[en] Mathematical models for the transport of radon through two strata media are described. The bilayer model reduces to a transport equation for a single layer of finite depth when the upper layer does not exist. The finite model approaches a simpler expression, an infinite model, when depths exceed several meters. Summarized are the media parameters for several land types found in the West Central Florida phosphate region. Measured flux values by land type are compared to predicted flux values for the respective land type. The bilayer model is used to demonstrate reclamation management to reduce radon flux at the soil surface