WEPP MODEL FOR RILL EROSION ESTIMATION IN A BRAZILIAN SEMIARID WATERSHED

PISCOYA, VICTOR CASIMIRO; SOUZA, WALDEMIR PEREIRA DE; CANTALICE, JOSÉ RAMON BARROS; CUNHA FILHO, MOACYR; MELO, ROBSON CARLOS PEREIRA DE; ARAÚJO FILHO, RENISSON NEPONUCENO DE

doi:10.1590/1983-21252020v33n327rc

Acessibilidade / Reportar erro

Brasil

Español English

sumário « anterior atual seguinte »

Sumário

Technical Note • Rev. Caatinga 33 (3) • Jul-Sep 2020 • https://doi.org/10.1590/1983-21252020v33n327rc copy

WEPP MODEL FOR RILL EROSION ESTIMATION IN A BRAZILIAN SEMIARID WATERSHED

ABORDAGEM WEPP EM EROSÃO DO SOLO PARA BACIAS HIDROGRÁFICAS DO SEMIÁRIDO BRASILEIRO

Authorship SCIMAGO INSTITUTIONS RANKINGS

ABSTRACT

Soil erosion is a major environmental problem in many parts of the world and represents a serious problem for sustainable agriculture and the environment, with direct and indirect impacts on soil quality and fertility. This study aimed to use the Water Erosion Prediction Project (WEPP) model to estimate rill erosion and determine soil physical and hydraulic properties, which are essential to investigate its performance. To this end, an experiment was carried out in the Exu Creek watershed, in Serra Talhada, semi -arid region of Pernambuco State (Brazil), under increasing flow rates: T1: 5.87 L min-1; T2: 12.10 L min-1; T3: 20.33 L min1; and T4: 27.57 L min-1. Liquid and solid discharges were sampled for determination and characterization of hydraulic parameters in preformed rill flows. Reynolds numbers between 2,019 and 6,929 and Froude numbers below 1 found in this study attest to occurrence of erosive rills. Soil losses due to rill erosion increased as flow rates increased. Rill erodibility was 0.0011 kg N-1 s-1, and critical shear stress (tc) was 1.91 Pa, collapsing rill sidewalls and increasing local uplift, wet perimeter, and rill hydraulic radius.

keywords:
Hydraulic relations; Flow rates; Erodibility; Shear stress

Grain size analysis			Classification
Sand	Silt	Clay	Texture	PD	BD
%			(g cm^-3)
59	21	20	Sandy loam	2.51	1.41

Parameter	Value
Area	579.40 Km²
Perimeter	138.89 Km
Watershed axial length	38.45 Km
Form factor	0.3876
Main Channel Length	58.09 Km
Main channel length folded	38.71 Km
Number of channels in the watershed	350 channels
Number of 1^st-order channels	176 channels
Number of 2^nd-order channels	40 channels
Number of 3^rd-order channels	10 channels
Number of 4^th-order channels	2 channels
Number of 5^th-order channels	1 channel
Total channel length	443.55 Km
Average channel length	1.27 Km
Drainage density	0.77 Km Km^-2
Hydrological density	0.61 channels Km^-2
Compactness coefficient	1.62
Highest watershed elevation	1006 m
Lower watershed elevation	400 m
Watershed altitude	606 m
Main channel slope	15.65 m km^-1
Sinuosity index	1.50
Concentration time	7.08 hours

Hydraulic Parameter	Applied flow (L min^-1)
Hydraulic Parameter	5.87	12.10	20.33	27.57
Q (L min ^-1)	5.12 B	7.86 B	17.22 A	20.15 A
V_m (ms^-1)	0.18 B	0.22 B	0.30 B	0.33 B
S (m m^-1)	0.06 A	0.07 A	0.06 A	0.06 A
R_e (adm)	2019.52 B	3210.11 B	5324.82 A	6929.97 A
F_r (adm)	0.48 A	0.65 A	0.80 A	0.82 A
log f (adm)	1.14 A	1.43 A	0.85 A	0.61 A
τ (Pa)	4.49 B	8.65 A	9.24 A	11.59 A

Parameter	Applied flow (L m^-1)
Parameter	5.87	12.10	20.33	27.57
Dr (Kg m^-2 s^-1)	0.0027 B	0.0075 B	0.0080 A	0.0223 A
SL (t ha^-1)	5.53 C	29.92 B	56.24 A	42.44 A

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