Noriaki Ohara, Ph.D., P.E.
Civil and Architectural Engineering and Construction Management
Professor

Education
- B.A. Civil Engineering, Chuo University, Japan, 1997
- M.A. Civil Engineering, Chuo University, Japan, 1999
- Ph.D. Civil Engineering, University of California, Davis, 2003
Research Interests
- Hydrologic Modeling
- Snow Hydrology
- Hydrologic Field Observation
- Hydrometeorology
- Theoretical Treatment of Scale Gap
Professional Affiliations
- American Society of Civil Engineers (ASCE)
- American Geophysical Union (AGU)
- Japan Society of Civil Engineers
Publications
- Jones, B., C. D. Arp, G. Grosse, I. Nitze, M. J. Lara, M. S. Whitman, L. M. Farquharson, M. Kanevskiy, A. D. Parsekian, A. L. Breen, N. Ohara, R. C. Rangel, and K. M. Hinkel, âIdentifying historic and future potential lake drainage events on the western Arctic Coastal Plain of Alaskaâ, Permafrost and Periglacial Processes, accepted, 2020
- Ohara N.*, and K. Yamatani, "Theoretical Stable Hydraulic Section based on the Principle of Least Actionâ, Scientific Reports, 9, Article number: 7957, 2019.
- Ishida, K., N. Ohara, A. Ercan, S. Jang, T. Trinh, M.L. Kavvas, K. Carr, M. L. Anderson, âImpacts of Climate Change on Snow Accumulation and Melting Processes over Mountainous Regions in Northern California during the 21st Centuryâ, Science of The Total Environment, accepted, 2019.
- He, S., N. Ohara*, âModeling Sub-Grid Variability of Snow Depth using the Fokker-Planck Equation Approachâ, Water Resources Research, 2019.
- He, S, N. Ohara*, and S.N. Miller âUnderstanding sub-grid variability of snow depth at 1 km scale using Lidar measurementsâ, Hydrologic Processes, 2019.
- Ishida, K., A. Ercan, T. Trinh, S. Jang, M. L. Kavvas, N. Ohara, Z. Q. Chen, S. Kure, and Dib. "Trend analysis of watershed-scale annual and seasonal precipitation in Northern California based on dynamically downscaled future climate projections", Journal of Water and Climate Change, 2018.
- Ishida, K., Ercan, A., Trinh, T., Kavvas, M. L., Ohara, N., Carr, K., & Anderson, M. L. âAnalysis of future climate change impacts on snow distribution over mountainous watersheds in Northern California by means of a physically-based snow distribution modelâ, Science of The Total Environment, 645, 1065-1082, 2018.
- Thayer, D., A. D. Parsekian, K. Hyde, H. Speckman, D. Beverly, B. Ewers, M. Covalt, N. Fantello, T. Kelleners, N. Ohara, and T. Rogers âGeophysical Measurements to Determine the Hydrologic Partitioning of Snowmelt on a SnowâDominated Subalpine Hillslopeâ, Water Resources Research, 54 (6), 3788-3808, 2018.
- Ohara, N.*, W.S. Holbrook, K. Yamatani, B.A. Flinchum, and J.T. St. Clair, âSpatial Estimation of Riparian Groundwater Domain within Alluvium Deposit of Mountainous Areasâ, Hydrological Processes, 32 (1), 30-38, 2018.
- Ishida, K., N. Ohara, M. L. Kavvas, Z. Q. Chen, and M. L. Anderson. "Impact of air temperature on physically-based maximum precipitation estimation through change in moisture holding capacity of air." Journal of Hydrology, 556, 1050â1063, 2018.
- Pleasants, M.S.*, T. Kelleners, and N. Ohara, "Analysis of snowpack dynamics during the spring melt season using point measurements and numerical modeling", Hydrological Processes, 31(25), 4568-4585, 2017.
- He, S.*, and N. Ohara, âA new formula for estimating the threshold wind speed for snow movementâ, Journal of Advances in Modeling Earth Systems (JAMES), 9(7), 2514-2525, 2017.
- Johnson, R. and N. Ohara*, âDynamic Equilibrium Modeling of Snow and Inland Glaciers under the Evolving Climate in Wyomingâ, Journal of Hydrologic Engineering, ASCE, 23(1), 04017056, 2017..
- Jang, S.*, M.L. Kavvas, K. Ishida, T. Trinh, N. Ohara, S. Kure, Z.Q. Chen, M.L. Anderson, G. Matanga, and K. J. Carr, âA Performance Evaluation of Dynamical Downscaling of Precipitation over Northern Californiaâ, Sustainability, 2017. doi:10.3390/su9081457.
- Jang, S.*, S. Kure, N. Ohara, M.L. Kavvas, Z.Q. Chen, K. J. Carr and, M.L. Anderson, âApplication of WEHY-HCM for Modeling Interactive Atmospheric-Hydrologic Processes at Watershed Scale to a Sparsely Gauged Watershedâ, Sustainability, 2017. doi:10.3390/su9091554.
- Trinh, T.Q.*, M.L. Kavvas, K. Ishida, K. J. Carr, and N. Ohara, "Projected 21st Century Climate Change on Snow Conditions over Shasta Dam Watershed by means of Dynamical Downscaling", Hydrological Processes, 2017. 31:2887â2901. .
- Ohara, N.*, M.L. Kavvas, M.L. Anderson, Z.Q. Chen, and K. Ishida, "Characterization of Extreme Storm Events using A Numerical Model Based Precipitation Maximization Procedure in Feather, Yuba, and American River Watersheds in California", Journal of Hydrometeology, 18 (5), 1413-1423, 2017.
- Ohara, N.*, âAn Eulerian Equation for Snow Accumulation Downstream of an Objectâ, Water Resource Research, Volume 53, Issue 2, 1525â1538, 2017.
- Peel, T., M. Ahmed, and N. Ohara, âInvestigating Safety-Effectiveness of Wyoming Snow Fence Implementations along a Rural Mountainous Freewayâ, Transportation Research Record (TRR), 2017.
- Trinh, T.Q.*, S. Jang, K. Ishida, N. Ohara, Z.Q. Chen, M.L. Anderson, Y. Darama, M.L. Kavvas, âReconstruction of Historical Inflows into and Water Supply from Shasta Dam by Coupling Physically Based Hydroclimate Model with Reservoir Operation Model." Journal of Hydrologic Engineering, ASCE, 10.1061/(ASCE)HE.1943-5584.0001391, 04016029. 2016.
- Chen, J.F.*, M.L. Kavvas, K. Ishida, T.Q. Trinh, N. Ohara, M.L. Anderson, and Z.Q. Chen, Role of Snowmelt in Determining whether the Maximum Precipitation Always Results in the Maximum Flood." Journal of Hydrologic Engineering, ASCE, 10.1061/(ASCE)HE.1943-5584.0001366, 04016032, 2016.
- Amin M.Z.M., A. J. bin Shaaban, N. Ohara*, M.L.Kavvas, Z.Q.Chen, S. Kure, and S. Jang, âClimate Change Assessment of Water Resources in Sabah and Sarawak, Malaysia, Based on the Dynamically Downscaled GCM Projections Using a Regional Hydroclimate Modelâ, Journal of Hydrologic Engineering, 10.1061/(ASCE)HE.1943-5584.0001242, 05015015., 2015.
- Ishida*, K., M.L. Kavvas, S. Jang, Z.Q. Chen, N. Ohara, M.L. Anderson, âPhysically Based Estimation of Maximum Precipitation over Three Watersheds in Northern California: Relative Humidity Maximization Methodâ, Journal of Hydrologic Engineering, ASCE, 20(10), 04015014, 2015.
- Ishida, K.*, M.L. Kavvas, S. Jang, Z.Q. Chen, N. Ohara, M.L. Anderson, âPhysically Based Estimation of Maximum Precipitation over Three Watersheds in Northern California: Atmospheric Boundary Condition Shiftingâ, Journal of Hydrologic Engineering, ASCE, 20(4), 04014052, 2015.
- Ohara, N.*, âA Practical Formulation of Snow Surface Diffusion by Wind for Watershed Scale Applicationsâ, Water Resources Research, Vol. 50, Issue 6, 5074-5089, 2014.
- Ohara, N.*, S. Kure, S. Jang, Z.Q. Chen and M.L. Kavvas, âModeling of Interannual Snow and Ice Storage in High Altitude Region by Dynamic Equilibrium Conceptâ, Journal of Hydrologic Engineering, ASCE, 19(12), 04014034, 2014.
- Ohara, N.*, M.L. Kavvas, Z.Q.Chen, L. Liang, M. Anderson, J. Wilcox and L.Mink, âModelling atmospheric and hydrologic processes for assessment of meadow restoration impact onăflow and sediment in a sparsely gauged California watershedâ, Hydrological Processes, 28, 3053â3066, 2014.
- Oh, N.H.*, B. Pellerin, P. Bachand, P. Hernes, S. Bachand, N. Ohara, M. L. Kavvas, B. Bergamaschi, and W. Horwath. âThe Role of Irrigation Runoff and Winter Rainfall on Dissolved Organic Carbon Loads in an Agricultural Watershedâ, Agriculture, Ecosystems and Environment, Volume 179, 1 October, 1â10, 2013.
- Kavvas, M.L.*, S. Kure, Z.Q. Chen, N. Ohara, and S. Jang, âWEHY-HCM for Modeling Interactive Atmospheric-Hydrologic Processes at Watershed Scale. I: Model Descriptionâ, Journal of Hydrologic Engineering, ASCE, Vol. 18, No. 10, pp. 1262-1271, 2013.
- Kure, S., S. Jang*, N. Ohara, M. L. Kavvas, and Z. Q. Chen, âWEHY-HCM for Modeling Interactive Atmospheric-Hydrologic Processes at Watershed Scale. II: Model Application to Ungauged and Sparsely Gauged Watershedsâ, Journal of Hydrologic Engineering, ASCE, Vol. 18, No. 10, pp. 1272-1281, 2013.
- Kure, S., S. Jang*, N. Ohara, M.L. Kavvas, and Z.Q. Chen, âHydrological Impact of Regional Climate Change for the Snowfed and Glacierfed River Basins in the Republic of Tajikistan: Statistical Downscaling of Global Climate Model Projectionsâ, Hydrological Processes, 2012.
- Kure, S., S. Jang*, N. Ohara, M.L. Kavvas, and Z.Q. Chen, âHydrologic Impact of Regional Climate Change for the Snowfed and Glacierfed River Basins in the Republic of Tajikistan: Hydrological Response of flow to Climate Changeâ, Hydrological Processes, 2012.
- Chen, Z.Q., Kavvas, M.L, Ohara, N.*, Anderson, M. L., and Yoon, J. âA Coupled Regional Hydro-Climate Model and its Application to the Tigris-Euphrates basinâ, Journal of Hydrologic Engineering, ASCE, Vol. 16, No. 12, 1059â1070, 2011.
- Ohara, N.*, Kavvas, M.L., Anderson, M.L., Chen, Z.Q., and Yoon J. âA Water Balance Study for the Tigris-Euphrates River Basinâ, Journal of Hydrologic Engineering, ASCE, Vol. 16, No. 12, 1071â1082, 2011.
- Chen, Z.Q., Kavvas, M.L, Ohara N.*, and Anderson, M.L. âImpact of Water Resources Utilization on the Hydrology of Mesopotamian Marshlandsâ, Journal of Hydrologic Engineering, ASCE, Vol. 16, No. 12, 1083â1092, 2011.
- Ohara, N.*, Chen, Z.Q., Kavvas, M.L., Fukami, K., and Inomata, H. âReconstruction of Historical Atmospheric data by A Hydroclimate Model for Mekong River Basinâ, Journal of Hydrologic Engineering, ASCE, Vol. 16, No. 12, 1030â1039, 2011.
- Shaaban, A.J., Amin M.Z.M., Chen, Z.Q., and Ohara, N.* âRegional Modeling Of Climate Change Impact On Peninsular Malaysia Water Resourcesâ, Journal of Hydrologic Engineering, ASCE, Vol. 16, No. 12, 1040â1049, 2011.
- Kure, S.*, Kavvas, M.L., Ohara, N., and Jang, S., âUpscaling of Coupled Land Surface Process Modeling for Heterogeneous Landscapes: Stochastic Approachâ, Journal of Hydrologic Engineering, ASCE, Vol. 16, No. 12, 1017â1029, 2011.
- Florsheim, J.L.*, B.A. Pellerin, N.H. Oh, N. Ohara, P.A.M. Bachand, S.M. Bachand, B.A. Bergamaschi, P.J. Hernes, M.L. Kavvas, âFrom deposition to erosion: Spatial and temporal variability of sediment sources, storage, and transport in a small agricultural watershedâ, Geomorphology, Volume 132, Issues 3â4, 272â286, 2011.
- Ohara, N., Kavvas, M. L.*, Kure, S., Chen, Z. Q., Jang, S., and Tan, E. âA Physically-Based Estimation of Maximum Precipitation over American River Watershed, Californiaâ, Journal of Hydrologic Engineering, ASCE, Vol. 16, issue 4, 351-361, 2011.
- Kavvas, M.L.*, Z.Q. Chen, M.L. Anderson, N. Ohara, J.Y. Yoon, and Fu Xiang. âA Study of Water Balances over the Tigris-Euphrates Watershedâ, Physics and Chemistry of the Earth, Elsevier, Vol. 36, 197-203, 2011.
- Ohara, N.*, Kavvas, M.L., Easton, D., Dogrul, C. E., Yoon, J., and Chen, Z.Q. âThe Role of Snow in Runoff Processes in a Sub-alpine Hillslope : Field Study in the Ward Creek Watershed, Lake Tahoe, California during 2000 and 2001 Water Yearsâ, Journal of Hydrologic Engineering, ASCE, Vol. 16, No. 6, pp. 521-533, 2010.
- Fu Xiang, Kavvas, M.L.*, Chen, Z.Q., Bandeh, H., Ohara, N., Kim, S., Jand S.H., Churchwell, R. âExperimental Study of Debris Capture Efficiency of Trash Racksâ, Journal of Hydro-environmental Research, No.3, 138-147, 2009.
- Ohara, N.*, Kavvas, M. L., and Chen, Z. Q., âStochastic Upscaling for Snow Accumulation and Melt Processes with PDF Approachâ, Journal of Hydrologic Engineering, ASCE, Vol 13, issue 12, 1103-1118, 2008.
- Kavvas, M. L., Yoon, J*, Chen, Z. Q., Liang, L., Dogrul, E. C., Ohara, N., Aksoy, H., Anderson, M. L., Reuter, J., and Hackley, S. âWatershed Environmental Hydrology Model: Environmental Module and Its Application to a California Watershedâ, Journal of Hydrologic Engineering, ASCE, Vol. 11, issue 3, 261-272, 2006.
- Ohara, N.*, and Kavvas, M. L. âField Observations and Numerical Model Experiments for The Snowmelt Process At A Field Siteâ, Advances in Water Resources, Elsevier, 29, 194-211, 2006.
- Kavvas, M. L.*, Chen, Z. Q., Dogrul, J., Yoon, J., Ohara, N., Liang, L., Aksoy, H., Anderson, M. L, Yoshitani, J., Fukami, K. and Matsuura, T. âWatershed Environmental Hydrology (WEHY) Model Based On Upscaled Conservation Equations: Hydrologic Moduleâ, Journal of Hydrologic Engineering, ASCE, Vol. 9, issue 6, 2004.
- Shimura, K., Ohara, N.*, Matsuki, H., and Yamada, T. âStudy on Flood Wave Using Unsteady Flow Analysisâ, Journal of Japan Society of Hydrology and Water Resources, Vol. 14, No. 3, May, 2001. (in Japanese)
