Permeabilidade do solo

Synopsis: If you've ever been to the beach, you should have noticed that right after the wave passes quickly, the sand is dry. If you enjoy one more ride off road should have noticed that the dirt roads after a rain formed pools of water enormous. Can you explain why this happens?
Source: UFMG - Pontociência, Janaina Garcia.
URL: http://www.pontociencia.org.br/experimentos-interna.php?experimento=877&PERMEABILIDADE+DOS+SOLOS#top