Here's a great project for children of all ages. Playing with dirt and water is always fun, but this project also teaches children "fluid dynamics" - how water systems work. Lakes, rivers, streams, rapids, tributaries, dams ... can be built, modified, and experimented with.

While experimenting, children learn the principles of erosion, gravity, and water flow in the guise of play. They also lay the foundation for an understanding and appreciation of natural river systems and waterways.

As our children learn the wonders of the natural world, their commitment to environmental responsibility becomes second nature.

Prepare the Site

Plot an area you can dedicate to this project: 6′ X 10′ is a nice size. Too much bigger can overwhelm the child and make the project seem too daunting.

Backyard River System diagram

Gently sloping ground is best. If the spot you’ve selected is level, you can create the slope by digging out the lower third of the plot and putting this soil on the upper third. Use rocks or wood for a partial retaining wall on the upper end.

Let the Kids Take Over

First, have the kids dig the lake, or reservoir, at the top end of the plot. This should not be too deep. The bottom of the lake should be no deeper than the lower end of the river system.

Dig a shallow lake on the low end to collect the water. You have the option of putting in a small submersible electric pump to make a ‘closed system’ which will let your river run continuously. Otherwise, let the kids run the hose at the top end and dig a small, narrow runoff trench at the bottom end to direct the stream where the runoff can be put to use.

Keep the principle of gravity in mind when digging your river system so the water flows in a continuous stream. Be careful not to dig the upper portion too deep or the current will be too slow. If you have dug too deep, add rocks to raise the bottom level.

Kids playing in the dirt with toys


Now comes the real fun, and remember, this is for the kids, so let them do it!

Design your river system: add twists and turns, wide sections and narrow stretches. Deeper stretches will slow the water down, shallow spots will speed it up. Add a few rocks (“boulders”) in the narrow sections to create “rapids.” Make side pools and tributaries. Make forks in the river to split it in two. The separate streams can rejoin, or continue on independently.

Change the depth in upper sections to create waterfalls. Use a flat rock behind a waterfall to keep it from eroding. Put gravel in the riverbed in shallow areas. See how it changes the water flow. Dig a narrow trough to one side of a shallow section and observe the results.

Make a dam at the upper lake using a piece of wood, or small branches and rocks. Have part of the dam able to open, a ‘floodgate’ to feed your river.

Let the kids use their small toy tractors and ‘earth-moving’ equipment to help with the digging and landscaping.


Stand back and watch the childrens’ fertile imaginations take over. Soon there will be bridges and side roads, hills and valleys, places for their small figurine toys and miniature cars and trucks. Transplant some weeds or small shrubs for vegetation, and give the kids some small supplies from toy railroad sets: people, trees, houses. Soon the children will create their own miniature eco-system, complete with town, farm, or forest.

A project like this can last the whole summer, and provide endless opportunity for creative changes to the system.

Eventually the kids will outgrow their river system, but their memories and lessons learned about the ways of water movement will stay with them. When the time is right, you can take a shovel and rake and, in a matter of hours, have your backyard plot returned to its orderly state. Or better yet, now you’re ready to plant your own backyard organic salad garden!

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