Citation:

Nissen, K., M. Borst, AND E. Fassman-Beck. Bioretention planter performance measured by lag and capture. Hydrological Processes. John Wiley & Sons, Ltd., Indianapolis, IN, 34(25):5176-5184, (2020). https://doi.org/10.1002/hyp.13927

Impact/Purpose:

This paper covers the performance of four bioretention planters in Hoboken, NJ. It describes factors leading to a fully-captured storm event. The time delay for the planters and factors that contribute to the length of the delay are outlined. The factors cover controllable and uncontrollable factors to consider in the design process. This paper will be of interest to the public, designers, local and state planners, academics, and EPA’s office of water.

Description:

Bioretention flow-through planters can manage stormwater with smaller space requirements or structural constraints associated with other forms of green infrastructure. This project monitored the hydrology of four bioretention planters at Stevens Institute of Technology from March 1, 2018 through August 8, 2019. Delaying runoff and capturing small rain events are often seen as benefits of bioretention systems. The water depth in the outflow and the volumetric water content near the inflow were measured. Rainfall characteristics were documented from an on-site rain gauge. This monitoring determined the time from the start of a rain event to the first outflow from each planter (lag). The initial moisture deficit (difference between pre-event volumetric water content and maximum measured volumetric water content), approximate runoff volume, and approximate runoff volume in the first half hour were analyzed to determine their effect on runoff capture and lag. During the monitoring period, 40% of observations had no measurable outflow. Logistic regression determined that initial moisture deficit and approximate inflow runoff volume were statistically significant in contributing to a fully captured storm. Despite the large hydraulic loading rate and concrete bottom, the planters demonstrate effective discharge lag, ranging from 5 to 1,841 minutes with a median of 77 minutes. Soil moisture and inlet runoff volume in the first half hour were significant in modeling the lag duration. These results represent a combination of controllable and uncontrollable aspects of green infrastructure: media design and rainfall.

URLs/Downloads:

Record Details: