In geomorphologic studies it is pointed out that the palaeo-geography of the area was composed of main water courses with direction SW-NE which from the Appennines entered the Adriatic Sea. At the same time their tributaries ran perpendicularly to the previous.

The border line regression and the persisting of orogenesis pushes, which rises the Appennines, increase the erosion action of the main water courses, which widen their catchment area through river capturing, leaving parallel valleys in the river beds. The present hydrographic network, which may appear complicated because of its apparent water courses independence, is in fact attributed to an evolution scheme characterised by successive river captures. It's in this particular mechanism that the origin and evolution of the “Gorge of Frasassi” and the “Gorge of Rossa” can be included. Then the opening and evolution of the “Gorge of Frasassi” were realised through progressive cuttings of the calcareous watershed represented by mountain Valmontagna – mountain Frasassi ,where the water courses diametrically opposed to each other, integrated both by rock breaks and by a particular and magnificent carsism, made possible water captures by the catchment area of Appennines, giving then birth to the present hydrographic order.