Lecture 4b - Infiltration Models

Question 1

What is the Green-Ampt Model based on?

Answer 1

application of Darcy’s Law and the assumption of a Sharp Wetting Front moving vertically downward under for forces of gravity and capillary suction

Question 2

What is stage one of the Green Ampt Modeling process?

Answer 2

compute cumulative infiltration (F) needed to cause ponding and the associated time to ponding, tp

Question 3

What is stage 2 of the Green Ampt modeling process?

Answer 3

compute values of f for assumed values of F and the associated time increment

Question 4

What is the SCS Curve Number Method for Runoff/Inflitration Prediction based on?

Answer 4

empirical curve numbers

Question 5

Explain group A soils.

Answer 5

high infiltration rates and consist of coarse sands and gravels

Question 6

Explain group b soils.

Answer 6

moderately well drained and consist of moderately fine to moderately coarse textures

Question 7

Explain group c soils.

Answer 7

slow infiltration rates and consist of fine grained soils or soils which posses a constriciting layer at depth

Question 8

Explain group d soils.

Answer 8

very slow infiltration rates and generally possess high clay contents

Question 9

What are the three Antecedent Moisture Conditions (AMC)?

Answer 9

AMC I = dry, AMC II = moderate, AMC III = wet