Recipe for a Sand Dune

Recipe for a Sand Dune. From the kitchen of Mother Nature. , 1. Dig a huge hole with a glacier. Use the ice to grind up millions of tons of rock and dirt and make ridges around the edge of the hole., 2. Fill the hole with glacial meltwater. Stir your brand new lake with strong prevailing northwest winds., 3. Find the grains of sand needed for your dunes that are mixed within the ridges. The challenge is to sort the sand from all the clay, pebbles, and rocks., 4. Use wind-whipped waves to erode the ridges and sort out the grains of sand. (The clay will settle to the bottom of the lake and the bigger rocks won’t move far.) The sand will be washed by waves and currents to the south and east parts of the lake., 5. Watch sandbars and beaches form at the water’s edge. Continue to use wind and waves to wash more sand to the beach and blow the “beached” sand inland., 6. Use marram grass, cottonwood and basswood trees to slow the wind so the sand grains are dropped. Watch the due rise higher and higher as the plants catch more sand., Note: This recipe can be tricky since the amount of water depends on rain and snow. When the lake level rises the dunes may erode; when the level falls the dunes will grow. Either result is natural and beautiful. Don’t get your heart set on just one level. Give the recipe room to move and enjoy the changes you see. That’s the beauty of nature’s recipe.