Caol and Lochyside Flood Protection Scheme

The Caol & Lochyside community North of Fort William has historically been subject to flooding from tidal, rivers and surface water sources. The last significant flood event occurred in 2005 due to high sea levels and resulted in over 20 properties being flooded. In response to the historic flooding Highland Council commissioned several studies to investigate flood risk in the area.  The studies identified that almost 300 properties could be at risk from a 1:200 year flood event.  An outline Flood Protection Scheme was developed taking cognisance of the various sources and scenarios.

The scheme constructed consists of three types of flood defence. A 1.2km embankment along the foreshore of Loch Linnhe to protect from coastal flooding and which incorporates an integrated footway / cyclepath and designed to facilitate the future construction of a wave wall due to rising sea levels.  An 800m concrete flood wall with incorporated flood gates and footpath along the bank of the River Lochy to protect from high river levels.  The installation of 3 number attenuation tanks, along with associated drainage behind the embankment and a pumping station on the bank of the river Lochy to protect from surface water flooding.

The studies and modelling were undertaken by JBA consulting with the design of the embankment, drainage and pumping station being undertaken by STANTEC.  The Highland Council designed the concrete flood wall.

The original design incorporated a 10,800 tonne clay core to prevent seepage along the length of the flood scheme.  RJ McLeod proposed an alternative solution that not only provided a cost saving but also reduced the carbon footprint by utilising a recycled plastic pile as a substitute.

Blindwells

Blindwells represents one of the largest brownfield redevelopment projects in the UK on a 128 hectare former opencast site that releases a brownfield site for the phased construction of 3,200 new homes, primary school, retail units and green space.

The re-engineering of the site presented significant challenges in terms of the scale, depth and variability of unconsolidated fill, with previous coal extraction having extended to 65 metres in depth.  Although the site had been restored by Scottish Coal it was not done with the intention for the site to be developed on.

Various ground improvement techniques were utilised to ensure a solution that was compliant with the specification, cost effective and met programme requirements.  A combination of soil consolidation using a surcharge mound 10 metres high and containing 850,000m³ was used in multiple phases across the site, after which HEIC was then applied to the site.  Overall, earthworks undertaken on site consisted of platforming to formation of 1,151,960m³, 6,448.776m³ used for surcharge (moved in phases) and HEIC treatment of 654,377m³.

Comprehensive performance testing was undertaken and adapted to the specific challenges of the site.  Monitoring of the effectiveness in turn allowed for further efficiencies in the ground engineering techniques to be achieved delivering further savings on cost and programme.

Following on from the sites re-engineering, enabling works were completed to deliver parcels of land ready for development by housebuilders.

Lochmaddy Pier Upgrade

The Lochmaddy project, coordinated by the Little Minch Routes Infrastructure Group which includes representatives from Highland Council, Comhairle nan Eilean Siar and partner organisations has been completed in anticipation of the arrival of two new vessels constructed in Turkey.

The new larger ferries being built for CalMac would require additional infrastructure at ferry terminals across the west coast of Scotland. George Leslie was responsible for completing all civil engineering works for the Lochmaddy project, including the extension, and strengthening of the pier, upgraded fendering, seabed dredging, land reclamation and extended marshalling and parking areas.

For the Pier Extension, we chose an Off-site construction of a reinforced concrete caisson as not to interrupt ferry services and then delivering to site and sinking the caisson onto the foundation. The Pier Extension works was required to facilitate the new, larger ferries that are proposed for the route that would not be able to berth at the facilities. Construction of new substation and connections to supply and distribution.

Camps Viaduct Underbridge Refurbishment

The 160-year-old Camps Viaduct Rail Underbridge, towering 35m over the river Clyde, underwent a significant refurbishment project, highlighting impressive engineering and historic conservation. Serving as a crucial link for the Hamilton-Motherwell-Newton line, this iconic eleven-span viaduct seamlessly integrates its curved design and masonry substructure, including abutments, wingwalls, and intermediate piers, into the natural landscape.

With careful planning and in-depth project management, the project modernised and preserved a vital heritage structure, extending its lifespan by 25 years, demonstrating how engineering excellence can contribute to both people and the planet.

The project included in river scour protection works, scaffold erection, vegetation management, steelwork repairs, and painting of the 1956 riveted metallic deck, utilising 60 tonne of steel, 5,000 litres of paint, and 150 tonne of grit.

The project was delivered on time, and within budget over the 61-week duration, with zero accidents or incidents ensuring safety remained paramount.  One key challenge for the team was accessing work areas for the scour protection works with the additional risk of working both in-channel and above the river – alleviated by the introduction of a modular floating pontoon.

The site team were proactive in ensuring that environmental risks were identified, and mitigation measures were implemented prior to commencement of works. Ecological surveys across two local council areas were undertaken to fully understand the extent of local biodiversity in the surrounding vicinity of the site. Mitigation measures included fish rescue operations removing the risk of watercourse contamination, reducing carbon emissions, and conserving natural resources.

A939 Gairnshiel Jubilee Bridge

The design of the new £3.8 million bridge meets the desire to create a sculptural yet robust form that responds to the natural formation of the glen. It maintains a slender profile by tapering the cross section of the lower portion of the deck. This delivers the necessary structural performance while making the construction depth appear thinner at the outer edges.

Featuring materials including recycled, locally sourced granite for the parapets and abutments and a weathering steel superstructure, the new Gairnshiel Jubilee Bridge is designed to have a distinct point of difference from the old while also intended as a contemporary interpretation of the original.

His Majesty, The King formally opened Aberdeenshire Council’s new Gairnshiel Jubilee Bridge on Royal Deeside today (Thursday, October 5, 2023)

Replacing the old existing bridge after 271 years of faithful service, the new structure has been named to commemorate Queen Elizabeth II’s Platinum Jubilee in 2022 – the year in which construction began.

St Andrews Landslip Remediation

This project involved the reinstatement of a land slip on a rock face adjacent to a beauty spot called Billinge Nook on the Fife Coastal Path in St Andrews. The project addressed a hazardous situation resulting from a burst wastewater pipe, the incident posed risks to third-party stakeholders and the general public due to its proximity to the Castle Course and the Fife Coastal Path.

An Innovative environmentally conscious solution, which carefully addressed the unique challenges posed by the location—a Site of Special Scientific Interest (SSSI) – was selected. The approach prioritised sustainability, ensuring minimal impact on the delicate ecosystem mitigating a larger scale civil engineering earthworks project thereby reducing the carbon footprint of the project. The solution was executed by means of specialist rope access operations as well as aerial logistical support by helicopter.

The project safeguarded the future of this cherished section of Fife Coastal Path, ensuring it remains natural and accessible. Locals and tourists alike can now revel in its beauty and delight in its scenic panoramas for years to come.

Crinan Canal Lock Gate 15 Replacement

Mackenzie Construction has been delivering the Scottish Canal’s winter works programme for three years along the Crinan Canal.

The most recent winter programme (23/24) saw the most challenging scope of works yet and involved the replacement of the sea lock, Lock 15. The main concern was regarding the placement of the crane required to complete the works. The sole viable location for a crane with the necessary lifting capacity was on the public access loop road encircling Crinan Village, thereby obstructing vehicular and pedestrian traffic. This obstruction had ramifications for residential, commercial, and touristic activities in the area. The projected duration for crane operations on the project was estimated to span approximately three months and so an alternative approach had to be developed.

The solution entailed the design, construction, and installation of a temporary platform capable of accommodating the crane needed for gate installation. It was also proposed that this platform could be adapted for reuse on other canal projects with minor adjustments, providing both a long-term solution and temporary works equipment for the client.

This innovative solution was a first for Scottish Canals, Mackenzie Construction and the industry.

Ullapool Shore Street and Inner Harbour Improvements

This project, based in Ullapool in the North-West Highlands of Scotland, was required to improve the A893 which was a narrow main street (Shore Street) in Ullapool serving as the main road for ferry access from Ullapool to Stornoway in the Western Isles. For many years the A893 had been cramped for ferry traffic, as well as local businesses and pedestrians who enjoyed the village both for commerce and recreation.

Activities included widening of Shore Street with a widened southern promenade, a new Shore Quay wall with pontoons, and a dredged Inner Harbour.

The main construction challenges included piling and land reclamation adjacent to an operational harbour (ferry, leisure and fishing use), new road construction and hard landscaping on a live busy trunk road containing multiple utilities, and working in a busy town centre environment close to businesses and residents.

The finished works have received widespread praise from locals and visitors alike, and the local community already see the works as their own, a sure sign of a successful community project.

The completed project is a shining example of what can be achieved when Statutory Agencies (in this case a Harbour Trust and a Roads Authority) with seemingly disparate responsibilities, actively engaging and fully collaborating with each other and the Community that they serve, to overcome barriers that may otherwise stand between them, and deliver substantially more, and at better value, than could otherwise be achieved by single Agency working.