How-to: `outflows` module¶

Writing an outflows CSV¶

The CustomOutflows class supports the creation of outflow CSV files. It provides a wrapper around the pandas.DataFrame object and converts outflows set in units of m³/day, or m³/hour, to m³/second.

Creating the outflows DataFrame¶

To create an outflows CSV, import the outflows module and initalise the CustomOutflows class. The duration of the timeseries is set with the start_datetime and end_datetime attributes. These attributes can be provided in the form of a pandas.Timestamp, datetime.datetime, or a valid datetime string. Make sure your start_datetime and end_datetime match the start and stop parameters used to configure &time block with NMLTime. Outflows can be defined at an hourly (1h) or daily frequency (24h) with the frequency attribute. An optional base_outflow attribute can be used to set a constant outflow. The input units of base_outflow will be in either m³/day or m³/hour depending on the frequency you set.

from glmpy import outflows

my_outflows = outflows.CustomOutflows(
    start_datetime="2020-01-01",
    end_datetime="2020-01-10",
    frequency="24h",
    base_outflow = 0.0
)

Set outflows for specific dates¶

By default, the CustomOutflows class will have a constant outflow rate for the entire simulation period. To set outflows for specific dates, use the set_on_datetime() method and provide a dictionary with dates (as keys) and outflows (as values):

outflows_dict = {
    "2020-01-02": 2, # 2m^3/day
    "2020-01-03": 4, # 4m^3/day
    "2020-01-04": 6 # 6m^3/day
}
my_outflows.set_on_datetime(outflows_dict)

Return the outflow DataFrame¶

To return the pandas.DataFrame of outflows, use the get_outflows() method:

outflows_dataframe = my_outflows.get_outflows()
print(outflows_dataframe)

        time      flow
0 2020-01-01  0.000000
1 2020-01-02  0.000023
2 2020-01-03  0.000046
3 2020-01-04  0.000069
4 2020-01-05  0.000000
5 2020-01-06  0.000000
6 2020-01-07  0.000000
7 2020-01-08  0.000000
8 2020-01-09  0.000000
9 2020-01-10  0.000000

Set outflows over a date range¶

Constant outflows can be set over a date range with the set_over_datetime() method:

outflows.set_over_datetime(
    from_datetime="2020-01-05",
    to_datetime = "2020-01-09",
    outflow = 5 # 5m^3/day
)

outflows_dataframe = my_outflows.get_outflows()

print(outflows_dataframe)

        time      flow
0 2020-01-01  0.000000
1 2020-01-02  0.000023
2 2020-01-03  0.000046
3 2020-01-04  0.000069
4 2020-01-05  0.000058
5 2020-01-06  0.000058
6 2020-01-07  0.000058
7 2020-01-08  0.000058
8 2020-01-09  0.000058
9 2020-01-10  0.000000

Writing the outflows file¶

Once the outflows have been defined, they can be saved as a CSV with the write_outflows() method:

outflows.write_outflows(file_path="outflows.csv")

How-to: outflows module¶