Building on a hilly site? Want more water? Use Incan design techniques!

The Incans, and this can especially be seen at Machu Picchu, needed to purify their water before and after use in order to give it back to the environment in a way that was sustainable. To accomplish this, they built their cities on terraces. Each of the terraces was constructed of a stone wall foundation around the perimeter. This was then filled with larges boulders, then large stones, then small stones, then gravel. The terrace will then filled to the brim with earth, which was either built upon or planted. This technique stored tens of thousands of gallons of pure, clean water for future use. If you live in an area that has at least 40 inches of rain per pear, this technique can work for you too!