| Report Year: 2009 |
| Browns Lake, Woodbury County |
| Summary Data Table |
| Parameter | 6/1/2009 | 7/6/2009 | 2009 | 2007 | 2006 | 2005 | 2004 | 2003 | 2002 | 2001 | 2000 |
| Lake Depth (m) | 2.5 | 2.6 | 2.6 | - | 2.7 | 2.9 | 2.8 | 2.6 | 2.7 | 2.8 | 2.7 |
| Thermocline Depth (m) | Nil | Nil | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A |
| Secchi Disk Depth (m) | 0.4 | 0.7 | 0.6 | - | 0.7 | 0.8 | 1.0 | 0.9 | 0.6 | 0.6 | 0.4 |
| Temperature(oC) | 22.6 | 26.4 | 24.5 | - | 20.7 | 25.3 | 24.9 | 24.6 | 24.2 | 25.7 | 27.1 |
| Dissolved Oxygen (mg/L) | 11.1 | 13.1 | 12.1 | - | 10.6 | 9.1 | 7.7 | 10.0 | 9.8 | 6.2 | 7.5 |
| Dissolved Oxygen Saturation (%) | 128 | 163 | 145.4 | - | 118.1 | 110.3 | 90.6 | 120.5 | 115.9 | 70.3 | 94.2 |
| Specific Conductivity (μS/cm) | 690.0 | 640.0 | 665.0 | - | 633.1 | 733.6 | 666.9 | 738.8 | 745.9 | 689.4 | 969.7 |
| Turbidity (NTU) | 49.2 | 10.0 | 29.6 | - | 9.2 | 12.1 | 10.6 | 21.7 | 27.2 | 37.9 | 31.8 |
| Chlorophyll a (μg/L) | 36.0 | 15.0 | 25.5 | - | 4.0 | 62.3 | 9.0 | 17.1 | 26.1 | 14.2 | 41.5 |
| Total Phosphorus as P (μg/L) | 72 | 73 | 73 | - | 30 | 101 | 48 | 57 | 75 | 100 | 295 |
| SRP as P (μg/L) | - | - | - | - | 3 | 5 | 7 | 4 | 2 | - | - |
| Total Nitrogen as N (mg/L) | 1.44 | 1.20 | 1.32 | - | 1.84 | 1.98 | 1.01 | 1.21 | 1.19 | 1.39 | 1.32 |
| (Phenate)Ammonia Nitrogen (NH3 + NH4+) as N (μg/L) | 16 | 34 | 23 | - | 43 | 53 | 215 | - | - | - | - |
| (Phenate)Ammonia Nitrogen (NH3) as N (un-ionized)(μg/L) | 1.6 | 4.6 | 3.1 | - | 3.5 | 5.9 | 24.4 | - | - | - | - |
| Nitrate + Nitrite (NO3 + NO2) as N (mg/L) | 0.12 | - | 0.12 | - | 0.88 | 0.73 | 0.16 | 0.14 | 0.23 | 0.19 | 0.16 |
| TN:TP ratio | 20 | 16 | 18 | - | 61 | 21 | 21 | 23 | 22 | 15 | 5 |
| pH | 8.5 | 8.4 | 8.4 | - | 8.3 | 8.4 | 8.4 | 8.4 | 8.5 | 8.0 | 8.0 |
| Alkalinity as CaCO3 (mg/L) | 195 | 175 | 185 | - | 163 | 180 | 153 | 136 | 163 | 137 | 180 |
| Silica as Si (mg/L) | - | - | - | - | - | 5.74 | 2.45 | 3.12 | 3.50 | - | - |
| Dissolved Organic Carbon (mg/L) | 8.85 | 6.79 | 7.82 | - | 5.91 | 8.42 | 6.98 | 10.09 | 10.14 | - | - |
| Inorganic Suspended Solids (mg/L) | 16 | 9 | 12 | - | 9 | 11 | 5 | 13 | 14 | 17 | 29 |
| Volatile Suspended Solids (mg/L) | 12 | 4 | 8 | - | 3 | 8 | 4 | 5 | 7 | 9 | 12 |
| Total Suspended Solids (mg/L) | 28 | 13 | 20 | - | 12 | 19 | 9 | 17 | 21 | 26 | 41 |
| Carlson Trophic State Index (Secchi)* | 73 | 65 | 69 | - | 65 | 64 | 60 | 61 | 67 | 67 | 73 |
| Carlson Trophic State Index (Chl a)* | 66 | 57 | 62 | - | 44 | 71 | 52 | 58 | 63 | 57 | 67 |
| Carlson Trophic State Index (TP)* | 66 | 66 | 66 | - | 53 | 71 | 60 | 63 | 66 | 71 | 86 |
| *Index values generally range between 0 and 100, with increasing values indicating more eutrophic conditions. |