Selecting Sustainable Drainage Structures Based on Ecosystem Service Variables Estimated by Different Stakeholder Groups

Miklas Scholz,Julie Radet-Taligot,Vincent Uzomah,Suhad Almuktar

doi:10.3390/w5041741

Abstract

In times of recession, expert systems supporting environmental managers undergo a revival. However, the retrofitting of sustainable water structures is currently undertaken ad hoc using engineering experience supported by minimal formal guidance. There is a lack of practical decision tools that can be used by different professions for the rapid assessment of ecosystem services that can be created when retrofitting water structures. Thus the aim was to develop an innovative decision support tool based on the rapid estimation of novel ecosystem service variables at low cost and acceptable uncertainty. The tool proposes the retrofitting of those sustainable drainage systems that obtained the highest ecosystem services score for a specific urban site subject to professional bias. The estimation of variables was undertaken with high confidence and manageable error at low cost. In comparison to common public opinion, statistically significant differences between social scientists and the general public for the estimation of land costs using the non-parametric Mann-Whitney U-test were found. It was also surprising to find no significant differences in the estimation of habitat for species by civil engineers and ecologists. The new methodology may lead to an improvement of the existing urban landscape by promoting ecosystem services.

Highlights

Traditional drainage often creates flooding and pollution problems in the lower catchment
Most ecosystem service variables did relate well to the natural environment such as biologically diverse parks (41% of all sites) and not to the built environment like impermeable car parks (33% of all sites). This relationship reduces the number of sites suitable for retrofitting of most sustainable drainage systems (SuDS), as car parks usually only perform well with respect to three ecosystem service variables [moderation of extreme events (MEE), storm runoff treatment (SRT) and fresh water (FW); Table 1]
The introduction of a weighting system (Table 3) that puts bias towards what a drainage engineer would perceive as more important variables for SuDS could increase the suitability of sites for retrofitting

Summary

Introduction

Traditional drainage often creates flooding and pollution problems in the lower catchment. The implementation of sustainable drainage systems (SuDS; UK) [1], which has similar characteristics to best management practices (USA) and water-sensitive urban design (Australia) [2], can help to solve these problems. The philosophy of SuDS is to promote infiltration of (partially) treated runoff into the ground [1]. Most SuDS techniques support attenuation of runoff before entering the watercourse, storage of water in natural contours, infiltration of partially treated runoff into the ground and evapotranspiration of surface water by vegetation [3,4,5]. The traditional objective of SuDS is to reduce the negative impact of urbanization on the quantity and quality of surface runoff, while simultaneously increasing amenity and biodiversity opportunities, where possible. Ecosystem services can be integrated within water-sensitive urban design [2] and multi-functional land use planning to maximize wider value opportunities for the benefit of humans and the environment

Objectives

Methods

Results

Conclusion