Node

🧱 1. What is a Node in SWMM?

In a SWMM model, a Node represents a point where flow converges, diverges, is stored, or is discharged — such as manholes, storage units, junctions, and pump inlets/outlets.

Node Type	Description
Junction	General connection point for conduits (accumulates flow/level)
Outfall	Exit point from the system (discharge location)
Storage	Temporarily stores flow (e.g., detention basin)
Divider	Splits flow based on conditions
Pump Node	Inlet/outlet point for a pump

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🧠 2. What You Can Do with pyswmm.Nodes

🔍 ✅ Readable Properties

from pyswmm import Simulation, Nodes

with Simulation("model.inp") as sim:
    node = Nodes(sim)["N1"]  # 'N1' is the node ID
    for step in sim:
        print(sim.current_time, node.depth, node.inflow, node.flooding)

Property	Description
depth	Current water depth (m)
inflow	Inflow rate (cms or cfs)
flooding	Flooding flow rate (m³/s)
head	Hydraulic head (depth + elevation)
overflow	Overflow discharge
total_inflow	Total internal + external inflow
volume	Volume of stored water (for storage units)

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⚙️ ✅ Writable Properties (for Certain Node Types)

Some nodes (e.g., Storage, pump-connected nodes) allow control during simulation:

node.target_depth = 2.5   # Set target water level

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🧪 Example: Flood Detection

from pyswmm import Simulation, Nodes

with Simulation("model.inp") as sim:
    nodes = Nodes(sim)
    node = nodes["J1"]

    for step in sim:
        if node.flooding > 0:
            print(f"⚠️ Flooding at {node.nodeid} at {sim.current_time} - {node.flooding:.3f} m³/s")

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📈 Use Cases Related to Nodes

Scenario	Description
Track water depth at specific node	Analyze flood-prone areas
Monitor storage depth	Useful for LID analysis, pump control, etc.
Analyze inflow patterns	Understand runoff timing per catchment
Calculate head differences	Determine pump operation needs

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🔧 Which Nodes Can Be Controlled?

• Most node properties are read-only (e.g., depth, inflow)
• Storage nodes allow target_depth to be set
• Pump nodes can be indirectly controlled using the Links module (pump ON/OFF logic)