Source-Based Modeling Of Urban Stormwater Quality Response to the Selected Scenarios Combining Future Changes in Climate and Socio-Economic Factors

Abstract

The assessment of future trends in urban stormwater quality should be most helpful for ensuring the effectiveness of the existing stormwater quality infrastructure in the future and mitigating the associated impacts on receiving waters. Combined effects of expected changes in climate and socio-economic factors on stormwater quality were examined in two urban test catchments by applying a source-based computer model (WinSLAMM) for TSS and three heavy metals (copper, lead, and zinc) for various future scenarios. Generally, both catchments showed similar responses to the future scenarios and pollutant loads were generally more sensitive to changes in socio-economic factors (i.e., increasing traffic intensities, growth and intensification of the individual land-uses) than in the climate. Specifically, for the selected Intermediate socio-economic scenario and two climate change scenarios (RSP = 2.6 and 8.5), the TSS loads from both catchments increased by about 10 % on average, but when applying the Intermediate climate change scenario (RCP = 4.5) for two SSPs, the Sustainability and Security scenarios (SSP1 and SSP3), the TSS loads increased on average by 70 %. Furthermore, it was observed that well-designed and maintained stormwater treatment facilities targeting local pollution hotspots exhibited the potential to significantly improve stormwater quality, however, at potentially high costs. In fact, it was possible to reduce pollutant loads from both catchments under the future Sustainability scenario (on average, e.g., TSS were reduced by 20 %), compared to the current conditions. The methodology developed in this study was found useful for planning climate change adaptation strategies in the context of local conditions.

Assessing the impact of socio-economic development and climate change on faecal indicator bacteria in the Betna River, Bangladesh

“…precipitation, discharge and temperature). This is in agreement with the findings of Borris et al (2016) and Sterk et al (2016). Changes in climatic factors do not affect microbial water quality negatively as higher precipitation increases discharge and runoff and thus dilute contaminants in the river (Rankinen et al, 2016), higher temperature increase the die-off of pathogens.…”

“…In this scenario, the population will grow rapidly and urbanisation is slow and poorly managed (Jiang and O'Neill, 2015). Such a world is struggling to maintain the living standards for a strongly growing population, [79] and economic goals are prioritized over environmental goals (Borris et al, 2016). We assume that in this scenario the proportion of population in the study area that has access to water supply and connection to sewers is not improved much.…”

“…Only few recent studies have applied a more consistent approach. For instance, Boris et al (Borris et al, 2016) used this approach to assess urban storm-water quality (focussing on suspended solids and heavy metals) and Zhuo et al (Zhuo et al, 2016) to quantify agricultural water availability. However, no quantitative study on surface water microbial water quality under socio-economic and climate changes scenarios has been published so far.…”

“…To develop adaptation and/or mitigation strategies, climate change impact assessment is important. The assessments are generally based on future scenarios, which reflect plausible future developments (Borris et al, 2016). In the present study, two scenarios (sustainability and uncontrolled) have been developed (details are in Section 5.2.3.3) that are based on the new approach developed for the IPCC (2014), which employs a new generation of scenarios (Moss et al, 2010) that include socio-economic scenarios (SSPs) and radiative forcing scenarios (RCPs) (Van Vuuren et al, 2011)to integrate future socio-economic development and climate change impacts.…”

“…Only a couple of recent studies have applied this approach. For instance, Borris et al (2016) applied this combined approach in assessing urban storm water quality (with respect to suspended solids and heavy metals)in Sweden and (Zhuo et al(2016) assessed changes in agricultural water availability for China. To our knowledge, our study together with Iqbal et al (2017) is the first study that applies a process based model to simulate the combined impacts of climate change and socio-economic development scenarios on microbial water quality in a river basin scale.…”