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Available data

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Continuous data

3 data types available - data from 1997-10-02 to 2026-08-22

Daily data

2 data types available - data from 1968-03-07 to 2026-08-21

Field measurements

2 data types available - data from 1968-01-19 to 2026-08-05

Discrete sample data

30 Observed properties (data types) available - with data from 2000-10-24 to 2009-08-20

5 Sampling activities

Peak measurements

2 data types available - with data from 1889-01-01 to 2024-07-24

Statistical tables for select daily data types

2 data types available - data from 1968-03-07 to 2026-08-20

Important information about this monitoring location

Datum of gage has been determined to be 1225.60 feet above NAVD 1988. To obtain water-surface elevations in NAVD 1988 add 1225.60 feet to gage height values.

Location details and information

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Operated in cooperation with:

Lower Colorado River Authority

USGS - Cooperative Matching Funds

Metadata Element	Location Metadata	Metadata Code
Agency	U.S. Geological Survey	USGS
Location identification number	08150700	n/a
Location name	Llano Rv nr Mason, TX	n/a
Site type	Stream	ST
Decimal latitude (WGS84)	30.6607368499375	n/a
Decimal longitude (WGS84)	-99.1092185450325	n/a
Latitude-longitude method	Interpolated from map	M
Latitude-longitude accuracy	Accurate to + or - 5 sec.	F
District	Texas	48
State	Texas	48
County	Mason County	319
Country	United States of America	n/a
Altitude of gage/land surface	1225.6 feet	n/a
Method altitude determined	GNSS2 - Level 2 Quality Survey Grade Global Navigation Satellite System	X
Altitude accuracy	0.24 feet	n/a
Altitude datum	North American Vertical Datum of 1988	NAVD88
Subbasin hydrologic unit	Llano	12090204
Drainage basin		n/a
Date of first construction		n/a
Drainage area	3247 square miles	n/a
Contributing drainage area	3242 square miles	n/a
Time zone abbreviation	CST	n/a
Site honors Daylight Saving Time	Y	n/a
National aquifer		n/a
Local aquifer		n/a
Local aquifer type		n/a
Well depth		n/a
Hole depth		n/a
Source of depth data		n/a

Monitoring location Llano Rv nr Mason, TX - USGS-08150700