Spatial distribution of post-settlement alluvium in the Middle Fork Vermillion River Valley, Illinois, USA

Human actions significantly impact landscapes’ evolution, influencing sediment production, transport, and storage. Previous work on the Upper Sangamon River Basin (USRB) in central Illinois demonstrated that the fly ash methodology for mapping Post-Settlement Alluvium (PSA) is relatively simple, effective, and inexpensive. We applied this method to 11 sites in the Middle Fork Vermillion River Basin (MFVRB) adjacent to the USRB. PSA in the MFVRB is 40-80 cm thick, like that of the USRB, indicating regional consistency in response to land use changes. However, PSA in the MFVRB is thicker in narrower valleys and thinner in wider valleys, displaying the opposite trend in the USRB. PSA thickness in the MFVRB is not linearly correlated with drainage area, stream power per unit area, or river slope. We propose a non-linear relationship between PSA thickness and valley width, where PSA thickness increases to a certain valley width before decreasing as the valley widens further. The differing relationships between PSA thickness and valley width and the scaling of valley width with drainage area in the two adjacent basins underscore the importance of local geological and geomorphic histories, which lead to differences in valley sedimentation and river responses to Euro-American agricultural land use changes.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Geology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2024

Author dc:creator

• Srivichainun, Nol

Contributors dc:contributor

• Anders, Alison M
• Rhoads, Bruce L

• Post-settlement
• Alluvium
• Fly Ash
• Middle Fork Vermilion River Basin
• Illinois

Statement dc:rights

• Copyright 2024 Nol Srivichainun

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/125693

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F125693