Showing posts with label SWMM5. Show all posts
Showing posts with label SWMM5. Show all posts

Tuesday, July 4, 2023

SWMM 5.2.3 Inlet Workflow from the Help File

SWMM 5.2.3 Inlet Workflow from the Help File

The process of conducting an inlet analysis using the Storm Water Management Model (SWMM) is quite thorough and systematic. Here, we provide a detailed expansion of the general workflow you've presented, demonstrating how to apply it to a simple street and sewer drainage system:

  1. Layout both the street and sewer networks: Begin by designing and sketching your street and sewer networks. This involves determining the locations of your roads, open channels, and sewer lines, as well as their interconnections. This layout forms the fundamental skeleton for your model. You can use GIS (Geographical Information System) data or manual drafting to aid in creating the layout.


  2. Assign subcatchment runoff and user-defined inflows to individual street nodes: Next, designate the runoff from surrounding land areas (subcatchments) and any user-defined inflows to the nodes within your street network. Runoff is the water flow that occurs when soil is infiltrated to full capacity and excess water from rain, meltwater, or other sources flows over the land. User-defined inflows could be point sources of water other than the subcatchment runoff. This assignment takes into account how rainfall will be distributed in the area and which roads it will likely flow down.


  3. Create a collection of Street cross-sections: Design a collection of street cross-sections. These cross-sections represent a vertical slice through the street, showing elements such as the roadway, sidewalks, and gutters. The cross-sections provide a detailed view of the street’s shape and slope, which are key factors influencing how stormwater flows.

  4. Assign specific Street cross-sections to individual street conduits: Each conduit in your street network should be assigned a specific cross-section from your collection created in the previous step. The assignment should accurately represent the actual structure of the street at the conduit's location.


  5. Create a collection of Inlet designs: After dealing with the streets, focus on creating a variety of inlet designs. These inlets are structures that allow stormwater to enter the drainage system from the street surface. They can have different designs depending on their size, shape, and the specific conditions they will be handling.


  6. Assign specific Inlet designs to selected streets: Once you have a collection of inlet designs, assign them to the specific streets within your network. Inlet placement depends on factors such as street slope, expected water flow, and city planning guidelines.


  7. Set appropriate analysis options and run a simulation: Configure the parameters for the SWMM analysis according to the objectives of your study, including the simulation duration, time steps, and any specific routing or runoff methods. Then, execute the simulation, which will use the SWMM algorithms to model how stormwater will flow through your designed network.


  8. Review the simulation results to see if flow spread and depth values are acceptable: After the simulation has run, assess the results. Examine key outputs like flow spread (the width of water flow on a street) and depth values at each inlet and node. Ensure that these values are within acceptable ranges as defined by your design standards. If the results are not satisfactory, you may need to revisit and revise your design, which may include altering the street layout, changing the assigned cross-sections, or modifying the inlet designs.

This detailed procedure offers a step-by-step guide to designing and analyzing a basic street and sewer drainage system using SWMM. It's essential to remember that real-world scenarios may require additional steps or considerations, depending on the specificities of the site, climate conditions, and regulatory requirements.

Inlets from the SWMM 5.2.3 help file

 Inlets from the SWMM 5.2.3 help file 

The Storm Water Management Model (SWMM) is a powerful hydrological simulation program, used for planning, analysis, and design related to stormwater runoff, combined sewers, sanitary sewers, and other drainage systems. This software models various components of these systems, including pipes, channels, and inlets. When modeling inlets with SWMM, you should consider the following key concepts:

  1. Inlet Assignment: Inlets are assigned to conduit links that represent either streets or open channels. In this context, conduits are used to represent the physical structures that carry flow in the drainage system, such as pipes, channels, and tunnels. Therefore, each inlet, representing a point of entry for stormwater into the system, needs to be linked to a specific conduit.


  2. Inlet Type and Conduit Cross-section: The type of inlet you choose is determined by the cross-section of the conduit it is assigned to. For instance, curb and gutter-type inlets are designated to conduits with a street cross-section. Meanwhile, drop inlets are used with conduits that have either a rectangular or trapezoidal cross-section. Alternatively, custom inlets can be placed in any type of conduit, providing greater flexibility in modeling.


  3. Node Assignment: Each inlet is assigned to a node, typically part of a sewer line, that will receive the flow captured by the inlet. A node represents a junction point in the system where the flow may divide or combine.


  4. Multiple Inlets: Multiple inlets of the same design and receptor node can be assigned to a single conduit. This is particularly useful when modeling two-sided streets. For on-grade placement, the flow captured by each inlet is determined sequentially, which means the flow approaching the next inlet in line is the bypass flow from the inlet before it.


  5. Inlet Operation: Users can determine whether an inlet operates on-grade, on-sag, or let SWMM decide based on the street layout and topography. An on-grade inlet is situated on a continuous grade, while an on-sag inlet is located at a sag or sump point. The latter is an area where all adjacent conduits slope towards the inlet, leaving no place for water to flow except into the inlet.


  6. Flow Capture: Flow capture for on-grade inlets is determined by the approach flow seen by the inlet. However, for on-sag inlets, it is a function of the depth of water at the sag point node. This distinction is crucial for correctly modeling the flow behavior.


  7. Clogging and Flow Capture Restriction: Inlets can be assigned a degree of clogging and a flow capture restriction. These factors account for potential real-world conditions that may impede the flow into the inlet, providing a more accurate representation of the system’s functionality.

Thursday, March 16, 2023

SWMM 5 Pond Infiltration Techniques

 SWMM 5 Pond Infiltration Techniques

Storm Water Management Model (SWMM) 5 provides multiple methods for simulating pond infiltration in urban drainage systems. These methods offer flexibility in addressing various scenarios and can be adapted to specific project requirements. Below are three approaches for modeling pond infiltration in SWMM 5:

  1. Pump Type 4: This classic SWMM 4 solution involves using a Pump Type 4 to simulate the relationship between pond depth and infiltration rate. While this approach has been utilized for a long time, it may not be the most efficient or intuitive method for newer users or for those who want to take advantage of SWMM 5 features.

  2. Seasonal or Monthly Evap Factor Adjustment: In this approach, users can modify the SWMM 5 Evap Factor for a pond to incorporate seasonal or monthly variations in infiltration loss. By simulating infiltration loss as an increase in Pan Evaporation, this method allows for more accurate representation of temporal changes in infiltration rates and offers an alternative to using pumps.

  3. SWMM 5 Outlet Structure: The latest SWMM 5 Outlet structure provides a more versatile solution for modeling pond infiltration. Users can create either a functional or tabular relationship to simulate infiltration loss as a function of pond depth. This method offers several advantages, including:

    • The ability to use multiple functions for more complex scenarios
    • A more intuitive representation of the infiltration process compared to using a pump
    • Additional features added by Lewis Rossman that enhance the flexibility and capabilities of the outlet structure

Experts such as Mike Gregory have also provided suggestions for modeling infiltration loss from ponds in the OP:ENSwmm.oprg Knowledge database. It is recommended to explore options 2 and 3, as they provide more advanced functionality and better representation of the infiltration process compared to using a Pump Type 4. By employing these techniques, users can effectively simulate pond infiltration in SWMM 5, leading to more accurate and reliable results for urban drainage system management and planning.

Friday, January 27, 2023

XPSWMM to ICM SWMM or ICM Process Pathways

 


#ProcessDescription
1Technical details about how XPSWMM models a featureThis process involves understanding the specific algorithms, equations, and data inputs used by XPSWMM to model different features of an urban drainage system, such as hydrology, hydraulics, and water quality. This includes understanding how XPSWMM calculates runoff, infiltration, evaporation, and other hydrologic processes, as well as how it models the flow and routing of water through the drainage system.
2The process of exporting a XPSWMM model to XPXThis process involves using the export functionality in XPSWMM to save the model in a format that can be used in the XPX software. This includes selecting the components of the model to export, specifying the export location, and ensuring that the exported file is in a format that can be read by XPX.
3The process of exporting a XPSWMM model to SWMM5This process involves using the export functionality in XPSWMM to save the model in a format that can be used in the SWMM5 software. This includes selecting the components of the model to export, specifying the export location, and ensuring that the exported file is in a format that can be read by SWMM5.
4The process of importing the SWMM5 model to ICM SWMMThis process involves using the import functionality in ICM SWMM to load the model exported from SWMM5. This includes specifying the location of the exported file, mapping the components of the model to the appropriate inputs in ICM SWMM, and checking for any errors or inconsistencies in the imported model.
5The process of importing the SWMM5 model to ICMThis process involves using the import functionality in ICM to load the model exported from SWMM5. This includes specifying the location of the exported file, mapping the components of the model to the appropriate inputs in ICM, and checking for any errors or inconsistencies in the imported model.
6Validating the ICM SWMM ImportThis process involves checking the imported model in ICM SWMM for errors or inconsistencies. This includes comparing the imported data to the original XPSWMM model, checking for missing or incorrect data, and making any necessary adjustments to the imported model before running the simulation.
7Converting the ICM SWMM network to ICMThis process involves converting the imported model in ICM SWMM to the format used by the ICM software. This includes mapping the components of the model to the appropriate inputs in ICM, and making any necessary adjustments to the imported model before running the simulation.
8Getting either ICM or ICM SWMM to runThis process involves configuring the software and the model, and then running the simulation. This includes setting the simulation parameters, specifying the time step and duration of the simulation, and specifying the output options.
9Compare answers to XPSWMMThis process involves comparing the results of the XPSWMM simulation to the results of the simulation run in ICM or ICM SWMM. This includes comparing the hydrographs, water surface elevations, and other output variables, and identifying any discrepancies or issues with the results.
10Technical details on how SWMM5 or ICM work compared to XPSWMMThis process involves identifying and implementing solutions to issues or problems that may arise during the use of the software or the simulation.

Saturday, December 24, 2022

Table comparing and contrasting the features of the Storm Water Management Model (SWMM5) and the EPANET Water Distribution System (WDS)

Table comparing and contrasting the features of the Storm Water Management Model (SWMM5) and the EPANET Water Distribution System (WDS)


FeatureSWMM5EPANET
SubcatchmentsSubcatchments represent the land area that contributes runoff to a stormwater system. They can be specified by size, slope, and land use.Junctions represent the points where pipes connect in a distribution system. They can be specified by demand and elevation.
LinksLinks model the flow of water through a stormwater system. They can be specified by size, material, and roughness coefficient.Pipes model the flow of water through a distribution system. They can be specified by size, material, and roughness coefficient.
JunctionsJunctions model the points where links connect in a stormwater system. They can be specified by elevation and initial water depth.Junctions model the points where pipes connect in a distribution system. They can be specified by demand and elevation.
OutfallsOutfalls model the points where water leaves a stormwater system, such as a stream or river. They can be specified by type and discharge coefficient.Valves are used to control the flow of water in a distribution system. They can be specified by type and setting.
StorageStorage models the volume of water that can be stored in a stormwater system. It can be specified by size, shape, and initial water depth.Reservoirs and tanks are used to model water storage in a distribution system. They can be specified by size and initial water level.
InfiltrationInfiltration models the infiltration of water into the ground,

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