West San Antonio Bay -- Cataloging Unit 12100404

• Central Texas Coastal Accounting Unit 121004
  
• Central Texas Coastal Subregion 1210
  
• Texas-Gulf Region 12 (There are 122 cataloging units in this region.)
  The state composition by area is 100.0% Texas.
  

  I. Graphical Locater Maps

  Roads

  Water Only

  8 Digit HUCs

  The area of this HUC in these maps is 281.9 km² ( 108.9 mi² ) [% in USA = 0.38, % in Region = 0.82]
  The area from the USGS is 155 mi².
  

  II. Flow Connections (upstream and downstream units)

  III. Named places in this watershed (total = 127)

  IV. Elevation Analysis

  This analysis is based on 112416 elevations on a 50 m grid within the area of this HUC.
  The mean elevation is 1.5 m ( 4.9 ft ) [% in USA = 0.71, % in Region = 0.82]
  The elevation standard deviation is 1.1 m ( 3.6 ft ) [% in USA = 0.52, % in Region = 0.82]
  The coefficient of variation is 73.3 %.
  The vertical relief is 7.0 m ( 23.0 ft ) [% in USA = 0.38, % in Region = 0.82]

  Elevation Percentiles

  	0 %	10 %	20 %	30 %	40 %	50 %	60 %	70 %	80 %	90 %	100 %
  meters	0.0	0.0	0.0	1.0	1.0	2.0	2.0	2.0	2.2	3.0	7.0
  feet	0.0	0.0	0.0	3.3	3.3	6.6	6.6	6.6	7.2	9.8	23.0

  

  V. Map Line Analysis

  Note- percentiles are for the feature density, not for the raw total lengths.
  

  line type	km	mi	km/km²	mi/mi²	% in USA	% in Region
  Perennial Shoreline	618.9	384.7	2.196	3.533	99.81	100.00
  Intermittent Shoreline	17.7	11.0	0.063	0.101	97.54	95.90
  Perennial Streams	6.1	3.8	0.022	0.035	9.90	12.30
  Intermittent Streams	5.2	3.2	0.018	0.030	8.57	8.20
  Canals	1.1	0.7	0.004	0.006	56.09	70.49
  1° roads	0.0	0.0	0.000	0.000	30.84	10.66
  2° roads	0.0	0.0	0.000	0.000	15.35	4.92
  3° roads	6.2	3.9	0.022	0.036	23.64	27.87
  4° roads	221.0	137.4	0.784	1.262	21.41	0.82
  Total Roads	227.3	141.2	0.806	1.297	19.47	0.82
  Railroads	0.0	0.0	0.000	0.000	12.60	5.74
  Pipes and Powerlines	0.0	0.0	0.000	0.000	8.67	1.64

  
  Of the natural water in this HUC, 3.53% (by length) is intermittent [% in USA = 9.19, % in Region = 4.92]

  VI. Other sites

  • EPA- Surf Your Watershed - Index of Watershed Indicators
  • USGS- Science in Your Watershed - Selected Realtime Streamflow Stations
  • CTIC- Known Your Watershed

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  1999 SEPT 4, Last updated on 2003 JAN 23
  
  D.L. Gustafson, dlg@rapid.msu.montana.edu