Lay out a gravity sewer network from the lots it serves. The studio accumulates equivalent population down each line, converts it to ADWF, peak dry weather flow with the population peaking factor and peak wet weather flow with infiltration and inflow, then checks every reach with Colebrook–White hydraulics for capacity, depth ratio, self-cleansing tractive force or minimum grade, velocity, cover, manhole spacing, drops and obvert matching — and can design the invert levels and pipe sizes for you, with a plan, long section, flow chart, 3D view, calculation sheets and Excel.
Scope & limitations
Preliminary sewer design for study and feasibility, in the manner of WSA 02. Adopt the water agency's loading and design criteria and have the design checked by a qualified engineer.
What the Sewer Design Studio does
Each manhole carries the lots it serves (converted to equivalent population), any external population and its catchment area for infiltration. Population and area accumulate down the network; ADWF comes from the per-EP flow, PDWF from the population peaking factor and PWWF adds groundwater infiltration and rainfall-dependent inflow per hectare.
Each reach is analysed with the Colebrook–White equation for a slimed pipe: full-bore capacity, the part-full depth and velocity at PWWF, and the tractive force at PDWF for self-cleansing. Checks cover capacity, depth ratio, self-cleansing (tractive force or the minimum grade for the pipe size), maximum velocity, cover in verges and roads, manhole spacing, the drop through each manhole and obvert matching.
One button designs the invert levels from the top of each branch — cover first, then the larger of the ground fall and the self-cleansing grade, with the manhole drops — and another sizes the pipes for capacity.
Output: a reticulation plan, a long section with the PWWF water surface and an invert and cover table, a flow chart by reach, a 3D view, PDF calculation sheets, A3 drawings and Excel.