Low-Impact Development (LID) in Coastal Watersheds: Infiltration Swale Pollutant Transfer in Transitional Tropical/Subtropical Climates

Aline Rech,Julio Cesar Rech,Jakcemara Caprario,Alexandra Rodrigues Finotti,Elisa Pacheco

doi:10.3390/w14020238

Abstract

The control of runoff pollution is one of the advantages of low-impact development (LID) or sustainable drainage systems (SUDs), such as infiltration swales. Coastal areas may have characteristics that make the implementation of drainage systems difficult, such as sandy soils, shallow aquifers and flat terrains. The presence of contaminants was investigated through sampling and analysis of runoff, soil, and groundwater from a coastal region served by an infiltration swale located in southern Brazil. The swale proved to be very efficient in controlling the site’s urban drainage volumes even under intense tropical rainfall. Contaminants of Cd, Cu, Pb, Zn, Cr, Fe, Mn and Ni were identified at concentrations above the Brazilian regulatory limit (BRL) in both runoff and groundwater. Soil concentrations were low and within the regulatory limits, except for Cd. The soil was predominantly sandy, with neutral pH and low ionic exchange capacity, characteristic of coastal regions and not very suitable for contaminant retention. Thus, this kind of structure requires improvements for its use in similar environments, such as the use of adsorbents in soil swale to increase its retention capacity.

Highlights

The worldwide growth of cities has caused significant problems for basic infrastructure systems, especially urban drainage [1,2]
The studied infiltration swale receives concentrations of inorganic and organic polthe treatment of their effluents, which may have contributed to the concentrations of lutants along with surface runoff
The swale exerts a good control of surface runoff and plays an important role in the Cd in groundwater

Summary

Introduction

The worldwide growth of cities has caused significant problems for basic infrastructure systems, especially urban drainage [1,2]. Sustainable urban drainage systems have been reported as very advantageous solutions for runoff control and they have been effectively applied in several countries such as France, the United States and Germany [6,7,8,9,10]. Infiltration swales are vegetated open channels that can treat and attenuate precipitation [11]. Such swales present simple constructive processes, are inserted into the urban landscape and provide rapid infiltration of runoff in roadways [12,13]. Surface runoff is a potential contaminant of groundwater due to the presence of metals, organic matter, nutrients, pesticides and emerging micropollutants [3,10,14]

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