Use of GIS for Hydrologic Model Parameter EstimationOHD/HSMB/Hydrologic Modeling GroupSeann Reed (presenter), Ziya Zhang, Yu Zhang, Victor Koren, Fekadu Moreda, Michael Smith, Zhengtao Cui

Presented at the RFC GIS Workshop, OHRFCJuly 17, 2007

OutlineGridded a-priori parameter estimation proceduresSAC-SMAPE, PE Adjustment FactorsSnow-17Distributed model routingCalibration Assistance Program (CAP)Polar stereographic/HRAPXmrgtoasc, asctoxmrgPre-processingDelivery

A priori SAC-SMA Parameter GridsVictor Koren methodology inputs:SCS curve number; assumed dry antecedent conditionstotal soil column depthtexture by layer

Three versions now being tested:STATSGO only (original)Miller and White (1998) 1-km gridded STATSGOCurve numbers vary spatially as a function of hydrologic soil group but not land use; assumed pasture or range land use CONUS coverageSTATSGO-GLCCGLCC: Global Land Cover Characterization (1-km resolution)Explicitly account for Land Use/Land Cover variationsCONUS coverageSSURGO-NLCDSSURGO: State Soil Geographic DatabaseNLCD: National Land Cover DatabaseHigher resolution inputsParameters derived for 25 states in southern US so far

State Soil Geographic Database (STATSGO)A Mapunit groups similar soils and may contain several non-contiguous polygons; each polygon may contain multiple soil typesMapunit sizes ~ 102 103 km2Attribute tables contain soil property information by layerSoil Survey Geographic Database (SSURGO) ~ 4 to 20 times more detailPolygon data for all counties expected to be available in standard digital format by 2008Surface Soil Textures in a 600 km2 Basin STATSGO vs. SSURGO

STATSGO and SSURGO contain both spatial and tabular information.SSURGO data schematic from Zhang et al. (2007), in review

Complex Soil Survey Databases Must Be SimplifiedFrom Zhang et al. (2007) This slide describes our assumptions for SSURGO simplifications

Miller and White (1998) used similar assumptions to convert STATSGO polygon data to a 1 km grid and 11 standard layers for the conterminous U.S.

Efficient processing of large data sets using GRASS, R, K Shell and Perl scripts Phases 1 and 2 run for each soil survey area and then merged to state and regional domains in Phase 3 Parameters aggregated to , , and 1 HRAP resolutions for hydrologic modeling Phase 3

Zhang et al. (2007), in review

Example SSURGO-NLCD Results:UZTWMBasic ResultBasic with Gap Filling

STATSGO-STATSGO_GLCCSTATSGO: UZTWMSTATSGO_GLCC: UZTWMMean: 54 mmMean: 51 mmSTATSGO STATSGO_GLCCSTATSGO STATSGO/GLCCForested Areas

PE and PE Adjustment Factor GridsPEKoren, Schaake, Duan, Smith, and Cong (1998)PE AdjustmentJulyJanuary

Gridded A-priori Estimates for Two Snow-17 ParametersDerived from:Aspect (500-m DEM)Slope Forest TypeForest Cover, %Anderson (2002) recommendations for MFMIN, MFMAX (Chapter 7-4)MFMINMFMAX

Flow Direction GridDigital Elevation Model and Derivatives (DEMs)Out-of-the-Box DEM Analysis

Flow AccumulationOut-of-the-Box DEM Analysis

StreamsStream linksSub-basins23456Out-of-the-Box DEM Analysis

Customized Algorithms for Analyzing DEMs with Low Accuracy in Flat AreasIdentify flat areas and digitized streamsModify elevation gridCompute new flow directions from Modified grid

Digital Elevation Models (DEMs) and DerivativesNOHRSC Data (CONUS by RFC)15 arc-second DEM (resampled from 3 arc-second)RF1 (1:500,000 stream vectors)Customized algorithms used to blend DEM and streamline data Used in IHABBS, ThreshR, CAP, and to derive first-cut HL-RDHM connectivity filesNational Elevation Dataset (NED) 1 arc-second (30-m resolution)Used NSSL derivative products for selected study areas (e.g. DMIP)No correction with digitized streams or basin boundariesNHDPlus Project DEM DerivativesMulti-agency effort to develop attributes for National Hydrography Data set (NHD)Uses several algorithms to forces consistency between DEM derivatives, NHD, and that National Basin Boundary Dataset Not necessarily best algorithms to correct DEMs, but looks to be the most practical and best available product for basin and stream delineation

Deriving Coarse Resolution (e.g. HRAP) Flow Directions from Higher Resolution DEMsHRAP gridCells flow to the wrong basin Out-of-the-Box Steepest Descent Algorithm Works Well for High Resolution DEMs but not for HRAP resolutionCell outlet tracing with an area threshold (COTAT), Reed (2003)Using networks derived from high-resolution DEMs improves the results

ABRFC ~33,000 cellsMARFC ~14,000 cells OHD delivers baseline HRAP resolution connectivity, channel slope, and hillslope slope grids for each CONUS RFC on the basis of higher resolution DEM data.HRAP Cell-to-cell Connectivity Examples

123Must choose this cell to get only subbasin 3, losing cells in the red box. 2 km resolution allows more accurate delineation of subbasin 3 Distributed Model Resolution Impacts the Accuracy of Basin Representation1: 2258 km22: 619 km23: 365 km2HRAP HRAP

Drainage Area Delineation Accuracies Open squares represent errors due to resolution only. Black diamonds represent errors due to resolution and connectivity. We correct for these errors by adjusting cell areas in HL-RDHM implementations. Both higher resolution input DEMs and use of finer resolution distributed models (e.g. HRAP) can be used to increase accuracy

Delineated from an HRAP Network Derived from 400-m Flow DirectionsDelineated directly from DEM resolution

Representative Slopes Are Extracted from Higher Resolution DEMS(North Fork of the American River (850 km2))Slopes from 30-m DEMHillslope Slope (1/2 HRAP Resolution)Average = 0.15Slopes of all DEM cells within the HRAP pixel are averaged.Main Channel Slope (1/2 HRAP Resolution)Average = 0.06Channel slopes are assigned based on a representative channel with the closest drainage area.

Local Channel Slope (1/2 HRAP Resolution)Average = 0.11Slope (m/m)

Main Channel Slope vs. Local Channel SlopeSlopes of each stream segment are calculated on the DEM grid(2) Model pixel slopes are assigned from representative segments (DEM cell) that most closely match either the cells cumulative or local drainage area. Segment Slopes (m/m)Cell slope -> pixel-wise local slopecCell slope -> pixel-wise main slopec

Calibration Assistance Program (CAP) Avenue-based , requires ArcView 3.x with the Spatial Analyst 1.1V. 1.0, 2000 (Seann Reed, Ziya Zhang, David Wang)Initially intended to: simplify initial parameter estimation for lumped modeling (assumed non-expert GIS user)facilitate extensibility and creative exploration for GIS expertsV. 1.1, 2002: Added tools to automatically define MAPX areas for OFS based on zone or basin polygons (Lee Cajina)2003 2007 no updates AWIPS migrates to Linux so future of ArcView 3.x applications is unclearV. 1.2, 2007: Minor enhancementsUpdated cover data from NOHRSC (1996-2003) Two new grids to support the frozen ground model are now provided Scripts updated to support new grids Scripts modified to allow most functions to run properly on Windows XP operating system (not functions that interact with OFS, e.g. MAPX)All data in Albers Equal Area Projection (equal area projection makes it easier to compute zone and basin areas)

CAP v. 1.2 Functionality Derive area-elevation curvesExport area-elevation to MCP input deck formatSub-divide basins into elevation zonesDerive elevation-precipitation plotsCompute basin or zonal mean, max, and min values of:precipitation (monthly, annual, and seasonal)potential evaporation (monthly, annual, and seasonal)potential evaporation adjustment factorspercent forestpercent of each forest typesoil-based estimates for 11 SAC-SMA parametersMean annual temperature (C) used in the frozen ground model (TBOT)Compute the dominant soil texture in a basins upper layer (STXT) used in the frozen ground modelDisplay NOHRSC historical snow images from (1990-2003)Display basin boundaries and defined zones on top of other data layers (e.g. snow cover, SAC parameters, etc.)Derive/export geographic information required to run NWSRFS-MAPX routines (must run on HP)

CAP Example Graphics

Future of CAP?NeedsRe-engineer CAP to move out of ArcView 3.x.Maintain original goals: (1) friendliness for non-GIS experts, (2) extensible for intermediate GIS users. Deliver refined a-priori parameter grids as they are developed (no problem)Deliver parameter estimation procedures via the new CAP (as opposed to delivering only pre-processed data)Many others . . .

Future of CAP?Possible Development PathsOrganize collaborative development project by hydrologists (local application in GRASS or ArcGIS?)PROS: Less expensive, short wait, easily customizable to meet local needsCONS: Requires field expertise and high level of coordination (from where?), risks lack of coordination and multiple versions, informal supportPush for official AWIPS development project by software engineersPROS: Would yield a more polished user friendly application, formal AWIPS supportCONS: Higher cost, longer wait, greater risk of no future enhancements if funds dry up, may be difficult to get a high enough priority to receive funding

Secant Polar Stereographic Map Projection(Basis for the HRAP coordinate system used in NEXRAD processing and distributed hydrologic modeling) Points are projected from the model earth to the image plane along a straight line drawn from the South Pole The secant image plane intersects the earth at 60 N (the standard latitude, o)oBImage PlaneABA'B'A Distances between points are elongated relative to true distances at latitudes below o but shortened at latitudes above o, e.g.:

A'B' > ABSouth PoleElevation View

HRAP grid is specified in the image plane of the polar stereographic map projection:True Side Lengths and Areas for HRAP Cells at Different LatitudesAlthough not ideal for hydrologic modeling, we can readily adjust HRAP cell areas to represent the true area when converting runoff depths to flow volumes. Polar Stereographic to HRAP

Sheet1

LatitudeLocationTrue Side Length (km)True Area (km2)

60Standard Latitude4.7622.681

50Winnipeg4.5120.321.0566129358

45Minneapolis4.3618.981.0930923738

35Memphis4.0216.131.1858498645

25Miami3.6313.181.3116838536

Sheet2

Sheet3

ESRI Polar Stereographic Projection ExampleSee also: http://www.nws.noaa.gov/oh/hrl/distmodel/hrap.htm**TRICK: Standard latitude is adjusted so that the HRAP earth radius of 6371.2 km can be used instead of the ESRI default 6370.997 km. As of Arc/Info 7.2, ESRI did not support a user defined radius for this projection.GRASS Input and Output Location Projectionsname: Lat/Lonproj: llellps: spherename: Stereographicproj: sterea: 1337.784777es: 0.0f: 0.0lat_0: 90.0000000000lat_ts: 60.0000000000lon_0: -105.0000000000k_0: 1.0000000000x_0: 401.0y_0: 1601.0Earth radius divided by 4762.5 (size of 1 HRAP cell)

HL-RDHM XMRG Grids to GIS and Backncols 1060nrows 821xllcorner -1905000.000000yllcorner -7620000.000000cellsize 4762.500000NODATA_value -1.000000ncols 1060nrows 821xllcorner 1.000000yllcorner 1.000000cellsize 1.000000NODATA_value -1.000000xmrgtoasc Header output with ster option:Header output with HRAP option:Arc/Info: asciigrid/gridasciiGRASS: r.in.gdal/r.out.gdalasctoxmrg Go to http://www.weather.gov/ohd_files/project-hydrology/index.phpAnd click on dhmworkshop link. 123

SummaryGIS data and tools provided valuable assistance in estimating hydrologic model parametersBecause algorithms to derive apriori parameters are complex, work cannot be done with out-of-the-box GIS functionsRecently, products delivered to the field from OHD are derived data set rather than data and softwareReasons include algorithm complexity (no need for everyone to learn)lack of a common GIS platformlimited resourcesEfforts to deliver data and programs should be considered in the future (potential added value by field developers and possibility of using better local data sources)New CAP should be considered

GIS-based Parameter Estimation for Lumped and Distributed Hydrologic ModelsCalibration Assistance Program (CAP) Arcview 3.xPrototype Tools Available to RFCsParameter GridsHRAP/XMRGESRI Grids and ShapefilesHydrology Laboratory Distributed Hydrologic Model(HL-RDHM)ThreshR ArcView 3.xIn-house ProceduresTools to derive A-priori Parameter GridsArcView 3.1 w/ Spatial Analyst (HP-UX)Arc/Info 7.x (HP-UX)GRASS 6.2R Statistical SoftwareFORTRAN/C/C++Derived Data LayersGRASS/ArcView/ArcInfoAsctoxmrg, xmrgtoascParameter GridsHRAP/ASCIIEdit/displayGridsABRFCs XDMS

Definition of GIS? A toolkit with high level access functions for interactive or automated management, analysis, and display of geographically referenced data.

My title should really be GIS and custom programs Main reason that we havent gotten into using ArcGIS 9.x is our desire to share data with non-GIS models that run on Linux and strict rules in our building about networking PC. Also, since the AWIPS move away from Linux we have halted or slowed any development to Soil data: 4 to 20 times more detail from STATSGO to SSURGOLanduse data: NLCD has 30 times the resolution of GLCCAnnotate with Annotate with Gridded data delivered via CAP and HL-RDHM

PE Data are from analysis of NOAA atlas 33 and 34 dataPE Adjustment factors are from an empirical relationshop between Eric Andersons calibrated values and gridded NDVI vegetation (8 year mean I think)If ok, wil be delivered via CAP.

Development tools: ArcView 3.x. w/ Spatial Analyst, FORTRAN (Moreda, 2006)Grid availability: Via CAP and HL-RDHM

Basin boundaries for lumped modelsFlow directions for distributed modelsStream characteristics(lengths, slopes, etc.)Hillslope slopes

Strategy pre-derive separate complex pre-processing schemes from hydrologic simulation. Simple framework.Using the same resolution grid as the available rainfall grids makes sense.

Would like to work from the most accurate DEM hydro derivatives available. Note that these algorithms are used to preprocess data delivered with HL-RDHM. The algorithms themselves are not yet delivered as either LAD or AWIPS partly because they rely on Arc/Info Grid software. Can think of enhancements e.g. automatically generating snow cover percentages for each elevation zoneCAP requires full GIS capabilities. These capabilities are not available in the current AWIPS environment (not met by XDMS, D2D, GFE). Should the full GIS share a GUI environment with these operational types of tools. What is full GIS? Will there be full GIS capabilities in AWIPSII. CAP is a model development tool. It is required for successful operations but it is not an operational tool that is used on an hour by hour, day by day basis. This is probably the main reason that it has not gotten enough priority to obtain software engineering resources. CAP requires full GIS capabilities. These capabilities are not available in the current AWIPS environment (not met by XDMS, D2D, GFE). Should the full GIS share a GUI environment with these operational types of tools. What is full GIS? Will there be full GIS capabilities in AWIPSII. CAP is a model development tool. It is required for successful operations but it is not an operational tool that is used on an hour by hour, day by day basis. This is probably the main reason that it has not gotten enough priority to obtain software engineering resources. Secant means a straight line cutting a curve at two or more points.Standard latitude is adjusted so that the HRAP earth radius of 6371.2 km can be used instead of the ESRI default 6370.997 km.CAP requires full GIS capabilities. These capabilities are not available in the current AWIPS environment (not met by XDMS, D2D, GFE). Should the full GIS share a GUI environment with these operational types of tools. What is full GIS? Will there be full GIS capabilities in AWIPSII. CAP is a model development tool. It is required for successful operations but it is not an operational tool that is used on an hour by hour, day by day basis. This is probably the main reason that it has not gotten enough priority to obtain software engineering resources. Main reason that we havent gotten into using ArcGIS 9.x is our desire to share data with non-GIS models that run on Linux and strict rules in our building about networking PC. Also, since the AWIPS move away from Linux we have halted or slowed any development to Future: Re-engineer CAP to work under new AWIPS.Integrate distributed modeling proprocessing tools into future CAP.