The Use of PCSWMM for Assessing the Impacts of Land Use Changes on Hydrological Responses and Performance of WSUD in Managing the Impacts at Myponga Catchment, South Australia

Muhammad Akhter,Guna Hewa

doi:10.3390/w8110511

Abstract

Personal Computer Stormwater Management Model (PCSWMM) was applied to investigate: (1) hydrological responses in the Myponga catchment as a result of land use changes; and (2) the possibility of adopting Water Sensitive Urban Design (WSUD) technologies (bio-retention cells) to manage resulting floods. Calibrated and validated models predicted the measured data with satisfactory accuracy and reliability. Different urbanization scenarios were tested. When the level of urbanization increased from 10% to 70%, mean discharge increased from 45% to 322%. Frequency of flood at 2-year Average Recurrence Interval (ARI) increased from 1 to 44 and frequency of floods at 100-year ARI increased from none to 8. At 70% urbanisation, trialled bio-retention facilities used as WSUD measures almost completely ameliorated 2-year ARI floods by reducing the frequency of such events from 44 to 2. Floods at smaller ARIs (2, 5, 10 and 20 years) were effectively managed by WSUD measures while floods at 50- and 100-year ARIs remained unchanged. The overall results improve understanding of the severity of the impacts of land use changes on the hydrology of a catchment and the ability of bio-retention cells to alleviate the risk of small to medium floods in the Myponga catchment.

Highlights

Growing populations are adversely impacting water resources at both a local and global scale
If it is assumed that climate change impact has not been significant within this short span of time, the observed trends suggest that land use change might have increased the fraction of impermeable surface area within the catchment, resulting in increased runoff volume and flow magnitudes
For the most part the Myponga catchment is characterised by suitable conditions, some parts of the Myponga contain fractured rock aquifers, which are not suitable for infiltration

Summary

Introduction

Growing populations are adversely impacting water resources at both a local and global scale. Urbanization is expanding in order to accommodate the increasing populations. The transition of a natural catchment into an urbanized catchment results in many environmental impacts. According to Elga et al [1] urban development is considered to be a source of pollution for water resources, while increasing flooding and threatening both people’s safety and the integrity of infrastructure on a broader scale. The severity of all these hydrological impacts can be dependent on the degree of urban development within a catchment [3]. The impacts of urbanization on the environment, in particular hydrological processes like flooding of a catchment, need to be quantified in order to set limitations on levels of permissible urban development [4]

Methods

Results

Conclusion