Example of a vegetated swale
What are Best Management Practices?
The Environmental Protection Agency defines stormwater BMPs as "methods that have been determined to be the most effective, practical means of preventing or reducing pollution from nonpoint sources." In December of 2006 the Pennsylvania Department of Environmental Protection published The PA Stormwater BMP Manual. You might find the following BMP's useful for the parking lot redesign.
Pervious Paving with Infiltration Bed
Subsurface Infiltration Bed
Vegetated Filter Strip
Infiltration Berm & Retentive Grading