Impact of climatic change on river discharge in the driest region of Poland

Figures & data

Fig. 1 Map of the Warta River catchment area showing the location of meteorological stations and gauges, and the climatic water balance (April–September) in 1970–2004 (according to Łabędzki 2011).

Fig. 2 Long-term variability of annual mean discharge of the Warta River (Gorzów Wlkp gauge) for 1896–2010.

Fig. 3 Long-term variability of annual mean discharge of the middle and upper Warta River (Poznań gauge) for 1822–2010.

Fig. 4 Long-term variability of annual mean discharge of the Noteć River (Nowe Drezdenko gauge) for 1901–2010.

Table 1 Annual mean discharges in the Warta and Noteć rivers in 1822–2010.

Gauge	Period	Annual mean discharge (m^3 s^-1)	SD	CV	Regression line formula	Linear trend (m^3 s^-1/10 years)	r
Gorzów Wlkp	1896–2010	210.5	55.549	0.26	y = 0.1176x − 19.07	1.18	—
	1901–2010	211.1	56.696	0.27	y = 0.1043x + 7.18	1.04	0.059
Poznań	1822–2010	97.0	32.625	0.34	y = 0.0797x − 55.66	0.80	0.134
	1901–2010	100.0	32.240	0.33	y = 0.0901x − 76.30	0.90	0.089
Nowe Drezdenko	1901–2010	69.7	15.526	0.22	y = 0.1129x − 151	1.14	0.233*

Notes: SD, standard deviation; CV, coefficient of variation; r, regression coefficient.

*Regression significant at the 0.05 confidence level.

Table 2 Mean  monthly and annual discharge (m³ s^-1) of the Warta River at Gorzów Wlkp for selected years between 1848 and 2010.

Period	Sub-period	Months												Year	Half-year
		Nov	Dec	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct		Nov–Apr	May–Oct
1848–2010	1848–1893*	187	233	288	345	374	341	229	171	151	151	148	156	231	295	168
	1896–1915*	143	192	249	277	323	307	233	138	120	119	118	128	195	248	143
	1921–1940	200	222	241	277	327	320	221	173	143	147	147	164	215	264	166
	1951–1970	160	188	198	254	301	311	230	168	133	138	132	137	196	235	156
	1981–2010	181	210	240	271	310	304	217	170	146	149	147	160	209	253	166
1981–2010	1981–1990	203	246	281	292	339	323	221	187	162	163	154	165	228	281	175
	1991–2000	171	199	233	252	287	295	214	147	150	151	154	160	201	240	163
	2001–2010	168	186	206	268	305	293	217	175	128	132	135	156	197	238	157
1848–2010	1848–2010	209	243	285	327	317	226	164	139	141	138	149	209	259	160	174

Note: *Calculated on the basis of water level and the formula Q = 40.348(H + 1.86)^1.7166.

Table 3 Mean monthly and annual discharge (m³ s^-1) of the Warta River at Poznań for selected years between 1848 and 2010.

Period	Sub-period	Months												Year	Half-year
		Nov	Dec	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct		Nov–Apr	May–Oct
1822–2010	1822–1840	55	76	102	117	185	158	93	63	50	46	49	50	87	116	58
	1841–1880	65	81	89	148	211	172	79	57	52	57	48	53	93	128	58
	1881–1920	73	102	106	131	191	184	99	63	65	59	54	57	99	132	66
	1921–1940	92	101	112	114	174	155	89	77	57	61	58	69	97	125	69
	1951–1970	70	84	83	123	156	156	99	73	57	65	55	56	90	112	68
	1981–2010	89	103	118	134	156	145	103	81	74	79	75	78	103	124	82
1981–2010	1981–1990	93	116	134	140	167	143	94	79	67	78	73	60	105	132	77
	1991–2000	86	101	118	123	141	144	100	69	87	86	80	82	101	119	84
	2001–2010	87	91	102	138	160	148	116	97	69	73	72	91	103	121	85
1822–2010	1822–2010	74	91	102	128	179	162	94	69	59	61	57	61	95	123	67

Fig. 5 Variability of annual mean discharge of the Warta and Noteć rivers for water years 1981–2010.

Table 4 Mean monthly and annual discharge (m³ s^-1) of the Noteć River at Nowe Drezdenko for selected years between 1848 and 2010.

Period	Sub-period	Months												Year	Half-year
		Nov	Dec	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct		Nov–Apr	May–Oct
1863–2010	1863–1892*	83	99	121	121	118	115	94	74	66	67	68	75	92	109	74
	1896–1910*	53	66	86	89	88	90	74	49	42	43	46	49	64	79	50
	1921–1940	72	81	93	94	96	95	79	60	50	55	57	61	74	88	60
	1951–1970	63	72	77	83	90	94	82	60	50	51	53	58	69	80	59
	1981–2010	67	77	82	91	100	96	76	61	54	53	56	61	73	85	60
1981–2010	1981–1990	78	93	96	100	109	108	83	74	65	62	61	66	83	97	69
	1991–2000	61	71	78	85	96	91	74	57	52	48	55	56	69	80	57
	2001–2010	61	69	72	87	96	87	70	53	46	48	51	60	67	79	55
1896–2010	1896–2010	64	74	85	89	94	94	78	57	49	51	53	57	70	83	57

Note: *Calculated on the basis of the water level and the formula Q = 23.3863(H + 1.50)^{1.66 368}.

Fig. 6 Relationship of mean discharge of the Warta River at Gorzów Wlkp and precipitation in the catchment area between the winter half-year (November–April) and summer half-year (May–October) in the period 1981–2010.

Table 5 Relationship of mean discharge in the Warta and Noteć rivers between the winter half-year (November–April) and summer half-year (May–October).

Whole period	Sub-period	Gauging station
		Gorzów Wlkp	Poznań	Nowe Drezdenko
1921–2010	1921–1940	1.59	1.81	1.47
	1951–1970	1.51	1.65	1.36
	1981–2010	1.59	1.63	1.45
1981–2010	1981–1990	1.65	1.80	1.45
	1991–2000	1.51	1.49	1.44
	2001–2010	1.60	1.59	1.46
1921–2010	1921–2010*	1.57	1.69	1.43

Note: *Weighted mean.

Fig. 7 Time series of basin decadal precipitation and its linear trend in the Warta River basin.

Table 6 Annual precipitation totals (mm) in the analysed stations in the Warta River basin.

Meteorological station	Record		Annual mean precipitation totals (mm)	SD (mm)	CV	Annual minimum precipitation totals (mm)	Annual maximum precipitation totals (mm)	Linear trend (mm/10 years)
	Period	Number of years
Bydgoszcz	1861–2010	150	516.9	96.685	0.19	287	811	1.51
Częstochowa	1891–2010	120	648.6	110.804	0.17	401	911	−3.78
Gorzów Wlkp	1875–2010	136	551.7	97.116	0.18	337	827	0.12
Kalisz	1921–2010	90	524.2	101.186	0.19	319	735	−7.66
Koło	1921–2010	90	523.2	94.106	0.18	307	798	5.24
Leszno	1848–2010	163	546.3	98.012	0.18	312	800	−2.01
Łódź	1904–2010	107	578.6	100.730	0.17	368	831	−1.25
Piła	1883–2010	128	560.6	101.311	0.18	324	821	−0.48
Poznań	1848–2010	163	510.5	96.754	0.19	286	794	2.11

Fig. 8 Relationship between precipitation in the winter half-year (November–April) and the summer half-year (May–October) at Poznań in the period 1848–2010.

Table 7 Annual and seasonal air temperatures (°C) in the Warta River basin in 1848–2010.

Period	Mean annual air temperature (°C)	Mean air temperature (°C) in seasons
		Spring (Mar–May)	Summer (Jun–Aug)	Autumn (Sep–Nov)	Winter (Dec–Feb)
1848–1880	8.0	7.27	17.76	8.20	−1.50
1881–1930	8.0	7.73	17.23	8.10	−1.07
1931–1950	8.1	7.90	17.70	8.47	−1.83
1951–1980	7.8	7.27	17.13	8.33	−1.50
1981–2010	8.6	8.57	17.80	8.63	−0.57
1848–1980	8.0	7.54	17.46	8.28	−1.48
1848–2010*	8.1	7.73	17.53	8.33	−1.27
1848–2010**	8.1	7.70	17.50	8.33	−1.20

Notes: *Arithmetic mean; ** weighted mean.

Fig. 9 Long-term variability of annual mean and average running 10-year air temperature (°C) at Poznań in the period 1848–2010.

Fig. 10 Relationship between the mean air temperature in the winter half-year (November–April) and the summer half-year (May–October) at Poznań in the period 1848–2010.

Łabędzki, L., et al., 2011. Estimation of reference evapotranspiration using the FAO Penman-Monteith method for climatic conditions of Poland. In: L. Łabędzki, ed. Evaporation [online]. Rijeka: InTECH Europe. Available from: http://www.intechopen.com/articles/show/title/estimation-of-reference-evapotraspiration-using-thefao-penman-monteith-method.for.climatic.conditi [Accessed 31 Mar 2011].

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