A “dry weather condition” is the period following at least 72-hours after the most recent precipitation event measuring at least 0.10 inches or more.
Dry weather screening involves locating, marking, and testing all stormwater outfalls in New Castle County. It is expected that approximately 3,500 outfalls will be screened as part of the permit process over the next 4 years. Stormwater outfall coordinates are recorded with a Global Positioning System (GPS), uploaded into a Geographic Information System (GIS) and the data is used to create a map of the system.
involves recording physical characteristics of the outfall such as size,
shape and location, and testing for the presence of pollutants if flow
is present in the outfall during a dry day. The purpose of the dry weather
screening is to identify any potential illicit discharges into stormwater
drainage system and to investigate and eliminate the sources of the illicit
weather sampling” is the collection of stormwater samples following
a dry weather condition, commencing within 20 minutes of the start of
precipitation with continued precipitation for 3.0 hours.