Above the ground water table to prevent possible ground water infiltration into the sewer system and 10 ft.
Nyc roof water detention.
Minimum and or per construction code away from building foundation.
Water performance standard including subsur face rooftop and stormwater recycling systems.
Porous open bottom detention facilities must be located a minimum of 3 ft.
These systems store and slowly release storm water to the sewer system detention or dispose of stormwater onsite retention through infiltra tion to soils below evapotranspiration and re cycling onsite.
These systems have an open bottom and can incorporate perforated pipe and stormwater chambers for added detention volume.
Installing a rooftop detention system is a low cost option that can help you meet the city s stormwater detention requirement.
Subsurface detention systems with infiltration capability provide temporary storage of stormwater runoff underground.
The department of buildings and the department of health.
Rooftop detention also known as a blue roof is designed to provide temporary storage and slow release of stormwater runoff.
It is a relatively simple concept that results in a controlled flow system of rainwater from the roof.
Represents a better rooftop option where a roof cannot handle the additional weight of a green roof.
The regulation of the cleaning and inspection of water tanks is provided by two separate new york city agencies.
This technique is most commonly used in dense urban areas where other methods of stormwater detention are impractical.
Provides equivalent stormwater detention to a green roof at a fraction of the cost.
Philip kraus ceo and owner of manhattan based fred smith plumbing heating notes that monitoring of rooftop water tanks falls under the purview of two agencies.
Systems are primarily designed with a gravel bed that stores water until it can infiltrate into the ground.
But a well engineered solution is essential.
As stormwater flows it sweeps up pollutants such as oils chemicals sediments pathogens and trash.
Hazen and sawyer recently designed a combination green and blue roof system for a building in new york city.
Rooftop detention systems or blue roofs temporarily store and gradually drain rainwater off a building s rooftop in order to slow the flow of stormwater into the city s sewer system when it rains.
Rather than being absorbed naturally into the ground much of new york city s stormwater eventually flows into storm drains or catch basins and from there into the sewer system.
