1. U.S. Department of the Interior U.S. Geological Survey Processing ArcHydro Datasets with NHDPlus Version 2, Emphasizing StreamStats Data Development Webinar Series—Part 4: StreamStats- specific Datasets and Tools Alan Rea and Pete Steeves ID and MA-RI Water Science Centers

2. Webinar Series Overview May 9—Concepts and Preprocessing May 23—ArcHydro Data Development June 6—Basin Characteristics June 19—StreamStats-specific Datasets and Tools NHDPlusV2—StreamStats Webinars May-June, 2012Page 4-2

3. Course Web Site http://streamstats09.cr.usgs.gov/Data PrepWorkshop/Workshop2012 / NHDPlusV2—StreamStats Webinars May-June, 2012Page 4-3

4. Today’s Agenda Discussion of Exercise 3 Regression regions: setup and processing Exclusion polygons: setup and examples NHD Navigation tools –Demonstration –Take-home exercise (optional) NHDPlusV2—StreamStats Webinars May-June, 2012Page 4-4

5. Discussion of Exercise 3 NHDPlusV2—StreamStats Webinars May-June, 2012Page 4-5

6. StreamStats Data Prep Workshop May 21-24, 2007Page 4-6 Regression Regions Many states are divided into regions with different regression equations In general, these regions are defined based on the set of gages that were used in the regression analysis Often there is no region polygon feature class developed You need to develop one

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8. Regions Peak-flow and bankfull equations

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11. StreamStats Data Prep Workshop May 21-24, 2007Page 4-11 Region Dataset Preparation We actually need a grid, with the values being the NSS region ID The NSS region IDs can change, so give us a grid having regions matching your regression report Must run RegionsPrepro to compute percent areas for regions by hucpoly

12. StreamStats Data Prep Workshop May 21-24, 2007Page 4-12 Which to show on the web?

13. StreamStats Data Prep Workshop May 21-24, 2007Page 4-13 Exclusion Polygons Used as an initial test before delineation If delineation point falls in an exclusion polygon 2 possibilites: –ExcludeCode = 1 No delineation allowed –ExcludeCode ≠ 1 Delineation with warning

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17. Exclusion Polygons— Advanced Treatment It is possible to have even more control with exclusion polygons For example, you can set it up so in certain areas only peak flows will be run, but not low flows The mechanics of this are difficult to explain Ask for more details if you need this NHDPlusV2—StreamStats Webinars May-June, 2012Page 4-17