Changes in flood characteristics and the flood driving mechanism in the mountainous Haihe River Basin, China

Figures & data

Figure 1. Study area: the seven hydrological areas and the selected hydrological stations. I: Shifokou; II: Mubi; III: Xitaiyu; IV: Daomaguan; V: Fuping; VI: Dage; and VII: Lengkou.

Figure 2. Remotely sensed land-use data of the Haihe River basin: (a) 1980 and (b) 2000.

Figure 3. The ZWHM-LUCC model structure. P: precipitation; EM: evapotranspiration; UH: unit hydrograph.

Table 1. Trend and change point test results of flood characteristics for the seven study sub-catchments. Bold indicates significant trend and change point. Numbers indicate sub-catchments in Fig. 1. FV: flood volume.

Sub-catchment	No.	Test statistic, U		Change point/year
		Total FV	Peak discharge	Total FV	Peak discharge
Shifokou	I	–2.12	–2.97	1979	1979
Mubi	II	–2.61	–0.25	1977	1982
Xitaiyu	III	–1.38	–1.42	1978	1982
Daomaguan	IV	–1.10	–2.75	1979	1979
Fuping	V	–2.40	–4.05	1982	1979
Dage	VI	–3.48	–3.28	1982	1979
Lengkou	VII	–2.68	–2.47	1979	1979

Table 2. Area (km²) of each land-use type in 1980 and 2000 for each sub-catchment.

Sub-catchment	Year	Agricultural land	Forest	Grassland	Water	Urban	Unused
Shifokou	1980	248.4	66.6	34.2	6.4	21.3	65.1
	2000	250.4	66.8	32.0	1.0	24.3	67.5
Mubi	1980	247.1	0.0	1.3	6.4	19.1	0.0
	2000	259.0	0.0	0.4	6.1	8.4	0.0
Xitaiyu	1980	48.5	26.2	45.8	2.0	3.0	0.0
	2000	60.3	34.9	30.4	0.0	0.0	0.0
Daomaguan	1980	74.3	136.5	470.1	12.4	6.0	0.0
	2000	52.9	169.4	476.8	0.0	0.2	0.0
Fuping	1980	135.6	613.5	1455.2	39.3	1.2	0.0
	2000	69.8	765.6	1409.3	0.0	0.0	0.0
Dage	1980	273.5	713.6	823.1	34.0	17.0	5.0
	2000	522.1	865.6	458.2	16.3	3.9	0.0
Lengkou	1980	78.6	213.6	198.8	9.9	2.1	0.0
	2000	82.8	216.6	201.0	0.0	2.6	0.0

Table 3. Increased storage capacity of small hydraulic structures (converted to runoff depth) and deep soil moisture.

Sub-catchment	Drainage area (km^2)	Increased storage capacity (mm)	Deep soil moisture
Shifokou	429	3.7	19.1
Mubi	275	6.2	27.3
Xitaiyu	127	6.4	24.5
Daomaguan	710	2.5	28.1
Fuping	2210	2.7	13.7
Dage	1850	1.2	19.2
Lengkou	856	2.0	20.4

Table 4. Calibrated values of the main parameters for the Shifokou sub-catchment.

Parameter	Meaning	Value
B	Exponent of soil moisture distribution curve	0.3
M	Exponent of infiltration capacity distribution curve	0.1
C	Evapotranspiration coefficient	0.1
FC1	Stable infiltration rate in arable land (mm/h)	2.409
KF1	Exponent of Horton infiltration curve in arable land (1/h)	0.335
FC2	Stable infiltration rate in forest area(mm/h)	2.12
KF2	Exponent of Horton infiltration curve in forest area(1/h)	0.212
FC3	Stable infiltration rate in grassland (mm/h)	2.157
KF3	Exponent of Horton infiltration curve in unused land (1/h)	0.364
FC4	Stable infiltration rate in unused land (mm/h)	2.480
KF4	Exponent of Horton infiltration curve in grassland (1/h)	0.350
KSS	Recession coefficient of interflow	0.1
KKG	Recession coefficient of groundwater	0.998

Table 5. Comparison of simulated and observed flood events in Shifokou sub-catchment. FV_O and FV_S: observed and simulated flood volume, respectively. FP_O and FP_S: observed and simulated mean flood peak, respectively. RE: relative error; NSE: Nash-Sutcliffe efficiency criterion.

Hydrological model	Flood event*	FVO (mm)	FVS (mm)	RE of FV (%)	FPO (m^3/s)	FPS (m^3/s)	RE of FP (%)	NSE
Calibration	590721	75.09	76.12	1.4	434.0	438.4	1.0	0.75
	640801	41.92	42.74	2.0	142.0	138.7	–2.3	0.72
	640813	34.64	30.21	−12.8	163.0	138.7	–14.9	0.70
	650718	26.66	26.68	0.1	162.0	149.3	–7.8	0.70
	670718	38.03	33.15	−12.8	144.0	146.6	1.8	0.70
	670820	27.99	23.43	−16.3	108.0	117.1	8.4	0.90
	690811	25.45	29.10	14.3	125.0	113.3	–9.4	0.79
	690902	41.06	44.22	7.7	295.0	264.7	–10.3	0.40
	700808	48.45	39.30	−18.9	135.0	118.6	–12.2	0.81
	700903	13.99	12.98	−7.2	83.3	88.0	5.6	0.87
	750729	61.16	70.05	14.5	340.0	278.5	–18.1	0.60
Validation	750811	99.60	106.21	6.6	396.5	412.0	3.9	0.66
	760724	13.15	12.80	−2.7	73.9	76.0	2.8	0.61
	770723	90.87	86.04	−5.3	252.0	264.9	5.1	0.90
	780725	19.20	19.78	3.0	155.0	156.9	1.2	0.81
	840809	34.84	30.65	−12.0	178.6	151.3	–15.3	0.73
	940813	38.96	33.68	−13.6	246.2	237.5	–3.5	0.75
	960810	35.68	38.82	8.8	256.5	273.6	6.7	0.68
	980713	120.13	117.31	−2.4	203.8	247.3	21.3	0.66

* e.g. 590721 indicates the flood event occurred on 21 July 1959.

Figure 4. Simulated (Δ) and observed (•) flood processes in Shifokou sub-catchment for flood events: (a) 670820 and (b) 700903.

Table 6. Effects of driving factors – groundwater depletion, land-use change and small hydraulic structures – on flood characteristics. FP: flood peak; FV: flood volume.

Sub-catchment	Return period (year)	Groundwater depletion (%)		Land-use change (%)		Small hydraulic structures (%)
		FP	FV	FP	FV	FP	FV
Shifokou	>10	–2.1	–1.4	–3.0	–3.9	–6.2	–6.9
	5–10	–2.0	–0.8	–9.2	–3.4	–18.7	–16.7
	<5	–2.4	–0.4	–4.7	–3.5	–33.9	–30.5
Mubi	>10	–2.8	–1.2	–1.3	–0.8	–4.6	–3.3
	5–10	–2.4	–0.8	–1.5	–2.8	–8.9	–18.4
	<5	–1.9	–0.5	–7.3	–3.2	–21.4	–9.2
Xitaiyu	>10	–1.8	–0.8	–5.9	–4.4	–2.0	–3.9
	5–10	–1.8	–0.8	–11.3	–9.0	–14.8	–10.4
	<5	–0.8	–0.3	–21.7	–15.8	–14.0	–9.0
Daomaguan	>10	–1.6	–0.5	–17.2	–1.4	–12.8	–7.6
	5–10	–1.9	–1.6	–21.0	–6.4	–22.0	–18.6
	<5	–1.8	–1.7	–23.2	–7.0	–28.9	–23.4
Fuping	>10	–2.9	–2.5	–2.6	–8.9	–5.5	–5.4
	5–10	–2.0	–2.0	–14.5	–14.6	–26.6	–10.6
	<5	–1.5	–0.7	–27.0	–15.9	–25.3	–13.3
Dage	>10	–1.2	–0.7	–30.0	–17.3	–6.7	–4.9
	5–10	–1.9	–1.5	–25.8	–15.7	–7.0	–5.6
	<5	–1.0	–0.6	–26.3	–22.5	–7.1	–6.5
Lengkou	>10	–1.3	–0.9	–2.4	–2.0	–3.5	–6.7
	5–10	–1.3	–0.8	–1.4	–1.9	–7.8	–8.0
	<5	–0.9	–0.5	–7.6	–1.6	–21.2	–17.3