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Flood monitoring and mapping for Emergency
Response in San Antonio-Texas Part
IbySilvana Alcoz
Term Project - CE 394K - GIS in Water Resources
Source photo http//www.hdrinc.com/information/
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Area under study Rosillo Creek Lower Salado
Creek watershed
Center for Research in Water Resources Model
Integration Framework for Floodplain Mapping
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Which is the land use in Rosillo Creek basin?
Source orthophotos TNRIS http//www.tnris.state.t
x.us
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Obtaining data from the Census 2000

• Census boundaries
• ESRIs Geography Network Census 2000 Tiger/Line
  Data
• This census boundaries are just boundaries, do
  not have census demographic data associated
• Coordinate system decimal degrees
• http//www.esri.com/data/download/census2000_tiger
  line
• Level of census geography chosen block groups
• Census database tables
• US Census Bureau, will be joined to the census
  geographic areas SF1 data is the basic
  information of the Census, we will be able to
  join it to the boundary through a common field
  called STFID
• http//factfinder.census.gov

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Hispanics as a proportion of total population of
each census blockgroup
Population under 5 as a proportion of total
population of each census blockgroup
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Percentage of house units that are rented occupied
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• To characterize the basin
• 1. Geodatabase - Center for Research in Water
  Resources Model Integration Framework for
  Floodplain Mapping (Projected Coordinate System
  Lambert_Conformal_Conic (feet))
• It includes
• 2 storm events
• Hydroresponse unit
• Time series tables
• - Basin
• - Hydroedge, Hydrojunctions, Hydronetwork
• No information on how the basin and network had
  been obtained
• 2. New Geodatabase
• National Elevation Dataset DEM grid
• National Hydrography Dataset to obtain the
  surface water drainage network (nhd coverage)
• Both datasets are in geographic coordinates -gt
  Projection chosen UTM zone 14N (meters)

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Seamless dataset of the USA

• NED
• user specifies geographic extent
• horizontal locations are referenced in decimal
  degrees of latitude and longitude
• a consistent grid spacing of 1-arc-second
  (approximately 30 meters) is used
• Elevation units are standardized to decimal
  meters
• The horizontal datum for NED is the North
  American Datum of 1983 (NAD 83)
• the vertical datum is the North American
  Vertical Datum of 1988 (NAVD 88). 40

http//seamless.usgs.gov/viewer.htm
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National Hydrography Dataset
HUC 12100301 Upper San Antonio
West Coordinate -98.64886855615 East
Coordinate -98.2209294179 North Coordinate
29.73515182874 South Coordinate 29.14713602515
nhd coverage has line, polygon, and node
topology
http//nhd.usgs.gov/data.html
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Results from ArcHydro Terrain Processing
Degree of agreement with input vector stream
Threshold to generate stream 2000 cells Flow
accumulation at the outlet is 86,235 cells, each
cell is 30mX30m, so the total area of the basin
is 77.6115 square km
Drainage density of the river network generated
(55951.65-14.93)/77611500 0.000721 Drainage
density of NHD river network (36883.37)/77611500
0.000475
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From 5m clipped contours with Rosillo Creek
basin Min. elevation 155 meters Max.
elevation 265 meters
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• Joining precipitation data to the generated
  catchment
• hydroresponse unit and time series table
• dont have any field in common with the
  catchment feature class to be joined.
• Then, spatial join, joining the attributes of
  features by their location, with the objective to
  get the storm event spatially aggregated by the
  catchment.
• Intersection feature class catchment and
  hydroresponse unit - 62 records each one with
  both attributes
• Temporal layer intersection feature class and
  time series table
• Microsoft access and ArcMap data manipulation to
  assign rain to catchments,
• First accumulating rain per area, then per
  HydroID

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Event 20-hour Storm 01 Jul 2002 at 0400
through 01 Jul 2002 at 2400 Variable
precipitation, inches per hour
Animation of storm event over Rosillo Creek Basin
using extension for ArcMap called the Tracking
Analyst
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• Use of ArcHydro tool accumulate based on
  NextDownID field, to accumulate the incremental
  volume of rain water for each catchment
  downstream
• Average depth of rainfall during the storm over
  the whole Rosillo creek basin
• 217 mm
• Accumulated volume at outlet
• 16,896,844 cubic meters
• Total area of Rosillo Creek basin
• 77,612,399 square meters

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• Continues Part II
• Acknowledegment
• Dr. David Maidment
• Oscar Robayo, PhD student