| Report Year: 2009 |
| Indian Lake, Van Buren County |
| Summary Data Table |
| Parameter | 7/22/2009 | 6/17/2009 | 2009 | 2007 | 2006 | 2005 | 2004 | 2003 | 2002 | 2001 | 2000 |
| Lake Depth (m) | 2.5 | 2.5 | 2.5 | - | - | 2.5 | 2.7 | 2.7 | 2.4 | 2.7 | 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 | 0.5 | - | - | 0.8 | 0.5 | 0.3 | 0.8 | 1.3 | 0.6 |
| Temperature(oC) | 23.7 | 24.1 | 23.9 | - | - | 29.0 | 25.6 | 24.3 | 30.0 | 25.7 | 27.0 |
| Dissolved Oxygen (mg/L) | 6.1 | 9.5 | 7.8 | - | - | 14.4 | 10.5 | 7.2 | 10.9 | 12.7 | 12.6 |
| Dissolved Oxygen Saturation (%) | 72 | 113 | 92.7 | - | - | 189.5 | 130.4 | 85.8 | 147.4 | 159.8 | 158.7 |
| Specific Conductivity (μS/cm) | 250.0 | 310.0 | 280.0 | - | - | 352.6 | 269.6 | 206.9 | 280.9 | 254.3 | 298.3 |
| Turbidity (NTU) | 34.0 | 10.4 | 22.2 | - | - | 64.3 | 41.1 | 56.0 | 32.6 | 40.4 | 26.5 |
| Chlorophyll a (μg/L) | 28.0 | 41.0 | 34.5 | - | - | 306.9 | 84.5 | 15.9 | 111.2 | 87.4 | 16.7 |
| Total Phosphorus as P (μg/L) | 242 | 143 | 192 | - | - | 217 | 194 | 214 | 166 | 141 | 306 |
| SRP as P (μg/L) | 23 | - | 23 | - | - | 48 | 39 | 44 | 12 | - | - |
| Total Nitrogen as N (mg/L) | 2.07 | 1.18 | 1.63 | - | - | 1.37 | 2.38 | 1.85 | 1.47 | 1.91 | 1.61 |
| (Phenate)Ammonia Nitrogen (NH3 + NH4+) as N (μg/L) | 56 | 143 | 100 | - | - | 48 | 85 | - | - | - | - |
| (Phenate)Ammonia Nitrogen (NH3) as N (un-ionized)(μg/L) | 4.2 | 13.7 | 9.0 | - | - | 9.8 | 10.8 | - | - | - | - |
| Nitrate + Nitrite (NO3 + NO2) as N (mg/L) | 0.12 | 0.12 | 0.12 | - | - | 0.12 | 0.12 | 0.14 | 0.12 | 0.12 | 0.12 |
| TN:TP ratio | 9 | 8 | 8 | - | - | 11 | 12 | 9 | 11 | 26 | 5 |
| pH | 8.2 | 8.3 | 8.3 | - | - | 8.9 | 8.8 | 8.3 | 9.1 | 8.5 | 7.3 |
| Alkalinity as CaCO3 (mg/L) | 93 | 122 | 108 | - | - | 122 | 117 | 64 | 95 | 95 | 158 |
| Silica as Si (mg/L) | - | - | - | - | - | 5.06 | 8.22 | 7.91 | 7.16 | - | - |
| Dissolved Organic Carbon (mg/L) | 6.39 | 5.47 | 5.93 | - | - | 8.50 | 7.69 | 13.42 | 13.12 | - | - |
| Inorganic Suspended Solids (mg/L) | 10 | 4 | 7 | - | - | 5 | 3 | 11 | 4 | 5 | 5 |
| Volatile Suspended Solids (mg/L) | 23 | 10 | 16 | - | - | 39 | 12 | 13 | 10 | 6 | 5 |
| Total Suspended Solids (mg/L) | 32 | 13 | 23 | - | - | 30 | 15 | 24 | 12 | 10 | 10 |
| Carlson Trophic State Index (Secchi)* | 73 | 66 | 69 | - | - | 63 | 71 | 76 | 63 | 56 | 68 |
| Carlson Trophic State Index (Chl a)* | 63 | 67 | 65 | - | - | 87 | 74 | 58 | 77 | 74 | 58 |
| Carlson Trophic State Index (TP)* | 83 | 76 | 80 | - | - | 82 | 80 | 82 | 78 | 76 | 87 |
| *Index values generally range between 0 and 100, with increasing values indicating more eutrophic conditions. |