H2OMAP and InfoSWMM Sediment Transport Modeling


H2OMAP SWMM and InfoSWMM Sediment Transport Modeling

Sanitary and combined sewer systems can carry substantial loads of suspended solids (waste solids) which can accumulate and cause blockages thereby impairing the hydraulic capacity of the sewer pipes (by restricting their flow area and increasing the bed friction resistance). H2OMAP SWMM and InfoSWMM can simulate the transport and gravitational settling of (total suspended solids including grit) over time throughout the sewer collection system under varying hydraulic conditions. As long as flow velocity exceeds the critical/terminal velocity, H2OMAP SWMM and InfoSWMM assumes that the sewage flow has the capacity to transport all incoming . Deposited  particles are also assumed to be scoured and transported downstream when velocity of the sewage flow exceeds the terminal velocity. Settling starts when flow velocity falls below the critical velocity. In the model, transport of thet particles is governed by advection implying that the particles are transported at local flow velocity. 

The sediment transport modeling using H2OMAP SWMM and InfoSWMM  requires only few inputs, namely limiting flow velocity, particle settling velocity, and source node(s) and initial concentrations (in mg/l) at the source nodes. 

In order to specify the first two inputs (i.e., limiting flow velocity and particle settling velocity), the user should first select from the quality tab which in turn activates the editing tabs for particle settling velocity and limiting flow velocity. Specification of source node(s) and its/their initial concentration is similar to the method described above in relation to pollutant transport. The default values used by the model for limiting flow velocity and particle settling velocity are 2 ft/s and 0.1 ft/s, respectively.  User specified values over rid these default figures .
H2OMAP SWMM and InfoSWMM  deposition (in kg)  in pipes and  concentration (in mg/l) at manholes,  wet wells, and outlets are the outputs reported following successful simulation of  transport for a collection system.


Comments

Post a Comment

Popular posts from this blog

Orifice and Weir flow calculations

Note: Orifice and Weir Flow Computations The orifice flow calculation proceeds as follows: 1. Initially and whenever the setting (i.e., the fraction opened) changes, flow coefficients for both orifice and weir behavior are computed as follows: a. For side orifices: Define Hcrit = h/2 where h is the opening height. b. For bottom orifices: i. For a circular orifice, compute area over length (i.e., circumference) as AL = h /4. ii. For a rectangular orifice compute AL = h*w/(2*(h+w)) where w is the opening width. iii. Compute Hcrit = Cd*AL/0.414 where Cd is the orifice discharge coefficient. At step 1b, the critical head for the bottom orifice, where orifice flow turns into weir flow, is found by equating the result of the orifice equation to that of the weir equation Cd*Area*sqrt(2g)*sqrt(Hcrit) = Cw*Length*sqrt(Hcrit)*Hcrit or Hcrit = (Cd * Area) / (Cw/sqrt(2g) * Length) The value of Cw/sqrt(2g) for a sharp crested weir is 0.414.
Read more

SWMM 5 Error Messages

Engine Error Number Description ERROR 101: memory allocation error.                                                                                             ERROR 103: cannot solve KW equations for Link                                                                                   ERROR 105: cannot open ODE solver.                                                                                              ERROR 107: cannot compute a valid time step.                                                                                     ERROR 108: ambiguous outlet ID name for Subcatchment                                                                            ERROR 109: invalid parameter values for Aquifer                                                                                  ERROR 110: ground elevation is below water table for Subcatchment                                                         
Read more

EMC Washoff in SWMM5

Image
There are four steps to using EMC concentrations in your network: 1. Define your pollutant by adding a pollutant using the Data=>Quality=>Pollutant command : 2. Define the Land Use by using the Data=>Land Uses command or the Land Use Editor: 3. Define Buildup to be None by clicking on the None Tab: 4. Define the EMC Washoff concentration by clicking on the Washoff Tab: This is where you would add a GW concentration More: http://www.swmm2000.com/
Read more