South Llano -- Cataloging Unit 12090203

• Middle Colorado-Llano Accounting Unit 120902
  
• Lower Colorado-San Bernard Coastal Subregion 1209
  
• 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 2431.9 km² ( 939.4 mi² ) [% in USA = 31.60, % in Region = 28.69]
  The area from the USGS is 937 mi².
  

  II. Flow Connections (upstream and downstream units)

  III. Named places in this watershed (total = 198)

  IV. Elevation Analysis

  This analysis is based on 970863 elevations on a 50 m grid within the area of this HUC.
  The mean elevation is 670.2 m ( 2198.8 ft ) [% in USA = 62.81, % in Region = 85.25]
  The elevation standard deviation is 39.2 m ( 128.6 ft ) [% in USA = 30.98, % in Region = 45.90]
  The coefficient of variation is 5.8 %.
  The vertical relief is 231.7 m ( 760.2 ft ) [% in USA = 33.68, % in Region = 48.36]

  Elevation Percentiles

  	0 %	10 %	20 %	30 %	40 %	50 %	60 %	70 %	80 %	90 %	100 %
  meters	505.3	609.4	639.6	660.7	670.0	676.0	694.5	700.0	701.0	705.8	737.0
  feet	1657.8	1999.3	2098.4	2167.6	2198.1	2217.8	2278.5	2296.6	2299.8	2315.6	2417.9

  

  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	22.0	13.6	0.009	0.015	11.61	7.38
  Intermittent Shoreline	4.8	3.0	0.002	0.003	63.57	43.44
  Perennial Streams	66.7	41.5	0.027	0.044	11.42	15.57
  Intermittent Streams	1041.9	647.6	0.428	0.689	61.49	76.23
  Canals	0.0	0.0	0.000	0.000	35.62	41.80
  1° roads	6.5	4.0	0.003	0.004	44.95	40.98
  2° roads	97.3	60.5	0.040	0.064	70.96	67.21
  3° roads	44.6	27.7	0.018	0.030	19.33	18.03
  4° roads	2657.4	1651.6	1.093	1.758	44.20	6.56
  Total Roads	2805.8	1743.8	1.154	1.856	39.60	5.74
  Railroads	0.0	0.0	0.000	0.000	12.60	5.74
  Pipes and Powerlines	51.9	32.3	0.021	0.034	40.17	27.87

  
  Of the natural water in this HUC, 92.19% (by length) is intermittent [% in USA = 90.48, % in Region = 93.44]

  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