Soakaway Tunnel System
The Soakaway Tunnel System application was developed in collaboration with HAURATON, a renowned European manufacturer of comprehensive stormwater management systems.
This tool provides an intuitive solution for designers, enabling the selection of soakaway tanks according to the DWA-A 138E guideline in three simple steps. The selection process is based on choosing the tank’s location, determining its maximum width, the type of terrain (green or trafficable), and the height of the tank. Next, the user inputs the parameters of the catchment area, soil, the surface layer above the tank, and the depth of the groundwater.
The application’s integration with PANDa data ensures reliable results, which is crucial for effective stormwater management system design. The total volume of the tank consists of the soakaway tunnels as well as the surrounding gravel fill. As the user inputs various parameters, a diagram of the tank displays the updated specifications.
The application is available in Poland.
Calculating the parameters of tunnel drainage systems
To properly select a tunnel drainage tank, you must provide:
- maximum width of the tank in meters,
- type of terrain – green/traffic-loaded area SLW 30,
- module height – either DRAINFIX TWIN 1 with a height of 0.435 m or DRAINFIX TWIN 1/1 with a height of 0.870 m,
- gravel fill – this is the height of the gravel fill above the DRAINFIX TWIN drainage modules, where the user enters a value from 0.3 to 0.5 m (with a default value of 0.3 m)
- collection coefficient for the fill – this is the water capacity of the gravel fill expressed as a percentage. The range of values is from 30 to 40% (default value is 30%),
- soil filtration coefficient – value determined based on the analysis of soil conditions at the location of the tank defining the filtration velocity in m/s,
- catchment area parameters – area of partial catchments with runoff coefficients,
- groundwater level – depth of groundwater occurrence expressed in meters, measured from the designed ground level,
- tank cover with soil – size of the backfill above the seepage tunnels expressed in meters, measured from the designed ground level to the upper edge of the DRAINFIX TWIN seepage modules.
Then it is necessary to select a precipitation model, the suggested one to use is PANDa, although the user can also use other available models, such as Bogdanowicz-Stachy, Suligowski or Błaszczyk. The probability of precipitation, i.e. the frequency of calculated rainfall, can be specified in the range from 10% to 100%, which corresponds to a frequency from 1 to 10 years.
The user also has the option to select the level of the risk factor: low, medium, high or very high, which increases the calculated volume of the tank by 20%, 30%, 40% or 50%, respectively.
Results of selecting parameters of tunnel seepage systems
The application will provide the following results:
- parameters of the selected tank: height, width and length – in addition to the recommended tank configuration, the user can select other options that differ in width and length of the tank,
- calculated number of seepage tunnel rows,
- calculated number of seepage modules in one row,
- proposed configuration and number of inspection chambers – the user can select the configuration of the inspection chamber layout from 4 available options: alternately (recommended), on the central line, in the corner (option 1) and in the corner (option 2).
In addition, the user obtains information about:
- the most unfavourable rainfall duration – the value that, together with the rainfall intensity, gives the largest required tank volume,
- the rainfall intensity for the most unfavourable rainfall,
- the calculated tank volume – this is the volume calculated for the most unfavourable rainfall intensity and its duration, additionally, the graph can be used to check the required tank volume for other rainfall durations,
- the total inflow to the tank for the most unfavourable rainfall duration – the graph can be used to check the inflow for different rainfall durations,
- the outflow from the tank during the most unfavourable rainfall – the graph can be used to check the outflow from the tank for other rainfall durations,
- the outflow from the tank after the rainfall has stopped,
- the infiltration area for the selected tank – it consists of the bottom area and the wall areas up to half the height of the DRAINFIX TWIN modules,
- the time it takes to empty the tank expressed in hours.
Calculation results
Once you have made the correct selection, you can download the results as a PDF file and place them in your project.
Additionally, at any time you can directly contact the manufacturer of the solution to ask about the details of the selection, the accuracy of the calculations or request a quote for the solution.
