From the Goglio road bridge we take the paved road towards Devero and follow it up to the fork in the road towards Ausone and Agaro (it is possible to leave the car here as well). We take the track towards Agaro up to past the third hairpin bend where a track towards Costa detaches on the right. The path proceeds along the mountainside, goes down to the river, and goes back up next to an ancient windmill towards the Agarina Alpine lodging houses. The track carries on flatly up until we arrive to the nice Walser village of Costa. We go back up a slight path up to where we cross the path which comes down from Piodacalva and we then start going up the H06 small path which crosses Balmelle and goes up to under the imposing Agaro Lake Dam, built in the years 1936-1938 thus sinking the basin where the ancient Agaro Municipality was built and populated for seven centuries by about one-hundred people. With the Enel service road we go up to the top of the dam in order to be able to see the lake from where we go back to the entrance of the tunnel. Going down from Agaro to Goglio we must pursue the tunnel in the plain within which the pressure pipeline can be found as part of the dam. The tunnel is 1.5 km long, and one must remember to turn on the light at the beginning of the tunnel (look for a switch with a timer). Upon exiting the tunnel we proceed along the road which goes by the nice Walser village of Ausone (also known as Opso in the Walser language), and continuing to follow the same road we return to Goglio.