How Wetlands Affect Floods

Abstract

It is widely recognised that wetlands play an important role in the hydrological cycle, influencing groundwater recharge, low flows, evaporation and floods. This has led to policies being formulated world-wide to conserve and manage wetlands to deliver these key services, especially flood risk reduction. Generic statements have often been published about wetland hydrological services but the term "wetlands" covers many land types, including wet woodlands, reedbeds, peat bogs, fens, and salt marshes. Each of these wetland types can have a hydrological function that is subtly different, making it difficult to generalise the flood reduction services of wetlands. In this paper we focus on two example wetland types (upland rain-fed wetlands and floodplain wetlands) to demonstrate why there are differences in flood functions both within and between wetland types. Upland wetlands generally tend to be flood generating areas while floodplain wetlands have a greater potential to reduce floods.2 However, landscape location and configuration, soil characteristics, topography, soil moisture status and management all influence whether these wetlands provide flood reduction services.

Effects of landscape configuration on mapping ecosystem service capacity: a review of evidence and a case study in Scotland

“…Linear elements can greatly reduce runoff (Borin et al 2010) and in the UK the presence of individual trees and shelterbelts increases the infiltration capacity of grazed pastures (Marshall et al 2009). The effect of land cover depends however on the amount of rainfall and diminishes with increasing soil saturation (Lull Pisani et al (2013), Macfadyen and Muller (2013), Veres et al (2013), Bianchi et al (2013), Martin et al (2013), Rusch et al (2013), Mitchell et al (2014), Morandin et al (2014) f Svensson et al (2000), Kells et al (2001), Potts et al (2003), Kremen et al (2004), Bodin et al (2006), Williams and Kremen (2007), Ricketts et al (2008), Winfree et al (2009), Isaacs andKirk (2010), Kennedy et al (2013), Morandin and Kremen (2013), Rollin et al (2013), Bailey et al (2014), Stanley and Stout (2014) g de la Fuente de Val et al (2006), Dramstad et al (2006), Borin et al (2010), Kienast et al (2012), van Zanten et al (2014 h Castelle et al (1994), Bartley et al (2006), Ludwig et al (2007), Bu et al (2008), Lenka et al (2012), Yang et al (2012), Shi et al (2013) and Reinhart 1972;Calder 2007;Acreman and Holden 2013). In mountainous catchments the riparian z...…”

“…First, ES capacity is affected by the specific location of land cover types (e.g., Ricketts et al 2008;Acreman and Holden 2013). Examples include discrete classes (riparian vs. non-riparian) or distance between land cover and a specific feature (e.g.…”

Testing peatland water-table depth transfer functions using high-resolution hydrological monitoring data

“…Such deep water tables as found at 297 four monitoring points during our study suggest a potentially degraded peatland system at 298 these locations. Indeed the water table never came within 10 cm of the surface at any point 299 in time for these four points although regular saturation and the development of saturation-300 excess and near-surface flow during rainfall events is a typical characteristic of fully 301 functioning blanket peat (Acreman and Holden, 2013;Holden and Burt, 2003b). Thus the 302 surface moisture content of the peat at these four points may not have been strongly related 303 to the water-table depth and may instead have been more controlled by individual rainfall 304 episodes.…”

Mapping wetland loss and restoration potential in Flanders (Belgium): an ecosystem service perspective.

“…Apart from reducing economic damage caused by floods (see e.g., Bullock and Acreman 2003, Acreman 2012, Acreman and Holden 2013, Walters and Babbar-Sebens 2016, both natural and artificial wetlands could produce additional adaptation services as water buffer areas to ensure sufficient water supply for the production Ecology and Society 21(4): 46 http://www.ecologyandsociety.org/vol21/iss4/art46/ of food crops in hot and dry periods (e.g., Chester andRobson 2013, Downard andEndter-Wada 2013). Artificial wetlands in cities and urban areas will become more important to reduce heat island effects and to buffer heavy rain (e.g., Persson et al 1999, Sun et al 2012.…”