Drainage that passes sign-off.
Rational-method flows, detention storage and pipe / channel capacity ready for the approver. Built for civil and site engineers.
Trapezoidal channel
Manning's equation · concrete-lined
These figures come from the Tenselo engine. Every result Tenselo produces shows the inputs it used and the method behind it, so the work can be checked rather than taken on trust.
Why it matters on the job
Flows by the method
Rational-method peak flows that planners and councils accept.
Capacity proven
Manning's pipe and channel capacity with velocity in the non-scour band.
Detention that fits
Storage volumes sized to hold the storm and release at the permitted rate.
16 Stormwater & Drainage calculators
Every calculator in this category, by its reference code. Running them needs a Tenselo subscription — subscriptions open soon.
-
STM-001 Culvert Capacity (HDS-5)
Headwater by inlet & outlet control -- circular, box & arch (FHWA HDS-5)
-
STM-002 Riprap / Rock Armour D50
Rock size for scour protection at outlets, beds & banks (Isbash method)
-
STM-003 Kerb & Gutter Flow Capacity
Triangular gutter flow & spread (HEC-22 / Izzard): flow at a spread, or the spread a flow makes
-
STM-004 Open Channel Calculator
Manning's equation -> flow, velocity, depth & regime for open channels / swales
-
STM-005 Rainfall IFD Design Intensity
Interpolate BoM IFD intensity to your design duration / Tc (feeds the Rational Method)
-
STM-006 Rainfall Runoff Volume
Runoff volume from a design rainfall depth and catchment
-
STM-007 Rational Method Peak Flow
Stormwater peak discharge Q = C.I.A (ARR / council minor drainage), optional Bransby-Williams Tc
-
STM-008 Time of Concentration
Catchment time of concentration (Bransby-Williams) for the Rational Method
-
STM-009 Bioretention / Raingarden (WSUD)
Filter surface area for a bioretention basin / raingarden (%-of-catchment or Darcy flow-through)
-
STM-010 Detention Basin Outlet (Stage-Discharge)
Low-level orifice + overflow weir discharge from a detention/OSD basin at a given water level
-
STM-011 First-Flush Capture Volume
Water-quality first-flush volume to capture/treat from a catchment
-
STM-012 French Drain Calculator
Perforated-pipe capacity + soil infiltration + aggregate storage & drawdown
-
STM-013 On-Site Detention (OSD) Storage
Screening detention volume to hold developed runoff to the permissible site discharge (modified Rational)
-
STM-014 Soakwell / Infiltration Sizing
Soakwell number & emptying time for roof/paved runoff (AS/NZS 3500.3 + WA practice)
-
STM-015 Area Drain Spacing Calculator
Grate capacity + ponding + travel time -> max drain spacing & number of drains
-
STM-016 Stormwater Pump Pit
Inflow -> pump duty, total dynamic head, pit volume & cycle check
Register your interest
Tenselo is in private beta with Australian water professionals. Leave your details and we’ll let you know the moment plans go on sale — no obligation, and we won’t pass your details to anyone.