Bing found the following results
Stream bed - Wikipedia
Riverbed Technology - Wikipedia
Riverbed Definition & Meaning - Merriam-Webster
RIVERBED | English meaning - Cambridge Dictionary
Streambed | Riverbed, Erosion & Sedimentation | Britannica
Learning to live with rivers, a matter of geomorphology
Understanding Rivers - National Geographic Society
Rivers and Streams: Life in Flowing Water - Nature
Glossary of River Terms - EnchantedLearning.com
How River Beds Move | Science