Maryland Heights and HR Green receive ACEC Grand Award
The Missouri chapter of the American Council of Engineering Companies (ACEC) recently honored the City of Maryland Heights and HR Green, Inc. with its Engineering Excellence Awards program. The chapter bestowed its Grand Award in the Sewer & Storm Water category for the 2011 Essex Avenue Improvements Project.
Prior to the project, Essex Avenue was a basic, unimproved roadway section with asphalt/chip-and-seal surfacing and open drainage. The project reconstructed the full length of Essex Avenue (approximately 1,900 feet) meeting the City’s residential roadway design standards with concrete pavement, integral vertical curbs, and an enclosed storm sewer system.
Most notably, Essex Avenue was one of the first roadway projects in St. Louis to satisfy the stringent Phase II stormwater regulations of the US Environmental Protection Agency (EPA), administered through the Metropolitan St. Louis Sewer District (MSD). These regulations require treatment of runoff from the roadway before discharge to natural waters, in order to meet pollutant removal goals, reduce channel erosion, prevent flooding and pass extreme flooding events.
Essex Avenue is in a residential area, and there was not sufficient room for traditional means of treating stormwater, such as detention ponds or rain gardens. Such methods would have required the acquisition and conversion of private lawns. HR Green addressed this challenge with the use of a proprietary system (CONTECH Vortechs® hydrodynamic separators) to remove floatable debris, oil and grease, and suspended solids. Hydrodynamic separator (HDS) units have been employed for many years in commercial development applications, such as parking lots, but their deployment in a linear roadway project was unusual when this project was being designed.