2025 Updates to the International Stormwater BMP Database Complete

Jane Clary, F.EWRI

The International Stormwater Best Management Practices (BMP) Database is a publicly accessible repository for stormwater BMP performance studies that began in the mid-1990s. In 2024, ASCE-EWRI and The Water Research Foundation entered into a new partner agreement that will continue the long-term collaboration on the BMP Database into the future with ASCE-EWRI now assuming the lead role with support from Mile High Flood District and Villanova University as new co-sponsors. Members of EWRI’s Urban Water Resources Research Council and others are part of a steering committee leading the project into the future.

During 2025, the partners supported upload of significant new studies and data sets into the database and updated on-line statistical analysis tools. The database stores performance information for over 780 BMPs throughout the U.S. and several other countries with over 410,000 water quality records for over 500 pollutants for BMPs such as bioretention, grass swales, extended detention basins, wetland basins, permeable pavement, manufactured treatment devices and others. Academic researchers and local governments voluntarily submit performance studies to the database to collaboratively advance stormwater management practice to improve water quality and protect drinking water sources.

As of January 2026, the on-line dynamic data retrieval and statistical analysis tool that enables researchers to conduct their own queries for specific BMPs and pollutant types now has access to an additional 25,000 water quality records. These records were added to the desktop version of the database over the past five years but funding had not been available for update of the online tool prior to the new partner agreement. The statistical analysis tool provides information on the number of studies, boxplots, time series plots, summary statistics and results of various hypothesis tests. Additionally, the user can download the underlying data used to generate the on-line statistical analysis to conduct their own independent analysis. Through user-defined query criteria, users can answer questions such as “How well do extended detention ponds reduce fecal indicator bacteria?” or “What data are available to evaluate the effectiveness of bioretention media for removal of the vehicle tire-related pollutant 6PPD-quinone?” Example boxplots illustrating data available for these two questions are shown in Figures 1 and 2.

Figure 1
Figure 2

Figure 1. Boxplots Showing Influent and Effluent Results for Extended Detention Basins for E. coli

Figure 2. Boxplots Showing Influent and Effluent Results for Bioretention Media for 6-PPD-quinone (Underlying Data Source: City of Spokane, WA, submitted 2025)

The project team is now actively seeking BMP performance studies to upload to the BMP Database in 2026, particularly studies completed over the last six years (2019-2025). The project team is actively collaborating with several of EPA’s Stormwater Centers for Excellence to identify studies for upload. As an example, the Southwest Stormwater Center of Excellence led by the Desert Research Institute and the Southern California Coastal Water Research Project (SCCWRP) includes identification of BMP studies in the Southwest targeted for upload to the BMP Database. Other collaborative efforts include working with the National Municipal Stormwater Alliance to increase street sweeping performance studies in the database. Please contact Jane Clary ([email protected]) to learn more about submitting data. ASCE-EWRI is seeking additional co-sponsors and funding partners to support the database. If you organization is interested in becoming a co-sponsor, please contact Brian Parsons ([email protected]).

EWRI Committee Leadership:
Chair: Holly Piza, P.E., Mile High Flood District (Denver, CO)
Vice Chair: Ryan Winston, Ph.D., P.E., Ohio State University
Secretary/Treasurer: Virginia Smith, Ph.D., Villanova University
Past Chair: Robert Traver, Ph.D., P.E., Villanova University

Technical Contacts:
Jane Clary, Wright Water Engineers, Inc. (Data Submission)
Marc Leisenring, P.E., Geosyntec Consultants (Web Tools)