Adding and Removing Elements

Add and remove paths follow m.add.<category>.<element_type>() and m.remove.<category>.<element_type>(). The API validates IDs, required fields, numeric values, enum-like inputs, and references before editing the INP document.

from swmmx import swmm

m = swmm(new="SI")

m.add.node.junction("J1", x=0.0, y=0.0, invert_elevation=10, max_depth=3)
m.add.node.outfall("OUT1", x=100.0, y=0.0, invert_elevation=9, type="FREE")

m.add.link.conduit(
    "C1",
    from_node="J1",
    to_node="OUT1",
    length=100,
    roughness=0.013,
    shape="CIRCULAR",
    diameter=1.0,
)

m.add.time.time_series("Rain1", data=[("2026-01-01 00:00", 0.0), ("2026-01-01 00:05", 5.0)])
m.add.hydrology.rain_gage("RG1", format="INTENSITY", interval="00:05", source_type="TIMESERIES", time_series="Rain1")
m.add.hydrology.subcatchment("S1", rain_gage="RG1", outlet="J1", x=0.0, y=0.0, area=1.0)

m.save("new_model.inp")
m.remove.link.conduit("C1")

Rules

Topic	Behavior
References	Referenced nodes, curves, time series, and related objects must exist before use.
Coordinates	Nodes require explicit `x`/`y`; subcatchments require centroid coordinates; rain gages can default to mapped extents.
Removal checks	Dependencies block deletion by default.
`force=True`	Performs only conservative implemented cascades, such as dependent conduit removal for some node deletions.
State flags	Add/remove sets `m.modified`; if results exist, `m.results_stale` becomes true.

m.add_element("node", "junction", "J2", x=200.0, y=0.0, invert_elevation=11, max_depth=2)
m.remove_element("node", "junction", "J2")

Detailed Add and Remove References

Add functions

Every public add endpoint, required/optional inputs, implementation status, coordinate rules, references, and examples.

Open section

Remove functions

Every public remove endpoint, ids input, force behavior, dependency checks, output summaries, and reserved endpoints.

Open section