2. UC 2006 Tech Session 1 Louis Wasson GeoResources Institute Mississippi State University Arc Hydro: A User’s Experience

3. UC 2006 Tech Session2 The Problem Find rain gauges in a specific watershed Find rain gauges in a specific watershed – There aren’t any … Sorry – Model results weren’t representative of the environment But I was curious. There had to be something better …

4. UC 2006 Tech Session3 Here’s what I want to do: Part I.Use NEXRAD Multi-Sensor Precipitation Estimate (MPE) for a better spatial estimation of rainfall. Part II.Determine how much rain fell into each delineated watershed and how much is flowing out.

5. UC 2006 Tech Session4 Part I. NEXRAD MPE precipitation data Ground Truthed NEXRAD What is MPE??

6. UC 2006 Tech Session5 Why use NEXRAD MPE over a surface rain gauge? A watershed is a rainfall collector with rainfall being the critical driving force in hydrologic modeling. A rain gauge opening is 8 inches in diameter which is equivalent to 12.5 x 10 -9 mi 2. Many rain gauges are not in the watershed of interest. Rainfall being based on a few observed points.

7. UC 2006 Tech Session6 Why use NEXRAD MPE over a surface rain gauge? KSCM6 = 2.38” MPE = 2.4 ETHM6 = 2.6” MPE = 2.25” ENBM6 = 1.5” MPE = 1.53” 4km x 4km grid

8. UC 2006 Tech Session7 Why use NEXRAD MPE over a surface rain gauge? Rain GaugeNEXRAD MPE

9. UC 2006 Tech Session8 Why use NEXRAD MPE over a surface rain gauge? Using MPE NEXRAD precipitation estimates we cover Mississippi almost 8,000 virtual rain gauges!

10. UC 2006 Tech Session9 Where can you get NEXRAD MPE data? Quality Controlled daily rainfall estimates. Lower Mississippi River Forecast Center http://www.srh.noaa.gov/rfcshare/precip_analysis.php?location=LMRFC It’s FREE!!

11. UC 2006 Tech Session10 Daily precipitation data comes in Polar Stereographic Projection. Hourly data arrives in a xmrg format. Data is not in TimeSeries format for ArcHydro applications Other issues!!

12. UC 2006 Tech Session11 Part II. – Delineate watershed catchments. – Determine how much rain fell in each catchment.

13. UC 2006 Tech Session12 ESRI Arc Hydro Data Model Hydrograph Channels Terrain Surfaces Rainfall Response Digital Orthophotos Relationships between objects linked by tracing path of water movement

14. UC 2006 Tech Session13 GeoDatabase? Schema? Schema? XM L? Feature Class? Feature DataSet? Extents? HydroResponseUnit?

15. UC 2006 Tech Session14 ESRI Arc Hydro Data Model Hydrologic DEM Delineate Catchments Outlets Junctions for Each Catchment Hydrologic Network

16. UC 2006 Tech Session15 I’ve got delineated catchments and a quality controlled rain fall data source with good spatial coverage. Know how do I get the rain fall data into the catchments?

17. UC 2006 Tech Session16 The HydroResponseUnit

18. UC 2006 Tech Session17 LMRFC MPE Point Grid HydroResponseUnit

19. UC 2006 Tech Session18 Time Series Transfer Rainfall to Catchments

20. UC 2006 Tech Session19 Arc Hydro consumes memory quick. Do not work in C: or system drive. Change your environment variables to change your ‘temp’ folder to a larger drive.Arc Hydro consumes memory quick. Do not work in C: or system drive. Change your environment variables to change your ‘temp’ folder to a larger drive. If Arc Hydro crashes during the Terrain Processing steps it is usually caused by something in the RivGrid folder. Delete the entire folder.If Arc Hydro crashes during the Terrain Processing steps it is usually caused by something in the RivGrid folder. Delete the entire folder. Understand what a Feature Dataset is all about. Correctly setup it’s spatial properties, especially the limits. You will get ‘out of bounds’ or ‘beyond spatial limit’ errors when you load data into Feature Classes.Understand what a Feature Dataset is all about. Correctly setup it’s spatial properties, especially the limits. You will get ‘out of bounds’ or ‘beyond spatial limit’ errors when you load data into Feature Classes. HydroID of the HydroResponseUnit polygons must be the same as the FID of your NEXRAD (MPE) data. Use the FID from the MPE point grid you get from the RFC.HydroID of the HydroResponseUnit polygons must be the same as the FID of your NEXRAD (MPE) data. Use the FID from the MPE point grid you get from the RFC. Use the CRWR Online Support System!Use the CRWR Online Support System! In Closing…