Storm water design manual

In this week’s work session, the Council will discuss the revised Prince George’s County Storm Water Design Manual. The purpose of the County revising its Stormwater Design Manual is to be current with the newly adopted Sate Law that provides for the protection of our waterways through environmentally sound land development practices.

The County’s Stormwater Management Design Manual is a design manual with lots of technical information for the purpose of providing design guidance to developer engineers who are engaged in developing parcels of land within in Prince George’s County. The manual includes design criteria, computations methods, review and permitting processes, and construction inspection. The new design manual emphasizes Best Management Practices (BMP) through Environmental Site Design (ESD) methods. Some examples of Non Structural BMP’s are: green roofs, which may be one of the common residential roofing terms, permeable pavement, reinforced turf, disconnection of rooftop runoff, sheet flow to conservation areas, rainwater harvesting, submerged gravel wetland, landscape infiltration, infiltration berms, dry wells, microbioretention, rain gardens, swales, and enhanced filters. The ESD is the actual design practice.

The impact on the City is good. The City will be compliant through County oversight by DER and DPIE with the Maryland Department of Environment (MOE) mandated regulations such as the National Pollutant Discharge Elimination System (NPDES) and Watershed Improvement Program, Phase II (WIP2) that require the reduction of Total Maximum Daily Load (TMLD) – which require the reduction of phosphorous, nitrogen, and suspended solids from entering our local and national waterways from land development activities. Overall, the impact to the City is what State law mandates. All developments must and will follow the Maryland State Stormwater Regulations. The County was granted the authority from the State to oversee that the stormwater management law is followed. The County has only incorporated the State regulations into their design manual.