Frequent Questions about Urban BMPs
Urban BMPs and the Urban BMP Effectiveness Database
What is an Urban BMP?
How are the Urban BMP Tool results sorted and displayed?
How can I use the Urban BMP Tool in my stormwater program?
Who is the Urban BMP Effectiveness Database developed for?
Using the Database
How do I search for Urban BMPs?
How do I use the Help tool?
How do I use the field search?
My search returned zero results. What do I do now?
What is a boolean search?
Urban BMPs and the Urban BMP Effectiveness Database
What is an Urban BMP?An Urban BMP is a technique, process, activity, or structure used to reduce the pollutant content of a stormwater discharge. BMPs include simple nonstructural methods, such as good housekeeping and preventive maintenance. BMPs may also include structural modifications, such as the installation of bioretention measures. The BMPs in this BMP effectiveness database are primarily structural BMPs. BMPs are most effective when used in combination with each other, and customized to meet the specific needs (drainage, materials, activities, etc.) of a given operation. Visit the National Menu of Stormwater BMPs page to access additional information about Urban Best Management Practices.
How are the Urban BMP Tool results sorted and displayed?The results of your search are first sorted by the BMP and/or pollutants that you selected. They are then sorted by the quality of the study (with three check studies displayed before two check studies) and then by effluent concentration (from lowest effluent concentration to highest). Results for volume reduction are sorted by the percent volume reduction (highest to lowest) for each BMP.
How can I use the Urban BMP Tool in my stormwater program?The Urban BMP Tool can help both plan reviewers and designers understand the relative performance of certain BMPs in reducing specific pollutants and in reducing stormwater volumes (see Three Keys to BMP Performance). There are many factors that affect BMP performance, so you should not rely on the BMP performance obtained from one study to estimate the performance of a BMP. Rather, results from the Urban BMP Tool may be used to assess the relative performance of a class of BMPs and the ranges of pollutant reductions and volume reductions they might achieve. Users are urged to explore the details of individual studies available through this tool, including the statistical summaries and other information available on the design, location, soils and rainfall data that were studied.
Who is the Urban BMP Effectiveness Database developed for?
This database was designed to help watershed planners, modelers, private landowners and local, state and federal agencies learn about the relative effectiveness Urban BMPs in reducing specific pollutants of concern, and in reducing the volume of stormwater discharged to waterways.
Using the Database
How do I search for Urban BMPs?Search the database using either the Database Search or BMP Selection Tool. The Database Search allows you to quickly find a study or BMP using keyword and field searches or by searching by percent effectiveness or inflow/outflow concentrations. The BMP Selection Tool provides additional search features designed to help you locate a specific BMP based on a range of related criteria.
How do I use the Help tool?
The blue Help box on the right side of your screen is designed to help you easily and effectively find help specific to your needs and the page you are currently viewing. Use the search field to find glossary entries, related frequently asked questions and tips. Enter your search terms, use the check boxes to indicate which type of help you are looking for, and click the "Go" button. The results of your search will be displayed in the lower portion of the box.
How do I use the field search?
The Field Search keyword search option allows you to search for one or more words that are contained within specific fields in the database. Use the dropdown-menus to select the field you wish to search and enter the keyword or words in the text field. Use the right-hand dropdown menu if you are searching more than one field. Selecting AND will return records that contain all of the keywords entered. Selecting OR will return records that contain any of the keywords entered.
My search returned zero results. What do I do now?
If your search returned zero, or no, results, it means that no data in the database matched your exact search criteria. Try performing your search again using less stringent, or fewer, search criteria.
What is a boolean search?
Boolean searches employ the use of logic operators to create specific search queries. This search engine allows you to use the boolean operators "OR", "AND" and "NOT". Use "OR" if you wish to retrieve record that relate to one or the other, or all of your search terms. For example, the search query "Detention Basin OR Biofilter" will return all records that relate to "Detention Basin", all records that relate to "Biofilter" and all records that relate to both. Adding additional terms to an "OR" search tends to increase the number of results. Use the "AND" operator to find records that contain both (or all) of the search terms. Searching for "Detention Basin AND Biofilter" then, will return records in which both search terms are present. Records relating only to Detention Basin or only to Biofilters will not be returned.
Glossary
- Best Management Practices (BMPs)
Schedules of activities, prohibitions of practices, maintenance procedures, and other management practices to prevent or reduce the discharge of pollutants to waters of the United States. BMPs also include treatment requirements, operating procedures, and practice to control plant site runoff, spillage or leaks, sludge or waste disposal, or drainage from raw material storage.
- Concentration
The density or amount of a pollutant, or other constituent, in solution. This is commonly measured as the average density of pollutants and expressed as milligrams/liter (mg/l).
- Effluent Concentration
The average concentration of a pollutant or other constituent in stormwater runoff flowing out of the BMP.
- Inflow
The volume of stormwater that enters a BMP.
- Influent Concentration
The average concentration of a pollutant or other constituent in stormwater runoff flowing into the BMP.
- Other Reported Measures of Performance
These are measures other than effluent concentration. Other reported measures of performance can include percent removal or similar measures.
- Outflow
The volume of stormwater that leaves a BMP.
- Percent Removal
For a BMP, the percentage difference between the effluent concentration and the influent concentration for a given pollutant parameter. Not a reliable indicator of BMP performance (see "Why percent removal is a poor measure of BMP performance").
- Percent Volume Reduction
The percentage of volume reduced between the maximum influent volume and the maximum effluent volume for a given time period.
- Quality of Study
A three tiered system to give users a rough indication of the thoroughness of the monitoring information that study is based on. Three checks indicate that the study came from the International Stormwater BMP Database
, while studies with two checks indicate that the source was obtained from another location. See "Understanding the Information Presented About Each Study" for more information.
- Synonym
Different words with similar meanings and therefore can be interchangeable. For example, bioswale and biofilter have similar meanings.
- Total Load Reduction
An estimate of the BMP removal efficiency target for reducing the total amount or load of pollutants (sediment, nutrients, oxygen-demanding material, or other chemicals or compounds) in stormwater runoff.
- Volume
The amount of stormwater (expressed in liters) that enters or leaves a BMP.
