Site ID:

249

Lat.

18.2891

Laos

Vientiane

River:

Nam Ngum

Long.

102.5378

Site name:

Tha Ngon

Contributing area:

16139

km2

Ratio to Comparison Station:

0.69

Latest measurement:

10-Nov-09

Mean annual runoff:

530

(2003-2007)

Hydrologic status:

Normal flow

Total runoff this year:

1264

Latest M/C ratio:

1.15

Seven day total:

Estimated current discharge:

174

m3/sec

Percent of mean 7-day total:

35.3

(today's value compared to mean for same period, 2003-2007)

Ice-cover determination:

5 yr recurrence flood:

2518

m3/sec

(from Log Pearson III analysis)

Status Codes: 1 = Low flow, 2 = Normal flow, 3 = Flood, 4 = Major Flood

2628

m3/sec

(from Gumbel Extreme Value analysis)

Comparison Station Information:

Tokwe Confluence D/s C/s (1495240)

Contributing Area:

7280

sq mi

23237

sq km

(Data from this gaging station are used for the calibration to discharge, with an adjustment for different contributing areas)

Notes:

Comparison station is placeholder, only; this site is not yet calibrated to actual discharge

Discharge and runoff, based on satellite remote sensing (NASA AMSR-E data)

(For U.S, sites, nearby ground station discharge may also be shown)

2008-Present

2002-Present

Annual

Monthly Total Runoff (mm), computed from above satellite-based discharge data

Runoff

(mm)

Jan

Feb

Mar

April

May

June

July

Aug

Sept

Oct

Nov

Dec

146

2002

no data

69.6

47.6

10.0

8.7

9.7

228

2003

29.0

16.0

13.5

4.7

7.5

46.5

54.6

32.5

13.2

2.8

1.4

6.2

268

2004

20.4

16.9

6.4

2.5

1.2

63.8

66.7

43.9

39.3

1.7

0.7

4.5

878

2005

16.1

36.0

38.0

45.3

9.2

51.6

96.0

166.2

210.1

130.0

24.5

54.5

623

2006

81.9

56.8

80.8

23.3

51.8

77.5

67.4

75.5

74.3

33.3

0.0

654

2007

111.0

63.2

45.0

30.6

49.0

59.9

62.2

31.1

67.4

45.8

37.2

51.1

1264

2008

103.6

100.1

67.2

29.5

40.0

64.6

141.1

353.0

109.3

102.9

69.2

83.9

687

2009

126.3

83.9

62.3

13.7

20.4

105.5

104.5

80.7

51.9

29.4

8.2

0.0

Discharge is estimated directly via a rating equation from the remote sensing data (M/C ratio) shown below.