Be sure to download the SWMM5 model before running the examples.

Printing Subcatchment Runoff

The following example prints subcatchment runoff values throughout a simulation.

# -*- coding: utf-8 -*-

from pyswmm import Simulation, Subcatchments

with Simulation("swmm_example.inp") as sim:
    S1 = Subcatchments(sim)["S1"]

    for step in sim:
        print(sim.current_time)
        print(S1.runoff)

Download this example file here.

Saving to a CSV File

The following example saves subcatchment pollutant buildup to a CSV file within a subdirectory at specified saving times.

# -*- coding: utf-8 -*-

import csv
import os
from pyswmm import Simulation, Subcatchments

ts = 60  # routing step (sec)
sph = 3600  # seconds per hour
times = [
    (1 / ts) * sph,
    (2 / ts) * sph,
    (3 / ts) * sph,
    (4 / ts) * sph,
    (5 / ts) * sph,
    (6 / ts) * sph,
    (7 / ts) * sph,
    (8 / ts) * sph,
    (9 / ts) * sph,
    (10 / ts) * sph,
    (11 / ts) * sph,
    (12 / ts) * sph,
]  # times to record buildup
i = 1
rec_step = 1

if not os.path.exists("buildup"):
    os.mkdir("buildup")

with Simulation("swmm_example.inp") as sim:

    for step in sim:

        if rec_step in times:
            with open(
                "buildup/pollut_buildup" + str("%i" % i) + ".csv", "w", newline=""
            ) as csvfile:
                load = csv.writer(csvfile, delimiter=",", quoting=csv.QUOTE_MINIMAL)
                load.writerow(["time:", sim.current_time])
                load.writerow(["Subcatchment", "Loading"])
                for subcatchment in Subcatchments(sim):
                    load.writerow(
                        [
                            subcatchment.subcatchmentid,
                            subcatchment.buildup["test-pollutant"],
                        ]
                    )
            i += 1

        rec_step += 1

Download this example file here.