Stories in Washington

Two Minute Takeaway: What Is Riprap?

A coastal shore lined with rocks with some illustrative additions.
Two Minute Takeaway Riprap demonstration. © TNC

Welcome to the Two-Minute Takeaway, a quick explanation of scientific terms and concepts we use regularly in conservation.

Along Washington’s coasts, communities look to their shores as a first line of defense against surging waves, strong storms and rising seas.

 Graphic explaining riprap.
Two Minute Takeaway What is Riprap? © TNC

Where natural coastal habitats have been removed, riprapranging from large rocks to massive concrete blocksis a man-made solution that can actually degrade the ecosystem. Riprap alters sediment transport and sand composition, depletes some invertebrate populations, and buries fish-spawning habitat, among other negative impacts.

When coastal habitats are preserved, nature’s innate resilience goes to work—trapping sediment and reducing wave energy to limit erosion and floods due to strong seas, filtering water and supporting important habitats.