Post-construction stormwater best management practices, or BMPs, are natural and engineered systems that control the quality, rate, and volume of stormwater runoff from developed areas. Examples of BMP systems include rain gardens, pervious pavement, green roofs, rainwater harvesting systems, wet ponds, and constructed wetlands BMPs are important for several reasons. First, they are a requirement of our region’s Phase II stormwater permit. In addition, urban streams and waterways need protection, and BMPs protect water quality in developing areas and improve urban stream water quality in already developed areas. How do you know if a development project requires BMPs? All development projects, public and private, that are not served by combined sewers and disturb greater than one acre will require post-construction BMPs. Development projects that are less than one acre may also be required to provide post-construction BMPs to address nearby downstream problems. If your project does require BMPs, what steps are needed to design the BMP, and how will it be approved? This is where MSD’s new Stormwater BMP Tool Kit is handy. The Stormwater BMP Tool Kit is a section on the MSD website with information on the processes and tools that MSD and its co-permittees use to implement the Phase II permit requirements for post-construction BMPs. The tool kit was designed for developers and engineers who submit plans to MSD and its Phase II co-permittees. MSD created the tool kit because we want projects to go through the stormwater permitting process as smoothly and as quickly as possible. The tool kit provides answers to frequently asked questions on various post-construction BMP policies. It will also provide a clearinghouse of tools and details for designers who are submitting plans for review. Please keep in mind that the Stormwater BMP Tool Kit is a “living document” and will evolve over time. Users should anticipate that more information will be added to the tool kit in the next few months.