The effect of climate change on urban drainage: an evaluation based on regional climate model simulations

Abstract

That we are in a period of extraordinary rates of climate change is today evident. These climate changes are likely to impact local weather conditions with direct impacts on precipitation patterns and urban drainage. In recent years several studies have focused on revealing the nature, extent and consequences of climate change on urban drainage and urban runoff pollution issues. This study uses predictions from a regional climate model to look at the effects of climate change on extreme precipitation events. Results are presented in terms of point rainfall extremes. The analysis involves three steps: Firstly, hourly rainfall intensities from 16 point rain gauges are averaged to create a rain gauge equivalent intensity for a 25 x 25 km square corresponding to one grid cell in the climate model. Secondly, the differences between present and future in the climate model is used to project the hourly extreme statistics of the rain gauge surface into the future. Thirdly, the future extremes of the square surface area are downscaled to give point rainfall extremes of the future. The results and conclusions rely heavily on the regional model's suitability in describing extremes at timescales relevant to urban drainage. However, in spite of these uncertainties, and others raised in the discussion, the tendency is clear: extreme precipitation events effecting urban drainage and causing flooding will become more frequent as a result of climate change.

A review of the potential impacts of climate change on surface water quality

“…For example, under a doubled CO 2 climate-change scenario the 1 in 100-year flood becomes a 1 in 10-year event for Canberra, Australia (Schreider et al, 2000). However, detailed hydrological modelling for urban areas continues to be confounded by a lack of high-resolution (space and time) climate-change scenarios (Grum et al, 2006;Wilby, 2007). Indeed, many climate models treat built areas as vegetated surfaces, whilst realistic simulations of localised, highintensity, summer precipitation events have yet to be realised (see Fowler & Ekström, 2009).…”

Understanding the Effects of Climate Change on Urban Stormwater Infrastructures in the Las Vegas Valley

“…Previous studies on climate change, Mailhot and Duchesne [20], Wernstedt and Carlet [22], Mailhot et al [30], Grum et al [35], He et al [36], and Brown [37] have suggested the replacement of the current design standard by a simple and robust method that includes the effects of climate change. However, these studies are limited for the following reasons.…”

Adaptation of Water Resources Management to Changing Climate: The Role of Intensity-Duration-Frequency Curves

“…The time-scales at which these events are described at are important, to assess whether the projections are relevant. Grum, Jorgensen, Johansen and Linde (2006) [28] concluded in their study of the impact of climate change on urban drainage that extreme precipitation events affecting urban drainage and causing flooding would become more frequent, therefore requiring changes in the design methodology for drainage systems.…”