Description: This feature class contains WSDOT’s stormwater drainage inlets. A drainage inlet is a chamber or well allowing for the entry of surface runoff to a closed stormwater conveyance system. Inlet type is chosen based upon its hydraulic and interception capacity as well as depth of flow, grade, super-elevation, and placement.The majority of the data collected so far are within the Phase I and Phase II 2009 NPDES Municipal Stormwater Permit Areas.This feature class has eight subtypes: Catch Basin, Concrete Inlet, Drop Inlet, Dry Well, Grate Inlet, Manhole, Other, amd Unknown.
Description: This feature class contains WSDOT’s stormwater discharge points. A stormwater discharge point is the point at which WSDOT loses, or obtains, jurisdictional responsibility of concentrated stormwater from a constructed stormwater conveyance feature. This includes locations where stormwater infiltrates into the ground at the end of a constructed stormwater conveyance, or enters surface waters of the state through a constructed stormwater conveyance. The majority of the data collected so far are within the Phase I and Phase II 2009 NPDES Municipal Stormwater Permit Areas. Additional data were collected during stormwater retrofit review and mapping in Total Maximum Daily Load areas that are outside of the permit area.This feature class has five subtypes: Incoming, Land Surface, Managed System, Subsurface, and Surface Water.
Description: This feature class contains WSDOT’s stormwater ponds as points. There are various types of stormwater treatment ponds which provide treatment and flow control by containing excess runoff for a considerable length of time and then releasing it by evaporation, plant transpiration, or infiltration; or holding surface and stormwater runoff for a short period of time and then releasing it to a surface or stormwater management system. Stormwater pond points are located at the midpoint of the pond edge closest to the highway.The majority of the data collected so far are within the Phase I and Phase II 2009 NPDES Municipal Stormwater Permit Areas.
Description: This feature class contains WSDOT’s stormwater flow restrictors. A flow restrictor is a device such as an orifice or weir that restricts the volume of stormwater flow through or at the outlet of a structure. It may be associated with a “control structure” as part of a “flow restrictor system” (see Standard Plans B-10.40, B-10.60).The majority of the data collected so far are within the Phase I and Phase II 2009 NPDES Municipal Stormwater Permit Areas.
Description: This feature class contains WSDOT’s stormwater ditches.A stormwater ditch is a long, narrow excavation dug in the earth for drainage, having a top width less than 10 feet at design flow. This can include various linear conveyances constructed of rock, gravel, earth, concrete, asphalt, or other material using forms, machinery, etc. It can also include a convergence in gradients of impervious surfaces (e.g., in a parking lot) designed to concentrate and convey stormwater.The majority of the data collected so far are within the Phase I and Phase II 2009 NPDES Municipal Stormwater Permit Areas.
Description: This feature class contains WSDOT’s stormwater curbs.A curb is the raised edge or perimeter barrier of a roadway surface or impervious paved surface such as a parking lot, foot path, or bike path. This feature class contains only curb segments actively concentrating and conveying stormwater flows (i.e., a curb located at the high side of a super-elevated roadway will not convey stormwater flow and therefore will not be mapped).The majority of the data collected so far are within the Phase I and Phase II 2009 NPDES Municipal Stormwater Permit Areas.
Description: This feature class contains WSDOT’s stormwater concrete barriers.Stormwater concrete barriers are barriers or walls, such as single-slope or K-barriers, which concentrate and convey stormwater flows, even if they were not designed or installed with the primary intent of being a conveyance. This feature class only contains concrete barrier segments actively concentrating and conveying stormwater flows (i.e., a barrier located at the high side of a super-elevated roadway will not concentrate and convey stormwater flows and therefore will not be mapped).The majority of the data collected so far are within the Phase I and Phase II 2009 NPDES Municipal Stormwater Permit Areas.
Description: This feature class contains WSDOT’s stormwater artificial paths. An artificial path is used to represent flow through a dispersion area, roadside slope polygon, or stormwater pond polygon when there is no other conveyance feature from the inlet to outlet structure. It is also used for areas where stormwater flow is briefly dispersed to sheet flow from the end of a conveyance and then concentrated again by another downstream conveyance prior to discharge. These paths are important for maintaining connectivity of the stormwater system GIS model. The majority of the data collected so far are within the Phase I and Phase II 2009 NPDES Municipal Stormwater Permit Areas.