Protecting a Camping Path from Heavy Rain

A Path That Washed Away

During a class camping trip, heavy rain sent water down a hillside. The moving water carried loose soil from the path leading to the campsite entrance. After the storm, deep ruts made the path difficult to use. Back at school, the class investigated designs for reducing this kind of damage.

Step 1: Students shaped matching clay hills in trays. They marked a path down each hill and spread 12 level teaspoons of dry sand along it. The sand represented loose path soil.

Step 2: Students changed the channels in the clay above each path. Channels are shallow grooves that water can follow. Design A had no channels. Design B had one channel pointing downhill toward the path. Design C had two slanted channels leading toward the tray's sides. Design D had four slanted channels leading toward the sides.

Step 3: A teacher poured two cups of room-temperature water through a sprinkler bottle over each hill in 30 seconds. The hill slope, path size, starting sand amount, bottle height, and pouring time stayed the same. Trays caught the water.

Step 4: Students collected the sand washed off each path. They let it dry without heating it, then measured it in level teaspoons. They rebuilt the hills with fresh sand and repeated the test twice. The graph adds the sand losses from three tests per design. The teacher also recorded how long each model design took to build. The models had no plant roots, and real storms can last much longer.