Assessing Stormwater Nutrient and Heavy Metal Plant Uptake in an Experimental Bioretention Pond

Giampaolo Zanin,Maurizio Borin,Lucia Bortolini

doi:10.3390/land7040150

Abstract

With the purpose to study a solution based on Sustainable Urban Drainage Systems (SUDS) to reduce and treat stormwater runoff in urban areas, a bioretention pond (BP) was realized in the Agripolis campus of the University of Padova, Italy. The BP collected overflow water volumes of the rainwater drainage system of a 2270 m2 drainage area consisting almost entirely of impervious surfaces. Sixty-six Tech-IA® floating elements, supporting four plants each, were laid on the water surface. Eleven species of herbaceous perennial helophyte plants, with ornamental features, were used and tested. The early growth results of the BP functioning showed that nearly 50% of the total inflow water volume was stored or evapotranspirated, reducing the peak discharge on the urban drainage system. Among plants, Alisma parviflora, Caltha palustris, Iris ‘Black Gamecock’, Lysimachia punctata ‘Alexander’, Oenanthe javanica ‘Flamingo’, Mentha aquatica, Phalaris arundinacea ‘Picta’, and Typha laxmannii had the best survival and growth performances. A. parviflora and M. aquatica appeared interesting also for pollutant reduction in runoff water.

Highlights

The high rate of urbanization has resulted in a large increase of impervious coverage in the landscape which can reach a very high percentage of the urban surface
The total inflow volume in the bioretention pond (BP) was 245 m3, and the water volume leaving the pond as outflow was
It is interesting to note that only 10% of the total potential runoff volume gave rise to overflow volume, because during the examined period the events were mostly of medium-low amount, perfectly managed by the existing rainwater drainage system

Summary

Introduction

The high rate of urbanization has resulted in a large increase of impervious coverage in the landscape which can reach a very high percentage of the urban surface. Rainwater in the urban landscape is mainly directed into the municipal drainage system, creating serious problems in case of heavy rains, such as local floods, river inundations, etc., and reducing water availability and quality [3]. Some environmentally sustainable approaches to urban development have been proposed as an alternative to the traditional ones to better manage the runoff in urban areas [7,8,9,10]. BMPs include stormwater planting, open channels, porous pavements, etc., in addition to a set of overall site design strategies and highly localized, small-scale, decentralized source control techniques, known as Low-Impact Development (LID) systems in the USA [13,14]

Objectives

Methods

Results

Conclusion