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Web/GIS Tools for Hydrologic Analysis of Watersheds

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Web/GIS Tools for Hydrologic Analysis of Watersheds Paul Bartholomew Mark Dougherty Brian McCormick Brian Thye Mining Web Sites for Hydrologic Data Digital Data and ... – PowerPoint PPT presentation

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Title: Web/GIS Tools for Hydrologic Analysis of Watersheds


1
Web/GIS Tools for Hydrologic Analysis of
Watersheds
  • Paul Bartholomew
  • Mark Dougherty
  • Brian McCormick
  • Brian Thye

2
Mining Web Sites for Hydrologic Data
  • Digital Data and Background Information Search

3
Sources of Hydrologic Background Information
  • Surf Your Watershed
  • http//www.epa.gov/surf/
  • EPA Watershed Information Site
  • http//www.epa.gov/surf3/hucs/

4
Surf Your Watershed
  • Locate your watershed by zip code, graphical
    interface, or landmark.
  • Find information on watershed index indicators
  • Find links to information on toxic releases and
    hazardous wastes in each watershed.

5
EPA Watershed Locator
6
EPA Site Offers Excellent Background Watershed
Information
Watershed Area and Total Stream Length.
Principle Aquifer Names and Basics on Underlying
Geology.
  • Many Types of Hydrologic Data
  • Community Water Sources.
  • Stream Flow Data.
  • Water Use Statistics.
  • Abstracts.

7
Obtaining Spatial Data Sets
  • National Atlas.gov
  • http//www.nationalatlas.gov/stlasvue.html
  • Department of Conservation and Recreation
  • http//www.dcr.state.va.us/dnh/manage.htm
  • ESRI
  • http//www.esri.com/data/index.html
  • Association Of Geographic Information
  • http//www.agi.org.uk/

8
Map Layers Data Warehouse Free ! Download
National Atlas map layers at no cost via file
transfer protocol.
  • Printed Maps
  • Map Layers Data Warehouse
  • Interactive Maps
  • Multimedia Maps

9
Data Layers Come In Shapefile Format
10
Map Data Warehouse Shapefile Example
11
 
Mining for Other Data Sets
12
Example Of Available Data Sets
13
Department of Conservation and Recreation Has A
List Of Experts To Help Locate Data Sources
  • Biological and Conservation Data .
  • Statewide set of 124,000 USGS quadrangles
    annotated with locations of natural heritage
    resources.
  • database management program.
  • over thirty interrelated computer files.
  • thousands of fields of information.
  • flexible interface for data retrieval, data.
    manipulation, and report generation.

http//www.dcr.state.va.us/dnh/manage.htm
14
Association OF Geographic Information
http//www.agi.org.uk/
  • On-Line GIS resources.
  • Conference Papers.
  • Extensive List of Related Links.

Questions Before We Go ON???
I didn't think so..
15
Topologically Burning A Stream Or How to Dig a
Bottomless River From Download to Delivery
  • What You Need
  • DEM and Streams DLG from USGS.
  • DLGLX155 and DLGDXF DOS Programs
    http//members.visi.netddbunch/dlglx.htm

16
USGS EROS Data Download http//edcwww.cr.usgs.gov/
doc/edchome/add/add.html
17
Downloading and Converting DLG Files To DXF
ERROS USGS Web Site
DLG By Graphic Search
18
Download All Hydrography Files
19
Unzip Files tar Files May Need To Be Double
Unzipped
  • Sdts.tar
  • Spatial Data Transfer Standard.
  • Taped Archive

20
Convert the opt to dxf CAD File
1) Rename file 452002.HY.opt - Change to
452002HY.dlg
2) Run dlgdxf DOS batch program that runs
DLGLX155 Program
dlgdxf
Output File dxf CAD file
21
Open The Files With Cad Reader Extension
22
Pre-Processing
  1. Query out Quad Boundaries.
  2. Convert Each File To A Shape File.

3) Merge Files.
23
Open DEM of Montgomery County
With All The Ingredients Prepared, We Can Begin
Cooking!
24
1) Convert Stream.shp File To Streamgrid Grid
File.
25
Prepare Stream Grid File
2) Use Map Calculator Under Analysis Tools
to Divide the Streamgrid theme by itself to
convert all cells to 0 or 1.
26
3) Multiply the Resulting Grid By The DEM
Output Grid contains DEM Elevations of Stream
Name DEMStream 4) Add 5000 To The Original
DEM Name DEMPlus
27
The Final Product Burned DEM
28
USGS National Hydrography Dataset (NHD)
  • USGS DLG hydrography
  • EPA Reach File Version 3
  • Data is combined per hydrologic cataloging unit
  • Stream lines are topologically correct including
    flow direction

29
Where is the data? nhd.usgs.gov
30
What is available?
31
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32
How do I get the data?
  • Available in ESRI ARC or USGS SDTS
  • Free download

33
What can I do with it?
Incorporate stream-related data into a
pre-existing GIS
34
Navigate up or downstream, main branch or
tributaries
35
From DEMs to Watersheds
  • Grid Function Based
  • Multiple Frontends
  • Inputs and Outputs vary based on application
  • Concepts from
  • ESRIs Hydro Extension
  • TNRCC Watershed Delineator

36
Processes in ESRIs Hydro Extension
  • Individual Commands or Batch Process
  • Easy Pre-processing
  • Limited capabilities

37
Identifying and Filling Sinks
  • Sinks are localized depressions in the DEM
  • Usually due to noise in the data set
  • Identifying and Filling eliminates small sinks
    while leaving large ones (lakes, rivers..)

Filled DEM
38
Flow Direction
  • Determines Direction of flow out of a cell
  • Requires a filled DEM for input
  • Uses D8 model of Flow direction

39
Flow Accumulation
  • Shows how many cells drain through a point
  • Used as an intermediate to delineate watersheds
    and stream segments
  • Result is similar in appearance to stream network

40
Subwatershed Delineation
  • Can produce gridded watersheds and polygons
  • Sensitive to minimum size
  • For 30m grid 500 cells corresponds to 4.5km2
    drainage area

10k cell minimum size
500 cell minimum size
41
Stream Delineation
  • Can be accomplished on Regular or Extra Crispy DEM

42
Stream Network is Topologically Correct
43
Advantages of Burned DEM
  • Comparison of DLG, and streams delineated from
    unburned DEM, and burned DEM

44
Uses of Subwatersheds and Stream Networks
  • Aggregate gridded parameters such as Curve
    Number, Precipitation
  • Finite element analysis calculations may be
    performed on subwatersheds
  • Create input for various hydrological modeling
    programs such as HEC-HMS

45
Capabilities of TNRCC Watershed Delineator
  • Delineate above a point from unprocessed DEM
  • Crop DEM by polygon
  • Preprocess cropped area with Hydro extension or
    TNRCC

46
Delineation Above a Point
47
DEM Extraction by Polygon
48
Working with Watershed Delineator
  • Paul Bartholomew
  • Mark Dougherty
  • Brian McCormick
  • Brian Thye

49
What is Watershed Delineator?
  • Watershed Delineator is a set of procedures,
    tools, and utilities
  • developed by TNRCC and ESRI
  • to delineate watershed boundaries on a digital
    elevation model.

50
Nuts and Bolts
  • Watershed Delineator is a series of algorithms
  • developed in ArcViews command language (Avenue
    script)
  • as an add-on extension.
  • Watershed Delineator makes the modeling process
    more efficient because it requires no external
    file sharing.

51
Nuts and Bolts (cont.)
  • Watershed Delineator provides three major
    functionality areas
  • Interactive delineation and data entry
  • Utilities
  • Miscellaneous functions

52
How do I get started with Watershed Delineator?
  • 1. Find a copy of WshdDel.avx script.
  • Script is available on ESRIs Water Resources CD
    (1999).
  • Script was not found
    on either the ESRI or the
    CRWR websites.

53
3. Load two file extensions.
54
Watershed Delineator interface
55
Batch Processing Delineate on Segments Delineate
on Polygons Delineate on Points
Extract GRID by Delineate on pt. Polygon
(no preproc.) Rectangle
Trace flow path Circle
Subtract polygns Calculate flow
length and Tc
not shown

Add an Outlet Point
Delineate on a Segment Delineate on a Point
56
How does Delineator work?
57
Source Watershed Delineator documentation
58
What does the display look like?
59
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60
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61
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65
Other delineation tools
  • A new Avenue script is available on the ESRI
    site

66
Other resources from ESRI
  • Search ESRIs Web Site for keyword
  • Watershed Delineator
  • You can download the following papers

67
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68
What is the data input?
  • Contour data
  • Point data
  • DEM files

69
What do I need to get watersheds?
  • TIN
  • Depressions

70
What will Land Development do?
  • Create types of watersheds
  • Depression
  • Boundary
  • Boundary Points
  • Flat Area

Create a false depression at the point of interest
HINT
71
What are the results?
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