Which factor contributes to increased flood hazards in waterways?

Increased sediment in streams significantly contributes to flood hazards in waterways. When sediment levels rise, often due to erosion from land disturbance or poor land management, it can lead to the clogging of waterways. This accumulation of sediment can reduce the channel capacity, causing water to back up and increase the likelihood of flooding during heavy rainfall or storm events. Furthermore, sediment can disrupt the natural flow of water, impacting the ecosystem and leading to further degradation and instability of the streambank, which can exacerbate flooding issues.

In contrast, clear-cutting forests can lead to higher runoff and erosion, but it does not directly correlate to the immediate increase in sediment levels in the same way. Reduced impervious surfaces typically lead to decreased flood hazards, as they allow for more absorption of water into the ground. Higher vegetation growth generally promotes stability in soil and helps in flood risk reduction by improving water absorption and slowing down runoff.