  We introduce a new phenomenological one-scale model for the evolution of
domain wall networks, and test it against high-resolution field theory
numerical simulations. We argue that previous numerical estimates of wall
velocities are inaccurate, and suggest a more accurate method of measurement.
We show that the model provides an adequate approximation to the evolution of
key parameters characterizing the evolution of the network. We use the model to
study possible scaling solutions for domain wall networks, and discuss some of
their cosmological consequences.
