USGS banner, with link to U.S. Geological Survey home page

WRIR 02-4030:
Streamflow and Water-Quality Data for
Selected Watersheds in the Lake Tahoe Basin,
California and Nevada, through September 1998

 table of contents iconTable of Contents
home page iconReport Home Page

Table 17. Comparison of monthly load summary statistics (sum, median, maximum, and minimum) and percent difference for load-estimation programs, ESTIMATOR and FLUX, for the 10 primary LTIMP sampling stations, through water year 1998, Lake Tahoe Basin, California and Nevada

[Abbreviation: kg, kilogram]

 

Third Creek
near Crystal Bay

Incline Creek
near Crystal Bay

Glenbrook Creek
at Glenbrook

Logan House Creek
near Glenbrook

Edgewood Creek
at Stateline

FLUX
(kg)

ESTIMATOR
(kg)

FLUX
(kg)

ESTIMATOR
(kg)

FLUX
(kg)

ESTIMATOR
(kg)

FLUX
(kg)

ESTIMATOR
(kg)

FLUX
(kg)

ESTIMATOR
(kg)

Dissolved nitrite + nitrate nitrogen

Sum

 1,550 1,530 3,320 2,320 523 317 55.8 65.2 554 538

Median

 5.95 5.91 15.8 9.65 1.65 .83 .10 .20 6.35 5.20

Maximum

 83.8 85.7 134 86.4 32.9 17.1 3.70 3.49 25.2 25.8

Minimum

 1.50 .88 4.30 1.30 0 .04 0 .01 1.80 1.31

Percent difference in sum

   1   -30   -39   17   -3

Dissolved ammonia nitrogen

Sum

 300 208 349 272 66.2 55.5 11.8 25.9 258 294

Median

 1.40 1.08 1.90 1.46 .40 .25 0 .06 2.60 1.72

Maximum

 11.7 7.88 8.00 10.5 2.10 3.17 .90 1.74 19.0 53.7

Minimum

 .50 .20 .90 .29 0 .01 0 .01 .30 .11

Percent difference in sum

   -31   -22   -16   119   14

Total nitrogen

Sum

 35,200 31,100 29,200 27,000 5,210 4,950 1,460 1,360 6,770 6,270

Median

 117 117 101 95.4 13.9 12.4 2.75 2.65 76.2 53.1

Maximum

 2,335 1,900 1,743 1,947 342 428 130 125 405 425

Minimum

 27.3 10.3 18.2 15.3 .30 .15 0 .07 17.8 13.5

Percent difference in sum

   -12   -8   -5   -7   -7

Soluble reactive phosphorus

Sum

 798 827 1,180 1,170 249 256 104 23.3 347 342

Median

 3.10 3.07 4.80 5.17 .80 0.74 .80 .05 4.05 3.82

Maximum

 41.0 55.2 58.8 69.4 15.4 18.8 2.90 2.08 24.5 27.5

Minimum

 .70 .64 1.10 1.03 0 .02 0 .01 1.50 1.40

Percent difference in sum

   4   -1   3   -78   -1

Total phosphorus

Sum

 8,930 8,180 7,300 6,990 2,630 1,150 147 142 1,580 1,520

Median

 26.0 24.2 25.3 22.9 10.5 2.59 .20 .24 17.2 14.6

Maximum

 875 576 550 610 156 135 15.4 14.3 169 166

Minimum

 6.20 3.55 4.00 2.30 .40 .09 0 .02 4.30 4.30

Percent difference in sum

   -8   -4   -56   -3   -4

Biologically reactive iron

Sum

 124,000 132,000 121,000 103,000 91,600 13,400 1,480 1,380 24,100 23,300

Median

 580 716 463 544 433 64.9 1.20 1.30 279 233

Maximum

 15,700 6,980 6,520 6,410 6,430 1,210 201 198 1,310 1,150

Minimum

 130 97.5 96.8 76.1 17.7 .62 0 .04 70.4 47.9

Percent difference in sum

   -6   -15   -85   -7   -3

Suspended sediment

Sum

 17,500,000 18,200,000 8,370,000 5,630,000 438,000 433,000 83,200 242,000 431,000 371,000

Median

 21,200 21,000 35,300 7,530 559 436 36.8 93.6 4,450 2,120

Maximum

 2,080,00 2,610,000 397,000 906,000 42,700 137,000 13,500 45,300 30,000 87,400

Minimum

 1,840 1,240 8,380 678 6.20 10.9 0 2.70 631 299

Percent difference in sum

   4   -33   -1   191   -14

 

 

Trout Creek at
South Lake Tahoe

Upper Truckee River at
South Lake Tahoe

General Creek
near Meeks Bay

Blackwood Creek
near Tahoe City

Ward Creek at
State Highway 89

FLUX
(kg)

ESTIMATOR
(kg)

FLUX
(kg)

ESTIMATOR
(kg)

FLUX
(kg)

ESTIMATOR
(kg)

FLUX
(kg)

ESTIMATOR
(kg)

FLUX
(kg)

ESTIMATOR
(kg)

Dissolved nitrite + nitrate nitrogen

Sum

 9,320 8,880 22,100 22,900 1,220 1,340 11,700 12,100 3,030 3,560

Median

 27.4 28.8 59.2 64.0 1.55 2.32 12.8 12.4 3.65 3.66

Maximum

 316 188 729 848 55.9 55.4 508 783 179 608

Minimum

 4.60 3.23 2.20 1.08 .20 .14 1.40 .43 0 .02

Percent difference in sum

   -5   4   10   3   17

Dissolved ammonia nitrogen

Sum

 1,310 883 3,530 2,740 385 313 1,140 1,080 591 513

Median

 9.45 5.74 13.6 10.5 .70 0.73 2.65 2.73 1.25 1.35

Maximum

 32.5 24.65 171 120 20.4 18.6 62.2 53.2 33.6 29.6

Minimum

 3.70 1.68 .50 .17 .10 .07 .30 .32 0 .01

Percent difference in sum

   -33   -22   -19   -5   -13

Total nitrogen

Sum

 75,900 72,900 211,000 200,000 24,100 23,700 77,600 73,000 591 513

Median

 314 293 489 413 26.1 22.1 93.3 77.1 1.25 1.35

Maximum

 3,710 4,300 13,700 13,100 1,610 1,550 10,600 12,200 33.6 29.6

Minimum

 66.5 48.0 13.2 14.3 1.60 1.44 6.70 6.84 0 .01

Percent difference in sum

   -4   -5   -2   -6   -13

Soluble phosphorus

Sum

 6,160 6,070 8,110 8,080 998 897 2,260 2,230 2,550 1,830

Median

 18.1 16.9 14.1 14.3 2.65 2.32 4.40 3.92 14.1 3.84

Maximum

 209 249 356 392 39.0 30.9 107 127 97.5 108

Minimum

 3.00 2.85 .40 .46 .30 .65 1.00 1.00 .10 .03

Percent difference in sum

   -1   0   -10   -1   -28

Total phosphorus

Sum

 103,000 36,200 64,200 61,300 9,120 8,500 43,700 30,100 23,700 13,300

Median

 140 87.7 95.4 101 12.6 11.3 31.9 28.6 15.3 15.3

Maximum

 5,990 1,910 3,130 3,160 407 425 6,620 6,180 11,200 2,240

Minimum

 12.6 8.38 2.10 1.97 1.40 1.35 4.20 5.00 0 0.09

Percent difference in sum

   -65   -5   -7   -31   -44

Biologically reactive iron

Sum

 4,820,000 205,000 646,000 755,000 24,800 30,000 243,000 420,000 143,000 272,000

Median

 1,340 1,060 1,010 1,160 34.4 32.5 327 265 60.7 51.7

Maximum

 535,000 13,000 30,600 64,700 1,960 3,960 11,500 183,000 24,100 127,000

Minimum

 250 190 24.3 27.8 2.30 3.42 37.3 67.6 .10 .18

Percent difference in sum

   -96   17   21   73   90

Suspended sediment

Sum

 21,800,000 18,900,000 53,500,000 56,300,000 3,500,000 3,670,000 31,500,000 255,000,000 17,200,000 46,500,000

Median

 40,600 24,900 40,900 34,200 785 789 6,010 4,240 3,950 1,750

Maximum

 1,130,000 1,380,000 3,670,000 7,950,000 914,000 986,000 6,450,000 207,000,000 4,470,000 37,600,000

Minimum

 3,120 432 227 384 54.4 83.8 129 178 15.4 32.2

Percent difference in sum

   -13   5   5   710   170

 

SUMMARY

Constituent

Range of percent difference

Wilcoxon signed-rank test

Test statistic, Ts

Accept null hypothesis, Ho

Results same/not

Nitrite + nitrate

-39 to 17

 24

8

Accept

Same

Dissolved ammonia

-32 to 119

 5

8

Reject

Different

Total nitrogen

-13 to -2

 0

8

Reject

Different

Soluble phosphorus

-78- to 5

 5

8

Reject

Different

Total phosphorus

-65 to -3

 0

8

Reject

Different

Biologically reactive iron

-96 to 90

 27

8

Accept

Same

Suspended sediment

-33 to 709

 25

8

Accept

Same