Peat is the remains of plant and animal constituents accumulating over time, under close to water-saturated conditions, forming a land-based organic deposit. A peatland is defined as an area with an accumulated peat layer at the surface of greater than 40-50 cm thickness (Charman, 2002, Rydin and Jeglum, 2013). Globally, peatlands cover 4.23 million km2 or 2.84% of the land surface (Xu et al., 2018) and represent at least a third of the global wetland area (Parish et al., 2008). It is estimated that peatlands store between a sixth and a third of all global soil carbon (Page et al., 2011, Yu, 2012). Peatlands have been claimed to deliver nationally and internationally valuable ecosystem services that contribute to human well-being, including regulating services, such as climate regulation, water quality moderation and natural hazard regulation (Currey et al., 2011, Holden, 2005, Yu et al., 2010), provisioning services including water provision, agricultural production and sources of energy (Joosten and Clarke, 2002, Safford and Maltby, 1998), as well as supporting services and cultural services (Bonn et al., 2016). Of these ecosystem services, water provision is an often-stated example. Peatlands are potentially important to the sustainable provision of potable water because water draining from peatlands is often of good quality, other than being rich in dissolved organic carbon (DOC). The literature often suggests that peatlands play important roles in water resource use (Grundling et al., 1998, Lee and Chai, 1996, Ong and Yogeswaran, 1991, Page and Rieley, 1998), and the streams or rivers that have flowed from peatlands may contribute to agricultural water, industrial water and domestic water (Osaki, 2016; Barthelmes et al., 2012; UNESCO, 2003). However, while the above papers make these statements, they do not actually demonstrate how important peatlands are for global water resources. There are similar unsubstantiated statements made at a local level. For example, many papers claim that approximately 70 % of Britain's drinking water comes from upland areas which are dominated by peatlands, but this figure has never been verified and was in fact mainly based on a study of the Tees catchment (Watts et al., 2001; Grayson et al., 2012; Labadz et al., 2010). Overall there is little quantitative evidence to show how important peatlands are globally for potable water resources despite their potentially large water storage role.
In addition, peatlands are threatened globally by climate change. Locally peatlands are threatened by severe anthropogenic pressures (e.g. drainage, resource extraction, burning, agriculture) to meet the increasing demand of water, food, and energy due to population growth and development. All of these disturbances may affect peatland hydrology and water quality. However, no global-scale work has been done to link peatland water resources data to peatland degradation caused by environmental change. This could be vital information for global and national policymakers and may also help provide underpinning support for further peatland protection and restoration.
Research aim and objectives
The overall aim of this project is to investigate the role of peatlands in providing global and regional potable water resources and understand the potential threat to these water resources from future environmental change. In order to accomplish this aim, the following research objectives have been defined:
1) to produce a most up-to-date global peatland map with geospatial information for further spatial analysis;
2) to develop the indexes to estimate the quantity and hotspots of global peatland-derived potable water;
3) to select and apply the physically processes model to determine the flow discharge and DOC dynamic in waters draining from the nine most important peat-fed catchments in the UK under climate change scenarios to the end of the 21st century.
University of Leeds & Chinese Scholarships Council
peatlands; hydrology; water; catchment management; soil; climate change; water quality; carbon cycling