Modelling of rainwater reduction and hydrological performance of selected green infrastructure (GI) facilities in urban catchments

	Scenario S₀	Scenario S₁	Scenario S₂	Scenario S₃	Scenario S₄	Scenario S₅	Scenario S₆	Scenario S₇
Precipitation duration	90 min (4.2 mm)	15 min	30 min	45 min	60 min	90 min	120 min	180 min
Average rainfall intensity [LPS/ha]*	7.8	273.32	175.33	134.52	105.37	74.81	59.55	42.46
Total precipitation p = 10% [mm]	4.2	24.60	31.56	36.32	37.93	40.40	42.88	45.86
Precipitation intensity p = 10% [mm/hr]	2.80	98.40	63.12	48.43	37.93	26.93	21.44	15.29

* LPS – litres per second

Table 2.

Spatial analyses based on the Database of Topographical Objects of the study area

Land use	Area
	ha	%
Roofs	1.12	26.9
Roadways, pavement, alleys	0.40	9.6
Single- and multi-family residential land	2.17	52.0
Biologically active areas	0.48	11.5
TOTAL	4.17	100.0

Results of detailed analyses of the study area using available databases: A — route of the drainage system; B — land use; C — elevation and directions of surface water runoff; D — subcatchment imperviousness

Rainfall mass curve and hyetograph of 4.2 mm precipitation (a) and flow observed at outfall W₁ (b) used for the calibration process

Table 3.

Values of the basic parameters for the land use groups in the study area obtained during the SWMM calibration process

Description	Imperv [%]		N Imperv	N Perv	Dstore Imperv [mm]	Dstore Perv	Zero Imperv [%]	Width
Description	min	max	N Imperv	N Perv	Dstore Imperv [mm]	[mm]	Zero Imperv [%]	A [m]
Building roofs-BUBD	87.47		0.010	0.045	3.69	3.69	36.00	0.7
Other roadway-SKJZ08	13.1	36.0	0.015	0.300	1.20	5.08	40.00	0.3
Local roadway-SKJZ06	34.6	49.5	0.010	0.300	1.20	5.08	40.00
Alley-SKRP01	2.0	3.2	0.011	0.280	1.20	5.08	40.00
Grass vegetation-PTTR01	1.0	2.5	0.140	0.280	5.08	7.62	20.00	0.3
Orchard-PTUT03	1.1	2.88	0.210	0.280	5.08	7.62	20.00
Single-family dwelling-PTZB02	2.0	4.02	0.105	0.280	5.08	7.62	20.00

Table 4.

The basic measures of fitness coefficients for built SWMM model

Indicator		Description	Formula	Obtained value	Assessment	Literature
NSEC	Nash-Sutcliffe Efficiency Coefficient	Compare the results of model’s response and measurement data	$1 - \frac{\sum_{t = 1}^{T} {(Q_{o}^{t} - Q_{s}^{t})}^{2}}{\sum_{t = 1}^{T} {(Q_{o}^{t} - \bar{Q_{o}})}^{2}}$	0.885	-∞ - 1; very good	[Titterington et al. 2017], [Moriasi et al. 2007], [Lin et al. 2017]
ISE	Integral Square Error	The accuracy of the matching between simulated and observed data	$\frac{\sqrt{\sum_{t = 1}^{T} {(Q_{o}^{t} - Q_{s}^{t})}^{2}}}{\sum_{t = 1}^{T} Q_{o}^{t}}$	0.02	0 – 3; excellent	[Shamsi et al. 2017]
RMSE	Root Mean Square Error	Differences between observed and simulated values	$\sqrt{\sum_{t = 1}^{T} (\frac{{(Q_{o}^{t} - Q_{s}^{t})}^{2}}{T})}$	0.442; < 0.5*1.307	less than half of the standard deviation; good	[Singh et al. 2004], [Moriasi et al. 2007]

Table 5.

Summary of the LID parameters used in the calibrated SWMM model according to [Bond et al. 2021]

Layer	Parameter	Unit	Bio-retention cells (BC)
Surface layer	Berm height	mm	250
	Vegetation volume	share	0.1
	Surface roughness	–	0.3
	Surface slope	%	1
	Swale Side Slope	run/rise	–
Soil layer	Thickness	mm	600
	Porosity	share vol.	0.45
	Field capacity	share vol.	0.121
	Wilting point	share vol.	0.057
	Conductivity	mm/hr	91
	Conductivity slope	–	44
	Suction head	mm	50
Storage layer	Thickness	mm	400
	Void ratio	voids/solids	0.54
	Seepage rate	mm/hr	2.6
	Clogging factor	–	0
Drain	Flow coefficient	mm/hr	5.4*
	Drain exponent	–	0.5
	Offset height	mm	200

* The parameter was calculated using formula (3)

Illustration of the implementation of green infrastructure (BC) in the study area of an existing housing estate.

Linear regression plot of R2 for a dataset of the measured rainwater flow (Q_o) at outfall W₁ and the simulated value (Q_s) based on the SWMM

Flow observed at outfall W₁ on August 26, 2023, along with the modelling results for the existing conditions, and for the scenario with the selected LID equipment implemented

Table 6.

The simulation results of the calibrated model for the entire study area at the sewer outfall for scenarios S₀–S₇

	Scenario S₀	Scenario S₁	Scenario S₂	Scenario S₃	Scenario S₄	Scenario S₅	Scenario S₆	Scenario S₇
no LID
Max flow [LPS]	4.6	449.2	464.0	454.8	393.1	359.3	349.9	266.2
Total volume [m³]	17	539	752	916	953	1008	1072	1139
with LID
Max flow [LPS]	0.0	17.5	31.6	31.7	25.2	22.6	22.1	17.6
Total volume [m³]	0	29	56	111	134	167	204	246
reduction
Max flow [LPS]	100%	96%	93%	93%	94%	94%	94%	93%
Total volume [m³]	100%	95%	93%	88%	86%	83%	81%	78%

Average reductions in the total volume and peak flow for scenarios S₀–S₇

Percentage distribution of the rainwater volume and storage volume of LID facility as a function of rainfall depth

Table 7.

Summary of the simulation results of the calibrated SWMM for individual LID facilities implemented in the study area for scenarios S₀–S₇

Scenario	S₀	S₁	S₂	S₃	S₄	S₅	S₆	S₇
Total Inflow (m³)	37.9	658.2	987.1	1234.8	1304.7	1404.0	1512.8	1629.2
Surface and Drain Outflow (m³)	0.0	32.7	133.6	273.6	318.7	385.4	458.9	538.8
Average inflow (L/m²)	0.008	0.139	0.208	0.260	0.275	0.296	0.319	0.344
Average outflow (L/m²)	0.000	0.007	0.028	0.058	0.067	0.081	0.097	0.114
Average reduction (%)	100	95	86	78	76	73	70	67

Dependence of the total inflow per 1 m² and reduction in rainwater for BC cells in the residential area under study for scenarios S₀–S₇

Maximum, minimum and average values of the rainwater inflow limit [L/m²] per 1 m² of surface area of LID facilities for scenarios S₀–S₇ for which there was a 100% quantitative reduction of inflow

Table 8.

Summary of the results obtained for the considered precipitation scenarios S₀–S₇

No.	Scenario	S₀	S₁	S₂	S₃	S₄	S₅	S₆	S₇
	*share LID storage in rainfall volume*
1A	Rainwater volume [m³]	365	2137	2742	3156	3296	3510	3725	3984
1B	Final LID storage [m³]	41	788	970	1024	1036	1057	1081	1108
1	Average share [%]	11%	37%	35%	32%	31%	30%	29%	28%
	*LID hydrological performance*
2A	Average inflow [L/m²]	0.008	0.139	0.208	0.260	0.275	0.296	0.319	0.344
2B	Average outflow [L/m²]	0.000	0.007	0.028	0.058	0.067	0.081	0.097	0.114
2	Average reduction [%]	100%	95%	86%	78%	76%	73%	70%	67%
	*average total inflow to LID with full reduction*
3	Fully reduced inflow [L/m²]	0.76	5.79	2.30	2.85	3.13	3.28	3.46	4.25
	*total outfall volume reduction*
4A	Total volume [m³]	17	539	752	916	953	1,008	1,072	1139
4B	Reduced volume [m³]	0	29	56	111	134	167	204	246
4	Average reduction [%]	100%	95%	93%	88%	86%	83%	81%	78%
	*outfall peak flow reduction*
5A	Peak flow [LPS]	4.60	449.16	464.03	454.78	393.10	359.34	349.85	266.20
5B	Reduced peak flow [LPS]	0.00	17.51	31.63	31.66	25.19	22.57	22.05	17.58
5	Average reduction [%]	100%	96%	93%	93%	94%	94%	94%	93%

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DOI: https://doi.org/10.2478/oszn-2025-0005 | Journal eISSN: 2353-8589 | Journal ISSN: 1230-7831

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Language: English

Page range: 1 - 20

Published on: Mar 11, 2025

Published by: National Research Institute, Institute of Environmental Protection

In partnership with: Paradigm Publishing Services

Keywords:

rainwater runoff,

stormwater management,

green infrastructure,

SWMM single-event calibration,

rain garden performance

Related subjects:

Life sciences,

Ecology

© 2025 Krzysztof Muszyński, published by National Research Institute, Institute of Environmental Protection
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Volume 35 (2024): Issue 3 (September 2024)

Modelling of rainwater reduction and hydrological performance of selected green infrastructure (GI) facilities in urban catchments

Figures & Tables

Figure 1.

Table 1.

Table 2.

Figure 2.

Figure 3.

Table 3.

Table 4.

Table 5.

Figure 4.

Figure 5.

Figure 6.

Table 6.

Figure 7.

Figure 8.

Table 7.

Figure 9.

Figure 10.

Table 8.

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