Scientific Investigations Report 2008–5162
U.S. GEOLOGICAL SURVEY
Scientific Investigations Report 2008–5162
Version 1.1, December 2008
Table 6. Statistical summary of nitrogen and phosphorus concentrations in water samples grouped by source, Park Avenue stormwater collection and detention system, South Lake Tahoe, California, water years 2006–07.
[The term “water year” means a 12-month period beginning October 1 and ending September 30. Sample collection sites described in table 1. Abbreviation: mg/L, microgram per liter; PA1, Park Avenue basin 1; n, sample count. Symbol: –, data not collected]
Statistic | Nitrogen (mg/L) |
Phosphorus (mg/L) |
|||
---|---|---|---|---|---|
Unfiltered | Filtered | Unfiltered | Filtered | ||
Stormwater inflow (PA1_inletA and PA1_inletB [n=22]) | |||||
Mean | 1,500 | – | 380 | 94 | |
Minimum | 390 | – | 79 | 30 | |
Median | 1,200 | – | 270 | 60 | |
Maximum | 7,400 | – | 1,500 | 380 | |
Detention-basin water at PA1_stage (n=7) | |||||
Mean | 1,500 | – | 570 | 48 | |
Minimum | 530 | – | 69 | 17 | |
Median | 890 | – | 380 | 43 | |
Maximum | 3,600 | – | 1,200 | 92 | |
Stormwater outflow from PA1_out (n=7) | |||||
Mean | 720 | – | 200 | 99 | |
Minimum | 220 | – | 66 | 27 | |
Median | 780 | – | 240 | 80 | |
Maximum | 970 | – | 310 | 260 | |
Ground water at all 11 observation wells (n=95) | |||||
Mean | – | 1,100 | – | 39 | |
Minimum | – | 82 | – | 3 | |
Median | – | 580 | – | 20 | |
Maximum | – | 7,700 | – | 420 | |
Ground water upgradient of PA1 (n=28) | |||||
Mean | – | 1,700 | – | 20 | |
Minimum | – | 82 | – | 3 | |
Median | – | 2,000 | – | 18 | |
Maximum | – | 4,600 | – | 61 | |
Ground water downgradient of PA1 (n=64) | |||||
Mean | – | 740 | – | 48 | |
Minimum | – | 82 | – | 6 | |
Median | – | 510 | – | 23 | |
Maximum | – | 7,700 | – | 420 | |
All stormwater samples (n=37) | |||||
Mean | 1,300 | – | 380 | 86 | |
Minimum | 220 | – | 66 | 17 | |
Median | 900 | – | 250 | 56 | |
Maximum | 7,400 | – | 1,500 | 380 |