Best management practices (BMP)

Post construction BMPs are land management practices designed to minimize, treat, and control runoff before entering our rivers, lakes and wetland to improve water quality after a project is complete. MDOT utilizes both structural and operational BMPs to protect receiving waters during construction and post-project. Information on construction stormwater BMPs can be found in the Soil Erosion and Sedimentation Control Manual and the Drainage Manual.

Structural post construction best management practices

Structural post construction best management practices (PC-BMP) can be a physical device or a more natural approach to treat the runoff leaving the MDOT system. Both types are designed to trap or filter pollutants from runoff, or reduce runoff velocities and remain in place permanently. Structural PC-BMP examples include:

• Hydrodynamic separator: A manufactured device that removes sediment and floatable material from stormwater. Typically used in urban areas.
• Check dam: A device constructed across ditch lines used to reduce velocity of concentrated flow. Reducing velocity increases infiltration and allows sediment to drop out.
• Vegetated buffer strips: A method to reduce sheet flow velocities. Also useful to establish permanent vegetative cover and prevent sloughing and loss of seed.
• Riprap: A permanent cover of rocks and cobblestone used to stabilize stream banks. It is very effective in protecting soil from high velocity flows.
• Stormwater basin: A constructed depressed area designed to retain, detain, or infiltrate stormwater. The basin can have a permanent pond or dry out between storm events.
• Rain garden: A planted area used in urban settings where stormwater is directed for plant uptake, storage, and infiltration prior to entering the storm sewer system.

Operational best management practices

An operational best management practice (BMP) uses preventative actions that involve operational planning and source controls. Operational BMP examples include:

• Employee training: MDOT teaches their employees about stormwater management, potential pollution sources, and BMPs.
• Identify illicit discharges to storm drains: Field investigations and follow-up visits for suspected problems within the MDOT drainage system are used to pin point sources and implement corrective actions.
• Clean and maintain storm inlets, catch basins and drain channels: Inlets, catch basins and manholes are periodically inspected and cleaned out using a vacuum truck.
• Street sweeping: Removes sediment on roads before it enters local waters.