San Marcos -- Cataloging Unit 12100203

• Guadalupe Accounting Unit 121002
  
• 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 3509.6 km² ( 1355.7 mi² ) [% in USA = 56.32, % in Region = 54.10]
  The area from the USGS is 1370 mi².
  

  II. Flow Connections (upstream and downstream units)

  III. Named places in this watershed (total = 601)

  IV. Elevation Analysis

  This analysis is based on 1402445 elevations on a 50 m grid within the area of this HUC.
  The mean elevation is 238.6 m ( 782.8 ft ) [% in USA = 29.80, % in Region = 56.56]
  The elevation standard deviation is 124.8 m ( 409.4 ft ) [% in USA = 60.92, % in Region = 95.08]
  The coefficient of variation is 52.3 %.
  The vertical relief is 533.0 m ( 1748.7 ft ) [% in USA = 54.95, % in Region = 93.44]

  Elevation Percentiles

  	0 %	10 %	20 %	30 %	40 %	50 %	60 %	70 %	80 %	90 %	100 %
  meters	82.0	121.0	136.8	152.0	167.0	182.8	213.1	289.0	354.9	434.5	615.0
  feet	269.0	397.0	448.8	498.7	547.9	599.7	699.1	948.2	1164.4	1425.5	2017.7

  

  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	198.9	123.6	0.057	0.091	38.70	37.70
  Intermittent Shoreline	2.4	1.5	0.001	0.001	48.84	30.33
  Perennial Streams	515.9	320.6	0.147	0.237	31.79	55.74
  Intermittent Streams	1481.4	920.7	0.422	0.679	60.82	72.95
  Canals	0.0	0.0	0.000	0.000	35.62	41.80
  1° roads	121.7	75.6	0.035	0.056	83.04	86.07
  2° roads	109.8	68.3	0.031	0.050	59.02	50.00
  3° roads	132.4	82.3	0.038	0.061	37.47	44.26
  4° roads	6266.4	3894.6	1.785	2.873	89.06	86.07
  Total Roads	6630.3	4120.8	1.889	3.040	86.69	86.07
  Railroads	161.0	100.1	0.046	0.074	55.00	57.38
  Pipes and Powerlines	304.9	189.5	0.087	0.140	90.72	93.44

  
  Of the natural water in this HUC, 67.49% (by length) is intermittent [% in USA = 67.60, % in Region = 57.38]

  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