Inland Hydrology and Coastal Ocean Compound Flooding

Summary

Compound inland-coastal flooding occurs because of concurrence of ocean related storm surge and inland flooding by heavy precipitation. Increasing number of compound flooding events highlights the necessity for development of modeling capabilities to support accurate model guidance which are capable of resolving such complex interaction between inland and coastal flooding. Our aim is to address what would be the best practice for producing high quality compound inland-coastal flooding given available coastal and inland hydrology modeling frameworks. Here we would like to look at this question from a scientific and engineering point of view.

Coastal ocean and inland hydrology models coupling

We are collaborating our NWS, OAR and NOS partners, model developers and wider community to develop required infrastructure to perform inland-coastal coupling for the NOS' operational coastal ocean models. See here a brief update on our progress and future plans.

ADCIRC

• Adaptive data driven mesh generation to support inland hydrology and coastal inundation coupling
• Testing strategies for including freshwater variables (e.g. stream flows and locally generated runoffs)
• Updating ADCIRC NUOPC/ESMF interface to accommodate seamless coupling among inland hydrology (NWM) and surface waves (WW3)

ROMS

• Testing NUOPC/ESMF model interface in NOAA NEMS environment
• Implementation of flexible freshwater source terms
• Considering open-channel type bottom roughness for rivers (e.g. Manning)

FVCOM

• Developing NUOPC/ESMF model interface in NOAA NEMS environment
• Testing flexible freshwater source terms for seamless NWM and FVCOM coupling

SELFE/SCHISM

• Testing flexible freshwater source terms for seamless NWM and SCHISM coupling for US East Coast (see below)

Simulating compound flooding events with a creek-to-ocean 3D approach

Creek-to-ocean 3D coastal modeling project is a collaborative and on-going effort between Coast Survey Development Laboratory of NOAA/NOS Office of Coast Survey and Prof. Joseph Zhang research group at the Virginia Institute of Marine Science (VIMS) .

For this study, the 3D baroclinic model SCHISM that presents a way to combine traditional hydrologic and ocean models in a single modeling platform is implemented. We took advantage of the polymorphism (i.e. a single model grid can seamlessly morph between full 3D, 2DV, 2DH and quasi-1D modes) of SCHISM model and simulate Hurricane Irene (2011) impact on Delaware Bay as an example of a seamless 1D-2D-3D model mesh. The domain includes the entire US east coast and Gulf of Mexico (Fig. 1a) with a high resolution down to 25 m in the Delaware Bay region (Fig. 1b).

Model Set-up

In this study, all the National Water Model river segments were included in the model set-up. This includes river segments that could be dry most times of the year and only get flooded during the intense precipitation events. This model set-up also includes the effect of baroclinicity of the ocean therefore, effects of ocean related inundation (e.g. storm surge) are resolved fully.

SCHISM and NWM coupling for Irene, 2011

An interactive web-based GIS viewer is available to see and interact with the results.

The left panel represents the Total Water Level above the ground (inundation level) including NWM discharges and Precipitation, and

The right panel represent the extra inundation due to compound inland-coastal and freshwater flooding (by subtracting total water surface elevation of full 3D case without NWM and precipitation from the one that includes NWM and precipitation)).

Delaware Bay compound flooding results

Figs 4 and 5 show that the effects of compound flooding could increase the inundation level (water above the ground) more than 2 meters due to compound inland-coastal flooding and backwater effects. The model also captured inland flooding events away from Delaware Bay main branch where the compound coastal and freshwater flooding are not the prime cause of the flooding ( i.e. inland river-related flooding).

Related Publications

1. F. Ye, Y. J. Zhang, H. Yu, W. Sun, S. Moghimi, E. Myers, K. Nunez, R. Zhang, H. V. Wang, A. Roland, K. Martins, X. Bertin, J. Du, Z. Liu. Simulating storm surge and compound flooding events with a creek-to-ocean model: Importance of baroclinic effects. Ocean Modelling, 145, 101526. 2020. doi: 10.1016/j.ocemod.2019.101526
2. Y.J. Zhang, Ye, H.C. Yu, W. Sun, S. Moghimi, E. Myers, K. Nunez, R. Zhang, H. Wang, A. Roland, K Martin, X. Bertin, J. Du, Z. Liu, Simulating compound flooding events in a hurricane. Part II: compound effects, 2020, Ocean Dynamics, doi: 10.1007/s10236-020-01351-x
3. S. Moghimi, S. Vinogradov, E. P. Myers, Y. Funakoshi, A. J. Van der Westhuysen, A. Abdolali, Z. Ma, F. Liu. Development of a Flexible Coupling Interface for ADCIRC Model for Coastal Inundation Studies. NOAA technical memorandum, NOS CS 41, 2019, doi: 10.25923/akzc-kc14
4. S. Moghimi , A.J. Van der Westhuysen, A. Abdolali, E. Myers, S. Vinogradov, Y. Funakoshi, Z. Ma, A. Mehra, F. Liu. Development of a Flexible Coupling Framework for Coastal Inundation. Journal of Marine Science and Engineering, 2020, arXiv: 2003.12652

Contact: Saeed.Moghimi@noaa.gov

Disclaimer: All model configurations and results are pre-decisional and for official use only.

Projects

Seamless Coupling of Storm Surge and Wave Models

Inland Hydrology and Coastal Ocean Compound Flooding

Related Links

Hurricane Explorer