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bdsfbdsfb NHDPlus for Corpus Christi Bay Term Project Report Nishesh Mehta 21st November 2006 OBJECTIVE To create a Geodatabase for the Corpus Christi Bay in the Arc ... – PowerPoint PPT presentation

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Title: bdsfbdsfb

1
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NHDPlus for Corpus Christi Bay
Term Project Report
Nishesh Mehta
21st November 2006

2

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OBJECTIVE

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

4
Data Requirements

http//www.horizon-systems.com/nhdplus/HSC-wth12.h
tm
NHDPlus dataset for
the region given below
(which contains the Corpus Christi Bay)
Texas Gulf Region 12 d

5
GIS Methodology1) To build a Geometric Network
on the NHDPlus Flowlines for the Texas Gulf

Create a new Geodatabase and add NHDFlowline
shp. file to it
Convert the Enabled and FlowDir Field type
Text Integer
Build the Geometric Network
Set Flow Direction
Now the Network is ready for tracing
Network tracing not possible without a
Geodatabase

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2) Cutting out CC Bay Watershed

Place Flags at a sub region outlet
Trace upstream
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
Relate various tables in the NHDPlus schema

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Courtesy- NHDPlus User Guide Pg. 5
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Fitting Everything into the Arc Hydro Format

Translation of the NHDPlus format to Arc Hydro
Build the Geometric Network
Building Relationship Classes in the
Geodatabase mirroring ones in the NHDPlus

NHDPlus Arc Hydro
NHDFlowline HydroEdge
NHDWaterbody Waterbody
USGSGage Monitoring Point, Hydrojunction
NHDLine NHDLine
NHDArea NHDArea
NHDPoint NHDPoint
Region Region
Subregion Subregion
Basin Basin
Subbasin Subbasin
Watershed Watershed
Subwatershed Subwatershed
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CC Bay Geodatabase - Salient Features

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

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CC Bay Database-Salient Features
Total Stream Length 22304.515 km
Total Catchment Area 44213.116 sq km
Longest Flow Path 983 km
Time taken to reach the Bay 29 days
of Catchment Area classified as National Land Coverage Data for Open Water 64.79
Mean Annual Precipitation in cm 62.72 cm/sqkm/yr
Mean Annual temperature in C 20.6 C
Mean Annual Flow 1250 cfs

Example of characteristics that may be estimated
using the NHDPlus dataset
Relationships embedded into the Geodatabase for
easy access to various tables

11
Future Work

Geospatial Information Complete
Environmental Information Populating the TS
tables using Weather Downloader
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

Questions?

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(No Transcript)
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Why NHDPlus?

The NHDPlus consists of 6 enhancements
(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
(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.
(5) Flow Accumulation grids - derived from
elevation models
(6) Land use, precipitation and temperature data
associated with each flowline catchment.