. It was found to act as an important fish nursery area for several commercially important species (such as bass, sprat, and herring), which were shown to be feeding in the realignment site. The site also provides nursery habitat throughout the entire tidal cycle (i.e. fish continue to use the site when it is disconnected from the sea, with the continuous utilisation of permanently flooded channels). In order to improve the site’s fish nursery function, the addition of shallow pools or pans was recommended along with research into creek configuration(design and density) (Brown et al., 2007).
'''Birds''': Badley and Allcorn (2006) concluded from four years’ of bird monitoring that the realignment supported ‘large numbers of wintering waterbirds, several species in nationally important (i.e. > 1%) of the UK population) numbers’. These include dark-bellied brent goose and golden and grey plover (for which the following respective peak counts were observed during the 2005/06 period: 1,727, 5,000 and 263). In 2006, the realignment did not contain areas of high enough elevation to support breeding waders, as it was completely inundated during spring tides. The adjacent saline lagoon has developed into a habitat of high ornithological value; it provides a home for breeding, roosting and wintering water birds. Avocets bred for the first time in South Lincolnshire on the newly created lagoon islands. Now, around 40 pairs of avocets choose the lagoon to breed each year. Furthermore large flocks of knot roost on the lagoon and nearby reservoir (RSPB website,
2010).
'''Morphology''': Whilst overall, the site appears to be draining well, in 2006, some 5.6ha were not draining after the tide has receded, with subsequent implications for sediment stability and vegetation development. In contrast to some other realignment sites (e.g. Tollesbury), creeks in the site were developing through the agricultural soil (Brown et al., 2007). PhD research (Symonds, 2006; Symonds and Collins, 2007) into the impacts of the realignment on intertidal morphology (undertaken at the University of Southampton) found that in the first one to two months following the breaching, the channels created within the breaches increased
substantially from 2m wide by 1m deep to 20m by 4m (see Figure 1a; also visible in Plate 2). However, this initial erosion was restricted to the breaches; it subsequently took almost two yearsof gradual erosion before the channels within the breaches, and the natural saltmarsh creeks they connect to, had eroded to a sufficient volume to allow the site to drain simultaneously with the fronting saltmarsh (and thus reduce the amount of standing water within the site during low water).
In addition to the erosion of the breaches, the managed realignment also directly impacted and creeks over the mid to lower intertidal zones (see Figure 1b). This was caused by the water draining from the managed realignment, following high spring tides, flowing over the intertidal zone as sheetflow and enhancing the natural creek development. This was a temporary effect; once the channels draining the site had reached sufficient dimensions to hold most of the water at most times, the sheetflow diminished considerably and the creeks returned to pre-realignment equilibrium. Unfortunately these changes in intertidal morphology made the area around an oyster farm, located to the south of the site, unstable and ultimately led to the closure of the farm.
L
'Always remember, it's not our river!'. By building relationships based on listening and understanding people's concerns we are making steady progress.
We used old paintings to show that the river was different in the past, and a highly prized landscape before most of the weirs were built. This shows the idea that the river is changing and not a fixed entity. In the UK you can find old paintings, searchable by area, at http://artuk.org. From the old paintings we learnt that before the weirs the river was still impounded in places, probably by natural cascades. This informed the geomorphological view of the reference condition, which had been considered to be riffle - pool to one where step-pool and even cascades would be found as well. So when removing weirs, care will be taken to understand which parts would have been natural, as the early weir builders would have built them in places which were already naturally impounded.
The old paintings also enable a conversation, when we engage the public, that is not just 'We want to take away your weirs' but 'we want to find your cascades and to find a more diverse river.'
They have also led to some interesting and subtle conversations with angling clubs and farmers. These have focused on the question of 'what condition do we restore to?' which moves away from a polarised position. +
C
* Willow cuttings look like they have had a low success rate, potentially spiral guard and cane may improve success.
* Thicker willow cuttings, may also have produced larger survival rates.
* Weed killer on planting positions weeks before being planted may have improved the success rate of riparian and wild harvest trees by reducing competition from grasses
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W
* Proactive discussion between the Environment Agency and the developers led to beneficial outcomes for both parties, and the creation of a multifunctional, more natural riverside environment.
* Use of coir rolls to stabilise the sediment accretion and bank reprofiling was insufficient and required rock roll installation.
* Success of sediment accretion between the terraces demonstrates good geomorphological understanding of processes and modelling.
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R
* The project team was able to draw upon experience from Belgium and The Netherlands to help determine the best layout of the large boulders on the ramp.
* Carbon calculators were used, and were able to highlight the transport of materials as a high carbon cost, leading to the successful sourcing of local materials to construct the ramp.
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*Engaging the local community is essential. This project employed a local Community Liaison Officer who was know to the local community and was on hand to answer questions, solve local issues and field queries to the technical working group and project board.
*In these early days of river restoration the project showed what could be expected from a restoration project and how it develops (might be different from anticipated) – this needs to be built into decision making process
*It is important to do a formal long-term management plan, and have a cooperating (and stable) land owner,
*Each of the partner organisations applied their resources together to provide a wealth of in-kind work to boost the already significant works budget,
*The project showed a whole suite of demonstration techniques (included in the Manual of River Restoration Techniques http://www.therrc.co.uk/rrc_manual.php)
*The project clearly showed the complexity of a linear system (compared with ponds), and that it's difficult to distinguish success between different components • The project gave a big boost to river restoration in the UK and showed that it is possible to undertake “large scale” (for that time) projects,
*Long-term monitoring (>3 years, especially of biological indicators) is crucial for accurate evaluation of success.
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S
*Water quality is still an issue with problems following heavy rain.
*The University has now adopted this area as an extension to their nature reserve and use it as an outdoor laboratory.
*Further reach restoration phases of works are being planned by the project partners both up and downstream.
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B
*We used local contractors to provide ECI assistance during the development of designs, this resulted in large costs increases (even from the ECI) at tender and we would ensure that more consideration is given to the right contractor providing this advice from the beginning of the project.
*Relied on existing relationships and partnerships to provide solutions to constraints on site which meant no legal framework was in place for agreed actions and organizations changed their approach to elements of the project at the last minute. In future we would ensure that legal agreements are in place around service mitigation prior to appointing a contractor.
*We did not appreciate or appropriately consider the ground contamination constraints at an early enough stage. A lack of prior experience of these issues and relying on previous reports led to misunderstanding the costs and constraints this would cause. For future projects we would ensure, where potential land contamination is present, that early involvement of experts is obtained, and budgets reflect possible additional costs.
*We have also learnt that, through perseverance, projects which many believe to be unachievable due to costs and constraints can be delivered in a manner which is cost beneficial and provide multiple benefits to people and wildlife.
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L
LakeAdmin - Chadwick lakes - Plan to improve the surface water quality and reservoir restoration in the Chadwick lakes area +
- The Plan is an opportunity not to be missed in order to establish actions and implement targets that can be beneficial for all the territory and also for the Chadwick lakes
- The Maltese Rural Development Plan and its actions represent an important set of tools and means for the implementation of Chadwick lakes Implementation Plan
- By matching Chadwick’s actions with the RDP policy is possible to legitimate and support economically the Chadwick lakes Implementation Plan
- the RDP gives an unique opportunity to strengthen the relations between different stakeholders by enhancing the already established National Rural Network
Possibility to work with the Network: involve all the local actors (farmers, NGOs, Planning Authority) and engage them in a bottom-up participatory process. +
E
- Despite the short period of time (5 years) of this project, we realized afterwards the importance of achieving a multi-scale assessment and an initial state (pre-restoration) prior to restoration work.
- We implemented a wide range of demonstration techniques and we compared them in terms of cost-effectiveness (see the Manual of River Restoration Techniques on http://www.walphy.be/index.php?page=guide-technique).
- Most of the restoration projects could be implemented without acquiring the land but rather through negociations with the local community. This underlines the importance of engaging the local community.
- The time span of the project allowed us only 1-2 years of monitoring (post-restoration). Fortunately, the SPW funded a long-term monitoring (>3 years), which is crucial for accurate evaluation of success, especially for biological indicators.
- Finally, we hope the project to give a boost to future restoration projets in Wallonia. +
B
- Despite the short period of time (5 years) of this project, we realized afterwards the importance of achieving a multi-scale assessment and an initial state (pre-restoration) prior to restoration work.
- We implemented a wide range of demonstration techniques and we compared them in terms of cost-effectiveness (see the Manual of River Restoration Techniques on http://www.walphy.be/index.php?page=guide-technique).
- Most of the restoration projects could be implemented without acquiring the land but rather through negociations with the local community. This underlines the importance of engaging the local community.
- The time span of the project allowed us only 1-2 years of monitoring (post-restoration). Fortunately, the SPW funded a long-term monitoring (>3 years), which is crucial for accurate evaluation of success, especially for biological indicators.
- Finally, we hope the project to give a boost to future restoration projets in Wallonia. +
R
- Good management practices
- Exchange of experience between Denmark and Germany about the Thick-shelled river mussel +
H
- Modelling can assist in opportunity mapping, impact assessment and development of intervention design<br>
- Demonstration events to show and discuss intervention approaches do work<br>
- Early dialogue with stakeholders on land management or catchment interventions helps to collect local knowledge, identify issues and constraints<br>
- Early dialogue with relevant regulatory, planning and consenting authorities on proposed interventions is essential<br>
- Working through all the requirements of formal planning and consenting for interventions is time consuming
- Need for clear guidance on the application of an NFM approach at a range of scales
Update from Autumn/Winter 2013 http://ccmhub.net/wp-content/uploads/2013/10/Holnicote-Flood-Meadows.pdf +
B
- Urban nature of the site
- Getting some local, neighbouring residents to understand and buy in to the project was difficult +
F
1. Developing our schemes to enable us to cater for, and be flexible to, an extensive range of farms has been important for the success of F4W. Carrying out farmer feedback surveys and independent annual audits has allowed us to continually learn and adapt our schemes to meet farmer needs and expectations.
2. Catchment management is a long term solution in terms of water quality improvements, especially in groundwater catchments where travel times can be 10’s of years. We have needed to develop a way of monitoring the progress of the schemes to ensure we meet our long term water quality targets.
3. The success of our schemes and high interest from farmers meant that we needed to increase the number of Agricultural Advisors in our catchments. At the start of 2015 we had a ratio of 1 Advisor to 333 farmers. From January 2018 we recruited more partnership advisors which now gives us a ratio of 1 Advisor to 210 farmers. +
U
1. The greatest detrimental impact upon river habitat is the legacy of past channel engineering. Straightening and widening of the channel and lowering of the river bed have disrupted/destroyed the natural pool-riffle sequence and disconnected the floodplain. The process of the river recovering these natural characteristics is very slow (centuries) because of the naturally low energy of the river and limited supply of coarse sediment.
2. Habitat improvement measures within the existing channel have generally been unsuccessful. Installed in-stream structures have not had the desired effect of creating scour and producing depth variation. This is because of the resistant nature of the predominantly clay substrate, loss of sediment (gravel) to historic channel engineering and lack of sediment (gravel) supply/retention within the present channel dimensions. Introduced brushwood and large woody material have improved cover and fish-holding habitat, but have not fundamentally changed the channel shape.
3. The weir removal at Easton has restored fish passage and better habitat to the formerly impounded reach upstream, although the above constraints (point 1) remain. Trout numbers observed in this reach indicate a recovery from past pollution incidents. +
R
1. Monitoring adds high value to prioritisation of interventions and advice
2. Working with landowners to achieve low cost solutions to management of pathways for sediment and nutrient inputs to the watercourse
3. working with partner organization to achieve delivery at low cost and high value
4. SUDS interventions requires detailed planning and communication, close working required to achieve vision and effective outcomes. +
1. Because of its proximity to the railway (< 30 m) it is required an approval from the railway authorities (Bane-Nor) in order to be able to daylight / deculvert the stream.
2. There can be quick clay (kvikkleire) in the area of restoration according to NVE (Norwegian Water Resources and Energy Directorate). This makes necessary to explore the ground stability before digging the pipe out of the ground. This will increase considerably the costs of the project. +
T
2009: 10-20 volunteer and community pay back days to remove invasive species (as mentioned above) including reedback/sedge planting. Management plan is in place. +