Stormwater Quality Design Manual (May 2007) - City of Sacramento ...

GlossaryGeneral Industrial Activities Storm Water Permit (Industrial GeneralPermit) — the general NPDES permit adopted by the State Board which authorizesthe discharge of stormwater from certain industrial activities under certainconditions.Head (hydraulic head) — In hydraulics, energy represented as a difference inelevation. In slow-flowing open systems, the difference in water surface elevation,e.g., between an inlet and outlet.Hydrograph — Runoff flow rate plotted as a function of time.Hydrologic Soil Group —TYPICAL INFILTRATION RATESSoil Type(Hydrologic Soil Group) Infiltration Rate (in/hr)A 1.00 – 8.3B 0.5 – 1.00C 0.17 – 0.27D 0.02 – 0.10Infiltration rates shown represent the range covered by multiplesources, e.g. ASCE, BASMAA, etc.Source: Venture County Technical Guidance Manual for StormwaterQuality Control Measures, July 2002.Illicit Connection means any man-made conveyance that is connected to the stormdrain system without a permit, excluding roof drains and other similar typeconnections. Examples include channels, pipelines, conduits, inlets, or outlets thatare connected directly to the storm drain system.Illicit Discharge means any discharge to the storm drain system that is prohibitedunder local, state, or federal statutes, ordinances, codes, or regulations. The termillicit discharge includes all non storm-water discharges except discharges pursuantto an NPDES permit, discharges that are identified as "allowable" in NPDESMunicipal Stormwater Permits, and discharges authorized by the Regional Board.Impervious Surface — Any material that prevents or substantially reducesinfiltration of water into the soil.Infiltration means the downward entry of water into the surface of the soil.Infiltration rate (or infiltration capacity) is the maximum rate at which a soil in agiven condition will absorb water.Inspection means entry and the conduct of an on-site review of a facility and itsoperations, at reasonable times, to determine compliance with specific municipal orother legal requirements.Sacramento and South Placer Regions Stormwater Quality Design ManualMay 2007Glossary–3