Beaver-pond sequences in northwestern Montana: Morphology and sedimentation

Abstract

Beaver ponds are prominent features in many mountain streams; in places occurring as sequences resembling stair steps. Beaver-pond sequence morphology and sedimentation patterns are poorly represented in the literature. I documented the morphology of two beaver-pond sequences in northwestern Montana by describing the sequences, mapping the ponds, and developing longitudinal profiles. I collected data on sediment depth, and took sediment samples along longitudinal and cross-pond transects. I analyzed the data for longitudinal and lateral patterns of sediment texture within ponds, and found no patterns. I further analyzed the data for correlation between distance from the head of each sequence and the percentage of sand in each sediment sample, and found no relationship. Finally, I found that older ponds sequester more sediment than younger ponds. Based on these results, I suggest additional research questions.