Great Sand Dunes National Park in Colorado is bordered on two sides by 13,000′ mountains. Herard Peak is seen here. As the snow melts in April and May it creates a wide shallow creek on the eastern edge of the dunes. This is the seasonal Medano Creek. It is perhaps my favorite part of the park and is what sets Great Sand Dunes apart from all other dune areas.
You can hike in the creek and on a hot day it feels like being at the ocean (at least for Coloradans). This creek has unique water surges due to the sand. The water pushes the sand and the sand builds up in small dams. Over time they give way to the water pressure and create water surges. This happens constantly during the flow making these surges look like waves within the shallow creek. It is very cool and can create waves as high as a foot according to the National Park Services’ website.
The creek disappears as it travels south and flows into an underground aquifer. The amount of water that is flowing will dictate the length of the creek. This is because the water needs to be absorbed through the sandy ground and into the aquifer.
The creek also helped to first create the dunes and now keeps them here. The sand blows up out of the southern valley and onto the dunes. Over time it get blown off the dunes and into the creek area. The water moves the sands south where it is dropped back in the valley to once again be picked up by the winds and re-deposited on the dunes.