2:1.1.1.2 Antecedent Soil Moisture Condition

SCS defines three antecedent moisture conditions: I—dry (wilting point), II—average moisture, and III—wet (field capacity). The moisture condition I curve number is the lowest value the daily curve number can assume in dry conditions. The curve numbers for moisture conditions I and III are calculated with the equations:

$CN_1=CN_2-\frac{20*(100-CN_2)}{(100-CN_2+exp[2.533-0.0636*(100-CN_2)])}$ 2:1.1.4

$CN_3=CN_2*exp[0.00673*(100-CN_2)]$ 2:1.1.5

where $CN_1$ is the moisture condition I curve number, $CN_2$ is the moisture condition II curve number, and $CN_3$ is the moisture condition III curve number.