College Gardens Park

Rockville, MD

The City of Rockville contracted CPJ with the task of rejuvenating an aging community park in concert with providing Stormwater Management (flood control and water quality improvement) and Stream Restoration work to protect the 2,100 foot downstream receiving water, known as the College Gardens Tributary to Watts Branch. This heavily impaired stream drains a 158 acre, 42% impervious catchment; a mixture of residential and light commercial use with little SM control. 

The four primary goals for rehabilitation work included:
  • Increased park patronage and aesthetic improvement
  • Cost efficient renovation of the park to provide SM
  • Reduction of  bank erosion along the Tributary
  • Protection and enhancement of natural resources
CPJ developed three alternative concepts to determine the most effective balance for SWM control and park amenities, based on input from City staff and the community.  CPJ evaluated several alternatives including SR along the entire length, onsite pond creation, and off-site SM. The option chosen involved the construction of an extended detention wetland pond encompassing the area of the existing pond but three times in scale. The design included a sediment forebay, aquatic wetland bench and a direct feed of storm flow via a flow splitter from an adjacent 54” diameter storm sewer. The design provides 50% of the water quality volume and 100% of the channel protection goal at the park per MDE standards.
Specific goals for this project included a 42% percent reduction of sediment being generated by streambank erosion along with an 80% removal of total suspended solids (TSS). The stream work was completed in February, 2009 ahead of the park renovation which was completed in December, 2009; the project is being monitored to determine project success.
CPJ worked closely with Slater and Associates to coordinate the pond design as part of a new park master plan with additional and improved park amenities as well as protection of existing natural resources.  The end product is a functional SWM facility that is a centerpiece of the park and jewel of the City’s park system.
© 2010 Charles P. Johnson & Associates, Inc.