Evolution of physicochemical species concentration in streams based on heavy rainfall event data obtained for high-frequency monitoring

Girardi, Rubia; Pinheiro, Adilson; Torres, Edson; Kaufmann, Vander; Garbossa, Luis Hamilton Pospissil

doi:10.1590/2318-0331.011616055

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Scientific/Technical Article • RBRH 21 (4) • Oct-Dec 2016 • https://doi.org/10.1590/2318-0331.011616055 copy

Evolution of physicochemical species concentration in streams based on heavy rainfall event data obtained for high-frequency monitoring

Evolução da concentração de espécies físico-químicas no curso da água após eventos de precipitação intensa obtida por monitoramento de alta-frequência

Authorship SCIMAGO INSTITUTIONS RANKINGS

ABSTRACT

Studies carried out over short time intervals assist in understanding the biogeochemical processes occurring relatively fast in natural waters. High frequency monitoring shows a greater variability in the water quality during and immediately after heavy rainfall events. This paper presents an assessment of the surface water quality parameters in the Atlantic Forest biome, caused by heavy rainfall events. The work was developed in two fluviometric sections of the Concordia River watershed, located in the state of Santa Catarina, southern Brazil. The spatial distribution of land use shows the predominance of Atlantic Forest in fluviometric section 1 (FS1) and pasture, forestry, agriculture, and Atlantic Forest in fluviometric section 2 (FS2). In each selected heavy rainfall event, the evolution rainfall height, the water level, and physicochemical parameters of water were analyzed. In all events, the water quality changed due to the heavy rainfall. After the events, an increase in water level and turbidity in both fluviometric sections were detected. In addition, the ammonium ion concentration increased in the river, and the pH value and nitrate concentration decreased. The electrical conductivity presented different behavior in each section. The dissolved oxygen concentration increased in 19 of 27 events. The principal component (PC1) correlated with the turbidity in FS1, and it correlated with level, turbidity, and pH in FS2.

Keywords:
Atlantic Forest; Ombrophilous Dense Forest; Water quality; In situ monitoring

Class	FS1 (%)	FS2 (%)
Pasture		17.54
Planted forest		14.40
Atlantic forest	100	45.10
Water body		1.11
Agriculture		15.65
Regeneration		2.30
Other		3.90

Rainfall event					Water level (cm)				Electrical conductivity (µS.cm^-1)				Ammonium (mg.L^-1)				Nitrate (mg.L^-1)				Turbidity (NTU)			Dissolved oxygen (mg.L^-1)				pH
N	Date	Start	Hour	Rainfall (mm)	Before	Hour		Level	Before	Peak		Hour	Before	Peak		Hour	Before	Peak ²		Hour	Before	Peak	Hour	Before	Peak		Hour	Before	Pico		Hour
1	01/03/12	15:52	15:52	26.9	31.0	17:15		56	21	23		17:00	0.49	2.85		17:00	0.99	0.23		17:00	0	251.6	17:00	7.17	7.78		17:00	7.00	5.12		17:00
2	14/03/12	17:07	17:07	14.6	29.0	19:15		35	21	24		18:00	0.36	2.43		18:00	0.65	0.35		19:00	0	10.3	19:00	7.19	7.62		19:00	7.20	6.99		18:00
3	26/03/12	21:52	22:07	19.1	30.0	23:45		44	19	15		23:00	0.78	2.07		23:00	0.42	0.13		23:00	24.1	368.4	00:00	7.60	8.13		00:00	6.80	6.21		00:00
4	11/04/12	22:07	22:37	15.2	30.0	00:00		43	20	22		23:00	0.76	5.13		23:00	0.29	0.09		00:00	0	36.5	23:00	7.69	7.95		00:00	6.86	6.05		01:00
5	04/11/12	17:52	18:07	33.1	29.0	20:15		54	21	16		18:53	0.02	0.30		18:53	7.48	0.49		18:53	0	777	21:23	7.30	8.10		19:23	7.53	6.44		19:53
6	07/12/12	13:07	13:22	17.7	29.0	16:15		39	22	24		14:53	0.02	0.10		14:53	8.83	4.32		13:53	0	25.5	13:23	7.03	7.42		15:23	7.52	7.28		19:53
7	16/01/13	17:22	17:52	35.1	35.1	19:45		58	19	23		19:50	0.04	0.50		18:50	4.98	0.19		18:50	0	2751	18:20	7.40	7.95		19:50	7.29	5.57		19:50
8	02/02/13	17:07	17:37	21.7	30.0	19:15		50	20	23		19:20	0.02	0.45		18:20	9.71	0.6		18:20	0	2281	22:20	7.17	7.63		18:20	7.47	6.12		18:50
9	18/02/13	20:22	21:22	17.7	41.0	22:45		66	17	25		22:20	0.013	0.26		21:50	12.47	0.16		21:50	34.7	1071	01:20	7.24	7.82		21:50	7.07	5.33		21:50
10	20/02/13	20:07	20:22	25.5	39.0	22:15		64	16	24		21:20	0.013	0.17		20:50	13.44	0.49		20:50	29.1	617	23:50	7.27	7.66		21:20	6.96	5.07		21:20
11	04/04/13	20:37	21:52	32.2	35.0	23:15		67	17	25		23:12	0.28	1.26		22:12				10:12	6.3	1618	01:12	7.46	7.76		23:12	6.79	5.23		23:12
12	28/11/13	20:22	21:52	25.9	33.0	02:15		41	21	24		00:25	0.09	0.34		00:25	4.20	1.3		22:55	0	222	22:55	7.14	7.85		00:25	7.26	6.09		00:25
P value (Shapiro-Wilk test)					0.664				0.115				0.058				0.0878				9.99E-06			0.988				0.266
t e tc value (paired t test)					-7.84		2.201		-2.35		2.20		-2.92		2.20		3.484		2,228		x			6,95		2,14		6,747		2,20
P value (Wilcoxon test)					x				x				x				x				0,0005			x				x
13	4/2/12	23:30	23:45	19.7	220	02:15		308	61	44		00:00	1.41	1.58		01:00	0.51	0.30		23:30	900	2084	02:00	6.16	6.30		00:00	6.02	5.73		01:00
14	1/3/12	16:00	16:15	23.3	197	20:15		326	58	44		20:00	0.33	0.68		19:00	1.12	0.59		19:00	126	3000	19:00	5.36	5.68		19:00	6.12	5.89		19:00
15	14/3/12	17:15	17:30	27.2	176	20:45		203	67	84		19:35	0.27	0.59		19:05	1.35	1.02		21:35	47	620	20:35	4.89	3.83		19:05	6.46	6.26		22:05
16	22/3/12	19:00	19:30	20.8	181	00:15		271	70	72		20:05	0.29	0.55		00:05	1.32	0.77		23:35	89	911	23:35	4.48	6.27		00:05	6.30	6.13		00:05
17	26/3/12	22:00	22:15	20.3	178	03:15		228	72	66		03:19	0.45	0.52		23:34	1.09	0.87		02:34	114	337	06:49	3.30	6.06		04:04	6.36	6.27		02:04
18	10/9/12	16:00	18:00	19.1	177	22:15		251	68	73		19:16	0.12	0.30		19:16	6.50	12.80		20:16	116	913	19:16	6.40	5.94		19:16	6.63	6.4		21:16
19	21/12/121	16:30	16:45	41.5	173	21:15		361	87	51		20:22	1.38	4.29		19:52	0.50	0.36		19:52	8	887	20:22	4.45	5.18		23:52	6.55	5.76		07:22
20	2/2/13	17:30	17:45	14.9	167	23:45		227	79	64		04:57	1.17	1.77		23:27	0.48	0.57		05:57	38	278	06:27	4.90	4.10		19:27	6.66	6.44		09:57
21	9/2/13	17:15	19:15	21.9	187	00:15		319	75	52		01:27	0.89	2.62		23:27	0.58	0.34		23:27	27	851	23:27	5.43	5.14		08:57	6.70	6.32		02:57
22	18/2/13	20:30	21:15	27.0	233	01:45		442	65	39		01:57	0.72	3.95		00:57	0.68	0.33		00:57	57	1122	00:27	5.38	4.87		23:57	6.56	5.93		01:27
23	20/2/13	20:00	20:30	35.2	289	00:15		497	50	30		23:57	0.75	3.02		23:27	0.96	0.34		22:57	154	1343	23:27	5.17	5.85		22:57	6.29	5.85		00:27
24	25/2/13	14:00	17:30	33.4	241	21:45		364	50	44		22:27	0.68	1.48		22:57	0.98	0.61		22:57	58	862	21:27	5.44	4.36		17:57	6.51	6.27		22:57
25	5/3/13	09:30	10:00	19.8	207	14:45		380	56	44		16:20	2.20	8.68		13:20	0.25	0.14		11:20	13	438	13:20	6.01	6.63		00:20	6.77	6.19		19:20
26	24/10/13	02:45	06:00	16.3	192	10:15		335	58	67		09:59	0.06	0.16		09:59	3.10	5.71		07:59	272	1885	08:59	6.14	5.66		07:59	6.88	6.49		12:59
27	28/11/13	21:00	22:00	30.2	178	01:45		272	76	71		00:29	0.07	0.16		01:29	3.25	3.71		22:59	241	2073	02:59	3.09	5.68		02:59	6.95	6.64		14:29
P value (Shapiro-Wilk test)					0.996				0.533				0.189				0.0022				2.38E-05			0.187				0.119
t e tc value (paired t test)					-8.08		2.145		2.679		2.145		-2.82		2.145		x				x			-2.63		2.145		6.948		2.145
P value (Wilcoxon test)					x				x				x				0.2769				0.0001			x				x

Parameter	Quality water after heavy rainfall in Ombrophilous Dense Forest (FS1)	Water quality after heavy rainfall in multiple land use area (FS2)
Electrical conductivity	Increase in electrical conductivity from 2 to 8. Maximum increase in electrical conductivity occurred between 53 min and 4 h 03 min after the rainfall began. In 8 of 12 events, the maximum alteration occurred less 2 h after precipitation began.	In 10 of the 14 events, the water had decreased ion concentration. Reduction of 6 to 36 µS.cm^–1; average of 16.9 µS.cm^–1. The maximum reduction occurred, on average, after 5 h after the rainfall began.
Ammonium	Concentration increased from 0.08 to 4.37 mg.L^–1; 1.16 mg.L^–1, on average. The biggest concentration increase occurred, on average, after 1 h 12 min of rainfall.	Concentration increased from 0.07 to 6.48 mg.L^–1; 1.30 mg.L^–1 on average. The maximum increase occurred about 4h 16 min after rainfall began.
Nitrate	Reduction of 0.20 to 12.95 mg.L^–1, with the average time being 1h 23 min after rainfall began.	Reduction of 0.11 to 0.62 mg.L^–1 in 11 of the 14 events. The maximum reduction occurred, on average, 4 h after rainfall began.
Turbidity	Turbidity increased, from 10.3 to 2751 NTU. In half of the events, the maximum turbidity continued until 2 h after the rainfall began. However, it oscillated between 16 min and 8 h 43 min, presenting average time of 2 h 57 min.	Turbidity increased from 223 to 2874 NTU; 1022 NTU on average. The maximum turbidity occurred between 2 h 30 mins and 13 h after the beginning of rainfall; 5h 17 min on average.
Dissolved oxygen	Little increase, from 0.26 to 0.80 mg.L^–1, with an average value of 0.50 mg.L^–1. The maximum value was found after 2 h of rainfall beginning.	In half of the events, an increase of 1.2 mg.L^–1 occurred (on average), and in the others, a decrease of 0.67 mg.L^–1 (on average). The extreme values were found, on average, after 5 h 41 min of the rainfall beginning.
pH	Reduction from 0.21 to 1.89; average of 1.19. The minimum value was found, on average, after 2 h 26 min of the rainfall beginning.	Reduction from 0.09 to 0.63; average of 0.337. The minimum value was found from 01 h 30 min to 10 h 14 min after the precipitation began, with an average time of 6 h 44 min.

FS1			FS2
PC	% variance	% CMT	PC	% variance	% CMT
PC 1	98.8310	98.831	PC 1	99.7740	99.774
PC 2	1.16830	99.999	PC 2	0.17703	99.951
PC 3	0.00071	100.000	PC 3	0.03167	99.983
PC 4	0.00035	100.000	PC 4	0.01403	99.997
PC 5	0.00004	100.000	PC 5	0.00287	100.000
PC 6	0.00001	100.000	PC 6	0.00036	100.000
PC 7	0.00000	100.000	PC 7	0.00001	100.000

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