EPA - Ireland's Environment, An Integrated Assessment - 2020

Chapter 5: Land and Soil Pressures on Soils as a Result of Land Management Practices Urbanisation and building account for some of the biggest losses of soil areas in Ireland. The European Environment Agency recognises that soil degradation is not well monitored, and often remains hidden, but its effects can be widespread and diverse in nature (EEA, 2019a). It also recognises that there is increasing evidence that land and soil degradation have major economic consequences, whereas the cost of preventing damage is significantly lower. Without careful management and monitoring measures, the negative impacts of intensive land use, coupled with climatic events, may result in irreversible land degradation (EEA, 2019b). Intensive land management can lead to negative impacts on soil biodiversity, which is the key driver of terrestrial ecosystem carbon and nutrient cycling. There are six overarching degradation processes that can impact on soils. These are soil sealing (where soils are closed off from the surface of the land, e.g. road and building developments close off soils from the land surface by building on top of it), erosion, organic matter decline, compaction, salination and landslides. The CORINE (Co-ordinated Information on the Environment) data series, produced by the European Environment Agency for the European Union, compiles geospatial environmental data in a standardised and comparable manner across Europe. The latest CORINE land cover data (2018) for Ireland supports previous research findings (Kiely, et al. , 2014) that the main soil quality pressure in Ireland relates to soil sealing. One of the reasons for this is the presence of a dense road network in what is a sparsely populated country (Prokop et al. , 2011). Artificial areas with sealed soil surfaces have increased by 65 per cent since 1990, although there has been little change since 2012. The sealing of soils impacts their ability to absorb pollutants, reduces their biodiversity and productivity and can also increase flooding in built areas by affecting natural drainage patterns. This in turn may lead to pollutants more easily entering our waters, potentially causing more widespread pollution. In urban areas, sustainable urban drainage systems, if correctly maintained, prevent pollutants entering our waters. Soil compaction is also a recognised key threat to the quality of Irish soils. It can lead to increased surface run-off, flooding, erosion and transport of nutrients and agrochemicals to open water (EC JRC, 2016a). Recently, the Global Assessment Report on Biodiversity and Ecosystem Services (IPBES, 2019) reported some startling findings. The assessment showed that, globally, about 75 per cent of the land surface has already been significantly altered and over 85 per cent of the wetland area has been lost. It stated that ‘nature across most of the globe has now been significantly altered by multiple human drivers, with the great majority of indicators of ecosystems and biodiversity showing rapid decline’ (p. 11). Human activity is a significant driver of degradation through poor or inappropriate land management practices. Practising sustainable land management and soil conservation principles at the heart of the planning process means shifting away from a reliance on zoning of greenfield lands towards more brownfield development opportunities in and around our major cities and towns. For example, for every 20,000 dwellings completed each year in Ireland, there could potentially be a loss of around 1150 hectares of greenfield agricultural land. 2 Typically, greenfield lands around Ireland’s major cities and towns contain high-quality, highly productive soils that, once sealed under new developments, are lost forever. Ireland must adopt a more proactive approach both nationally and locally in addressing this decline in nature. Better land management is an important step in this approach. The publication of the National Planning Framework in 2018, which introduced the first brownfield development target to deliver at least 40 per cent of all new homes nationally within the built-up footprint of existing settlements (Government of Ireland, 2018, p. 29), is an important first step. Clear definitions of what does and does not constitute brownfield development in mandatory planning guidelines, the widening of brownfield targets to embrace the increasingly greenfield nature of new business parks and employment locations, and effective monitoring of the implementation of targets using geographical information systems data will be essential. 2 Assuming that 20% (4000 homes) of the 20,000 dwellings are constructed annually as one-off dwellings in countryside settings and require a site area of a minimum of 0.5 acres (total 809 hectares) under the EPA Code of Practice for Wastewater Treatment Systems for Single Houses (2010); 20% (4000 homes) of the housing provision is brownfield development, i.e. redevelopment of formerly developed lands; and 12,000 homes are constructed at an average density (minimum under planning guidelines) of 35 dwellings per hectare, resulting in a land area requirement of 340 hectares. 101