The Performance Analysis of Two Relatively Small Capacity Urban Retrofit Stormwater Controls

Abstract

This paper details field investigations that were conducted on the performance of small capacity urban retrofit stormwater control measures. The objective of the two year study (2013)(2014)(2015) was to provide performance data on stormwater retrofits that could not be fully sized according to conventional standards due to space constraints. In many states performance credits are not granted to stormwater management controls that are not designed to manage regionally derived water quality volumes. In retrofit applications there may exist numerous limitations to conventionally sized systems such as limited rights of way, setback distances or existing utilities. The larger scale objective of green infrastructure implementation is to improve receiving water quality and therefore even undersized systems, to some extent, meet this objective.This study introduces data on two systems: an innovative bioretention design with a water treatment residual amended filter media and an internal storage reservoir; and an undersized linear subsurface gravel wetland sized to optimize both phosphorus and nitrogen removal. The systems were retrofitted into existing developed areas and were sized at less than the water quality volume due to limited space at each location. The bioretention system (IBSC) was constructed in a commercial area in the town of

Highly Resolved Rainfall-Runoff Simulation of Retrofitted Green Stormwater Infrastructure at the Micro-Watershed Scale

“…To avoid subverting the existing system, the stormwater structures must be accurately represented in the hydrological model. Recent studies related to retrofitted GSI measures in urban developments have recognized the lack of detailed information about the existing drainage system as the main obstacle in modeling and implementation [26][27][28].…”

Sustainability

“…High (median 75% or greater) sediment and metal removals were observed for both systems. Total phosphorus removal was higher than conventional bioretention systems and total nitrogen was reduced by roughly 20% for median effluent concentrations of 1.4 mg/L (Houle et al, 2017). Two constructed wetlands in Brisbane (Australia) were monitored for two to four years after construction showing that both effectively reduced nutrient concentrations (nitrogen and phosphorus) and provided effective habitat (Greenway, 2017).…”

A Survey of Trends and Developments in Green Infrastructure Research

“…Although peripheral to the wider notion, referring to "green" best management practices in urban areas as "green infrastructure" helps sustain ecological systems. It is clear, however, that the phrase "blue-green infrastructure" is used in an urban environment, with a focus on stormwater control as a key component in developing a sustainable, multifunctional city [9]. Blue-green architecture [10] refers to a smaller scale use of these elements in building design.…”