N. K. Rastogi
0246810 m
Normal2.0 m
RISING WATER
Naman Kishan Rastogi PhD Candidate, University of Colorado Boulder

Naman Kishan Rastogi

Building a real-time operational early warning system for riverine flooding: river stage forecasting and flood inundation mapping at multiple-day lead times, with the Brahmaputra River Basin as the primary testbed.

Education

Ph.D. in Civil Engineering

2023 to Early Spring 2027
University of Colorado Boulder, CGPA 4.00/4.00, Advisor: Prof. Balaji Rajagopalan

M.Tech in Water Resources Engineering

2021 to 2023
Indian Institute of Science (IISc), Bangalore, CGPA 9.0/10.0, Advisor: Prof. Pradeep P. Mujumdar

B.Tech in Civil Engineering

2016 to 2020
G. B. Pant Institute of Engineering and Technology, Pauri, Uttarakhand, 91%, Institute Topper

Research Pipeline

The lens sweeps across the basin behind this page, zooming in on where calm flow gives way to flood risk.

HBPP
precip post-processing
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BHNM
stage forecasting
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BRACE
SWOT WSE reconstruction
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HEC-RAS
ensemble inundation

Bayesian hierarchical modeling

Stage and streamflow forecasting via hierarchical Bayesian networks (BHNM), and space-time precipitation post-processing (HBPP), in R and Stan.

SWOT satellite hydrology

Gauge-informed reconstruction of continuous water surface elevation from sparse SWOT altimetry (BRACE), across the Brahmaputra, Willamette, and CONUS-scale networks.

Causal & network analysis

Bayesian Causal Networks linking Brahmaputra streamflow and Colorado River drought to ENSO, IOD, and MJO drivers.

Probabilistic inundation mapping

Ensemble HEC-RAS 2D simulations driven by posterior stage samples, producing exceedance probability flood maps.

Research Experience & Projects

Unless noted otherwise, the work below is part of my Ph.D. research at the University of Colorado Boulder.

Real-Time Operational Early Warning System for Riverine Flooding

  • Developed a Bayesian hierarchical network model (BHNM) in R and Stan for probabilistic river stage forecasting at multiple day lead times across a rain-fed river network, published in Journal of Hydrology (doi:10.1016/j.jhydrol.2025.132894).
  • Built a space-time Hierarchical Bayesian Precipitation Post-Processor (HBPP) correcting spatial and temporal biases in ensemble precipitation forecasts over the Brahmaputra (about 580,000 km²) and Narmada (about 98,800 km²) basins; corrected forecasts drive VIC and SAC-SMA hydrologic models feeding the stage-forecasting framework (Water Resources Research, under review).
  • Coupled corrected ensemble forecasts with HEC-RAS 2D hydraulic simulation to generate ensemble-member probabilistic flood inundation and exceedance probability maps for an urban reach, validated against gauge and SWOT observations (Water Resources Research, under review).
  • Compiling an integrated gauge, SWOT, and precipitation dataset spanning 3,400+ river nodes as an open data descriptor (Nature Scientific Data, in preparation).
  • The framework is designed to generalize beyond the Brahmaputra to other large, data-scarce, monsoon-fed river basins.

Reconstructing River Water Surface Elevation from Sparse SWOT Observations (BRACE)

  • Reconstructed continuous sub-hourly water surface elevation across 569 SWORD nodes on the Willamette River, Oregon, from sparse SWOT altimetry, cross-validated against USGS gauges and independent pressure transducers (Water Resources Research, under review).
  • Extended BRACE to jointly model Sentinel-2-derived river width and SWOT width at matched nodes.
  • CONUS-scale extension: applying BRACE across 250+ USGS gauges to benchmark against OPERA DSWx-HLS and SWOT width products, and to isolate rain-affected versus non-rain WSE behavior.

Teleconnections & Atmospheric Science: Causal Drivers in the Brahmaputra and Colorado Basins

  • Built causal analysis models in R to map teleconnection hotspots driving interannual flood variability in the Brahmaputra Basin, identifying ENSO, IOD, and MJO as dominant SST and atmospheric circulation pathways (Earth's Future, doi:10.1029/2026EF008056).
  • Applied the same causal framework to diagnose atmospheric and oceanic drivers behind the 25-year drought over the Colorado River Basin.

Non-Stationary IDF Curve Modeling under Climate Change for Urban Flood Risk

M.Tech Thesis, Indian Institute of Science (IISc), Bangalore
  • Modeled non-stationary rainfall extremes using GEV-based IDF curves with climate-informed covariates.
  • Developed future IDF relationships for Bangalore under CMIP6 SSP scenarios using Python, R, QGIS, and ArcGIS.
  • Applied LSTM disaggregation, PCA, and fuzzy clustering to support flood design (EGU, doi:10.5194/egusphere-egu23-2673).

Water Resource Vulnerability Index for Hilly Districts of Uttarakhand

B.Tech Project, Govind Ballabh Pant Institute of Engineering and Technology
  • Evaluated hydrological, environmental, and socioeconomic indicators to quantify district-level water stress.
  • Built a composite WRVI using normalization and weighted indexing in Python and Excel.
  • Created regional vulnerability maps using ArcGIS to support policy recommendations.
SAFE GROUND Evacuated safely

Current Projects

Real-time operational early warning system

This entire page's backdrop is the live simulation: watch the water surface elevation climb on the clock below, then click the button to see what changes when a warning goes out ahead of time.

SAFEWARNINGDANGERCATASTROPHIC
2.0 mForecast water surface elevation
Warning system: off
Illustrative simulation of the forecast-to-warning pipeline, not live sensor data.
CONUS

BRACE at continental scale

Applying BRACE across 250+ USGS gauges to benchmark WSE against OPERA DSWx-HLS and SWOT width products.

Width

Sentinel-2 & SWOT width fusion

Jointly modeling Sentinel-2-derived river width and SWOT width at matched Willamette nodes.

Drought

Colorado River causal drivers

Diagnosing atmospheric and oceanic precursors behind the 25-year Colorado River Basin drought.

EGA

Brahmaputra network extension

Extending the published BCN paper with Exploratory Graph Analysis and correlation networks.

Monsoon

All-India monsoon precipitation

Causal drivers of All India Summer Monsoon Precipitation using graph-based Bayesian networks, feeding an upcoming AMS 2027 abstract.

Publications

2026
Understanding streamflow variability in the Brahmaputra River Basin through Bayesian causal networks
Rastogi, N. K., Nanditha, J. S., & Rajagopalan, B., Earth's Future Published
doi.org/10.1029/2026EF008056
2025
Bayesian hierarchical network model for forecasting daily river stage for rainfed river networks
Rastogi, N. K., Rajagopalan, B., & Ossandón, Á., Journal of Hydrology, 654, 132894 Published
doi.org/10.1016/j.jhydrol.2025.132894
2026
Space-time hierarchical Bayesian post-processing of ensemble precipitation forecasts (HBPP) across the Brahmaputra and Narmada basins
Rastogi, N. K., Kleiber, W., & Rajagopalan, B., Water Resources Research
Submitted May 2026, reviewer comments received Oct 2026
2026
Reconstructing continuous river water surface elevation from sparse SWOT satellite observations using a Bayesian hierarchical framework
Rastogi, N. K., Minear, T. J., & Rajagopalan, B., Water Resources Research
Under review
2026
Integrated riverine flood warning system coupling river stage predictions with ensemble hydraulic modeling
Rastogi, N. K., Rajagopalan, B., Hopson, T., & Minear, T. J., Water Resources Research
Under review
In prep
Gauge-informed Bayesian hierarchical reconstruction of SWOT water surface elevations across the Brahmaputra River Basin
Rastogi, N. K., Deka, P., Minear, T. J., Rajagopalan, B., & Saharia, M., target: Nature Scientific Data
Data Descriptor, drafting

Conferences & Talks

Flood Forecasting & Precipitation

2026"A Bayesian Reconstruction for Continuous River Water Surface Elevation (BRACE) from Sparse SWOT Satellite Data", AGU Fall Meeting Poster, upcoming
2026"A Space-Time Statistical Model for Post-Processing of Daily Precipitation Forecasts", Rastogi, Rajagopalan & Kleiber, AGU Fall Meeting Poster, upcoming
May 2026"Reconstructing Continuous River Water Surface Elevation from Sparse SWOT Satellite Observations Using a Bayesian Hierarchical Framework", Rastogi, Minear & Rajagopalan, CIRES Rendezvous, CU Boulder Poster
Apr 2026"A Space-Time Statistical Model for Post-Processing of Daily Precipitation Forecasts", 20th HydroScience Symposium, CU Boulder Oral
Jul 2026"Can Sparse Satellite Overpasses Be Turned Into a Continuous River Record? Bayesian Reconstruction And Continuous River Elevation (BRACE)", NSF-NCAR-UCAR-UCP-CIRES Student Summer Conference Poster / Lightning talk
Dec 2025"Integrated riverine flood warning system coupling river stage predictions with hydraulic modeling", Rastogi, Rajagopalan, Hopson & Minear, AGU Fall Meeting, New Orleans Poster
Apr 2025"A Bayesian-hydraulic hybrid framework for monsoon flood warning in the Brahmaputra Basin", HydroScience Symposium, CU Boulder Oral
Dec 2024"Bayesian hierarchical network model for forecasting daily river stage in a river network", AGU Fall Meeting, Washington, DC Poster
May 2024"Bayesian hierarchical network model for forecasting daily river stage in a river network", CIRES Rendezvous, CU Boulder Poster
Apr 2024"Bayesian hierarchical network model for forecasting daily river stage in a river network", HydroScience Annual Symposium, CU Boulder Oral
Apr 2023"Impact of climate change on non-stationary IDF curves for urban areas", European Geosciences Union (EGU) General Assembly, Vienna Poster

Climate Teleconnections & Drought

2027"Causal Drivers of All India Summer Monsoon Precipitation Using Graph Based Bayesian Networks", AMS Annual Meeting Upcoming
Dec 2025"Understanding interannual variability of river basin flows through Bayesian causal networks", Rastogi, Nanditha & Rajagopalan, AGU Fall Meeting, New Orleans Poster
May 2025"Understanding streamflow variability in the Brahmaputra River Basin: A Bayesian network approach", CIRES Rendezvous, CU Boulder Poster

Invited Talks

Nov 4, 2026"A Bayesian Reconstruction for Continuous River Water Surface Elevation from Sparse SWOT Satellite Data", Boase Seminar Series, University of Colorado Boulder, USA
Nov 2025"Advances in Bayesian Hierarchical and Causal Network Models for Riverine Flood Forecasting and Hydroclimate Diagnostics", Imperial College London, UK
Nov 2025"From Climate Drivers to Flood Inundation: A Bayesian Framework for Understanding and Predicting Monsoon River Hazards", EGNR 601, Ball State University, USA
Nov 2025"Bayesian Hierarchical and Causal Network Based Models for Riverine Flood Risk Warning and Assessment", Indian Institute of Remote Sensing (IIRS), ISRO, India
Nov 2025"Integrated Riverine Flood Warning System Coupling River Stage Predictions with Hydraulic Modeling", Kotak School of Sustainability, IIT Kanpur, India
Sep 2025"An Integrated Framework for Riverine Early Flood Risk Warning and Assessment", Boase Seminar Series, University of Colorado Boulder, USA
Dec 2024"Bayesian Hierarchical Network Model for Forecasting Daily River Stage in a River Network", Boase Seminar Series, University of Colorado Boulder, USA
2024"Bayesian Hierarchical Network Model for Forecasting Daily River Stage in River Networks", Indian Institute of Technology Roorkee, India

International Academic Visits

  • UK Centre for Ecology & Hydrology (UKCEH): explored ongoing research in flood hydrology and basin-scale hydrological modeling.
  • Imperial College London: engaged with researchers to learn WSI-MOD, an open-source tool for integrated water resource planning and simulation.
  • University of Exeter: attended sessions on damage assessment frameworks and causal mechanisms behind hydrological extremes.

Internships & Teaching

  • Teaching Assistant, CVEN 5454 (Probability & Statistical Methods for Natural and Engineered Systems), University of Colorado Boulder, Fall 2024, 2025, 2026. Instructor: Prof. Balaji Rajagopalan; graded assignments and held office hours for R/Python-based statistical modeling coursework.
  • Summer Industrial Training, ONGC, Dehradun, June to July 2019: retrofitting of B.S. Negi Bhawan and construction of a new building for the Exploration and Development Directorate.
  • Field Training, Irrigation Division, Rishikesh, June to July 2018: construction and supervision of irrigation canal works.
  • Field Training, Drainage Division, Dehradun (PWD, Uttarakhand), December 2017 to January 2018: construction and maintenance of sewer drainage infrastructure.

Awards & Honors

Graduate Student Research Award (GSRA), CIRES, CU Boulder, 2026 to 2027
CECA Travel Fund Award, CIRES, CU Boulder, 2026
Graduate School Travel Grant, CU Boulder, for AGU 2025
Graduate School Travel Grant, CU Boulder, for AGU 2024
Awtar and Teji Singh Fellowship, CU Boulder, 2023 to 2024
Ranked 2nd, M.Tech Civil Engineering Cohort, IISc Bangalore, 2023
All India Rank 399, GATE Civil Engineering, among about 115,000 candidates, 2021
Top 2% Performer, NPTEL Structural Engineering, IIT Kharagpur, 2018

Service & Memberships

AGU Fall Meeting 2026: Primary convener, Session H096, "Land-Ocean-Atmosphere Drivers of Hydroclimatic Extremes: Prediction and Early Warning in the South Asian Monsoon," with co-conveners Balaji Rajagopalan, Manabendra Saharia, and Priyam Deka. Invited speaker: Dr. Madhavan Nair Rajeevan.

  • President, American Water Resources Association (AWRA), CU Boulder Student Chapter, 2026 to 2027 (previously Secretary, 2025 to 2026).
  • President, Water Buffs Student Organization, CU Boulder RSO, 2026 to 2027 (previously Secretary, 2025 to 2026).
  • CECA Member, CIRES, University of Colorado Boulder, 2023 to 2027.
  • Member, American Geophysical Union (AGU), 2024 to present.
  • Member, American Meteorological Society (AMS), 2026 to 2027.
  • Certified, RiverWare course, Center for Advanced Decision Support for Water and Environmental Systems (CADSWES), University of Colorado Boulder.
  • Mentor, Student Activity Cell (SAC), GBPIET, 2019 to 2020.
  • President, Literary Bureau, GBPIET, 2019 to 2020.
  • Editor-in-Chief, ECHO (Annual University Newspaper); published writer, Times of India and regional dailies, 2016 to 2020.

Skills & Coursework

Programming

RPythonMATLABStan

Modeling & GIS

HEC-RASMODFLOWVICSAC-SMARiverWareArcGISQGISSWMM

Coursework

Water Resource Systems & Management Statistical Learning Hydrological & Groundwater Modeling Remote Sensing & GIS Advanced Data Analysis Atmospheric Thermodynamics & Dynamics

Contact