| Report Year: 2011 |
| White Oak Lake, Mahaska County |
| Summary Data Table |
| Parameter | 6/20/2011 | 8/8/2011 | 9/19/2011 | 2011 | 2010 | 2009 | 2007 | 2006 | 2005 | 2004 | 2003 | 2002 | 2001 | 2000 |
| Lake Depth (m) | 4.9 | 4.6 | 4.4 | 4.6 | 4.6 | 4.8 | - | - | 5.3 | 5.2 | 5.2 | 4.8 | 4.9 | 5.2 |
| Thermocline Depth (m) | 1.9 | 1.5 | Nil | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A |
| Secchi Disk Depth (m) | 0.5 | 0.4 | 0.6 | 0.5 | 0.5 | 0.4 | - | - | 0.6 | 1.4 | 1.1 | 0.7 | 0.5 | 0.3 |
| Temperature(oC) | 23.7 | 29.7 | 17.7 | 23.7 | 24.9 | 23.2 | - | - | 28.3 | 24.1 | 25.2 | 27.6 | 25.6 | 24.5 |
| Dissolved Oxygen (mg/L) | 9.7 | 11.6 | 3.0 | 8.1 | 10.8 | 6.9 | - | - | 13.2 | 9.1 | 10.7 | 7.1 | 17.4 | 8.0 |
| Dissolved Oxygen Saturation (%) | 114 | 153 | 31 | 99.5 | 131.7 | 80.6 | - | - | 169.8 | 108.6 | 131.8 | 89.8 | 211.1 | 95.4 |
| Specific Conductivity (μS/cm) | 230.0 | 220.0 | 240.0 | 230.0 | 200.0 | 253.3 | - | - | 279.8 | 270.7 | 269.0 | 288.4 | 216.1 | 203.9 |
| Turbidity (NTU) | 50.1 | 31.2 | 11.0 | 30.8 | 19.4 | 18.3 | - | - | 83.3 | 12.3 | 20.0 | 33.0 | 44.0 | 43.7 |
| Chlorophyll a (μg/L) | 50.0 | 40.4 | 27.9 | 39.4 | 41.4 | 43.7 | - | - | 136.6 | 23.8 | 21.4 | 41.3 | 83.0 | 11.7 |
| Total Phosphorus as P (μg/L) | 153.3 | 148.4 | 98.6 | 133.4 | 121.1 | 152.2 | - | - | 125 | 83 | 121 | 115 | 170 | - |
| SRP as P (μg/L) | 15.2 | <11 | <11 | <11 | <8 | <9 | - | - | 1.3 | 13.4 | 3.0 | 15.4 | - | - |
| TKN (mg/L) | 0.9 | 2.6 | 2.3 | 2 | 2 | - | - | - | - | - | - | - | - | - |
| Total Dissolved Solids (g/L) | 0.2 | 0.1 | 0.2 | 0.1 | - | - | - | - | - | - | - | - | - | - |
| Total Nitrogen as N (mg/L) | - | - | - | - | - | 1.7 | - | - | 1.62 | 1.35 | 1.41 | 1.21 | 2.15 | 2.34 |
| (Phenate)Ammonia Nitrogen (NH3 + NH4+) as N (μg/L) | <145 | <145 | 610.92 | 220 | <136 | <130 | - | - | 53 | 39 | - | - | - | - |
| (Phenate)Ammonia Nitrogen (NH3) as N (un-ionized)(μg/L) | <PQL | <PQL | 12 | <PQL | <PQL | <130 | - | - | 28 | 6 | - | - | - | - |
| Nitrate + Nitrite (NO3 + NO2) as N (mg/L) | 3.60 | <0.4 | <0.4 | 1 | <0.5 | - | - | - | 0.13 | 0.34 | 0.16 | 0.31 | 0.43 | 0.42 |
| TN:TP ratio | - | - | - | - | - | 11 | - | - | 13 | 17 | 12 | 14 | 13 | - |
| pH | 8.6 | 9.0 | 7.8 | 8.5 | 8.8 | 8.6 | - | - | 8.9 | 8.5 | 8.7 | 8.5 | 8.6 | 8.1 |
| Alkalinity as CaCO3 (mg/L) | 81 | 79 | 83 | 81 | 82 | 100 | - | - | 102 | 89 | 71 | 94 | 93 | 130 |
| Silica as Si (mg/L) | - | - | - | - | - | - | - | - | 4.09 | 2.63 | 2.62 | 5.44 | - | - |
| Dissolved Organic Carbon (mg/L) | <7.6 | <7.6 | <7.6 | <7.6 | <6.4 | 7 | - | - | 6.71 | 13.78 | 12.76 | 12.79 | - | - |
| Inorganic Suspended Solids (mg/L) | 27 | <5 | <5 | 12 | 8 | 17 | - | - | 3 | 4 | 4 | 4 | 5 | 16 |
| Volatile Suspended Solids (mg/L) | 11 | 21 | <8 | 13 | 9 | 10 | - | - | 11 | 6 | 11 | 10 | 10 | 7 |
| Total Suspended Solids (mg/L) | 38 | 25 | 10 | 25 | 17 | 27 | - | - | 14 | 10 | 15 | 14 | 15 | 23 |
| Carlson Trophic State Index (Secchi)* | 72 | 74 | 67 | 70 | 70 | 72 | - | - | 67 | 55 | 58 | 64 | 69 | 76 |
| Carlson Trophic State Index (Chl a)* | 69 | 67 | 63 | 67 | 67 | 68 | - | - | 79 | 62 | 61 | 67 | 74 | 55 |
| Carlson Trophic State Index (TP)* | 77 | 76 | 70 | 75 | 73 | 77 | - | - | 74 | 68 | 73 | 73 | 78 | - |
| *Index values generally range between 0 and 100, with increasing values indicating more eutrophic conditions. |