Surface Water Hydrology Lecture 13: Infiltration

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Surface Water HydrologyLecture 13 Infiltration

• Readings
• Applied Hydrology Sections 4.3 and 4.4
• Handbook of Hydrology Sections 5.1 and 5.2
• Soil texture and classification
• Soil water properties, K(q), Y(q)
• Infiltration
• Green-Ampt method

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Particle size measurement
Seives of progressively smaller size to get size
Distribution of soil
http//www.soils.agri.umn.edu/academics/classes/so
il2125/doc/s2chp1.htm
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Soil Classification
USDA particle size classification lt 0.002mm is
clay 0.002 0.5mm is silt 0.5mm 10mm is sand gt
10mm is gravel
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USDA Soil Texture Triangle
A soil with 30 sand, 40 clay and 30 silt is a
Clay Loam
Silt 100 - Sand - Clay
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Variation of Saturated Hydraulic Conductivity
with Soil Texture
K
Se
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Y
K
q
q
K
Interconnection of Soil water properties
Y
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Double Ring Infiltrometer
Measure rate of fall in inner ring
Infilration
http//www.alwi.com/wastewater.php
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Infiltration by Hortons method
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Infiltration into a soil water column
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2
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Green-Ampt method
Relative saturation
Incremental change in soil water content as
wetting front passes
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Green-Ampt Parameter Definitions
Relative saturation
Incremental change in soil water content as
wetting front passes
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Math for Green Ampt
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Green-Ampt Parameters