Assessing stormwater reduction through green infrastructure: RecoveryPark (Detroit, Mich.)

Illustration of proposed green infrastructure installation for RecoveryPark

Utilizing abandoned urban land for stormwater management

In many urban watersheds, including Detroit, MI, stormwater (excess rainfall or snowmelt that is not absorbed by the ground) can cause problems such as flooding, erosion, and sedimentation; property and habitat damage; harm to fish and aquatic organisms; and degradation of water quality. Throughout the metropolitan Detroit area, adverse impacts from combined sewer overflows into the Detroit River have increased interest in stormwater management and control. Swaths of abandoned urban land have been identified as potential locations for the installation of stormwater control measures to mitigate these flows including green infrastructure, which uses natural processes to reduce or delay peak flows and volumes of stormwater runoff by holding stormwater on-site, encouraging infiltration, and enhancing ET.

Typical site plan for RecoveryPark which incorporates green infrastructure

One of these locations, RecoveryPark, is a 40-acre area located about 2.5 miles northeast of downtown Detroit. Until recently, most of this city-owned land was vacant, but the nonprofit RecoveryPark entered into a five-year agreement with the city to purchase the land and convert it into an urban farm staffed by people with barriers to employment. Sustainable resource management, including stormwater management, is one of the goals for the successful implementation of RecoveryPark.

Study objectives

In collaboration with the Great Lakes National Program Office and the Office of Research and Development (two program areas within the U.S. Environmental Protection Agency), the Detroit Water and Sewerage Department (DWSD), and Lawrence Technological University, this study will assess how stormwater control measures affect flow and water-budget dynamics in an urban setting. To quantify changes in stormwater flows resulting from the installation of green infrastructure, this study will:

• Improve the understanding of rainfall, runoff, and infiltration in an urban environment through collection of high-resolution data at water-level monitoring and sewer-flow monitoring sites.
• Evaluate hydrologic and meteorological data to analyze the hydraulic performance of the stormwater control measures after implementation.
• Develop a model that simulates hydrologic processes, quantifies elements of the local water budget, estimates the effectiveness of stormwater control measures, and helps identify gaps in our understanding of the hydrologic processes affected by the stormwater control measures.

Monitoring of site hydrology and hydraulics is needed to fully understand the effectiveness of the stormwater control measures and to provide the performance data needed to design future phases of the proposed stormwater capture system envisioned for RecoveryPark.

Illustration showing the effect that green infrastructure could have on the urban water cycle at RecoveryPark. As shown by the relative sizes of the arrows, stormwater runoff and sewer flows may decrease; whereas infiltration, evapotranspiration, and groundwater recharge may increase. (Modified from a graphic by Don Carpenter and Rachel Pieschek, Lawrence Technological University.)

Study description

The area of RecoveryPark that is currently being redeveloped covers approximately 10 city blocks (0.07 mi²), which will include installation of green infrastructure (grass swales). Assessment of the effects of the stormwater control measures implemented at RecoveryPark will consist of three phases: 

1. The monitoring approach used at RecoveryPark includes 24 USGS groundwater monitoring wells instrumented to collect groundwater levels at multiple depths along with temperature and specific conductance. Soil moisture will also be measured at several depths. Seven in-pipe flow meters were installed by DWSD to monitor sewer discharge and a USGS weather station also was installed to collect data on precipitation and potential evapotranspiration.
2. The testing component includes a feasibility assessment of soil moisture content monitoring in the soils around RecoveryPark.
3. The modeling component will help identify the processes that have the greatest influence on the observed water balance and the uncertainty associated with them.

Benefits

This study addresses two major challenges facing the Great Lakes region: (1) mitigation of the adverse impacts of stormwater runoff, and (2) urban revitalization and approaches to reclaim abandoned land in urban settings. Stormwater control measures are often proposed to mitigate stormwater runoff impacts, yet in practice, the hydrologic and hydraulic response of various types of stormwater control measures have not been well documented. This study will provide information necessary to make informed decisions about the effectiveness of the RecoveryPark approach to both of these challenges.

The data collected during this study also could be used to design other stormwater control projects in urban areas around the Great Lakes. The methods developed here for an urban site complement current work focused on agricultural runoff and could be implemented in other study areas. The data produced also may improve the design and construction of stormwater control measures. Additional insights also might inform how aging urban infrastructure (for example, leaking sewer pipes) can affect conveyance of stormwater.

RecoveryPark case study timeline