DDOT Green Infrastructure Standards
Washington, DC
AMT recently developed Low Impact Development (LID)/Green Infrastructure (GI) standards for the District Department of Transportation (DDOT). BMP types focused primarily on bioretention, permeable pavement, and tree space design to retrofit the District’s public rights-of-way. The new standards provide anyone developing in the public realm with the engineering guidance necessary to create beautiful and regulatory compliant stormwater solutions. Specialists from a range of disciplines including civil engineering, landscape architecture, soil science, and urban forestry were assembled into a LID Advisory Council to support AMT in this effort, and majors tasks included:
Data Collection: Data was collected both regionally and nationwide, to include literature review, phone interviews, and research into the effectiveness of LID features, compliance monitoring, and maintenance challenges. Some data was gathered through site visits and BMP inspections (case studies) with a photo log and inspection reports for existing BMPs that have been successful.
Literature Review: Data was separated by source, setting, climate, and context, to determine which would be most applicable for each BMP type based on details of each design approach, materials, construction techniques and long-term maintenance requirements.
LID/GI Standards: Standards, guidelines, special provisions and standard CADD details were developed. Drawings and specifications were prepared as supplements to DDOT’s Standard Drawings and Standard Specifications for Highways and Structures, and design guidelines were written as a supplement to the DDOT Design and Engineering Manual. An illustrative guidebook was also produced to present the practices of Green Infrastructure, in a format more broadly accessible to the public. The AMT team also reviewed previous designs and incorporated emerging technologies and research findings into the new standards. Deliverables included a Maintenance Program outline, BMP Performance Measures, BMP Fact Sheets, and BMP Checklists.
DDOT Program Support: After adopting the new standards, DDOT continued to engage AMT in their green infrastructure program. AMT helped review engineering designs for compliance with the new standards. AMT has also attended project development meetings at the Department of Zoning, and has performed training of in-house staff and others on green infrastructure.
