| Report Year: 2011 |
| Lake Iowa, Iowa 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) | 7.9 | 7.3 | 7.9 | 7.7 | 7.4 | 8.1 | - | - | 8.0 | 8.4 | 8.5 | 8.8 | 8.4 | 7.7 |
| Thermocline Depth (m) | 5.5 | 3.1 | 6.0 | 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) | 0.8 | 0.6 | 0.8 | 0.7 | 0.6 | 0.6 | - | - | 2.5 | 2.4 | 0.8 | 1.1 | 1.3 | 1.1 |
| Temperature(oC) | 20.7 | 28.8 | 18.3 | 22.6 | 24.1 | 23.1 | - | - | 25.4 | 23.2 | 25.0 | 26.6 | 22.9 | 26.2 |
| Dissolved Oxygen (mg/L) | 8.4 | 10.2 | 5.2 | 7.9 | 10.8 | 8.6 | - | - | 11.7 | 9.0 | 9.5 | 9.2 | 9.1 | 10.7 |
| Dissolved Oxygen Saturation (%) | 94 | 132 | 55 | 93.8 | 129.5 | 100.7 | - | - | 142.2 | 105.8 | 114.1 | 113.8 | 104.8 | 132.3 |
| Specific Conductivity (μS/cm) | 290.0 | 240.0 | 270.0 | 266.7 | 263.3 | 246.7 | - | - | 272.3 | 321.2 | 256.8 | 364.5 | 235.0 | 236.4 |
| Turbidity (NTU) | 11.4 | 24.6 | 13.6 | 16.5 | 12.9 | 26.0 | - | - | 13.8 | 5.1 | 20.7 | 12.2 | 17.7 | 56.1 |
| Chlorophyll a (μg/L) | 38.8 | 38.3 | 47.6 | 41.6 | 22.6 | 49.7 | - | - | 158.0 | 44.5 | 33.8 | 20.9 | 26.5 | 26.0 |
| Total Phosphorus as P (μg/L) | 52.5 | 56.9 | 127.2 | 78.9 | 86.7 | 101.9 | - | - | 42 | 60 | 66 | 60 | 80 | - |
| SRP as P (μg/L) | <11 | <11 | <11 | <11 | <8 | <9 | - | - | <1 | <1 | 1.0 | 1.0 | - | - |
| TKN (mg/L) | 1.3 | 2.5 | 2.1 | 2 | 2 | - | - | - | - | - | - | - | - | - |
| Total Dissolved Solids (g/L) | 0.2 | 0.2 | 0.2 | 0.2 | - | - | - | - | - | - | - | - | - | - |
| Total Nitrogen as N (mg/L) | - | - | - | - | - | 1.7 | - | - | 1.32 | 2.49 | 1.48 | 1.12 | 2.35 | 1.58 |
| (Phenate)Ammonia Nitrogen (NH3 + NH4+) as N (μg/L) | <145 | <145 | 752.54 | 271 | 198 | <130 | - | - | 96 | 153 | - | - | - | - |
| (Phenate)Ammonia Nitrogen (NH3) as N (un-ionized)(μg/L) | <PQL | <PQL | 19 | <PQL | <PQL | <130 | - | - | 33 | 17 | - | - | - | - |
| Nitrate + Nitrite (NO3 + NO2) as N (mg/L) | <0.4 | <0.4 | <0.4 | <0.4 | <0.5 | - | - | - | 0.21 | 0.55 | 0.18 | 0.26 | 0.91 | 0.13 |
| TN:TP ratio | - | - | - | - | - | 17 | - | - | 34 | 44 | 22 | 23 | 29 | - |
| pH | 8.3 | 8.9 | 7.9 | 8.3 | 8.6 | 8.7 | - | - | 8.9 | 8.6 | 8.8 | 8.6 | 8.3 | 7.9 |
| Alkalinity as CaCO3 (mg/L) | 113 | 98 | 101 | 104 | 112 | 104 | - | - | 99 | 118 | 74 | 93 | 83 | 151 |
| Silica as Si (mg/L) | - | - | - | - | - | - | - | - | 2.76 | 4.37 | 3.02 | 2.73 | - | - |
| Dissolved Organic Carbon (mg/L) | <7.6 | <7.6 | <7.6 | <7.6 | <6.4 | 7 | - | - | 9.10 | 5.66 | 12.00 | 9.30 | - | - |
| Inorganic Suspended Solids (mg/L) | 6 | <5 | <5 | <5 | <4 | 8 | - | - | 13 | 1 | 5 | 3 | 5 | 4 |
| Volatile Suspended Solids (mg/L) | <8 | <8 | 8 | <8 | <9 | 14 | - | - | 13 | 9 | 9 | 5 | 5 | 5 |
| Total Suspended Solids (mg/L) | 11 | 7 | 10 | 9 | 11 | 22 | - | - | 14 | 9 | 14 | 9 | 9 | 7 |
| Carlson Trophic State Index (Secchi)* | 64 | 69 | 64 | 65 | 67 | 68 | - | - | 47 | 47 | 64 | 58 | 57 | 59 |
| Carlson Trophic State Index (Chl a)* | 66 | 66 | 68 | 67 | 61 | 69 | - | - | 80 | 68 | 65 | 60 | 63 | 63 |
| Carlson Trophic State Index (TP)* | 61 | 62 | 74 | 67 | 69 | 71 | - | - | 58 | 63 | 65 | 63 | 67 | - |
| *Index values generally range between 0 and 100, with increasing values indicating more eutrophic conditions. |