Areas of application

StormTac Web is a user-friendly stormwater and recipient model, a tool for action planning (such as watershed management plans within the Water Directive) and design. By using the application, your investigations and design process will be carried out in accordance with the latest data and methods.

The quantity calculation of design flow and required flow detention volumes takes into consideration the design rain duration, rain return time, safety factors, updated runoff coefficients and current climate factors.

The quality pollutant calculation takes updated land use specific concentration data into consideration.

Typical applications include the following:

• Calculate stormwater flows, pollutant concentration and loads of more than 80 substances in the (sub)watershed outlets and from more than 100 land uses, by employing land use specific runoff coefficients and concentrations from a large amount of flow proportional data.

• Design transport conduits such as sewers, ditches, gutters and channels.

• Design and calculate both the treatment and/or flow detention effects of up to 10 optional BMPs (SUDS) in series. The design considers site specific parameters such as the share of submerged vegetation area, inlet pollutant concentration and flow detention volume. The following facilities can be designed in StormTac Web:

– dry ponds and underground basins with cassettes for flow detention
– wet ponds (ponds with permanent pool)
– constructed wetlands
– sedimentation basins (screens in ponds/wetlands or in the recipient water body)
– biofilters (bioretentions facilities, rain gardens)
– macadam ditches (infiltration trenches, open ditches fully or partly filled with macadam)
– swales (open grass ditches with a sloop less steep than 1:2)
– grass ditches (open grass ditches with a sloop of 1:2 or more steep)
– structural soil (macadam mixed with soil)
– dry ponds (ponds without permanent pool, with bottom outlet and dry between rain events)
– biochar (optional addition)
– underground retention basins
– macadam basins (soakaways)
– underground vault structures with filter (baffle boxes)
– drain inlets (filters located at catch basins, gully pot or well filters)
– oil separators (including lamella oil separators)
– filter strips (buffer strips)
– green roofs (designed as a land use)

• Estimate allowable pollutant loads on the recipient, the required load reduction and changed recipient concentrations to meet the water quality criteria of the receiving water.