2. The World of GIS Hydro ‘98 David R. Maidment University of Texas at Austin Presented by:

3. Introduction: Why and How? u GIS Hydrology is maturing into a coherent technology u CD-ROM presents –instructional exercises with supporting data –online reports, theses and dissertations –digital atlas of the world water balance –8 spatial hydrology analysis modules covering all phases of the hydrologic cycle u Access using a web browser, start from gishyd98.htm

4. Acknowledgements u GIS Hydro ‘98 is a team effort –CRWR: Center for Research in Water Resources, University of Texas at Austin (graduate students, research associates) –DHI: Danish Hydraulic Institute (Borge Strom) –BYU: Engineering Computer Graphics Laboratory, Brigham Young University (Jim Nelson, Norm Jones, Alan Zundel) –EPA: Office of Water, Office of Science & Technology, U.S. Environmental Protection Agency (Andrew Battin) –ESRI (Steve Kopp, Dean Djokic, Zichuan Ye) –many research sponsors and collaborators

5. Site Map and Quick Tour Spatial Information system Spatial Information system Atlas Library Classroom Spatial Hydrology Analysis system Spatial Hydrology Analysis system GIS Hydro ’98 (gishyd98.htm) GIS Hydro ’98 (gishyd98.htm) Watershed Characterization Atmosphere and Soil Water Runoff and Routing Hydraulics Water Quality Collaborators EPA DHI BYU

6. Digital Classroom: Learning GIS in a Week Step-by-step exercises: General instruction in the use of ArcView & Arc/Info application Application projects: Sample applications for better understanding of GIS Numerous Web Links: Spatial data and information resources related to GIS Hydrology

7. Digital Library: What could be more convenient ? General Internet Data Sources Sources of Spatial Hydrology Data Online Reports in Adobe Format 12 Masters Theses 4 PhD Dissertations Project Reports

8. Digital Atlas: World Water Balance Spatial Data Africa Asia Australia Europe N. America S. America Texas Political Runoff Exercises & Applications in English, en Français, en Español, em Portugués! Online: http://www.crwr.utexas.edu/atlas/

9. GISHydrologic Modeling Environmental descriptionProcess representation Data Input Model Results Synthesis of GIS and Modeling

10. Linking Data and Models Integrated Spatial Database GIS Hydro ‘98 Models Watershed Characterization Runoff & Routing Hydraulics Water Quality Atmosphere & Soil Water

11. Traditional approach Spatial Hydrology Process Representation Environmental Description Process-based Modeling Map-based Modeling Hydrologic Modeling

12. Model 1 Model 2 Models Data base Data sources 1 2  Form the model within the frame of the available data Data-Driven Modeling

13. Users Hydrologic simulation Time series data Spatial hydrologic model Spatial data Real World Spatial Hydrologic Modeling Concept

14. t t t I Q t  Continuous time hourly, daily  Steady state mean annual  Seasonal monthly  Single event Dealing with Time Variation

15. Two tasks: I. Environmental description using a map II. Process representation using equations Modeling Procedure

16. Environmental description Process representation  1. Study design  2. Terrain analysis  3. Land surface description  4. Subsurface description  5. Hydrologic data representation  6. Soil water balance  7. Water flow  8. Constituent transport  9. Impact of water utilization  10. Presentation of results Ten Step Procedure for Modeling

17.  Objectives of the study?  Range and subdivision of the spatial domain?  Duration and subdivision of the time horizon?  Variables to be computed? Step 1. Study Design

18. Computational effort ~ LMN LMN < 10,000,000 for execution within ArcView Number of: Spatial units = L Variables computed = M Time intervals = N Time Variables Space N M L Space, Time, and Process Variables

19. Mean annual flow and transport on a raster grid Time Variables Space N=1 M L Time-Averaged Modeling

20. Land Characterization (Land use, Soils, Climate, Terrain) Water Characterization (water yield, flooding, groundwater, pollution, sediment) Relationships between land type and water characteristics Land and Water Interaction

21. Land Characterization (Land use, Soils, Climate, Terrain) Non Point Source Pollution (mean annual flows and pollutant loads) Adapt Water to the Land System Water Characterization (water yield, flooding, pollution, sediment)

22. Land Characterization (Land use, Soils, Climate, Terrain) Water Characterization (water yield, flooding, pollution, sediment) CRWR-PrePro (GIS Preprocessor for HEC-HMS flood hydrograph simulation) Adapt Land to the Water System

23. CRWR-PrePro: HMS Preprocessor Geographic DataSchematic Diagram Increasing Scale  Increasing Complexity

24. Digital Elevation Model (DEM)

25.  Vector representation as points, lines and areas  Raster representation on a grid of DEM cells Vector Raster OutletStreamWatershed Raster-Vector Equivalence

26. + =  Take a mapped stream network and a DEM  Make a grid of the streams  Raise the off-stream DEM cells by an arbitrary elevation increment  Produces "burned in" DEM streams = mapped streams “Burning In” the Streams

27.  Begin with an elevation grid  Flow in direction of steepest descent Eight-Direction Pour Point Model

28. 787269715849 746756494650 695344373848 12 21 22 11 16 31 12 19 24 53 61 5855 47 34 68 74 64 ElevationFlow direction grid Flow Direction Grid

29. Flow Direction u Water flows to one of its neighbor cells according to the direction of the steepest descent. u Flow direction takes one out eight possible values.

30. Flow direction grid Implied network between cell centers Grid Network

31. 000000 011220 037540 7 1 20 35 24 0 1 0 1 2 0 00 0 4 0 0 0 Number of upstream cells Classification of flow accumulation Number of cells > 6 = stream 0 cells = watershed boundary 1122 3754 7 1 20 35 24 1 1 24 Flow Accumulation Grid

32. Flow Accumulation u Flow accumulation is an indirect way of measuring drainage areas (in units of grid cells).

33. Types of Outlets and Nodes Stream junction node Stream headwater node System outlet node User-defined node Sub-basin Stream

34. Stream Segmentation u Stream segments (links) are the sections of a stream channel connecting two successive junctions, a junction and an outlet, or a junction and the drainage divide.

35. Watershed Delineation u The drainage area of each stream segment is delineated.

36.  What DEM cell size to use?  Cell size = Region area / 1,000,000  What size watershed to delineate?  Watershed > 1000 cells Thousand-Million Rule

37. Cell Size Watershed Area (km 2 ) Typical Application 1” (~ 30 m) 3” (~ 100 m) 15” (~ 500 m) 30” (~ 1 km) 3’ (~ 5 km) 5’ (~ 10km) 5 40 1000 4000 150,000 400,000 Urban watersheds Rural watersheds River basins, States Nations Continental Global Application of Digital Elevation Models

38. Raster to Vector Conversion u Streams and watersheds are converted from raster to vector format.

39. Dissolving Spurious Polygons u Cells connected to the main watershed polygon through a corner are defined as a separate polygon (spurious polygon). u These polygons are dissolved into the main polygon.

40. Watershed Parameters Flow length upstream and downstream Average Curve Number Slope and length of the longest flow-path Identification of the longest flow-path Lag-time SCS Unit Hydrograph

41.  distance downstream to outlet Flow-Length Function in ArcView  distance to upstream divide

42. Flow Length Downstream to the Watershed Outlet

43. Flow Length Upstream to the Watershed Divide

44. Longest Flow-Path Total flow length = upstream length + downstream length

45. V 21 V 11 V 41 V 31 V 61 V 51 V 32 V 12 V 22 V 42 V 52 V 62 V 23 V 13 V 33 V 53 V 43 V 24 V 16 V 15 V 14 V 63 V 34 V 44 V 54 V 64 V 25 V 35 V 45 V 55 V 65 V 26 V 36 V 46 V 56 V 66 Velocity magnitudeVelocity direction V = aS b S = slope a,b = land cover coefficients Velocity Field

46.  time to outlet (weighted flow length) Time = Distance x 1 Velocity Flow Time Computation

47. Isolation of a Sub-System

48. Connection to HEC-HMS HMS SchematicParameter Transfer HMS Basin File Ferdi’s code

49. Upper Mississippi Flood Study

50. Streams and Subwatersheds 162 subwatersheds each with a USGS gage at the outlet defined using 15” (500m) DEM Rivers defined by EPA River Reach File 1 (RF1)

51. CRWR-Prepro Schematic Network Inlets Mississippi River Missouri River Outlet (Mississippi R. at Thebes, Ill)

52. HEC-Hydrologic Modeling System HMS Basin file CRWR-PrePro HEC-HMS Model Schematic

53. Land Characterization (Land use, Soils, Climate, Terrain) Non Point Source Pollution (mean annual flows and pollutant loads) Adapt Water to the Land System Water Characterization (water yield, flooding, pollution, sediment)

54. Possible Land-Water Transform Coefficients Water Land

55. Map-Based Surface Water Runoff Runoff, Q (mm/yr) Precipitation, P (mm/yr) Accumulated Runoff (cfs) P Q Runoff Coefficient C = Q/P

56. Water Quality: Pollution Loading Module DEM Precip. Runoff LandUse EMC Table Concentration Load Accumulated Load Load [Mass/Time] = Runoff [Vol/Time] x Concentration [Mass/Vol]

57. Expected Mean Concentration Land Use EMC Table derived from USGS water quality monitoring sites

58. Total Constituent Loads Input for Water Quality Model Water Quality: Land Surface -Water Body Connection Bay Water Quality

59. Water Quality: Water Quality Analysis (Balance) Advection of Chemicals Advection + Dispersion Advection + Dispersion + Decay Flow of Water

60. Salinity Concentration and Mass Fluxes in Corpus Christi Bay. Fluxes Flow of water Advection Dispersion Loads Transport of Constituents Finite Segment Analysis Water Quality: Water Quality Analysis (Balance)

61. Flood Hydraulics u Given the flood discharge (HEC-HMS), what is the water surface elevation (HEC- RAS, River Analysis System) u How to draw flood plain maps? HEC-RAS AVRAS Cross-section mapping

62. Flood Hydraulics: Stream Geometry Data l Determine cross-section elevations from TIN terrain data l HEC-RAS pre- and post-processing using avRAS (ArcView) or HEC AMLs (Arc/Info) l Visualize floodplain TINs with ArcView’s 3D Analyst extension as flood rises

63. Hydraulics: RAS Stream Geometry Data l Digital orthophoto serves as a base map upon which to digitize the stream l Avenue scripts create an ArcView cross-section table from the HEC-RAS output text file l Link cross-section table records to cross-section locations on the digitized stream

64. GIS - River Analysis System (AVRAS) Pre Processor (Avenue) GIS GIS RAS Import RAS 2.0 GIS RAS Export Post Processor (Avenue) GIS Hydraulic Input Dean Djokic & Zichuan Ye (ESRI)

65. Stream Bed Shape in ArcView Cross-sections

66. Flood Plain in HEC-RAS

67. Floodplain in ArcView

68. Floodplain in ArcView 3-D Analyst

69. Spatial Hydrology Virtual Campus Courses u ESRI Virtual Campus course on Spatial Hydrology (http://campus.esri.com/campus/home/home.cfm) u University of Texas GIS in Water Resources online course during Fall 1998 (limited enrollment) (http://www.ce.utexas.edu/prof/maidment)

70. DHI: Hydraulic & Water Resources Engineering MIKE SHE MIKE BASIN MIKE 11 MOUSE DHI Models Pipe Networks River Basin Networks 1-D River Modeling Hydrologic Modeling Danish Hydraulic Institute

71. BYU: Surface and Groundwater Flow Integrates digital terrain models with standard runoff models such as HEC-1, TR-20, TR-55. Subsurface Representation and Model Interface for Groundwater Simulation: MODFLOW, MT3D, MODPATH, SEEP2D, and FEMWATER. Two-Dimensional Surface Water Model Interface for RMA2, RMA4, RMA10, HIVEL2D, FLO2DH (FESWMS), ADCIRC, CGWAVE, WSPRO, SED2D- WES, and DAMBRK. Brigham Young University

72. EPA: Water Quality TOXIROUTE NPSMQUAL2E US Environmental Protection Agency ArcView Preprocessor for Water Quality Models

73. GIS Hydro ‘98: Conclusions u Most comprehensive digital information source presently available for GIS hydrology u Digital Classroom, Library and Atlas u 8 analysis modules covering all phases of the hydrologic cycle, both water quantity and quality u Strong contributions from DHI, BYU and EPA u Online courses for further learning