Installing New Lawns at Parliament Square Gardens
GLC, Origin Amenity Solutions, and Inscapes worked as a team to install the new lawn at Parliament Square in preparation for the King’s Coronation, and ongoing improvement to the lawns of Parliament Square Gardens for the general public.
Heras fencing was installed around the lawn area to enable the works to be carried out safely and after installation of the turf so that it could maintained without the usual heavy footfall. The cycle lane opposite Westminster Cathedral was closed for a week to enable vehicle movements to be undertaken safely in what is a very busy area. The scope of the project involved koroing 50mm off the existing surface which produced approximately 200 tonnes of very good topsoil that was taken to a local recycling centre for reuse. It also meant that 50mm of turf could be installed without increasing the height of the lawn above its existing levels. Unfortunately, we encountered the wettest spring since 1981 and this just added to the challenge, but conditions we are familiar in working. PSG is on top of Westminster Tube Station and the Jubilee line. This meant there were other challenges such as strict weight restrictions on equipment used and the extremely busy location in central London both in terms of traffic and pedestrians with large equipment. Therefore, every element had to have robust risk assessments, method statements, and lifting plans for lorries using HIABs for removing soil, delivering fencing and moving the irrigation container.
It was important that the lawns would root and have a period to grow in whilst the weight of the 50mm turf gave the surface stability. To overcome this, we installed a permanent pop-up irrigation system under the lawns. As PSG does not have a regular water or power supply, we installed a water tank. All the control equipment and a generator within a 10ft by 8ft shipping container. This enabled us to generate the required 6kva of power and store 4000L of water that was fed from the water hydrant and undertake the irrigation by night. In addition to this we manufactured a safe cover for the hydrant point so there was no risk to the public as the hydrant is in the pavement area. The container also supplied us the power required for the robotic mower and the GPS system used to guide it. The container was removed for the Coronation but as the pipe work and pop-ups are permanently in the lawn, it means we can connect the container again in the future if there is a dry period, or when the lawns undergo a renovation.
The surface was prepared for turfing after the irrigation pipe work was installed in extremely challenging weather conditions, however we were able to prepare the surface with the Harley rake. We used thick cut turf that was installed with the tracked turf installation machines. So, this resulted in transportation of 11 loads due to the extra weight. This was done on a return load basis in order to utilise vehicle efficiency. The plant and equipment was also returned to our yard on the lorries bringing turf to site to reduce empty mileage.
The lawn was mown with a Husqvarna robotic mower primarily, as it cuts small amounts of grass which creates a nutrient rich micro mulch; which not only creates a healthier lawn but creates no commercial waste and less noise pollution. It also freed up the time for staff on site to undertake other works involved in the overall project, which involved the planting of 280 rootballed lavender plants.
When the temporary fencing and container were removed from site, a specialist 20m reach HIAB lorry was used to ensure we adhered to all the load limits within the tolerances of the tube line that runs below Parliament Square. This was also part of the equipment selection to undertake the work as there were weight restrictions due to the tube line.
Maintenance is being undertaken by an employee based in London to carry out daily mowing and irrigation as required. The feeding regime was specified by Origin Amenity Solutions, following an independent soil sample testing, and including a site-specific nutritional report. Headland Tricure AD Granules, Rigby Taylor granular Pro-Seed Fertiliser 8-12-8+3MgO+ Zn+ Seaweed, Granular Apex Organic 15-3-9+2Fe + 4CA) +MgO + 6S &5% Humic Acid have been applied plus a liquid application of Rapid Response.
280 rootballed Lavender plants were sourced and transported to site, planted, and mulched along with two Magnolia trees, and 2,135 bedding plants. Five days before the Coronation the lawn was mowed with a roller mower to stripe the lawn, hedges were trimmed, and the final touches continued until the Coronation.