Introduction to Bioretention
Cory L. Horton, P.E.
This four hour
online course provides an introduction the integrated management practice of
bioretention. This course is intended for practicing engineers, and others,
who seek to gain knowledge to implement stormwater treatment using bioretention.
After completing the course the student will have a greater understanding of
when, where, and how to implement bioretention. The course content is based
on the Prince George's County Maryland publication The Bioretention Manual
Chapter 1 Rev. 2002 (31 pages). This publication introduces the reader
to bioretention, the critical processes of bioretention, different applications
of bioretention, and the factors involved with the design of bioretention.
This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course materials.
At the conclusion of this course, the student will understand the following concepts:
This course is
intended for practicing engineers, and others, who seek to gain knowledge to
the integrated management practice of bioretention.
Urbanization causes drastic changes in the biological, ecological, and hydrologic makeup of the land. Construction inevitably causes some degree of compaction of the soil, the loss of vegetation density, the creation of impervious surfaces, and the loss of bio-diversity. This in turn changes a watershed's response to precipitation. The most common effects are decreased infiltration and evapotranspiration and decreased travel time, which often significantly increases peak flows and total runoff volume.
Water quality is also affected by urbanization. Increased flow during runoff events and decreased flow during dry weather periods and have an adverse impact on local surface waters. The loss of infiltration, and hence base flow, can result in increased temperature and decreased oxygen available for aquatic life in streams. Natural channels also undergo morphologic changes such as channel widening, downcutting, and accelerated erosion when accommodating additional runoff volumes.
What is Bioretention?
a water quality and quantity control practice designed to use the properties
of plants, microbes, and soils to mimic the pre-developed hydrologic regime
and to remove pollutants from storm water. Bioretention is a Low Impact Development
(LID) Integrated Management Practice (IMP). Hydrologic functions of storage,
infiltration, and ground water recharge, as well as the volume and frequency
of discharges are maintained through the use of integrated and distributed micro-scale
stormwater detention and treatment areas.
How does the LID bioretention IMP compare to conventional stormwater management?
Conventional stormwater management (CSM) arose from the need to prevent downstream flooding. CSM aims to limit peak flow rates by using macro-scale treatment measures. CSM does not attempt to mitigate for the increased runoff volume created by additional imperviousness. Bioretention integrates ecological and additional environmental considerations, such as water quality and water quantity into the design.
Why is bioretention gaining Popularity?
The public and
stormwater professionals are becoming aware that conventional stormwater management
is not addressing all of the impacts of urbanization. Bioretention is merely
another tool to help minimize impacts to the environment.
The purpose of this course is to provide guidance on the design of stormwater projects using bioretention. You will be directed to the Prince George's County Maryland website to study The Bioretention Manual Chapter 1 (2001Rev. 2002, 4.19 MB, 31 pages, PDF file format).
You need to open or download above documents to study this course.
the potential to address impacts from urbanization that conventional stormwater
management (CSM) is currently neglecting. The use of this microscale integrated
management practices has the potential for improving water quality, reducing
runoff volume, improving aesthetics, and mimicking the existing hydrologic conditions
better than CSM.
For additional technical information related to this subject, please visit the following websites or web pages:
Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.