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 3: Basin Characteristics 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 3-2

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

4. Today’s Agenda Discussion of Exercise 2 Basin Characteristic Considerations Computing Overlay Grids XML Configuration Computing Global BC’s Continuous Parameter Grids (CPGs) Take-home assignment: Exercise 3 NHDPlusV2—StreamStats Webinars May-June, 2012Page 3-4

5. Discussion of Exercise 2 Typos in Steps 3, 4, corrected 5/30 Slow startup of ArcCatalog Setting ArcHydro to make FGDB’s Add Compact DB at end of global setup “Big Picture” Overview NHDPlusV2—StreamStats Webinars May-June, 2012Page 3-5

6. NHDPlus NED 1”or NED 1/3” DEM Streams, NHDFlowLines 100K NHD or 24K NHD Walls Outer required Inner optional WBD and/or HUC TopoGrid (optional) HydroDEM.aml Water Bodies for Bathy. Grad. and Drain Plugs - optional Flow AccumAdjust Catchment Polygons (CATCHMENT) Drainage Line (DRAINLINE) and Adjoint Catchment (ADJOINTCATCHMENT) processing Head water HUCS Stream Definition (STR) Stream Segments (LNK) Catchment grid (CAT) Create Global.mdb Regions Prepro Setup Basin Chars Global Params Input Basin Char Grids StreamStats Online Populate StreamStatsDB Gage information Setup data for Web Display Exclusion Polygons METADATA for All spatial datasets Non Head water HUCS Coastal DEM

8. Basin Characteristics Considerations Need to compute for sites outside state/area of interest Different overlay datasets by state Ideally prefer national/international datasets Best to compute with ArcHydro XML configuration Continuous parameter grids (faster) Page 8NHDPlusV2—StreamStats Webinars May-June, 2012

9. Page 9 MA Fixed Sites and Study Area

10. Where are overlay grids stored? We have two options: 1.Single statewide grid in “bc_layers” folder, OR 2.In each HUC workspace ArcHydro looks first in MXD, then in HUC workspace, then in bc_layers NHDPlusV2—StreamStats Webinars May-June, 2012Page 3-10

11. Categorical (percent-area) Characteristics e.g. percent forested area Reclassify land-cover grid –1 for forest categories –0 for all other values NHDPlusV2—StreamStats Webinars May-June, 2012Page 3-11

12. Computing percent slope StreamStats Toolbox, Misc. Utilities Computes slope grid for each HUC workspace Run using batch grid (right-click on tool) NHDPlusV2—StreamStats Webinars May-June, 2012Page 3-12

13. XML Configuration ArcHydro uses an XML configuration to define basin characteristics and many other parameters The XML comes from a template XML file, which is read when you open a new MXD, then it is stored in the MXD You can change the XML in the MXD using the ArcHydro Tools XML Manager You can change the default for all MXDs permanently NHDPlusV2—StreamStats Webinars May-June, 2012Page 3-13

14. Continuous Parameter Grids (CPGs) CPGs are used to speed up basin characteristics Precompute b.c.’s for every grid cell To get b.c., just read value for outlet point CPG’s take many hours to prepare Tools in SS Toolbox, Misc. Utilities NHDPlusV2—StreamStats Webinars May-June, 2012Page 3-14

15. NHDPlusV2—StreamStats Webinars May-June, 2012Page 3-15 Flow Direction Grid (FDR) Derived from DEM Each cell points down hill to the neighboring cell with the lowest elevation Direction encoded by powers of 2 3264128 161 842

16. ElevationFlow direction NHDPlusV2—StreamStats Webinars May-June, 2012Page 3-16

17. NHDPlusV2—StreamStats Webinars May-June, 2012Page 3-17 Flow direction Flow accumulation

18. NHDPlusV2—StreamStats Webinars May-June, 2012Page 3-18 Categorical “Weight” grid Weighted Flow accumulation

19. NHDPlusV2—StreamStats Webinars May-June, 2012Page 3-19 Continuous “Weight” grid Weighted Flow accumulation

20. NHDPlusV2—StreamStats Webinars May-June, 2012Page 3-20 Weighted Flow accumulation Average basin elevation

21. CPG XML Configuration Use PointExtractOp function See Idaho_10m StreamStats configuration for examples NHDPlusV2—StreamStats Webinars May-June, 2012Page 3-21