Claypans usually occur as remnants of old drainage systems or as areas that receive localised run off from surrounding sandy or rocky rises. They exist under natural flooding and drying regimes where floodwater carrying its load of sediment eventually slows to a standstill and deposits what is left of its load – usually fine lightweight clay particles. This low lying shallow water can remain for some time before it gradually soaks in to the ground and leaves a dry cracked clay surface. Claypans are often dismissed as patches of bare, flat and lifeless wasteland, however they provide a water storage service in areas where water is scarce. Although filled irregularly and unpredictably this storage is necessary for the life of many arid zone plants and animals, many of whom have adapted to take advantage of the opportunities that claypans provide. As a claypan fills it immediately provides an opportunity for seeds that have been lying around to germinate and grow and for dormant eggs from creatures like shield shrimps and desert fish to hatch. Frogs that have buried themselves deep into the ground resurface and begin to feed and breed. Insects and birds take advantage of the growing food supplies and will fly in from dry areas and remain while the claypan is moist before moving on to new opportunities when the claypan has finally dried up again.