Inquiry about the Unit of flooding_loss Extracted by pyswmm

[CwhGIS]

Hi everyone,

I’m a beginner with pyswmm, and I’ve encountered an issue with unusually large flood depths while coupling SWMM and LISFLOOD simulations. To better understand this problem, I’d like to inquire about the unit of flooding_loss when extracting data from SWMM’s .out file using pyswmm.

During my SWMM simulation, I set the unit to cms (cubic meters per second). When using pyswmm to extract flooding_loss, what is its unit? Is it cubic meters (m³) or something else? This is crucial for my subsequent analysis and coupling simulations.

Here’s the code I’m using to extract.

import pyswmm 
from pyswmm import Output, SubcatchSeries, NodeSeries, LinkSeries, SystemSeries
import geopandas as gpd
import swmmio
import pandas as pd
import numpy as np

f_inp=r"F:\\test.inp"
f_out=r"F:\\test.out"
f_bci1=r"F:\\lisflood82\\EXAMPLE\\test.bci"
f_bdy1=r"F:\\lisflood82\\EXAMPLE\\test.bdy"

model=swmmio.Model(f_inp)
nodes=model.nodes
df=nodes.dataframe.reset_index(drop=False)

temp_time=None
temp={}
with Output(f_out) as out:
    with open(f_bdy1, "w",encoding="utf-8") as f_bdy, open(f_bci1, "w",encoding="utf-8") as f_bci:
        f_bdy.writelines("auto generated junctions\n")
        
        for _, node in df.iterrows():
            if node.Name not in ["Node_2","J1","J2","J3","J4","J5","J6","J7","J8"]:  # Check if the point is on the outer side of the coupled area
                key = [k for k in NodeSeries(out)[node.Name].flooding_losses.keys()]
                
                key = pd.to_datetime(key)
                
                
                values = [v for v in NodeSeries(out)[node.Name].flooding_losses.values()]
                
                key=key-pd.to_timedelta(key[0].hour, unit='h') \
                        -pd.to_timedelta(key[0].minute, unit='m') \
                        -pd.to_timedelta(key[0].second, unit='s')
                
                time = [key.hour[i] * 3600 + key.minute[i] * 60-60 for i, _ in enumerate(key)]
                
                if np.max(values)!=0:
                    temp[node.Name]=np.max(values)
                
                if temp_time==None:
                    temp_time=time
                else:
                    assert temp_time==time
                    
                if not all(value == 0 for value in values):  # Exclude points where all flooding losses are zero
                    #print(values)
                    f_bci.writelines(f"P\t{node.coords[0][0]}\t{node.coords[0][1]}\tQVAR\t{node['Name']}\n")
                    
                    bdy_str=[]
                    bdy_str.append( f"{node.Name}\n{len(time)}\tseconds\n")
                    print(max(values))
                    
                    for i, _ in enumerate(time):
                        bdy_str.append("%.6f\t%d\n"%(values[i],i*300))
                      
                    bdy_str="".join(bdy_str)
                    f_bdy.write(bdy_str)

[karosc]

I believe the output unit in pyswmm should be the flow rate unit that is selected in the inp file option section.

If you selected cms in the options section, the flooding_loss reported by pyswmm should be the flooding rate at that node in cms.