WRAP Hydro Data Model: Its Structure and application to find Input Parameters for the Water Rights Analysis Package Centre For Research In Water Resources UT Austin

Objectives To build a hydro data model for the WRAP project called WRAPHydro from the basic Arc Hydro model. To devise a new method of defining the basin boundary to act as an analysis mask for processing grids and watersheds. To develop a new vector based method for determining watershed parameters using the WRAPHydro model. To verify the validity of dividing the basin into sub regions for parameter development. To explore the possibility of efficiently adding stream lines and control points after completing the process of developing the parameters so as to facilitate editing and updating of database.

Study Area: Guadalupe River Basin

Arc Hydro Framework A geospatial and temporal data model for water resources HydroJunction HydroEdge Watershed Arc Hydro framework Personal Geodatabase Hydro Edge Hydro Junction Watershed Network Relation Feature Dataset

Arc Hydro toolset

WRAP Hydro toolset

WRAP Hydro Model

Base Data Seamless DEM Buffered HUCs NHD network for region 12 And control points

Preprocess: Raster Buffered DEM Burn the Streams Fill the sinks Flow Direction Grid

Preprocess: Vector

Creating a Mask and flow direction grid

Delineation problems Without Surrounding streams With Surrounding streams

Delineation without burning streams

Hydro ID assignment Unique Ids for each feature 7 digit integers  WRAPJunctions prefixed with 1  WRAPEdges prefixed with 2

Watershed delineation 1) HydroIDs of Junctions to JunctionIDs of Edges 2) JunctionIDs of Edges to DrainIDs of Watershed

Parameters: Next Down ID Identifies the next downstream junction and populates the NextDownID with the HydroID of the junction downstream

Parameters: Length Down Lengths obtained in meters from the shape_length field in WRAPEdge Length converted to miles

Connectivity Diagram

Parameter: Drain Area, CN and PR

Accumulating values downstream Wshed 1Area = 2.47 CN = PR = Wshed 2 Area = 3.49 CN = PR = Wshed 3 Area = CN = PR =

Regionalization Schematic Diagram

Regional WRAPHydro model

Regional HydroIDs 7 digit integers, WRAPJunction Ids prefixed by 1 and WRAPEdge Ids prefixed by 2 Regional Ids 01 through 04

Placing outlets

Merging the Regions

Process Rasters are processed in parts A point is placed at the outlet of each sub basin Watersheds are delineated for each part The WRAPJunctions, WRAPEdges and WRAPWatersheds for all the four parts are merged and a network is built The NextDownID value for the four outlets are manually entered Rest of the processing for the parameters is done as for the whole basin

Adding new junctions This creates a new watersheds file and updates all the other parameters as well. However, both these tools do not compute the length downstream and the LengthDown field has to be populated using the ‘Find Length Downsream for Junction’ tool in ArcHydro toolset.

Removing a junction The NextDownID of the upstream junction, the JunctionID of the upstream edge and the DrainID of the Watershed the deleted junction delineated are automatically updated. Figure shows four junctions with HydroIDs 1 through 4 and the DrainIDs of the respective watersheds. If junction 2 is removed, the NextDownID of junction 1 changes from 2 to 3 [Figure 8.2 (B)] and the DrainID of watershed 2 changes to 3 [Figure 8.2 (C)]. The watersheds are dissolved based on DrainID. The rest of the parameters are determined the usual way.

Adding a stream segment Case I Case II

Results – Stream gage comparisons

Area

Length Down

Average CN and Precip