Hydrophobic sand erodibility remediation with biopolymers under long-term environmental conditions
- 1University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
- 2Corresponding author.
Abstract
This paper investigates the advantages and limitations of hydrophobic sand surficial improvement using biotreatments. Xantham gum (X.G.) at different concentrations in sand represents the biopolymer class of materials. The study aims to simulate wildfire-burned sands through highly hydrophobic sands at various high and low-rain-intensity slopes in controlled experimental conditions. In addition, a 6-month exposure to environmental conditions like wind, rain, tree debris, and animal interactions assesses the effectiveness of long-term treatment. Results show that sand type is a governing parameter, and fine sands require the highest X.G. percentage. During prolonged rain, surface morphology evolves with ridges that can fail. Results show that, at a 50 mm/h rain, when left uncured, the XG-soil mix provides catastrophic erosion, more so than untreated hydrophobic sand, while those with 1 %–3 % X.G. concentrations in the mixed layer cured for 24 h yielded significantly less erosion. Therefore, the study proposes covering hydrophobic slopes with X.G. and hydrophilic sand mix sprayed with 16.5 % water per X.G. and sand mix mass and cured for 24 h. During environmental studies, initial treatments of uncured 0.5 % X.G. mixed with sand provided little erosion reduction compared to the unmitigated hydrophobic slopes but mostly observed even more erosion. With fully formed channels in the slopes, the top layer, re-covered with a 3 % XG-sand mix and cured, shows the effects of the mitigation technique on previously eroded slopes. At a higher intensity than the previous storms, this method performs better than the 0.5 % X.G. uncured mix, but overwetted sections that were not dry before the next storm led to enhanced erosion. Cumulative erosion between rain events reveals similar erosion trends between the three sand types, with fine sand slopes eroding slightly more.
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BibTeX
@article{rosas2026hydrophobic,
title = {{Hydrophobic sand erodibility remediation with biopolymers under long-term environmental conditions}},
author = {Jonathon Chavez De Rosas and Ingrid Tomac},
journal = {Biogeotechnics},
year = {2026},
month = oct,
doi = {10.1016/j.bgtech.2025.100180},
url = {https://doi.org/10.1016/j.bgtech.2025.100180},
note = {CC BY},
}
RIS
TY - JOUR
TI - Hydrophobic sand erodibility remediation with biopolymers under long-term environmental conditions
AU - Jonathon Chavez De Rosas
AU - Ingrid Tomac
PY - 2026
DA - 2026/10/30
JO - Biogeotechnics
DO - 10.1016/j.bgtech.2025.100180
UR - https://doi.org/10.1016/j.bgtech.2025.100180
AB - This paper investigates the advantages and limitations of hydrophobic sand surficial improvement using biotreatments. Xantham gum (X.G.) at different concentrations in sand represents the biopolymer class of materials. The study aims to simulate wildfire-burned sands through highly hydrophobic sands at various high and low-rain-intensity slopes in controlled experimental conditions. In addition, a 6-month exposure to environmental conditions like wind, rain, tree debris, and animal interactions assesses the effectiveness of long-term treatment. Results show that sand type is a governing parameter, and fine sands require the highest X.G. percentage. During prolonged rain, surface morphology evolves with ridges that can fail. Results show that, at a 50 mm/h rain, when left uncured, the XG-soil mix provides catastrophic erosion, more so than untreated hydrophobic sand, while those with 1 %–3 % X.G. concentrations in the mixed layer cured for 24 h yielded significantly less erosion. Therefore, the study proposes covering hydrophobic slopes with X.G. and hydrophilic sand mix sprayed with 16.5 % water per X.G. and sand mix mass and cured for 24 h. During environmental studies, initial treatments of uncured 0.5 % X.G. mixed with sand provided little erosion reduction compared to the unmitigated hydrophobic slopes but mostly observed even more erosion. With fully formed channels in the slopes, the top layer, re-covered with a 3 % XG-sand mix and cured, shows the effects of the mitigation technique on previously eroded slopes. At a higher intensity than the previous storms, this method performs better than the 0.5 % X.G. uncured mix, but overwetted sections that were not dry before the next storm led to enhanced erosion. Cumulative erosion between rain events reveals similar erosion trends between the three sand types, with fine sand slopes eroding slightly more.
SN - 2949-9291
ER -