Proposed Green Infrastructure Interventions - NatureScot Offices

1. Introduction

1.1 Project brief

The purpose of this project is to identify interventions to increase the quantity and quality of green infrastructure at a series of NatureScot offices. Green infrastructure (sometimes called blue-green infrastructure) is the network of soil, vegetation and water that provides ecosystem services. Although greenspace is part of most office developments, it was usually conceived and implemented at a time before the ecosystem approach was established, before sustainable drainage systems were widely understood, when vegetation was considered to be ornamental and not infrastructure and when the importance of conserving biodiversity was often overlooked. In addition, there is a tendency for people to overlook the potential to establish green infrastructure in urban settings and close to as well as on buildings. The intention with this project is to identify cost-effective, multifunctional green infrastructure interventions that can improve conditions for staff, increase climate resilience, increase biodiversity and serve as demonstration projects. This report deals with the NatureScot offices in Aberdeen, Clydebank, Cupar, Edinburgh, Golspie and Hamilton. At this stage, the interventions described are proposals, with an indication of their character, location, size and a suggested budget. Detailed design is not included in this study.

1.2 Background and policy

The importance of green infrastructure has come to the fore because of its role in improving and maintaining health and wellbeing, in boosting biodiversity and in helping urban areas to adapt to climate change. NatureScot is leading the way in promoting green infrastructure in Scotland, with projects like the Green Infrastructure Strategic Intervention.

Scottish Planning Policy (SPP) identifies green infrastructure as an essential part of long-term environmental performance and climate resilience. It seeks to significantly enhance green infrastructure, including improving access to and the quality of greenspace and green networks, particularly in and around urban areas, to create healthier communities and neighbourhoods that are more resilient to climate change, and to encourage investment and development. It identifies the importance of green networks, greenspace, street trees and other vegetation, green roofs, wetlands and other water features, and coastal habitats to help Scotland mitigate and adapt to climate change. Local development plans also encourage green infrastructure. Both Scottish Planning Policy and the national Land Use Strategy support the significant enhancement of green infrastructure in urban areas as it contributes to Scotland’s prosperity.

• Gov.uk - Green infrastructure: design and placemaking

1.3 Benefits of GI

A significant body of evidence has been gathered that demonstrates the many environmental, social and economic benefits of green infrastructure, which include:

• Supporting biodiversity
• Improving water quality
• Reducing flood risk
• Urban cooling
• Reducing energy consumption
• Improving air quality
• Encouraging physical activity
• Improving mental health
• Increasing property values and investment

For more information on the evidence of the benefits of green infrastructure see the report by Scottish Natural Heritage (2014). Forest Research has published a review of the evidence for the benefits of green infrastructure.

2. Aberdeen

2.1 Location

NatureScot’s office in Aberdeen is in Inverdee House, part of the SEPA facility at Baxter Street, Torry, Aberdeen AB11 9QA (see Figure 2.1).

2.2 Setting and character

Figure 2.1 shows the location of the NatureScot office in Inverdee House in Aberdeen. Inverdee House is a ‘BREEAM excellent’ facility developed by SEPA and a housing association about ten years ago. It brings together SEPA, JNCC and NatureScot in one office. The site is at the mouth of the River Dee, close to the harbour. Industrial sites are to the west and immediate east and residential areas to the south. Balnagask Golf Course is about 200m to the east. Rough coastal vegetation occurs across the road at the mouth of the Dee.

2.3 Site visit

On 22 September 2020, Gary Grant and Dusty Gedge visited the site in order to identify and photograph locations with potential for the creation of new green infrastructure or the enhancement of existing features.

2.4 Identifying projects

During the site visit, it was noted that the site already has a small wildflower meadow to the immediate south of the main building, and there is a garden that can be enjoyed by staff. The building itself is zinc clad, with internal downpipes, and is not suited to the retrofitting of green roofs, green walls or downpipe disconnection planters. Our emphasis here is to demonstrate some new sustainable drainage technologies, which probably weren’t in the minds of the designers when the complex was conceived, and also to boost biodiversity. Once projects are being identified, there is the principle of looking for multifunctionality. Climate change adaptation, whereby the site becomes better prepared for sudden downpours or summer heatwaves, was another key consideration, as well as the objectives of improving biodiversity, amenity and wellbeing. As with other NatureScot sites, consideration was given to proposals that would be demonstration projects as well as having a practical purpose.

2.5 Suggested projects

Figure 2.2 shows the locations of the suggested projects, which are as follows:

1. Austrian gravel lawns in car park
2. Car park rain garden
3. Wildflower strip on road frontage
4. Green roof on bicycle shelter

These suggestions are discussed in more detail in the sections that follow.

Project 1. Austrian gravel lawns in car park

Description: The car park has sealed surfaces combined with permeable block paving. It is proposed that sections of block paving are replaced with Austrian Gravel Lawn (Please note that this website is not in English). Austrian gravel lawn is a vegetated surface designed to take the weight of vehicles, including fire trucks. It is built up by rolling specific gravel mixtures in layers and seeding with a range of low-growing acid grassland grasses and wildflowers. Austrian gravel lawn is ideal for car parks where vehicles are not continuously stored. It is permeable and can therefore be a component in a sustainable drainage system (reducing run-off rates and cleaning surface water), it avoids the use of concrete and plastics and brings biodiversity to areas which would otherwise be barren. It could be combined with buried biochar to sequester carbon. The exact layering would depend on the existing sub-base – it would probably be possible to replace the paving with an Austrian gravel lawn top layer over the existing sub-base (if it is free-draining).

Benefits: 

• Reduction in rainfall run-off
• Improvements in water quality
• Increase in biodiversity
• Natural materials
• Could be a demonstration or research project

Budget: £13,250 for all three parking areas marked on the plan (450 m² - see the three areas on Figure 1.2) or £7,000 for the 200 m² central area only. (Costs based on £2,000 for design/PM, and £25 per m² for removal of existing blocks, supply, installation and seeding of Austrian gravel lawn.)

Maintenance: Occasional mowing depending on the rate of growth. Mowing could be undertaken by robot mower.

Programme: Installation of the first phase or pilot could be by summer 2021. Freshly installed bays need to be protected until vegetation has established.

Project 2. Car park rain garden

Description: There is an opportunity to create a demonstration car park rain garden at the western end of the western car park (see Figure 2.2). One parking bay could be excavated and backfilled with a gravel drainage layer, and a sandy loam layer above that would be planted with suitable species (that is, species that can survive occasional inundation as well dry periods). Once full, the rain garden would overflow into the existing drainage system. The rain garden would reduce and delay peak flows and improve water quality, with pollutants being broken down by microbes within the rain garden soil.

Benefits: 

• Reduction in volume of run-off
• Delay of peak flow
• Improvements in quality of run-off
• Increase in biodiversity, amenity
• A demonstration project

Budget: £6,000 (based on an area of 10 m² - assumes a rate of £50 per m² for excavation, disposal, new fill, edging, pebbles, planting and a fixed design fee of £1,000.)

Maintenance: Weeding of planted beds, removal of litter and checking of outlets - two visits per annum suggested.

Programme: Consultation and detailed design are required. Installation in summer/autumn 2021 could be possible.

Project 3. Wildflower strip on road frontage

Description: Along the site boundary on Greyhope Road, in front of the building and the boundary fence, is a gravel strip. It is proposed that any existing unwanted plants are pulled up before seeding it with a locally appropriate coastal wildflower seed mix at a rate of 3g per m². Gravel is an ideal substrate for sowing wildflowers and will need no preparation apart from the removal of any existing unwanted plants.

Benefits: 

• Increase in biodiversity and amenity

Budget: £50 (based on an area of 100 m²) for seed purchase. (Seeding could be undertaken by member(s) of staff.)

Maintenance: Annual cutting in autumn and removal of arisings.

Programme: Seeding could be done by staff in winter 2020/21.

Project 4. Green roof on bicycle shelter

Description: The existing steel bicycle shelter, near the main pedestrian entrance, could be retrofitted with a marine plywood deck roof, EPDM waterproofing and a biodiverse extensive green roof (substrate seeded and plug planted). See Green Roof Training for more details. There is an opportunity for a training/educational event to coincide with the planting.

Benefits: 

• Increase in biodiversity and amenity
• Reduction in run-off
• A demonstration project
• Opportunity to make the planting a training event

Budget: £2,400 (based on an area of 24 m² and an estimated rate of £100 per m²)

Maintenance: Annual check and weeding.

Programme: Once funding is secured and consultation undertaken, this could be installed in spring 2021.

Aberdeen Summary Table

Project	Description	Budget	Benefits	Maintenance
1. Austrian gravel lawns in car park	Existing block paving replaced with Austrian gravel lawn	£13,250	Reduced flood risk, biodiversity, amenity, reduction in mowing	Occasional mowing
2. Car park rain garden	Rain garden excavated and planted in parking bay	£6,000	Reduced flood risk, improved water quality, biodiversity, amenity, demonstration/research project	Weeding, replacement planting, checking outlet
3. Wildflower strip on road frontage	Gravel strip seeded with coastal wildflowers	£50	Biodiversity, amenity	Annual cut with cuttings removed
4. Green roof on bicycle shelter	Biodiverse extensive green roof retrofitted to existing cycle shelter	£2,400	Reduced flood risk, biodiversity, amenity	Annual check and weeding of roof

 

3. Clydebank

3.1 Setting and character

Figure 3.1 shows the location of Mariner Court in Clydebank Business Park, part of a post-industrial area. The site was itself part of the Singer sewing machine factory, which was serviced by railway yards and the adjacent Forth & Clyde Canal. The factory was demolished in 1980 and replaced with the existing business park in 1990. The business park and the wider area has been landscaped with lawns, trees and shrubberies in a conventional commercial ornamental style. Beyond the railway to the north of the site, there are residential areas and golf courses. Four kilometres beyond that, there is agricultural land. The former shipbuilding yards by the River Clyde to the south are in the process of being renewed, with some areas with self-established vegetation yet to be developed. The railway and canal provide valuable green infrastructure and ecological corridors, connecting the area to the wider countryside.

3.2 Site visit

On 21 September 2020, Gary Grant visited the site in order to identify and photograph locations with potential for the creation of new green infrastructure or the enhancement of existing features.

3.3 Identification of interventions

During the site visit, NatureScot staff indicated how the site is used, issues and concerns, and what new facilities might be of interest. In identifying projects, there is a preference for those that are multifunctional. Where existing green infrastructure does occur, the emphasis would usually be on increasing biodiversity or improving surface drainage. Climate change adaptation, whereby the site becomes better prepared for sudden downpours or summer heatwaves, was another key consideration, as well as the objectives of improving amenity and wellbeing. There is interest in staff having space to relax or engage in growing outside. There is currently relatively little use of outside spaces; however, staff do watch birds using a bird feeder outside Caspian House (to the west) and people do sometimes sit outside the office to the immediate south. Also in this location, to the immediate south of Caspian House (close to the bin storage area), puddles can form following heavy rain.

3.4 Suggested projects

Figure 3.2 shows the locations of the suggested projects, which are as follows:

1. Downpipe disconnection planter
2. Vertical rain garden on garage
3. Staff pocket park
4. Green roof on bin store
5. Wildflowers around bird feeder
6. Woodland floor wildflowers under trees
7. Car park rain garden (kerb cut)

Project 1. Downpipe disconnection planter

Description: Where there are existing downpipes feeding directly into drains, there are opportunities to connect downpipe planters, which can slow the flow and thereby reduce flood risk. These planters receive water from downpipes, which flows into a void beneath the planter. Plants are self-irrigated via wicks. When the tank is full, water can overflow into the drain. Such planters also provide an opportunity to bring planting and colour into locations where there may otherwise be limited opportunities for greening. They will be enjoyed from inside and outside the building. Planters are from specialist suppliers and may be sized to suit the location. Planting can include species that are known to attract pollinating insects (e.g. the RHS Plants for Pollinators list). A single planter is proposed as a demonstration; however, further planters can be installed wherever there are downpipes.

Benefits: 

• Reduces flood risk
• More plants for pollinators and amenity
• A demonstration of easy retrofit

Budget: £2,500 (to supply, install and plant).

Maintenance: Minimal. Plants can be looked after by staff.

Programme: This project would require permission from the landlord; however, it could be installed quickly once this is secured.

Project 2. Vertical rain garden

Description: A series of slimline tanks behind a 5m x 2.5m green wall receive water from downpipes. Wicks fed into the tanks from the planters take water to the planters, which means that the green wall is self-irrigated and is in effect a vertical rain garden. This is a system that has been successfully used in London.

Benefits: 

• A multifunctional installation
• Reduction in flood risk
• Provision of habitat
• Improvement to air quality
• Provision of evaporative cooling in summer
• An amenity

Budget: £10,000 (to design, supply and install)

Maintenance: This is a low-maintenance green wall, only requiring attention if plants need to be trimmed or replaced.

Programme: This project would require permission from the landlord, as well as a period of design development (mainly planting design), meaning that it could be achieved in the medium term.

Project 3. Staff pocket park

Description: An existing shrubbery at the southern end of Caspian House can be grubbed up and replaced with a small garden with seating and planted areas. A green screen (a wire fence panel with pre-grown ivy) can be used to provide a visual barrier between the bin store and the new pocket park. Existing soil should be removed to a depth of 500mm and a gravel bed and gravel drainage provided to improve drainage. Fresh clean topsoil can be provided for staff to use to grow vegetables or flowers of their choice. Benches can be provided to allow staff to sit and enjoy the space. Staff can decide on planting, and plant and maintain the garden.

Benefits: 

• Would solve localised drainage problem (surface water)
• Existing shrubbery is a litter trap and past its best
• Would be a morale booster and would make a space in a sun trap that staff could enjoy during breaks

Budget: Total £4,000: removal of existing shrubs, excavation, disposal of existing soil and filling with gravel and soil by contractor - £1,500; purchase and installation of green screens - £1,000; two benches - £1,000; plants and tools - £500.

Maintenance: This can be maintained by staff (weeding, planting).

Programme: This project would require permission from the landlord and a period of design and consultation, meaning that it could be achieved in the medium term.

Project 4. Green roof on bin store

Description: The existing bin store has substantial brick pillars that would be capable of taking the weight of a timber and plywood roof deck covering approximately 10 square metres that could support a biodiverse extensive green roof. The roof deck and waterproofing could be provided by a contractor and the green roof design and installation could be a training exercise involving staff and volunteers (once a temporary handrail is provided for safe access during installation). Information on how to create small green roofs is available as a download or a specification can be provided by GIC.

Benefits: 

• Reduction in run-off
• Provision of summer cooling
• Boost to biodiversity
• This roof would be visible from the first-floor office
• A valuable demonstration project and training exercise
• Working with the landlord(s), could be replicated across the estate

Budget: £5,000 (£2,000 for supply and installation of deck and waterproofing and £1,000 for substrate, plug plants and seed; £2,000 for a training event).

Maintenance: An annual inspection and removal of weeds in late autumn is recommended.

Programme: Permission would be required and lead-in for design, plus the setting of a training date, therefore it is likely that a few months would be needed before implementation.

Project 5. Wildflowers around bird feeder

Description: An area of existing cotoneaster shrubs can be removed (or moved) to provide a space for wildflowers to be sown, and ground cultivated before the seed is sown over the winter. General-purpose native wildflower seed mixes are available. Similar interventions can be replicated across the estate.

Benefits: 

• Increase in biodiversity (floristic diversity, attracts pollinating insects)
• Overlooked by staff

Budget: £200. (Removal of existing shrubs and cultivation, plus purchase of seed. Seeding can be undertaken by staff.)

Maintenance: Annual cut with cuttings removed for composting. Can be cut by staff with a scythe.

Programme: Subject to funding and permission, this can be seeded in winter 20/21.

Project 6. Woodland ground flora under trees

Description: Grass that is currently mown under trees can be converted to woodland ground flora by lifting turf, planting with bulbs and plug plants and seeding. Similar schemes could be replicated across the estate.

Benefits: 

• Increase in biodiversity (floristic diversity)
• Overlooked by staff
• Reduction in mechanical mowing

Budget: £1,000. (Removal of turf - £500; cultivation plus purchase of bulbs, plugs and seed - £500.) Planting can be undertaken by staff.

Maintenance: Annual weeding, if required.

Programme: Subject to funding and permission, this can be implemented during winter 20/21.

Project 7. Car park rain garden (kerb cuts)

Description: The proposal is to cut through the existing kerb to allow some surface water to flow into a rain garden or tree pit in the planted bed, with an area of existing soil removed and replaced with stones and free-draining sandy loam. This is likely to benefit the trees. If trees are replanted, subject to confirmation of levels/topography, new larger pits designed to receive run-off should be created (e.g. Stockholm method).

Benefits: 

• Improved surface water management
• Improved conditions for trees
• Demonstration of simple SuDS retrofit

Budget: £1,000 for each cut through kerb and pit with stones and sandy loam designed to receive run-off. The project can be extended to more pits if the budget is available.

Maintenance: Annual check to remove debris. The existing vegetation cutting regime to continue.

Programme: This project will require permission from the landlord, a consultation period and specification. It could be implemented in the medium term.

Clydebank Summary Table

Project	Description	Budget	Benefits	Maintenance
1. Downpipe disconnection planter	Retrofitted SuDS planter by downpipe	£2,500	Reduced flood risk, biodiversity, amenity, demonstration	Weeding, replanting by staff
2. Vertical rain garden on garage	Green wall with tanks behind	£10,000	Reduced flood risk, biodiversity, summer cooling, amenity	Weeding, replacement planting
3. Staff pocket park	Seating and planting beds for staff in former shrubbery	£4,000	Improved drainage, food growing, staff amenity	Weeding, planting by staff
4. Green roof on bin store	Biodiverse extensive green roof on deck on brick pillars of bin store	£5,000	Reduced flood risk, biodiversity, amenity, training opportunity	Annual weeding
5. Wildflowers	Area around bird feeder cleared and sown with native wildflowers	£200	Biodiversity, amenity	Annual cut with cuttings removed (by staff)
6. Woodland ground flora	Turf under trees stripped and woodland wildflowers planted	£1,000	Biodiversity, reduction in mowing	Annual weeding
7. Car park rain garden (kerb cut)	Existing kerb cut through into rain garden or Stockholm tree pit	£1,000	Reduced flood risk, improved tree health. Could be repeated across bay or wider site	Existing vegetation cutting regime to be maintained

 

4. Cupar

4.1 Location

The study area includes NatureScot’s office in Cupar, part of the SRUC Elmwood Campus at Carslogie Road, KY15 4JB (see Figure 4.1).

4.2 Setting and character

The site is part of the campus of the rural college, established in the grounds of Elmwood House in the 1950s. The site is on the western fringe of Cupar, which is a country town. Duffus Park is to the immediate east, Cupar Sports centre is to the immediate north and Bell-Baxter High School and suburban residential streets are across the main road to the south. Arable farmland is approximately 400m to the north-west. The surface geology of the area is glacial till - a mixture of gravels, sands and clay.

4.3 Site visit

On 22 September 2020, Gary Grant and Dusty Gedge visited the site in order to identify and photograph locations with potential for the creation of new green infrastructure or the enhancement of existing features.

4.4 Identifying projects

During the site visit, it was noted that the site already has pleasant grounds and surroundings and that there is a garden that can be enjoyed by staff. The campus, however, has large expanses of roofs and large car parks, which could exacerbate surface water flooding following sudden downpours. Once projects are being identified, there is the principle of looking for multifunctionality. Climate change adaptation, whereby the site becomes better prepared for sudden downpours or summer heatwaves, was another key consideration, as well as the objectives of improving biodiversity, amenity and wellbeing. As with other NatureScot sites, consideration was given to proposals that, as well as having a practical purpose, would be demonstration projects that might be used in research and education, particularly relevant at Cupar given the academic activity on-site and the nearby presence of a high school.

4.5 Suggested projects

Figure 4.2 shows the locations of the suggested projects, which are as follows:

1. Biodiverse green roofs/blue roofs
2. Car park rain gardens

Both of these suggestions have various options, which are discussed in more detail in the sections that follow.

Project 1. Biodiverse extensive green roofs/ blue roofs

Description: Most of the more expansive, relatively lightweight roofs on-site are unlikely to be suitable for greening; however, some of the lower roofs may be suitable for retrofitting green roofs. The lower roofs (outlined in red in Figure 4.2) receive run-off from the larger upper roofs via downpipes. Subject to sufficient capacity in the structure (to be confirmed by a structural engineer), it would be possible to retrofit extensive green roofs to these lower roofs, either in their entirety or in part. The extensive green roofs would be biodiverse (with industry-standard substrate, seeded and plug planted with native wildflowers). The depth/weight of the build-up would be determined once the engineer’s report is available. Given that pulses of rainwater are directed to these lower roofs by downpipes, an option, subject to detailed design, would be to deliberately create ephemeral wetlands or pools on the roof with dammed outlets, adding to the biodiversity and creating extra capacity for storage of rainwater (a blue roof).

Benefits: 

• Reduction in rainfall run-off from roofs
• Summer evaporative cooling
• Increase in biodiversity
• Research opportunities

Budget: £29,000 for all lower roofs (250m²) and £13,000 for a single 90m² section of roof. Both budgets include £2,000 for the engineer’s fee and £2,000 for design/PM. Supply and installation are based on a rate of £100 per m².

Maintenance: Annual check to unblock outlets, removal of invasive species, etc.

Programme: A medium-term project – it will require engineering and design input. Installation may be possible by autumn 2021.

Project 2. Car park rain gardens

Description: The large car park at the north of the site is sloping from west to east. Following rain, water flows down the slope and onto the road. There is evidence that the existing drains are overwhelmed following heavy downpours. The proposal is to create rain gardens where existing traffic islands on asphalt are indicated by hatching. We suggest two options: a single rain garden in the central island or three rain gardens on the existing hatched areas. Surface water (which may be carrying pollutants) would run down the slope and flow directly into the rain garden(s) or would be intercepted by channel drains which would then direct water into the rain gardens. Each rain garden would be created by excavating a hole that would be backfilled with aggregate and a sandy loam that would be planted with suitable species (that is, species that can survive occasional inundation as well dry periods). Once full, water from each rain garden would overflow onto the street and re-enter the existing drainage system. The rain gardens would reduce and delay peak flows and improve water quality, with pollutants being broken down by microbes within the rain garden.

Benefits: 

• Reduction in volume of run-off
• Delay of peak flow
• Improvements in quality of run-off
• Increase in biodiversity
• Amenity
• Opportunity for research

Budget: £15,000 for all three rain gardens (circa 20 m²) or £8,000 for a single central rain garden (circa 10 m²) – the cost for design and build approach for excavation, disposal, new fill, planting, kerbs, channel drains.

Maintenance: Weeding of the planted beds, removal of litter and checking of the outlets - two visits per annum suggested.

Programme: Consultation and detailed design are required. Installation in 2021 may be possible.

Cupar Summary Table

Project	Description	Budget	Benefits	Maintenance
1. Green roof	Retrofitted extensive green roof with options for wetland features	All lower roofs: £29,000 Reduced area: £13,000	Reduced flood risk, biodiversity, cooling in summer, demonstration project, research	Annual weeding, checking of outlets
2. Car park rain gardens	Rain garden(s) created within existing hatched areas in car park	3 rain gardens: £15,000 1 rain garden: £8,000	Reduced flood risk, improved water quality, biodiversity, amenity, demonstration project, research	Checking outlets, litter removal, weeding, clearing channel drains, replacement planting

 

5 Edinburgh

5.1 Location

The study area includes NatureScot’s office at Silvan House, 231 Corstorphine Road, Edinburgh EH12 7AT (see Figure 5.1).

5.2 Setting and character

Silvan House, the site of the NatureScot office in Edinburgh, was built in 1974 and renovated in 2009. The site consists of a five-storey modern office building with car parks and incidental landscape. There are many mature trees on-site. The site slopes away to the south. There are residential streets to the north-west, west and south-west. There is a golf course to the south-east and Edinburgh Zoo is across the main road to the north-east. The surface geology is glacial till, with a mixture of clay, silt, sands and gravels. Surface drainage is by conventional downpipes and drains.

5.3 Site visit

On 21 September 2020, Dusty Gedge visited the site and met with staff to identify and photograph locations with potential for the creation of new green infrastructure or the enhancement of existing features.

5.4 Identifying projects

During the site visit, staff indicated that there is a history of surface water flooding, with water flowing down the slope and gathering in the car park at the south of the site - a problem that is likely to intensify with climate change. At this site, given the problems with surface water, it may be advisable to install several features, in order to maximise the ability of the site overall to store rainwater and slow the flow. Our emphasis is always to increase biodiversity; however, at this site, there is an opportunity to demonstrate some sustainable drainage technologies, which weren’t in the minds of the designers when the complex was conceived. Climate change adaptation, whereby the site becomes better prepared for sudden downpours or summer heatwaves, is a key consideration as well as the objectives of improving amenity and wellbeing. As with other NatureScot sites, consideration was given to proposals that would be demonstration projects as well as having a practical purpose.

5.5 Suggested projects

Figure 5.3 shows the locations of the suggested projects, which are as follows:

1. Green wall(s)
2. Rain gardens in existing planted beds
3. Wildflower gravel strip
4. Wildflower bank
5. Austrian gravel lawns in car park
6. Green roof

These suggestions are discussed in more detail in the sections that follow.

Project 1. Green walls

Description: The north-facing facades of the buildings consist of masonry that (subject to confirmation by a structural engineer) could be covered with green walls. Green wall panels or fabric panels could be planted with a range of shade-tolerant plants including ivy, ferns and woodland and hedgerow wild flowers, to create year-round interest and to boost biodiversity. There is also the possibility of harvesting rainwater from the roof to irrigate the wall(s). Irrigation tanks that can be automatically emptied before a storm can collect rainwater that would otherwise enter the surface drainage system. If a modular green wall is deemed to be too expensive, an alternative approach would be to grow climbing plants onto the masonry or onto a wire trellis.

Benefits: 

• Increase in biodiversity and amenity

Budget: £100,000 per wall - £200,000 for both walls (based on an area of 200 m² per wall and a rate of £500 per m²). The cost includes design, supply, installation, irrigation and planting. The cost of the wire trellis and climbing plants is likely to be less than £10,000 per wall.

Maintenance: Three visits per year using the existing gondola for two technicians to weed and replant as required. Irrigation to be monitored remotely by the maintenance company. The annual maintenance cost is likely to be in the region of £3,000 per wall. Maintenance of the wall of climbing plants would require an annual visit to trim the plants, check the trellis and replant as required –the cost is likely to be in the region of £1,000 per annum.

Programme: This would require agreement from the landlord, investigation, consultation, design, and may require planning permission. Once funding is secured, installation might be possible by autumn 2021.

Project 2. Rain gardens in existing planted beds

Description: In five locations, both in front of and behind the building, existing planted beds can be remodelled as rain gardens. Existing soil and vegetation can be removed and replaced with gravels at the base, below a sandy loam soil that is free-draining and water absorbent. These beds would need to be modified so that surface water enters them through gaps in the kerbs, with overflow notches to allow excess water to flow back into the road. There should also be a freeboard above the soil level, which can store water for a few hours following a downpour. The modified beds can be replanted with drought-tolerant species with a documented value for wildlife that can withstand occasional inundation.

Benefits: 

• Reduction in flood risk
• Improvement in water quality
• Increase in biodiversity
• Amenity

Budget: £25,000 (based on a total area within the 5 rain gardens of approximately 100 m² and a rate of £250 per m²).

Maintenance: Annual check of inlets and outlets. Weeding and replanting as required.

Programme: Consultation and detailed design are required. Installation in 2021 might be possible.

Project 3. Wildflower gravel strip

Description: An existing gravel bed can be cleared of existing shrubs and seeded with a native wildflower mix. Staff can seed this bed and monitor it.

Benefits: 

• Increase in biodiversity and amenity

Budget: £200: £100 for shrub removal and weeding; £100 for seed purchase.

Maintenance: 50% cut every year on rotation, with cuttings removed.

Programme: This could be prepared and seeded in time for the 2021 growing season.

Project 4. Wildflower bank

Description: The existing bank between the car park and path is covered with paving slabs (see Figure 5.9). The proposal is to remove these slabs, remove the surface material beneath, replace it with a low nutrient stony sub-soil and seed it with wildflowers. The shady nature of this location means that a woodland edge seed mix might be best suited.

Benefits: 

• Increase in biodiversity and amenity
• Reduction in run-off

Budget: £1,500: £1,000 based on an area of 40 m² and an estimated rate of £25 per m² to remove existing slabs and spoil; £400 for supply and installation of low-nutrient subsoil; and £100 for seed.

Maintenance: 50% cut on rotation each year, with cuttings removed.

Programme: Once approval and funding are received, installation and seeding in 2021 might be possible.

Project 5. Austrian gravel lawns in car park

Description: Sealed surfaces in the car parks at the southern part of the site exacerbate surface water flooding. It would be possible to excavate some of these sealed surfaces and create Austrian gravel lawn, which is designed to take occasional vehicular traffic, but is free draining and vegetated and capable of storing water. Biochar could also be buried in the gravel, sequestering carbon. Figure 5.11 shows a central area in the car park at the south-western part of the site being converted to Austrian gravel lawn. (Please note that this website is not in English.) However, other parking spaces along the southern boundary could also receive a similar treatment.

Benefits: 

• Reduction in volume of run-off
• Water quality improvements
• Increase in biodiversity
• Improved amenity for neighbours
• A research and demonstration project

Budget: £9,500, allowing for a design fee of £2,000 (Austrian experts) and assuming implementation at a rate of £25 per square metre to remove and replace 300 square metres of asphalt.

Maintenance: Occasional mowing in summer - could be undertaken by robot mower.

Programme: Permission from the landlord, funding, consultation and detailed design are required. Installation in 2021 might be possible. Seeded areas would require protection from traffic during establishment.

Project 6. Green roof

Description: A green roof could be fitted to the small utility building on the southern boundary of the site (subject to checks on structure). Existing waterproofing to be covered with protective fleece, substrate and seeded/plug planted. This is a shady site, so account would need to be taken of that when selecting seed and plug plants. For more information on small green roofs, see Green Roof Training.

Benefits: 

• Biodiversity
• Amenity
• Reduced run-off
• A demonstration project

Budget: Suggested budget - £3,000: £720 for structural report; £2,250 for green roof (45 m² at a rate of £50 per m²).

Maintenance: Annual check to remove weeds and check outlet.

Programme: Once funding and permission are secured, planting in spring or autumn 2021 might be possible.

Edinburgh Summary Table

Project	Description	Budget	Benefits	Maintenance
1. Green walls	Modular green walls on north-facing facades	£100,000 per wall	Biodiversity, amenity	Three visits per year by two technicians
2. Rain gardens	Five existing planted beds can be modified as rain gardens	£25,000 for five rain gardens	Reduction in flood risk, improvements in water quality, increase in biodiversity, amenity	Annual check, weeding
3. Wildflower gravel strip	Existing gravel strip cleared and seeded with wildflowers	£200	Increase in biodiversity, improvements in amenity	Occasional mowing, 50% per annum on rotation
4. Wildflower bank	Existing paved slope depaved and seeded with wildflowers	£1,500	Increased biodiversity, improved amenity, reduced run-off	Occasional mowing, 50% per annum on rotation
5. Austrian gravel lawn in car park	Existing asphalt replaced with Austrian gravel lawn	£9,500	Reduced flood risk, improved water quality, biodiversity, amenity. Demonstration project	Robot mower in summer
6. Green roof	Green roof retrofitted to utility building	£3,000	Increased biodiversity, improved amenity, reduced run-off – a demonstration project	Annual check with weeds removed

 

6. Golspie

6.1 Location

The study area includes NatureScot’s office in Golspie at The Links, Golspie Business Park, Golspie, Sutherland, KW10 6UB (see Figure 6.1).

6.2 Setting and character

The Golspie NatureScot office was built in 2008. The site is on a small modern business park on the western fringe of the conurbation. Golspie is a planned village established in the early nineteenth century on the North Sea coast, with Dunrobin Castle to the north-east. The site itself is close to the railway station, with a golf course and improved grassland to the south, and a residential estate and forestry across the A9 to the north. The ground rises steeply to the north-west. There is rough pasture to the immediate west of the site, with the business park extending to the east. The surface geology is of raised gravels, sands and silts of marine origin. The site is sloping towards the south and has a conventional landscape, dominated by amenity grassland. Surface drainage has conventional downpipes and drains, but also includes rainwater harvesting and permeable paving. Surface water drains into a pond to the immediate south of the site.

6.3 Site visit

On 23 September 2020, Dusty Gedge visited the site and met with staff to identify and photograph locations with potential for the creation of new green infrastructure or the enhancement of existing features.

6.4 Identifying Projects

During the site visit, staff indicated that there is an interest in having more wildflowers on-site, suggested that an orchard is established, expressed an interest in having an outdoor space for breaks and meetings and explained that there is a concern over strong sunlight on some office windows. The building itself is modern and not suited to the retrofitting of a green roof. Our emphasis here is to demonstrate some more sustainable drainage technologies, which probably weren’t in the minds of the designers when the complex was conceived, and also to boost biodiversity. Climate change adaptation, whereby the site becomes better prepared for sudden downpours or summer heatwaves, was another key consideration, as well as the objectives of improving amenity and wellbeing. As with other NatureScot sites, consideration was given to proposals that, as well as having a practical purpose, would be demonstration projects.

6.5 Suggested projects

Figure 6.2 shows the locations of the suggested projects, which are as follows:

1. Wildflowers on gravel strips
2. Wildflower bund
3. Swale in southern lawn
4. Rain garden to north of building
5. Rain garden traffic calming
6. Orchard
7. Seating area for staff

These suggestions are discussed in more detail in the sections that follow.

Project 1. Wildflowers on gravel strips

Description: Existing gravel strips occur along the southern margin and to the west of the building. It is proposed that existing unwanted plants are pulled out and that these areas are seeded with a native wildflower mix at the rate of 3g per square metre. Gravel is an ideal substrate for sowing wildflowers and will require little preparation.

Benefits: 

• Increase in biodiversity and amenity

Budget: £50 (based on an area of 100 m²) for seed purchase. To be seeded by member(s) of staff.

Maintenance: Biennial cutting in autumn and removal of arisings, one half cut one year and the other half cut the following year.

Programme: Seeding could be undertaken by staff in winter 2020/21.

Project 2. Wildflower bund                  

Description: Material excavated for the construction of swales and rain gardens can be used to create a bund, which can subsequently be sown with a native wildflower mix. Clean (low nutrient) material should be used to cap the feature to encourage plant diversity. Bare areas on the south-facing side of the bund will be colonised by mining bees and other invertebrates.

Benefits: 

• Reduction in cost of disposal of excavated material
• Increase in biodiversity, amenity

Budget: £2,600, based on an assumed volume of 100 m³ and rate of £25 per m³, and £100 for wildflower seed. It may be possible to reduce the cost by incorporating this into the budget for swales/rain gardens.

Maintenance: Occasional cutting - once every two years is suggested, on a rotation, to maintain diversity of structure and overwintering vegetation for invertebrates.

Programme: Consultation and detailed design are required. This is likely to be associated with a larger package of works. Installation in 2021 might be possible.

Project 3. Swale in southern lawn

Description: Run-off from the car park can be directed into a shallow swale, which would be excavated in parallel with the car park. Overflow from the swale can flow along a stony channel into the existing pond. The swale can be sown with a native damp grassland wildflower mixture at a rate of 3g per m². The material excavated can be used to make a bund (See Project 2).

Benefits: 

• Improved surface water management
• Improved water quality
• Increase in biodiversity

Budget: £2,100: £2,000 for excavation; £100 for seed purchase.

Maintenance: Annual check, litter collection and cut every second year on rotation, with cuttings removed.

Programme: Consultation and detailed design are required. This is likely to be associated with a larger package of works. Installation in 2021 might be possible.

Project 4. Rain garden to north of building

Description: Downpipes on the northern side of the building could be diverted across the path via channel drains into rain gardens. Rain gardens would be excavated and backfilled with free-draining sandy loam and planted with suitable perennials (drought-tolerant but also able to withstand temporary inundation). Freeboard above the soil and below the outfall would provide some storm storage. Overflow from the rain gardens would be directed back into the existing drains. There is the possibility of using excavated material in a wildflower bund (see Project 2.)

Benefits: 

• Increase in biodiversity and amenity
• Reduction in run-off
• A demonstration project

Budget: £5,000, based on an area of 40 m² and an estimated rate of £100 per m², plus £1,000 for channel drains, overflow, etc.

Maintenance: Annual check of outlets and weeding.

Programme: Consultation and detailed design are required. Installation in 2021 might be possible.

Project 5. Rain garden traffic calming

Description: Street rain gardens could be created on the road within the business park. These would be Portland (Oregon) style rain gardens, where road run-off enters the rain garden and overflow re-joins the street and subsequently enters the existing conventional road gully. These build-outs can also be used as traffic calming elements - a better option than speed bumps, which endanger people in ambulances and damage vehicles. Up to six rain gardens could be established in pairs as a demonstration project.

Benefits: 

• Reduction in volume of run-off
• Water quality improvements
• Increase in biodiversity and amenity
• Traffic calming
• A research and demonstration project

Budget: £3,000 per rain garden (including excavation, kerbs, rain garden soil, planting). All six would cost £18,000. With a design input of £2,000, the project would cost £20,000.

Maintenance: Annual check of outlets and weeding.

Programme: Consultation and detailed design are required. Installation of the first in 2021 might be possible.

Project 6. Orchard

Description: There is space within the grassy area at the south of the site to establish an orchard (the exact location to be determined - see Figure 6.2 for the suggested location). A variety of apples, including Scottish varieties, traditional pears, cobnuts, raspberries and other soft fruits could be featured. (For example, see Scottish fruit trees). Once the ground is cleared and prepared, this is a project that could be implemented by staff and/or volunteers.

Benefits: 

• Food
• Improved staff morale and wellbeing
• Biodiversity (pollinators)

Budget: Suggested budget - £2,000: £30 per tree; £1 per raspberry cane. Site clearance, tools and soil improvers, etc., would be required.

Maintenance: Occasional mowing, weeding and annual pruning.

Programme: Planting in spring or autumn of 2021 might be possible.

Project 7. Seating area for staff

Description: Close to the orchard, in the grassy area at the south of the site, a seating area could be established. It is suggested that an area of Austrian gravel lawn is established as a base (hard-wearing, free draining and seeded with a native acid grassland seed mix). Find more information on Austrian gravel lawns. Seating should also be provided (it is suggested that there are three benches seating nine, or six with social distancing). A local craftsperson could be commissioned to make the benches from local timber to showcase this capability. An option would be to have a fabric rain shelter (garden gazebo) or similar. The seating area could be used on a daily basis for breaks and meetings and could also be a focal point for people working on the adjacent orchard.

Benefits:

• Improved staff morale and wellbeing
• Biodiversity
• A demonstration (Austrian gravel lawn and local crafts and timber)

Budget: £3,000 - £1,000 for Austrian gravel lawn (assuming 10 m²); £2,000 for three double benches.

Maintenance: Occasional mowing of Austrian gravel lawn and oiling of timber benches.

Programme: Establishment in 2021 might be possible.

Golspie Summary Table

Project	Description	Budget	Benefits	Maintenance
1. Wildflowers on gravel strips	Three existing gravel strips seeded with wildflowers	£50	Biodiversity, amenity	Annual or biennial mowing
2. Wildflower bund	Bund created in southern lawn using spoil from other projects. Seeded with native wildflowers	£2,600	Increase in biodiversity, amenity. Reduction in cost of disposal for other projects	Annual or biennial cutting
3. Swale in southern lawn	Swale to receive run-off from car park	£2,100	Improved surface water management, improved water quality, biodiversity, amenity	Litter collection and occasional cutting
4. Rain garden to north of building	Rain garden fed by downpipes	£5,000	Reduced flood risk, biodiversity, amenity. Demonstration project	Annual check and weeding
5. Rain garden traffic calming	Series of street rain gardens	£3,000 per rain garden	Reduced flood risk, improved water quality, biodiversity, amenity. Demonstration project	Litter removal, annual check and weeding
6. Orchard	Orchard of apples, pears, nuts and soft fruits	£2,000	Food, staff wellbeing, biodiversity	Occasional mowing, weeding and pruning
7. Seating area for staff	Rustic benches set on gravel lawn	£3,000	Staff wellbeing, demonstration of Austrian gravel lawn, showcase of local crafts and timber products	Occasional mowing, oiling of benches

 

7. Hamilton

7.1 Location

The study area includes NatureScot’s office at Cadzow Court, 3 Wellhall Road, Hamilton, ML3 9BG (see Figure 7.1).

7.2 Setting and character

Cadzow Court is in the Allanshaw Industrial Estate in Hamilton. The site was part of a colliery and railway complex in the nineteenth century, with the present-day light industrial and office estate established in the 1980s. There is an industrial area to the south; however, much of the neighbourhood is residential. There is a lawn with trees and shrubberies in front of Cadzow Court. To the east is a railway cutting which is heavily vegetated, and the railway forms a valuable green infrastructure corridor linking the town centre to the open countryside 5km to the south and the open countryside of the Clyde Valley to the north. The Cadzow Burn, which is at the surface to the south-west of the site, is culverted along the southern edge of the Allanshaw Industrial Estate.

7.3 Site visit

On 21 September 2020, Gary Grant visited the site in order to identify and photograph locations with potential for the creation of new green infrastructure or the enhancement of existing features.

7.4 Identification of interventions

During the site visit, a member of the NatureScot staff indicated how the site is used, issues and concerns, and what new facilities might be of interest. In identifying projects, there is a preference for those that are multifunctional. Where existing green infrastructure does occur, the emphasis would usually be on increasing biodiversity or improving surface drainage. Climate change adaptation, whereby the site becomes better prepared for sudden downpours or summer heatwaves, was another key consideration, as well as the objectives of improving amenity and wellbeing. There is interest in staff having space to relax or engage in growing outside. There is currently relatively little use of outside spaces; however, staff do use the car park (which is unvegetated) and also overlook the lawn on the Wellhall Road frontage.

7.5 Suggested projects

Figure 7.2 shows the locations of the suggested projects, which are as follows:

1. Woodland ground flora under trees on front lawn
2. Rain garden fed by the downpipe
3. Downpipe disconnection planter
4. Green roof bin store
5. Planters and seating area for staff
6. Wildflowers seeded in gravel strip by the wall in the car park
7. Wildflowers seeded in gravel strip by the outside wall
8. Green roof on extension

Project 1. Woodland ground flora under trees in the front lawn

Description: Grass that is currently mown under trees can be converted to woodland ground flora by lifting the turf, planting with bulbs and plug plants and seeding.

Benefits: 

• Increase in biodiversity (floristic diversity)
• Reduction in mechanical mowing

Budget: £500: Removal of turf - £250; cultivation plus purchase of bulbs, plugs and seed - £250. Planting can be undertaken by staff once the turf is removed by the contractor.

Maintenance: Annual weeding, if required.

Programme: Once permission is granted and funding secured, this could be implemented in winter 20/21.

Project 2. Rain garden fed by the downpipe

Description: A demonstration rain garden can be created in the front lawn to receive rainwater from an existing downpipe. A take-off pipe and surface drain can feed a new rain garden, which would be a planted bed with vegetation that can withstand occasional inundation and periods of low rainfall. Before planting can take place, an area of lawn can be excavated to a depth of about 600mm and filled with a free draining sandy loam. Exceedance flows can be directed to the existing drain via overflow and sub-surface pipes. The image and budget are based on an area of four square metres; however, the rain garden could be larger if funds are available.

Benefits: 

• Reduces flood risk
• Provides habitat for pollinators
• A demonstration project.

Budget: £4,000 to design, supply and install.

Maintenance: This is low-maintenance, with annual weeding and occasional trimming or replacement of plants as required.

Programme: This project would require permission from the landlord, as well as a period of design development (mainly planting design), meaning that it could be achieved in the medium term.

Project 3. Downpipe disconnection planter

Description: An existing downpipe on the southern facade of the building could be connected to a pre-fabricated SuDS planter. Water from the downpipe would flow into a void beneath the planter. Plants are self-irrigated via wicks. When the tank is full, water can overflow into the drain. Such planters also provide an opportunity to bring planting and colour into locations where there may otherwise be limited opportunities for greening. This would be enjoyed from inside and outside the building. Planters are from specialist suppliers and may be sized to suit the location. Planting can include species that are known to attract pollinating insects (e.g. the RHS Plants for Pollinators list). A single planter is proposed as a demonstration; however, further planters can be installed around the perimeter of the car park wherever there are downpipes.

Benefits: 

• Reduced flood risk
• Increase in biodiversity (floristic diversity, attracts pollinating insects)
• Demonstration project
• Overlooked by staff

Budget: £2,500 per planter, for supply and installation.

Maintenance: Occasional weeding or replanting can be carried out by staff.

Programme: Once permission is granted by the building owner and funding is secured, this could be installed immediately.

Project 4. Green roof bin store

Description: A galvanised steel bin store complete with biodiverse green roof and habitat features, manufactured off-site, can be purchased and installed in the location where the bins are currently stored.

Benefits: 

• Green roof will absorb rainfall and provide wildlife habitat

Budget: £5,000 for purchase, delivery and installation.

Maintenance: Annual safety check and weeding of roof (if required).

Programme: This project could proceed as soon as funding is secured.

Project 5. Planters and seating area for staff

Description: A pair of benches and a pair of raised planters could be provided for staff. Planters can be for staff to grow vegetables and/or as part of a gardening club.

Benefits: 

• Amenity
• Wellbeing boost for staff

Budget: £3,000 for two raised planters with soil, gardening tools and two benches.

Maintenance: Maintained by staff.

Programme: This project could proceed as soon as funding is secured.

Project 6. Wildflower strip seeded by the wall in the car park

Description: The existing gravel strip can be weeded and then seeded with general purpose native wildflower mix.

Benefits: 

• Increase in biodiversity and amenity

Budget: £100 for purchase of seed (seeding to be undertaken by staff).

Maintenance: Maintained by staff by annual cut with cuttings removed.

Programme: This project could proceed as soon as funding is secured, with seeding during autumn/winter.

Project 7. Wildflower strip seeded by the outside wall

Description: The existing gravel strip can be weeded and then seeded with general purpose native wildflower mix.

Benefits: 

• Increase in biodiversity and amenity

Budget: £100 for purchase of seed (seeding to be undertaken by staff).

Maintenance: Maintained by staff by annual cut with cuttings removed.

Programme: This project could proceed as soon as funding is secured, with seeding during autumn/winter.

Project 8. Biodiverse extensive green roof on extension

Description: A biodiverse extensive green roof can be retrofitted on the extension (approximately 5 square metres), subject to confirmation by an engineer that the roof has sufficient strength. An edge trim would be required, Permablox reservoir board, 80mm of substrate and seeding with a green roof seed mix (e.g. Emorsgate ER1F or similar) and wildflower plugs. The specification to be provided by GIC.

Benefits: 

• Reduction in run-off
• Increase in biodiversity
• Summer cooling
• Amenity (overlooked from the stairwell)

Budget: £2,000 - £500 for the engineer’s fee, the remainder for supply and installation of the green roof.

Maintenance: Annual check with weeds removed.

Programme: This project could proceed as soon as funding is secured. Planting during the summer period should be avoided.

Hamilton Summary Table

Project	Description	Budget	Benefits	Maintenance
1. Woodland ground flora	Woodland ground flora planted under trees in front lawn	£500	Biodiversity, amenity, reduction in mowing	Annual weeding
2. Rain garden fed by downpipe	Rain garden excavated and planted in existing lawn	£4,000	Reduced flood risk, biodiversity, amenity, demonstration project	Weeding, replacement planting
3. Downpipe disconnection planter	Retrofitted SuDS planter by downpipe	£2,500	Reduced flood risk, biodiversity, amenity	Weeding, replanting by staff
4. Green roof bin store	Biodiverse extensive green roof on prefabricated steel bin store	£5,000	Reduced flood risk, biodiversity, amenity	Annual check and weeding of roof
5. Planters and seating area for staff	Two raised planters and two benches	£3,000	Amenity, wellbeing	Gardening club (staff)
6. Wildflower strip on wall by car park	Seeding of existing gravel strip with wildflowers	£100	Biodiversity, amenity	Annual cut with cuttings removed
7. Wildflower strip on outside wall	Seeding of existing gravel strip with wildflowers	£100	Biodiversity, amenity	Annual cut with cuttings removed
8. Biodiverse extensive green roof on extension	Biodiverse extensive green roof on existing extension	£2,000	Biodiversity, reduced flood risk, summer cooling, amenity	Annual check with weeding as required