Infiltração - Hidrologia Básica
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Infiltração - Hidrologia Básica


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de argila total) e ainda com camada densificada a uns 50cm de 
profundidade. Ou solos arenosos como B, mas com camada argilosa quase impermeável ou horizonte 
de seixos rolados. 
 
GRUPO E - Solos barrentos como C, mas com camada argilosa impermeável ou com pedras. Pode 
também não possuir tal camada, mas apresenta teor total de argila superando 40%. No caso de terras 
roxas este teor pode alcançar 60% (no caso D, 45%). 
 
c.2 - Condições de Uso e Ocupação do Solo 
 
A Tabela 7.1 a seguir fornece valores de CN para os diferentes tipos de solo e respectivas condições de 
ocupação. 
 
Essa Tabela refere-se à condição II de umidade antecedente do solo. 
 
Q-A-P=G e 
G+AS ;AP com
S+A-P
)A-(P=Q
i
ii
i
2
i
\u2265\u2265 
 
 0,8S+P
)0,2S-(P=Q
2
 
 
HIDROLOGIA BÁSICA 
Capítulo 7 - Infiltração 
 
 
 
 
7.6
c.3 - Condições de Umidade Antecedente do Solo 
 
O método do SCS distingue 3 condições de umidade antecedente do solo: 
CONDIÇÃO I - solos secos - as chuvas nos últimos 5 dias não ultrapassam 15mm. 
CONDIÇÃO II - situação média na época das cheias - as chuvas nos últimos 5 dias totalizaram entre 
15 e 40mm. 
CONDIÇÃO III - solo úmido ( próximo da saturação ) - as chuvas nos últimos 5 dias foram superiores 
a 40mm e as condições meteorológicas foram desfavoráveis a altas taxas de evaporação. 
 
A Tabela 7.2 permite converter o valor de CN para condição I ou III, dependendo das necessidades do 
projetista. 
 
TABELA 7.1 - Numeração das Curvas de Escoamento Superficial de Chuvas Intensas Conforme o 
Complexo Hidrológico do Solo com a sua Cobertura Vegetal (Condição II de 
umidade antecedente) 
\u2554\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2566\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2566\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2566\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2557
\u2551 COBERTURA VEGETAL OU \u2551 DEFESA \u2551 SITUAÇÃO \u2551 GRUPO HIDROLÓGICO \u2551
\u2551 OU TIPO DE USO \u2551 CONTRA \u2551 HIDROLÓGICA \u2551 DO SOLO \u2551
\u2551 DO SOLO \u2551 A \u2551 DA \u255f\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2562
\u2551 \u2551 EROSÃO \u2551 INFILTRAÇÃO \u2551 A \u2502 B \u2502 C \u2502 D \u2502 E \u2551
\u2560\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u256c\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u256c\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u256c\u2550\u2550\u2550\u256a\u2550\u2550\u2550\u256a\u2550\u2550\u2550\u256a\u2550\u2550\u2550\u256a\u2550\u2550\u2550\u2563
\u2551 Arado, quase sem \u2551 SR \u2551 Boas \u2551 65\u2502 80\u2502 88\u2502 92\u2502 95\u2551
\u2551 cobertura vegetal \u2551 C \u2551 Boas \u2551 65\u2502 78\u2502 88\u2502 90\u2502 92\u2551
\u255f\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u256b\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u256b\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u256b\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2562
\u2551 Cultivos de ciclo \u2551 SR \u2551 Más \u2551 80\u2502 72\u2502 81\u2502 87\u2502 90\u2551
\u2551 curto e arações \u2551 SR \u2551 Boas \u2551 52\u2502 66\u2502 75\u2502 82\u2502 85\u2551
\u2551 frequentes \u2551 C \u2551 Más \u2551 56\u2502 65\u2502 78\u2502 84\u2502 87\u2551
\u2551 \u2551 C \u2551 Boas \u2551 48\u2502 60\u2502 72\u2502 78\u2502 82\u2551
\u2551 \u2551 CT \u2551 Más \u2551 52\u2502 62\u2502 74\u2502 80\u2502 84\u2551
\u2551 \u2551 CT \u2551 Boas \u2551 45\u2502 55\u2502 67\u2502 75\u2502 80\u2551
\u255f\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u256b\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u256b\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u256b\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2562
\u2551 Cultivos de ciclo \u2551 SR \u2551 Más \u2551 58\u2502 65\u2502 73\u2502 82\u2502 88\u2551
\u2551 médio, arações \u2551 SR \u2551 Boas \u2551 54\u2502 62\u2502 70\u2502 79\u2502 85\u2551
\u2551 anuais \u2551 C \u2551 Más \u2551 55\u2502 64\u2502 72\u2502 78\u2502 84\u2551
\u2551 \u2551 C \u2551 Boas \u2551 50\u2502 60\u2502 67\u2502 75\u2502 83\u2551
\u2551 \u2551 T \u2551 Más \u2551 52\u2502 62\u2502 70\u2502 77\u2502 82\u2551
\u2551 \u2551 T \u2551 Boas \u2551 48\u2502 55\u2502 65\u2502 73\u2502 80\u2551
\u255f\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u256b\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u256b\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u256b\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2562
\u2551 Semeação densa ou a \u2551 SR \u2551 Más \u2551 56\u2502 64\u2502 72\u2502 80\u2502 86\u2551
\u2551 lanço; cobertura curta, \u2551 SR \u2551 Boas \u2551 50\u2502 58\u2502 66\u2502 76\u2502 82\u2551
\u2551 mas densa, como a das \u2551 C \u2551 Más \u2551 54\u2502 60\u2502 69\u2502 76\u2502 83\u2551
\u2551 leguminosas e dos \u2551 C \u2551 Boas \u2551 48\u2502 56\u2502 64\u2502 72\u2502 80\u2551
\u2551 postos em rodízio \u2551 T \u2551 Más \u2551 50\u2502 58\u2502 65\u2502 75\u2502 80\u2551
\u2551 \u2551 T \u2551 Boas \u2551 40\u2502 52\u2502 60\u2502 70\u2502 70\u2551
\u255f\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u256b\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u256b\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u256b\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2562
\u2551 Pastagem velha com \u2551 \u2551 Más \u2551 65\u2502 70\u2502 78\u2502 85\u2502 90\u2551
\u2551 arbustos \u2551 \u2551 Médias \u2551 60\u2502 66\u2502 75\u2502 82\u2502 87\u2551
\u2551 \u2551 \u2551 Boas \u2551 56\u2502 62\u2502 72\u2502 79\u2502 84\u2551
\u2551 \u2551 C \u2551 Más \u2551 55\u2502 62\u2502 70\u2502 78\u2502 86\u2551
\u2551 \u2551 C \u2551 Médias \u2551 42\u2502 59\u2502 67\u2502 75\u2502 82\u2551
\u2551 \u2551 C \u2551 Boas \u2551 50\u2502 56\u2502 64\u2502 72\u2502 79\u2551
\u255f\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u256b\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u256b\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u256b\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2562
\u2551 Mata, \u2551 \u2551 Más \u2551 32\u2502 40\u2502 55\u2502 67\u2502 76\u2551
\u2551 Capoeira velha \u2551 \u2551 Boas \u2551 18\u2502 25\u2502 42\u2502 58\u2502 70\u2551
\u255f\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u256b\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u256b\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u256b\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2562
\u2551 Gramados tratados \u2551 \u2551 Más \u2551 65\u2502 72\u2502 78\u2502 84\u2502 88\u2551
\u2551 \u2551 \u2551 Boas \u2551 59\u2502 67\u2502 74\u2502 81\u2502 86\u2551
\u255f\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u256b\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u256b\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u256b\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2562
\u2551 Estradas de terra \u2551 SR \u2551 Más \u2551 80\u2502 85\u2502 90\u2502 93\u2502 95\u2551
\u2551 \u2551 C \u2551 Boas \u2551 74\u2502 80\u2502 86\u2502 90\u2502 92\u2551
\u255a\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2569\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2569\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2569\u2550\u2550\u2550\u2567\u2550\u2550\u2550\u2567\u2550\u2550\u2550\u2567\u2550\u2550\u2550\u2567\u2550\u2550\u2550\u255d
SR = sulcos retos 
HIDROLOGIA BÁSICA 
Capítulo 7 - Infiltração 
 
 
 
 
7.7
C = cultivo acompanhando as curvas de nível 
T = terraceamento 
 
 
 
TABELA 7.2- Conversão das Curvas CN para as diferentes Condições de Umidade do solo \u2554\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2557
\u2551 NUMERAÇÃO DAS CURVAS PARA AS CONDIÇÕES DE SATURAÇÃO \u2551
\u2560\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2564\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2564\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2563
\u2551 I \u2502 II \u2502 III \u2551
\u2560\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u256a\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u256a\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2563
\u2551 100 \u2502 100 \u2502 100 \u2551
\u2551 87 \u2502 95 \u2502 99 \u2551
\u2551 78 \u2502 90 \u2502 98 \u2551
\u2551 70 \u2502 85 \u2502 97 \u2551
\u2551 63 \u2502 80 \u2502 94 \u2551
\u2551 57 \u2502 75 \u2502 91 \u2551
\u2551 51 \u2502 70 \u2502 87 \u2551
\u2551 45 \u2502 65 \u2502 83 \u2551
\u2551 40 \u2502 60 \u2502 79 \u2551
\u2551 35 \u2502 55 \u2502 75 \u2551
\u2551 31 \u2502 50 \u2502 70 \u2551
\u2551 27 \u2502 45 \u2502 65 \u2551
\u2551 23 \u2502 40 \u2502 60 \u2551
\u2551 19 \u2502 35 \u2502 55 \u2551
\u2551 15 \u2502 30 \u2502 50 \u2551
\u2551 12 \u2502 25 \u2502 45 \u2551
\u2551 9 \u2502 20 \u2502 39 \u2551
\u2551 7 \u2502 15 \u2502 33 \u2551
\u2551 4 \u2502 10 \u2502 26 \u2551
\u2551 2 \u2502 5 \u2502 17 \u2551
\u2551 0 \u2502 0 \u2502 0 \u2551
\u255a\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2567\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2567\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u255d
 
 
c.4 - Roteiro de Cálculo 
 
1 - Determinar as condições de saturação do solo; 
2 - Determinar grupo hidrológico do solo; 
3 - Através da Tabela 7.1 da cobertura vegetal e do grupo hidrológico, determinar o CN 
para a condição II; 
4 - Transformar o CN para a condição desejada pela Tabela 7.2; 
5 - Uma vez com a curva CN conhecida e com a precipitação total, a Figura 7.4, fornece 
o escoamento superficial. 
 
d) Coeficientes da fórmula de Horton oriundos da classificação hidrológica dos solos 
 
A experiência do SCS permite a indicação de valores aproximados de fo, fc e k da fórmula de 
HORTON (ver Tabela 7.3). 
 
 
 
 
 
 
TABELA 7.3- Aplicação da Fórmula de Horton para Diferentes Tipos de Solos \u2554\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2566\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2557
HIDROLOGIA BÁSICA 
Capítulo 7 - Infiltração 
 
 
 
 
7.8
\u2551 \u2551 Classificação Hidrológica do Solo (SCS)\u2551
\u2551 Parâmetros da Fórmula de Horton\u2560\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2564\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2564\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2564\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2563
\u2551 \u2551 \u2502 \u2502 \u2502 \u2551
\u2551 \u2551 Tipo A \u2502 Tipo B \u2502 Tipo C \u2502 Tipo D \u2551
\u2560\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u256c\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u256a\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u256a\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u256a\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2563
\u2551 taxa de infiltração inicial do \u2551 \u2502 \u2502 \u2502 \u2551
\u2551 solo seco: fo (mm/h) \u2551 250 \u2502 200 \u2502 130 \u2502 80 \u2551
\u255f\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u256b\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2562
\u2551 taxa de infiltração final do \u2551 \u2502 \u2502 \u2502 \u2551
\u2551 solo úmido: fc (mm/h) \u2551 25 \u2502 13 \u2502 7 \u2502 3 \u2551
\u255f\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u256b\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2562
\u2551 fator de forma-expoente K \u2551 2 \u2502 2 \u2502 2 \u2502 2 \u2551
\u255a\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2569\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2567\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2567\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2567\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u255d
 
 
d) Medição Direta da Capacidade de Infiltração 
 
A maneira mais precisa de determinar a capacidade de infiltração é através da medição da 
diferença entre a quantidade de água precipitada e o escoamento superficial, o que pode ser 
feito por meio de estudos hidrológicos em bacias hidrográficas representativas. Para o caso 
de irrigação não há necessidade de muita precisão, podendo-se determiná-la com o auxílio 
de infiltrômetro, que é mais rápido. Tais infiltrômetros podem ser de dois tipos: de 
inundação e de aspersão. 
 
O infiltrômetro de inundação consta de dois anéis concêntricos medindo respectivamente ao 
redor de 40 a 16 cm de diâmetro que são cravados no terreno até uma profundidade de 10 a 
15 cm. A cravação não deve ser feita por percussão, o que além de provocar a penetração 
irregular do cilindro, vai rompendo a estrutura da camada de solo em contato com o 
cilindro. A melhor maneira é utilizar um macaco hidráulico, que é colocado sobre uma tábua 
apoiada no cilindro. A finalidade do cilindro externo é manter verticalmente o fluxo de água 
do cilindro interno, onde é feita a medição da capacidade de infiltração. Aplica-se água em 
ambos os cilindros mantendo uma lâmina líquida de 1 a 5 cm, sendo que no cilindro interno 
mede-se o volume aplicado