Geomorphic Heterogeneity

Understanding form and function across biomes through the lens of heterogeneity.

What is Geomorphic Heterogeneity?

Heterogeneity is simply the state of being diverse. Geomorphic heterogeneity refers to the spatial and temporal diversity of geomorphic units across the landscape, where a geomorphic unit is a landform shaped by a given process (e.g., point bars, channels, etc.).

Geomorphic heterogeneity in the channel and floodplain can result from and influence geomorphic, hydrologic, and biotic processes. I am interested in both looking at drivers of heterogeneity as well as the impact of geomorphic heterogeneity on fluvial ecosystems.

Image: Examples of geomorphic unit maps for river corridors in Utah (A, C, D, F) and Arizona (B, E) from Scamardo et al. (2023, JGR:ES).

Drivers of geomorphic heterogeneity in dryland, ephemeral streams

Photo: Ephemeral stream channel and floodplain, Twentyfive Mile Wash, Utah.

My research on heterogeneity has largely focused on variably inundated environments, including floodplains, ephemeral streams, and floodplains along ephemeral streams. Ephemeral streams make up the majority of river networks in drylands, yet are understudied compared to perennial rivers. Along with cross-agency collaborators, I am using field surveys, remote sensing, and morphodynamic modeling to understand how vegetation, morphology, and flood regime drive heterogeneity in ungauged, ephemeral watersheds across drylands like the southwestern U.S.

Read about it:

Scamardo, J., Nelson, P.A., Nichols, M., and Wohl, E., 2022, Modeling the relative morphodynamic influence of vegetation and large wood in a dryland ephemeral stream, Arizona, USA, Geomorphology 417. https://doi.org/10.1016/j.geomorph.2022.108444

Scamardo, J., Nichols, M., Rittenour, T., and Wohl, E., 2023, Drivers of Geomorphic Heterogeneity in Unconfined Non-Perennial River Corridors. Journal of Geophysical Research: Earth Surface, 128(8). https://doi.org/10.1029/2023JF007102

Scamardo, J. and Wohl, E., 2023, Recognizing the ephemeral stream floodplain: Identification and importance of flood zones in drylands. Earth Surface Processes and Landforms, https://doi.org/10.1002/esp.5754

Geomorphic heterogeneity influences flood attenuation

Geomorphic heterogeneity is also thought to be linked to a variety of ecosystem functions. Through interdisciplinary collaborations within the Cooperative Institute for Research to Operations in Hydrology, we are using sensor networks and hydrodynamic modeling to investigate how floodplain heterogeneity along rivers can attenuate flood hydrographs.

This work is on-going -- stay tuned for updates.

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