Water Quality Improvements at Oxford Crossing

As part of Montgomery County’s responsibility to ensure the proper functioning of stormwater management facilities and reduce pollutants in our local streams and rivers, the County’s Department of Environmental Protection will retrofit an existing stormwater management facility (dry pond) into a Submerged Gravel Stormwater Management System (SGSMS) in the Oxford Crossing Community. The project location drains to Turkey Branch, which drains to Middle Rock Creek, which flows into Rock Creek, and eventually into the Potomac River. This improvement will significantly improve water quality and address failing infrastructure.

PROJECT DETAILS

Submerged Gravel Stormwater Management System (SGSMS)

Typical SGSMS at full maturity, in the Spring/Summer.

Typical SGSMS, immediate post-construction.

Typical SGSMS at full maturity, in the Winter.

Retrofitting the existing dry pond to a Submerged Gravel Stormwater Management System (SGSMS) will add water quality treatment function while expanding the facility’s stormwater storage volume to reduce flows downstream.

  • The existing dry pond provides limited water quality treatment.
  • Various components within the existing facility are failing and in need of maintenance or replacement.
  • Structural deficiencies include sediment accumulation, failing and rusting pipes, no trash rack to collect floating debris, and drains clogged with debris and sediment.
  • There is no direct access to suitably maintain the facility.
  • Retrofitting the existing dry pond facility to a SGSMS will improve facility function by addressing structural deficiencies within the current stormwater management system to provide sediment and pollutant reductions before stormwater enters the Potomac River Watershed.
  • The SGSMS retrofit will also provide increased detention capacity to better manage stormwater volume during heavy rain and storm events, reducing instances of flooding and improving community resiliency.
  • Replacing rusting metal infrastructure with a concrete riser will extend the facility’s longevity and help reduce future maintenance requirements (managed by the County).

The retrofit will be achieved through the following design elements:

  • Excavating the existing sloped pond bottom
  • Re-grading the existing pond side slopes to increase active stormwater storage volume.
  • Replacement of metal structures with concrete structures.
  • Removalof two rusting metal pipes that have reached the end of their service life and replacement with concrete pipes.
  • Installation of gravel media.
  • Construction of a feature at the pond inlet to capture sediment and trash, which is then removed during regular maintenance.
  • Establishment of permanent access to the facility from Connecticut Avenue.
  • Installation of native vegetation to support water quality treatment and improve overall aesthetics.
  • Construction is currently scheduled to begin in January 2025 and will last approximately five to six months. Most excavation and truck traffic will occur within an 8-10-week window in the middle of construction.
  • Community members will have the opportunity to review concept plans before construction at various points in the planning process and will be invited to walk the site with the GreenVest team before and after construction.
  • The project must pass rigorous review processes led by County, State and Federal agencies developed to maximize facility safety, minimize environmental impacts and ensure modern design standards are met.
  • Temporary staging and construction access and parking will occur along Connecticut Avenue.
  • GreenVest will work to relocate the existing maintenance access feature from where it currently exists within the Oxford Crossing community to Connecticut Avenue.
  • Tree removal will be limited to a small street tree and several evergreens along Connecticut Avenue to provide construction access to the site. Any trees removed will be replaced post-construction with community input on tree selection.
  • The project must pass rigorous review processes led by County, State and Federal agencies developed to maximize facility safety, minimize environmental impacts and ensure modern design standards are met.

Submerged gravel stormwater management systems (SGSMS) are small-scale filters that mimic natural hydrologic and ecological processes to capture and treat stormwater runoff, filtering sediment and pollutants through a combination of wetland plants and gravel media. The systems are designed to capture and treat 1” of rainfall over a 24-hour period.

PROJECT UPDATES

News & Updates

Check back regularly for up-to-date project news and information, including construction alerts and opportunities to meet with the project team.

December 4, 2023 Community Meeting Recap
GreenVest hosted a second, virtual public meeting on December 4th to provide residents with updates on the stormwater facility retrofit project at Oxford Crossing.
November 2023 Community Update
PROJECT UPDATES Upcoming Virtual Community Meeting Join the Greenvest team on Monday, December 4, at 7 p.m. for a virtual meeting with Oxford Crossing
Virtual Community Meeting w/GreenVest, 12/4 @7pm
Join us for an opportunity to learn more about water quality and stormwater management improvements in the Oxford Crossing Community. Community Meeting Details Date:

PROJECT RESOURCES

Learn More

Frequently Asked Questions

Montgomery County holds a Municipal Separate Storm Sewer System Permit (“MS4 Permit”) issued by the Maryland Department of the Environment under authority delegated from the U.S. Environmental Protection Agency which imposes several water quality improvement requirements and goals on the County. This project will support the County’s efforts to achieve water quality requirements by addressing failing stormwater infrastructure and retrofitting a dry stormwater management pond.

  • The existing stormwater management facility serving the Oxford Crossing community has various deficiencies including rusting metal structures; decaying and eroding outlet pipes; no trash rack to catch floating debris; sediment accumulation at the facility’s drainpipe which blocks water flow and decreases pipe capacity; and no direct maintenance access to the facility. The proposed work will address these deficiencies.
  • The existing facility does not treat or in any way address water quality. The proposed Submerged Gravel Stormwater Management System (SGSMS) will trap sediment, nutrients, and other pollutants, thereby improving water quality.
  • Construction is currently scheduled to begin in Winter 2025 and will last approximately five to six months. Most excavation and truck traffic will occur within an 8-10-week window in the middle of construction.
  • Temporary construction access, staging, and parking will occur along Connecticut Avenue.
  • Once construction is complete, GreenVest will work to relocate the existing maintenance access feature from where it currently exists within the Oxford Crossing community to Connecticut Avenue.
  • All project work will follow strict soil erosion and sediment control requirements set by both the State and the County to minimize dust during construction.
  • Techniques such as wetting throughout the day, street sweeping dust screens, and stabilized construction entrance will be utilized to minimize dust and dirt during construction.
  • There will be some noise disruption during construction. In addition to compliance with standards set forth in the Montgomery County DEP’s Noise Control Law, GreenVest will use noise mitigation techniques to minimize impacts to adjacent property owners. Night work is not anticipated.
  • Most of the excavation work will occur below foundation elevations, which will make vibration unlikely for adjacent residents. However, it is possible that homeowners within 50 feet of the project could feel minimal vibration during excavation.
  • GreenVest provides a 1-year guarantee on the completed project which includes providing any required maintenance. After this time and into the future Montgomery County will be responsible for structural maintenance of the SGMSM facility, including:
    • Removal of sediment accumulation and debris, if necessary, after major storms.
    • Semi-annual removal of sediment, invasive plant species and replanting in any poorly established areas.
    • Removal of accumulated vegetation and replanting, if necessary, every 2-3 years.
  • The HOA will continue to be responsible for non-structural maintenance in this area, as it is currently.
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For a full list of FAQs, click here.

PROJECT CONTACTS

Contact the Project Team

Residents can sign up to receive email updates and/or text alerts and ask questions of the project team through the contact information below and the form to the right.

Email :

info@GreenOxfordCrossing.com

Translation Services :

If you would like project information in another language or format, or if you require the services of an interpreter, please contact hilary@GreenOxfordCrossing.com.