Eco-engineering with Soils

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1 Eco-engineering with Soils Dr David Hackett Solum Environmental June 2012

2 Ecology within development sites The position of ecology within the development process has advanced significantly over the last 3 decades: From accommodation of protected species within wildlife areas the landscape architect typically defining an area within the site landscape to which a management plan, written by an ecologist, is applied. Increasingly incorporated into the design, to include green roofs and green walls, in satisfaction of PPS9, BREEAM, BAPS, HAPS and Soil Management Plans. Eco-engineering/design, to include whole-site eco-resource audit and design. The following have proven to be significant drivers in this process: Wildlife and Countryside Act (1981) advancing the protection of species and habitats Rio Summit, 1992 The Convention of Biological Diversity establish biodiversity and catalysing biodiversity action plans First Soil Action Plan for England, beginning of the recognition of the value of soils within the national context. Flood and Water Management Act (2010) impetus for the application of SuDS

3 Soils as ecosystems Soils are increasingly recognised as valuable habitats in their own right and not just growing media: there is more biodiversity in soils than on them. The UK is exceptional in Europe in the threats to soil biodiversity through: Land-use change Human intensive exploitation Invasive species Soil compaction Soil erosion Soil organic matter decline Soil pollution Soils threats map

4 Amelioration and Inoculation The amelioration of soils with the addition of organic material and introduction of earthworms is a technique employed to support badger populations at a remediated site near Glasgow

5 Why make/enhance soils? The physical resource: Degradation and loss Parliamentary Office of Science and Technology, UK SOIL DEGRADATION July 2006: Soil degradation involves both the physical loss (erosion) and the reduction in quality of topsoil associated with nutrient decline and contamination. It has implications for the urban environment, pollution and flooding, through loss of storage capacity, soil-sealing etc. In 2006, 2.2 million tonnes of topsoil was being eroded annually in the UK and over 17% of arable land showed signs of erosion. 20% of all upland peat is currently at risk The goal should be initially to prevent loss then increase capacity

6 Audit and value : unusual habitats Minuartia verna(spring sandwort) on lead spoil, Peak District National Park Unusual substrates, including industrial wastes, give rise to unusual, often unique, habitats. Heather, lichens and broyphyteson mine spoil, Bolton an acid substrate in a largely alkaline area

7 Audit and Value : Ephemeral habitats Former GEC site, Stonebridge, North Liverpool. This particular transitory habitat has value in supporting invertebrates and Schedule 1 bird species, but is only present as a result of the clearance of the former industrial site. Whether such habitats are recognised and protected is presently largely a function of a what stage they are surveyed and considered for planning permission.

8 Budget and resources widen the scope for creativity Legislation and planning have increased the drivers for the enhancement of biodiversity Green walls Technology and applied science are increasing the options from conservation to translocation and creation Green roofs

9 The tools: Industry guides

10 BS Topsoil and Subsoil Standards for Traded Soils

11 Amending and specifying soil characteristics

12 Geological reference The underlying geology has a fundamental influence on the soils generated and the nature of the vegetation supported. This together with microclimatic conditions are major considerations in design

13 Made soils: Characteristics Made soils/subsoils Are soils constructed from recycled and site-won materials Replicates qualities of natural topsoilsin supporting plant growth in terms of fertility, ph, drainage characteristics etc Naturally occurring v Made soils Naturally occurring soils: highly variable, biologically active media, developed through interaction of environmental and biogenic process on exposed geology. More biodiversity in soils than on them. Nitrogen fixing and carbon recycling An ecosystem and biodiverse resource to be conserved. Made soils: growing media which can be specifically tailored to suit end uses. No weed seeds when using PAS 100 compost and subsoils Reduction in maintenance cost for supporting vegetation Sustainable No living organisms (unless specifically introduced)

14 Landscape scenario

15 Design options

16 Eco-engineering is multi-disciplinary The mechanics of water flow etc The bigger picture and resolution of conflicting priorities through design Engineering Landscape Design Planning Ecology The potentials and constraints for habitat creation Advances will come from multi-disciplinary understanding