ASI Analysis Tools



Some of the tools

we use...

  • DAT
  • TAP
  • FLOW 3D
  • SWMM





Our Analysis Basis

ASI has extensive experience in the computational modeling of the flows in water transmission/distribution systems, sewers and tunnels, pumping stations, forcemains, and the liquid and sludge streams at water and wastewater treatment plants (WWTPs).  The engineers at ASI are experts in this field and have successfully provided services on projects including the design of pumping stations, regulator, metering, control, valve and gate structures, and pipelines for water, wastewater and sludge. Also, ASI has analyzed transients and surges in existing and proposed tunnels, relief sewers and forcemains, and has developed operational control strategies and designed surge control facilities for these systems.


  • Hydraulic transient analysis and design of surge control facilities for capture/transport tunnels
  • Wastewater collection system studies with modeling using SWMM and TAP
  • Dye-dilution testing of sewage flow meter accuracy

Water Supply

  • Hydraulic transient analysis and design of surge control facilities for water transmission pipelines
  • Water transmission and distribution system modeling using EPANET and other programs
  • Water reservoir modeling using FLOW-3D

Flow Meter Network Data Analysis Tool (DAT)

The Data Analysis Tool (DAT) is

a database and analysis program that allows the user to create and maintain a complete and high quality data set for all typical flow meter types.   DAT offers the following unique meter network data management features.

  • Imports depth, velocity, and flow rate data
  • Automates and documents repair of missing/questionable meter data
  • Displays and allows graphical review, repair, and processing of meter data
  • Repair tools include: correlations, rating curves, interpolations between data drop outs, and dry weather pattern substitution
  • Statistically identifies dry weather days
  • Calculates dry weather patterns
  • Generates customizable reports for periods of interest (e.g. months)  and storm events
  • Reports peak HGLs, flow rates, and volumes (total and incremental for meter districts)

Transient Analysis Program (TAP)

The Transient Analysis Program (TAP) is


a state-of-the-art computational hydraulics program that simulates steady-state, gradual time-varying, and rapidly-varying flow conditions under both open channel and closed conduit flow regimes in a system of channels/conduits.  With TAP, transitions can freely occur between open channel and closed conduit conditions even under rapidly-varying flow conditions.  TAP properly simulates the open channel and pressurized wave fronts that can result in a system of channels/conduits from opening/closing gates, turning pumps on/off, raising/lowering of gates and rapid filling.  TAP can simulate open channel hydraulic conditions in steep, mild and adverse conduits.


TAP is useful in analyzing water supply, storm water, drainage, irrigation, combined sewer, and sanitary sewer systems.  TAP does an excellent job of calculating detailed steady-state gradually-varied flow profiles through channels/conduits and water/wastewater treatment facilities.  TAP can be used to simulate flood routing in open channel/conduit systems.   TAP also can be used to evaluate operation and control schemes, including real-time control schemes.


  • TAP is set-up and ran using a graphical user interface. 
  • The system of conduits is defined by junctions that  are connected by links that can be: pipes, valves/gates, pumps or weirs.
  • Boundary conditions are specified at junctions and may include fixed or time-varying flow inputs, flow withdrawals, or water surface elevations.
  • Storage is included at junctions, and junctions can be specified to be vented (allowing air entrance), or not vented.


ASI Dye-Dilution (ASIDD)

Over the years, ASI has developed the dye-dilution technique

for flow rate verification.  Dye-dilution testing is a detailed procedure that combines field, laboratory and analytical procedures to compute flow rate based on the dilution of a fluorescent dye at non-visible concentrations.  

ASI has developed an in-house software program called ASI Dye-Dilution (ASIDD) to streamline data collection and processing during dye-dilution testing.  ASIDD provides a means for data to be simultaneously collected, graphed, and reviewed.  The software also allows for real-time test troubleshooting, repeatable and consistent analysis methods, and test error analysis. 

ASIDD is used to calculate flow rate through a sewer reach during a discrete time interval which is compared to flow rate determined from a meter, pump curves, wet well drawdown times, or other flow rate measurement technique.  This comparison is used to determine an adjustment factor which is generated in ASIDD which can easily be tracked over the lifespan of the flow measuring instrument.


ASI has licensed software, FLOW-3D, 

to conduct three dimensional computation fluid dynamic modeling. FLOW-3D is a powerful and highly-accurate multi-physics computational fluid dynamics (CFD) package that we use in-house to conduct analyses on complicated fluid problems that cannot be identified with one-dimensional calculations.  This is a specialized tool that can be used for many situations from determining headloss in a complex structure, settling characteristics in a tunnel or tank, determining the effects of baffles in a flow stream, flow tracer in reservoirs or other treatment structures among countless other applications.  ASI has utilized the CFD on many projects for our own internal use and specifically on the following projects.