bdsfbdsfb NHDPlus for Corpus Christi Bay Term Project Report Nishesh Mehta Nishesh Mehta 21 st November st November 2006

OBJECTIVE To create a Geodatabase for the Corpus Christi Bay in the Arc Hydro Framework and using the NHDPlus Dataset To create a Geodatabase for the Corpus Christi Bay in the Arc Hydro Framework and using the NHDPlus Dataset

Data Requirements NHDPlus dataset for NHDPlus dataset for the region given below (which contains the Corpus Christi Bay) Texas Gulf Region 12 d

GIS Methodology 1) To build a Geometric Network on the NHDPlus Flowlines for the Texas Gulf Create a new Geodatabase* and add NHDFlowline shp. file to it Create a new Geodatabase* and add NHDFlowline shp. file to it Convert the “Enabled” and “FlowDir” Field type Convert the “Enabled” and “FlowDir” Field type Text Integer Text Integer  Build the Geometric Network  Set Flow Direction Now the Network is ready for tracing * Network tracing not possible without a Geodatabase

2) Cutting out CC Bay Watershed Place Flags at a sub region outlet Place Flags at a sub region outlet Trace upstream Trace upstream Export the selected feature in a new shape file Export the selected feature in a new shape file Use the “Select by location” option to select all the regions intersecting the newly selected flowlines from all other shape files included in the NHDPlus dataset Use the “Select by location” option to select all the regions intersecting the newly selected flowlines from all other shape files included in the NHDPlus dataset Relate various tables in the NHDPlus schema Relate various tables in the NHDPlus schema

Courtesy:- NHDPlus User Guide Pg. 5

Fitting Everything into the Arc Hydro Format Translation of the NHDPlus format to Arc Hydro Translation of the NHDPlus format to Arc Hydro Build the Geometric Network Build the Geometric Network Building “Relationship Classes” * in the Geodatabase mirroring ones in the NHDPlus Building “Relationship Classes” * in the Geodatabase mirroring ones in the NHDPlus NHDPlusArc Hydro NHDFlowlineHydroEdge NHDWaterbodyWaterbody USGSGageMonitoring Point, Hydrojunction NHDLine NHDArea NHDPoint Region Subregion Basin Subbasin Watershed Subwatershed

CC Bay Geodatabase - Salient Features Network Tracing and Arc Hydro Tools may be used for analysis Network Tracing and Arc Hydro Tools may be used for analysis Watershed – helpful in analysis of the CC Bay Watershed – helpful in analysis of the CC Bay NHDPlus Advantage – Enhanced Information NHDPlus Advantage – Enhanced Information Mean Annual Streamflow and Velocity Mean Annual Streamflow and Velocity Flow Accumulation grids Flow Accumulation grids Land use, precipitation and temperature Land use, precipitation and temperature

CC Bay Database-Salient Features Example of characteristics that may be estimated using the NHDPlus dataset Example of characteristics that may be estimated using the NHDPlus dataset Relationships embedded into the Geodatabase for easy access to various tables Relationships embedded into the Geodatabase for easy access to various tables Total Stream Length km Total Catchment Area sq km Longest Flow Path983 km Time taken to reach the Bay29 days % of Catchment Area classified as National Land Coverage Data for Open Water 64.79% Mean Annual Precipitation in cm62.72 cm/sqkm/yr Mean Annual temperature in C20.6 C Mean Annual Flow1250 cfs

Future Work Geospatial Information – Complete Geospatial Information – Complete Environmental Information – Populating the TS tables using Weather Downloader Environmental Information – Populating the TS tables using Weather Downloader Integrating various Soil Characteristics for CC Bay Integrating various Soil Characteristics for CC Bay Using Web Services (NEXRAD, NetCDF Server ) to make it a comprehensive database of hydrological information which can be used for modeling Using Web Services (NEXRAD, NetCDF Server ) to make it a comprehensive database of hydrological information which can be used for modeling

Questions? Questions?

Why NHDPlus? The NHDPlus consists of 6 enhancements: The NHDPlus consists of 6 enhancements: (1) Value Added Attribute (VAA) - Attributes to analyze the flow network quicker; (1) Value Added Attribute (VAA) - Attributes to analyze the flow network quicker; (2) Catchments Polygons- the drainage area of each individual NHD flowline with known flow direction based on elevation data; (2) Catchments Polygons- the drainage area of each individual NHD flowline with known flow direction based on elevation data; (3) Geometry-Improvements to produce more accurate flow navigation and improvements to the naming of water features; (3) Geometry-Improvements to produce more accurate flow navigation and improvements to the naming of water features; (4) Mean Annual Streamflow and Velocity-for each flowline with known flow direction. (4) Mean Annual Streamflow and Velocity-for each flowline with known flow direction. (5) Flow Accumulation grids - derived from elevation models; (5) Flow Accumulation grids - derived from elevation models; (6) Land use, precipitation and temperature data associated with each flowline catchment. (6) Land use, precipitation and temperature data associated with each flowline catchment.