DETERMINANT PLUVIOMETRIC CHARACTERISTICS OF SEDIMENT TRANSPORT IN A CATCHMENT WITH THINNED VEGETATION IN THE TROPICAL SEMIARID

SOUSA, MARCOS MAKEISON MOREIRA DE; PALÁCIO, HELBA ARAÚJO DE QUEIROZ; ANDRADE, EUNICE MAIA DE; RIBEIRO FILHO, JACQUES CARVALHO; MOURA, MATHEUS MAGALHÃES SILVA

doi:10.1590/1983-21252020v33n322rc

Acessibilidade / Reportar erro

Brasil

Español English

sumário « anterior atual seguinte »

Sumário

Agricultural Engineering • Rev. Caatinga 33 (3) • Jul-Sep 2020 • https://doi.org/10.1590/1983-21252020v33n322rc copy

DETERMINANT PLUVIOMETRIC CHARACTERISTICS OF SEDIMENT TRANSPORT IN A CATCHMENT WITH THINNED VEGETATION IN THE TROPICAL SEMIARID

CARACTERÍSTICAS PLUVIOMÉTRICAS DETERMINANTES NO TRANSPORTE DE SEDIMENTOS EM MICROBACIA COM VEGETAÇÃO RALEADA NO SEMIÁRIDO TROPICAL

Authorship SCIMAGO INSTITUTIONS RANKINGS

ABSTRACT

Knowing determinant factors of erosive process is essential to adopt soil conservationist and loss-mitigation measures. Therefore, the objective of this work was to assess the correlation between rainfall characteristics and sediment transport in the Semiarid region of Brazil. The study was conducted at the Iguatu Experimental Basin in the state of Ceará, Brazil, in a watershed with area of 1.15 ha. The vegetation was thinned by removal of plants with diameters below 10 cm, and the area remained with an arboreous cover of 60%. The following variables were evaluated from 2012 to 2016: rainfall depth (mm), rainfall duration (hours), maximum rainfall intensity in 5, 10, 15, 20, 30, 45, and 60 minutes (mm h^-1), mean rainfall intensity (mm h^-1), rainfall depth in the previous 5 days (mm), runoff depth (mm), and transported sediment (kg ha^-1). The records showed 158 rainfall events, 27 with surface runoff and 24 with sediment transport. The correlations were investigated by multivariate analysis of principal components (PC). The model explained 84% of total variance with four PC-PC1, PC2, PC3, and PC4 were formed, respectively, for disaggregating power of rainfall on soil particles, represented by the rainfall intensities; soil water content; runoff depth and sediment transport; and rainfall duration and interval between rainfalls. The highest factorial weight was found for the maximum intensity in 20 minutes, indicating the need for further hydrological studies focused on this variable at basin scale in areas of the Semiarid region of Brazil subjected to thinning of the vegetation.

Keywords:
Water erosion; Precipitation; Surface runoff

Climatic and vegetation characteristics			Physical and chemical soil attributes
Variable	Value	Unit	Horizons	A	B	BCv
Mean rainfall depth	880.1	mm	Layer (cm)	0 to 5	5 to 21	21 to 31
Maximum monthly mean temperature	31.7	ºC	Sand (g kg^-1)	137	205	182
Maximum monthly mean temperature	31.7	ºC	Silt (g kg ^-1)	447	405	470
Minimum monthly mean temperature	20.3	ºC	Clay (g kg ^-1)	416	390	348
Minimum monthly mean temperature	20.3	ºC	Silt / Clay	1	1	1
Mean annual solar radiation	5.63	kWh m ^-2 day ^-1	C (g kg ^-1)	24.1	13.3	10.2
Mean annual insolation	2897.6	h year ^-1	pH	7.6	8.2	8.2
Mean annual air relative humidity	61.8	%	Ca (cmol_c kg ^-1)	35	43	39
Mean annual air relative humidity	61.8	%	Mg (cmol_c kg^-1)	12	10	8.6
Mean annual wind speed	2.1	m s ^-1	K (cmol_c kg^-1)	1.04	0.37	0.29
Mean annual wind speed	2.1	m s ^-1	Na (cmol_c kg^-1)	0.13	0.13	0.15
Mean ET₀	1988	(mm year ^-1)	H + Al (cmol_c kg^-1)	1.7	1.2	1.2
Aridity index	0.44	-	CaCO₃ (cmol_c kg^-1)	145	144	151
Mean ground vegetation	100	%	P (mg kg^-1)	42	62	59
Mean arboreous vegetation	60	%	Electrical conductivity (dS m^-1)	0.48	0.3	0.29

Years	Total rainfall depth (mm)	Number of RE	Number of RE with runoff	Number of RE with sediment transport	Runoff depth (mm)	Sediment transport (Kg ha ^-1)
2012	764.7	34	11	8	35.41	290.56
2013	613.1	31	2	2	39.37	111.78
2014	772.1	36	13	13	58.25	306.85
2015	521.1	29	0	0	0,00	0,00
2016	679.8	28	1	1	1.08	6.63
Total	3350.8	158	27	24	134.11	715.82

	RD	I5	I10	I15	I20	I30	I45	I60	RI	PRD1	PRD2	PRD3	PRD4	PRD5	ROD	TS
RD	1.00
I5	0.67	1.00
I10	0.72	0.97	1.00
I15	0.73	0.95	0.99	1.00
I20	0.75	0.94	0.98	0.99	1.00
I30	0.78	0.92	0.96	0.98	0.99	1.00
I45	0.83	0.88	0.92	0.94	0.96	0.98	1.00
I60	0.87	0.85	0.89	0.91	0.93	0.96	0.99	1.00
RI	0.32	0.53	0.54	0.52	0.50	0.46	0.42	0.40	1.00
PRD1	-0.03	-0.05	-0.02	0.00	0.01	0.03	0.04	0.02	-0.11	1.00
PRD2	-0.01	0.02	0.04	0.06	0.07	0.08	0.07	0.05	-0.05	0.68	1.00
PRD3	0.00	0.05	0.06	0.06	0.05	0.06	0.05	0.03	-0.03	0.54	0.83	1.00
PRD4	0.03	0.10	0.11	0.11	0.10	0.10	0.08	0.07	-0.04	0.46	0.68	0.88	1.00
PRD5	0.06	0.10	0.11	0.11	0.10	0.10	0.09	0.09	-0.02	0.41	0.63	0.82	0.95	1.00
ROD	0.68	0.37	0.40	0.41	0.41	0.45	0.52	0.57	0.31	-0.02	0.05	0.08	0.17	0.18	1.00
TS	0.50	0.26	0.28	0.28	0.27	0.31	0.33	0.36	0.25	-0.06	0.13	0.20	0.29	0.31	0.79	1.00

Variable	Components
Variable	PC 1	PC 2	PC 3	PC 4
I20	0.987	0.033	0.083	-0.045
I15	0.981	0.033	0.090	-0.078
I30	0.980	0.039	0.124	0.007
I10	0.972	0.022	0.089	-0.100
I45	0.962	0.024	0.188	0.055
I5	0.944	0.008	0.070	-0.121
I60	0.936	0.004	0.244	0.093
RD	0.755	-0.062	0.473	0.268
PRD3	0.015	0.926	0.108	-0.034
PRD4	0.038	0.904	0.224	-0.052
PRD2	0.045	0.871	-0.007	0.017
PRD5	0.043	0.870	0.250	-0.063
PRD1	0.034	0.704	-0.191	0.114
TS	0.177	0.120	0.915	-0.052
ROD	0.349	0.016	0.861	-0.001
RAD	0.166	-0.060	0.067	0.897
RI	0.486	-0.109	0.173	-0.695
Eigenvalue	8.10	4.04	1.56	1.42
Variance explained %	44.99	22.45	8.68	7.87
Variance accumulated %	44.99	67.45	76.13	84

Universidade Federal Rural do Semi-Árido Avenida Francisco Mota, número 572, Bairro Presidente Costa e Silva, Cep: 5962-5900, Telefone: 55 (84) 3317-8297 - Mossoró - RN - Brazil
E-mail: caatinga@ufersa.edu.br

Acompanhe os números deste periódico no seu leitor de RSS

[1] *Corresponding author