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

Figure 1.

Figure 2.

Figure 3.

Figure 4.

Figure 5.

Figure 6.

Figure 7.

Figure 8.

Figure 9.

Figure 10.

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−∑t=1TQot−Qst2∑t=1TQot−Qo¯2 1 - {{\mathop \sum \nolimits_{t = 1}^T {{\left( {Q_o^t - Q_s^t} \right)}^2}} \over {\mathop \sum \nolimits_{t = 1}^T {{\left( {Q_o^t - \overline {{Q_o}} } \right)}^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	∑t=1TQot−Qst2∑t=1TQot {{\sqrt {\mathop \sum \nolimits_{t = 1}^T {{\left( {Q_o^t - Q_s^t} \right)}^2}} } \over {\mathop \sum \nolimits_{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	∑t=1T(Qot−Qst2T) \sqrt {\sum\limits_{t = 1}^T {({{{{\left( {Q_o^t - Q_s^t} \right)}^2}} \over T})} }	0.442; < 0.5*1.307	less than half of the standard deviation; good	[Singh et al. 2004], [Moriasi et al. 2007]

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

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 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%

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

Analyzed scenarios

	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

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
	min	max				[mm]		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

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%