1. National Water Model (Provided by NOAA)
By YONGLI ZHANG

2. National Water Model Overview:
Forecast streamflow for 2.7 million river reaches and other hydrologic information on 1km and 250m grids.
Providing “street level” water information and guidance.
Can help forecasters predict when and where flooding can be expected.
designed to provide more closely integrated water predictive capabilities to promote resilience to water risks.

3. National Water Model

4. National Water Model How it Works:
Simulates the water cycle with mathematical representations of the different processes and how they fit together, including representation of physical processes such as snowmelt and infiltration and water movement through the soil layers varies significantly with changing elevations, soils, vegetation types and a host of other variables.

5. National Water Model Framework and configurations:
Analysis and assimilation: snapshot of current hydrologic conditions.
Short-Range: 15-hour deterministic (single value) forecast.
Medium-Range: 10-day deterministic (single value) forecast.
Long-Range: 30-day ensemble forecast

6. National Water Model Output:
All NWM output will be stored in NetCDF format in one of three file types:
1km gridded NetCDF (land surface variables and forcing)
250m gridded NetCDF (ponded water depth and depth to soil saturation)
Point-type NetCDF (stream routing and reservoir variables)
Output is also available for display on the interactive zoomable mapping interface mapping interface.

7. National Water Model
Output File Content-Configuration 1&2, the same output content

8. National Water Model
Output File Content-Configuration 3:

9. National Water Model
Output File Content-Configuration 4

10. National Water Model

11. Sample Output

12. Sample Output

13. Sample Output

14. Sample Output

15. Sample Output

16. Flood Prediction based on NWMgx

17. Questions:
Given a location (flood control sensor location), how to find the corresponding output of NWM?
The interactive map, you click point then it gives output of that point including location, can we specify the longitude and latitude on our own?
The way I can think of is that we download the output of NWM from website, then search the output file, then locate the closest point to the user specified long/lat, and extract the output for that point.
Does it/NWM consider the stream info? The downstream effect?
1km/250m grid cells, does it give the same output for all points inside the same grid cell? Or does one grid cell has more than points, considering 2.7 million points.
2.7 million points the whole US, how many points in Harris County?
Is there any software or GUI available for us to use instead of what is provided on the website (map et. al)?
The website gives link to the output, does it include all the 2.7 millions points? I do not have enough time to look at it.
Based on the description, the output content includes the velocity of stream, doesn’t it? The interactive map on the website only has one output variable streamflow.
What is the prediction accuracy of the NWM?

18. Questions: How do we create a subset? such as Harris County.
What about velocity prediction?
It looks like it predicts stream flow and velocity, what about water level?