Background
There has never been a more important time for people to have access to the natural environment, especially in urban environments where social and economic inequality is greatest and physical and mental health are challenged. As Leicester’s largest local nature reserve, Aylestone Meadows plays a vital and unique role in the local community – supporting important habitats, species and environments all whilst providing amenity for local residents and visitors.
The area acts as a commuting route for workers and school children, and is popular with dog walkers, cyclists, runners, and horse riders. Aylestone Meadows has started to flood more frequently and dramatically during periods of heavy rainfall, which is causing challenges for access and a reduction in amenity value. As the environment and climate have changed, the existing paths and board walks no longer provide the access required to maximise this wonderful asset.
The addition of natural flood risk management interventions and increased flood storage within the Meadows provides a hugely important mechanism to reduce flood risk whilst improving the natural environment for people and wildlife. As the country’s leading environmental contracting specialist, Sanctus were delighted to deliver a series of environmental interventions to make this ambition a reality.
The Programme
Sanctus’ work at Aylestone Meadows forms part of the River Soar and Grand Union Canal Access and Environmental Improvement Programme and is funded by the Local Growth Fund (LGF) through the Leicester and Leicestershire Enterprise Partnership (LLEP). The partnership includes Leicester City Council, The Environment Agency and The Canal & River Trust to provide access and environmental improvements along the canal and river corridor between 2015 and 2021.The delivery programme comprised three overlapping phases.
- In channel and riverside works to improve sinuosity and restore nature channel processes;
2. Wetland creation and elevation / installation of new boardwalk;
3. Realignment of footpath, river-bank protection & vegetation works.
Throughout the delivery programme Sanctus sought to maximise added social value. This included creating opportunities for four full time assistants provided through Leicester City Council and a local charity, Leicestershire Cares, as well as opportunities for schools and involvement in the ecological aspects of the programme.
The Challenges
Working within an Active Flood Plain
In planning for the works at Aylestone Meadows, Sanctus recognised the need to prepare for adverse weather conditions and corresponding fluctuations in river levels expected when working on a floodplain. As a result, in channel works and those neighbouring the water course were front loaded in the programme when better weather was most likely. Throughout all works, upstream flow conditions were monitored at Freemans Weir and South Wigston Weir through the EA flood warning service. In addition, the site compound and welfare facilities were located at higher ground and outside of the floodplain and no plant or machinery was left within the flood plain when not in use.
Sanctus also minimised the impact of poor weather conditions by selecting lighter weight, low ground pressure machinery (working with HVO fuel and biodegradable hydraulic fluids) aligned with our commitment to working sensitively and delicately.
Site Security
Aylestone Meadows is located within an area at risk of antisocial behaviour, therefore additional mitigations were required to ensure the security of people, plant, and equipment during works. Some of the unique interventions included; detailed planning to design out opportunities for anti-social behaviour by minimising equipment left on site to avoid opportunistic theft, strategically positioning large equipment and plant such that they themselves form a physical security barrier, the provision of clear signage marking the site compound, welfare and working area(s), the selection of vandal-proof facilities and secure fencing around the site compound, welfare facility and plant when not in use and the deployment of a specialist remote security system with integrated CCTV, alarm and voice challenge function which is monitored 24/7.
Managing Public and Contractor Interaction
A key success criterion for the works was to deliver all contracting with minimum impact on access and amenity of this hugely important local nature reserve. Public engagement with a wide range of interested groups was paramount and as such early communication, public notices and effective signage helped inform people about the planned works and warned of limited restrictions to certain areas, including those with active plant and machinery. Through all works a support team of local volunteers, who knew the Meadows well and understood local concerns, ensured fantastic communication with visitors, residents and commuters alike. By using expert machine operatives, Sanctus were able to move material safely around the Meadows without closing any footpaths or cycleways. This also ensured that fencing could be kept to a minimum and was only used for demarking discrete closed (site) areas, reducing impact on the site and costs to the client. This approach was supported by Sanctus ensuring that all heavy plant movements, mobilisation activities and deliveries occurred during specific time windows when the Meadows would have fewer visitors and supported by banks persons throughout.
Permitting & Licensing
Permitting and Licensing were essential to securing permission to complete the works and ensuring Sanctus act in accordance with the Environmental Permitting Regulations. Sanctus supported the council in securing a Flood Risk Activity Permit and a bespoke Environmental Permit before work commenced on site, which allowed the team to manage risks to water quality and ecological receptors.
Water Quality & Fisheries Mitigation
Sanctus’ in-house ecologists were on site throughout works to monitor water quality and ecological / environmental receptors. In the first instance, water quality readings (Dissolved Oxygen, pH, Temperature, Turbidity) were recorded to establish a baseline condition (also accounting for external factors, to include air temperature and river flow). The baseline condition was used to monitor potential deteriorating conditions throughout the works programme and was recorded daily. This approach ensured that in-channel working areas could be enclosed with sediments and silt curtains to protect against sediment being mobilised or release downstream. Similarly, by defining discrete working areas, this avoided the need to perform a fish rescue as the localised disturbance in the channel meant that larger fish species and wildlife were unlikely to remain in these locations.
Environment Protection Measures
The River Biam is designated as an ordinary watercourse and is a tributary of the River Soar. Collectively this waterbody is classified as moderate, failing for biological quality (macrophytes) and physicochemical quality (phosphate) elements. Reasons for not achieving good status are point source sewage discharge and diffuse source transport drainage. Despite the current classification the waterbody and surrounding catchment provides valuable habitats and a corridor for migratory fish and wider terrestrial species.
Biosecurity
Sanctus operate strict biosecurity controls on all sites and appreciate the ecological harm that the introduction and / or spread of Invasive Non-Native Species (INNS) can cause. In line with our enhanced biosecurity protocols, all equipment was disinfected with an appropriate treatment (in this case, shoe picks, hard brushes and Virkon S Aquatic). Sanctus personnel followed best practices with the Check, Clean, Dry prevention method throughout works in line with our in-house biosecurity training. All plant and machinery delivered and used on site was inspected for foreign objects by staff trained in the identification of INNS and disinfected again before leaving site.
Contracting Works
- In Channel and Riverside Works to Improve Natural Channel Processes
At present, the River Biam channel offers limited habitat diversity and is a straight channel with no meanders. Sanctus successfully excavated critical sections of the riverbank over a 130m reach to create a more sinuous, dynamic and natural channel. Throughout all works the previously outlined sediment mitigations and water quality monitoring were in place. Excavated material was moved to a neighbouring receptor site where it was placed ahead of preparation and seeding for further habitat creation at the conclusion of the programme of works. In line with a commitment to working with natural processes and interventions, Sanctus recommended the use of habitat improvement additions along the channel with root wads locked into the bank, extending into the channel. Within each discrete working footprint, as agreed with the client on site, an appropriately sized rubber tracked excavator was used to grade and sensitively excavate the bank down to water level. Individually selected root wads were then placed within each excavation, with the root wad facing out into the open river channel – creating new wet-wood habitat. Once placed, untreated timbers were driven either side of the trunk (within the bank) and securely tied. When secured, excavated material was placed back on top of the tree section secured within the bank.
2. Wetland Creation and Installation of New Boardwalk
Under the supervision of the Client’s Ecologist and Ecological Clerk of Works, Sanctus successfully conducted surface clearance and excavation of two new wetland areas creating space for water and nature. Following mechanical preparation at both sites and the spoil receptor site, a seeding and planting regime was agreed with the client. The new boardwalk was delivered in line with the detailed specification provided by the client’s design team. This was challenging to match a 20-year-old product used previously and required the re-engineering of a subframe structure where new and old sections of boardwalk meet to ensure accessibility, especially for visitors with different mobility requirements. The new boardwalk provides improved access, elevated from the previously flooded walkways and much more sympathetic with the way people enjoy the Meadows, following a former desire line that had developed within the green landscaping.
3. Realignment of Footpath, River-Bank Protection & Vegetation Works
Improving access to the natural environment is a key feature of the Aylestone Meadows project and as such Sanctus improved a number of sections of path and walkway. All plant and machine movements and operations were guided by a banks person and members of the public were alerted to the works using appropriate signage. This dynamic approach avoided closure of much of the meadows such that amenity access was not impacted. Sections of historic bank protection had failed (submerged coir rolls and wooden posts) and required improvement. This called for the removal of redundant material in the channel under sediment controls and its replacement / improvement. Ahead of the wetland creation works, self-set willow trees were removed, enabling willow faggots to be made under the guidance and supervision from the Sanctus Ecologist. Under supervision from the Ecological Clerk of Works, the willow faggots and a locally sourced fallen tree were installed to create a sympathetic bank protection system. Behind the retaining system, a permeable geo-textile membrane was installed and backfilled with suitable site won material to prevent further erosion of the footpath. The new path comprised 40mm high Eco Grid mats placed along a 52m section of path and filled with gravel.
Social Value
Sanctus’ environmental improvement works seek to deliver multifunctional benefits for people, wildlife and the environment. Many of these projects provide the potential to add significant social value to the local community. At Aylestone Meadows, in partnership with the Leicester Employment Hub and Leicestershire Cares, Sanctus provided a range of full-time placement opportunities targeted at unemployed young adults. This allowed four local people to gain valuable practical work experience in environmental engineering, ecology and site management whilst contributing to the improvement of their local, environment. The success of this approach is highlighted in the below feedback received from the Employment Hub Manager at Leicester City Council. When speaking about one of the full-time placements, “the opportunity has been fantastic… Chris has absolutely blossomed, and the impact on his mental health has been so much more than I could have hoped.”
Conclusion
There has never been a more important time for people to access the natural environment, especially in urban environments where social and economic inequality is greatest and physical and mental health are frequently challenged. Sanctus are delighted to have helped restore and improve Aylestone Meadows, creating space for nature and water through the addition of natural flood risk management interventions at the very heart of Leicestershire helping deliver environmental, ecological and social value for many years to come.
