Machine Learning-Based Flood Risk Assessment in Urban Watershed: Mapping Flood Susceptibility in Charlotte, North Carolina
Abstract
1. Introduction
- Examining the influence of hydrological and geomorphological factors on flood susceptibility in the Briar Creek watershed.
- Evaluating the predictive performance of various machine learning algorithms—including bagging, logistic regression, and XGBoost—to identify the most suitable model for flood risk assessment in the Briar Creek watershed.
- Producing a detailed flood susceptibility map of the Briar Creek watershed to support urban flood management, disaster preparedness, and policymaking.
2. Study Area
3. Materials and Methods
3.1. Data Acquisition and Processing
3.2. Machine Learning Model Selection
3.3. Hyperparameter Tuning (Grid SearchCV)
4. Results and Discussions
4.1. Correlation Analysis of Flood Conditioning Factors
4.2. Performance Metrics of Machine Learning Models
4.3. ROC Curve Interpretation
4.4. Feature Importance for Machine Learning Models
4.5. Flood Risk Susceptibility Map
4.6. Limitations and Potential Directions for Future Research
5. Conclusions
Author Contributions
Funding
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Data Type | Source | Temporal Coverage |
---|---|---|
Digital Elevation Model (1 m) | National Map Viewer—U.S. Geological Survey | 10 October 2024 (Published Date) |
Land Use/Land Cover (30 m × 30 m) | Multi-Resolution Land Characteristics Consortium | 2019 |
Precipitation (mm, 5 min interval) | National Water Information System (NWIS) | 1 January 2015–31 December 2022 |
Streamflow (m3/s, 5 min interval) | NWIS | 1 January 2015–31 December 2022 |
Soil Data | NRCS Geospatial Data Gateway | 22 October 2024 (Published Date) |
Model | Hyperparameter | Values Considered |
---|---|---|
Logistic Regression | Regularization Strength (C) Penalty Solver | 0.01, 0.1, 1, 10 12 liblinear, lbfgs, saga |
Bagging | n_estimator max_samples max_features | 50, 100, 150 0.5, 0.75, 1.0 0.5, 0.75, 1.0 |
XGBoost | n_estimators learning_rate | 50, 100, 150 0.00001, 0.0001, 0.01, 0.1 |
Model | Accuracy | Precision | Recall | F1 Score |
---|---|---|---|---|
Logistic Regression | 0.9792 | 1 | 0.9583 | 0.9787 |
Bagging | 0.9375 | 0.92 | 0.9583 | 0.9388 |
XGBoost | 0.9583 | 1 | 0.9167 | 0.9565 |
Model | Very High Risk (%) | High Risk (%) | Moderate Risk (%) | Low Risk (%) | Very Low Risk (%) |
---|---|---|---|---|---|
Logistic Regression | 5.55 | 8.66 | 12.04 | 21.56 | 52.20 |
Bagging | 0.25 | 22.47 | 19.23 | 18.50 | 39.55 |
XGBoost | 0.31 | 6.37 | 9.19 | 13.85 | 70.28 |
Agreement Between Models | Overlapping High-Risk (%) |
---|---|
All Models | 1.63 |
Logistic Regression and Bagging | 5.90 |
Logistic Regression and XGBoost | 1.76 |
Bagging and XGBoost | 1.97 |
Models | Very High Risk (%) |
---|---|
FEMA’s Classification | 5.29 |
Logistic Regression | 5.55 |
Bagging | 0.25 |
XGBoost | 0.31 |
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Shrestha, S.; Dahal, D.; Bhattarai, N.; Regmi, S.; Sewa, R.; Kalra, A. Machine Learning-Based Flood Risk Assessment in Urban Watershed: Mapping Flood Susceptibility in Charlotte, North Carolina. Geographies 2025, 5, 43. https://doi.org/10.3390/geographies5030043
Shrestha S, Dahal D, Bhattarai N, Regmi S, Sewa R, Kalra A. Machine Learning-Based Flood Risk Assessment in Urban Watershed: Mapping Flood Susceptibility in Charlotte, North Carolina. Geographies. 2025; 5(3):43. https://doi.org/10.3390/geographies5030043
Chicago/Turabian StyleShrestha, Sujan, Dewasis Dahal, Nishan Bhattarai, Sunil Regmi, Roshan Sewa, and Ajay Kalra. 2025. "Machine Learning-Based Flood Risk Assessment in Urban Watershed: Mapping Flood Susceptibility in Charlotte, North Carolina" Geographies 5, no. 3: 43. https://doi.org/10.3390/geographies5030043
APA StyleShrestha, S., Dahal, D., Bhattarai, N., Regmi, S., Sewa, R., & Kalra, A. (2025). Machine Learning-Based Flood Risk Assessment in Urban Watershed: Mapping Flood Susceptibility in Charlotte, North Carolina. Geographies, 5(3), 43. https://doi.org/10.3390/geographies5030043