| Report Year: 2009 |
| Crystal Lake, Hancock County |
| Summary Data Table |
| Parameter | 6/24/2009 | 7/29/2009 | 2009 | 2007 | 2006 | 2005 | 2004 | 2003 | 2002 | 2001 | 2000 |
| Lake Depth (m) | 5.1 | 5.3 | 5.2 | 3.2 | 1.9 | 2.0 | 1.9 | 1.9 | 2.0 | 2.1 | 2.0 |
| Thermocline Depth (m) | 3.9 | 4.9 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A |
| Secchi Disk Depth (m) | 2.4 | 1.4 | 1.9 | 0.4 | 0.4 | 0.4 | 0.7 | 0.5 | 0.2 | 0.3 | 0.2 |
| Temperature(oC) | 24.4 | 23.4 | 23.9 | 23.5 | 23.5 | 26.1 | 24.2 | 23.0 | 24.1 | 23.8 | 22.8 |
| Dissolved Oxygen (mg/L) | 9.0 | 13.0 | 11.0 | 9.7 | 13.1 | 10.9 | 11.7 | 12.0 | 9.3 | 9.0 | 8.3 |
| Dissolved Oxygen Saturation (%) | 107 | 152 | 129.8 | 113.7 | 152.7 | 134.4 | 140.3 | 141.9 | 112.0 | 109.1 | 95.4 |
| Specific Conductivity (μS/cm) | 370.0 | 320.0 | 345.0 | 304.7 | 320.8 | 377.0 | 362.3 | 367.5 | 385.8 | 330.2 | 371.3 |
| Turbidity (NTU) | 4.7 | 10.9 | 7.8 | 55.7 | 340.7 | 31.5 | 45.7 | 32.4 | 80.1 | 69.9 | 109.8 |
| Chlorophyll a (μg/L) | 37.0 | 28.0 | 32.5 | 92.5 | 136.1 | 215.6 | 78.6 | 15.4 | 96.6 | 165.0 | 80.6 |
| Total Phosphorus as P (μg/L) | 93 | 115 | 104 | 159 | 439 | 517 | 348 | 173 | 287 | 312 | 355 |
| SRP as P (μg/L) | 1 | 8 | 4 | 22 | 47 | 304 | 207 | 20 | 91 | - | - |
| Total Nitrogen as N (mg/L) | 2.02 | 1.77 | 1.90 | 3.79 | 2.44 | 2.81 | 3.17 | 2.81 | 1.61 | 3.12 | 2.55 |
| (Phenate)Ammonia Nitrogen (NH3 + NH4+) as N (μg/L) | 87 | 48 | 68 | 447 | 16 | 78 | 498 | - | - | - | - |
| (Phenate)Ammonia Nitrogen (NH3) as N (un-ionized)(μg/L) | 18.6 | 21.4 | 20.0 | 31.6 | 1.1 | 24.4 | 75.2 | - | - | - | - |
| Nitrate + Nitrite (NO3 + NO2) as N (mg/L) | 0.41 | 0.12 | 0.25 | 1.08 | 0.12 | 0.47 | 0.85 | 0.66 | 0.19 | 0.95 | 0.30 |
| TN:TP ratio | 22 | 15 | 19 | 24 | 6 | 7 | 11 | 20 | 6 | 13 | 7 |
| pH | 8.7 | 9.2 | 8.9 | 8.6 | 9.1 | 9.2 | 9.0 | 9.0 | 8.9 | 8.0 | 7.3 |
| Alkalinity as CaCO3 (mg/L) | 165 | 132 | 149 | 131 | 144 | 175 | 164 | 113 | 125 | 130 | 146 |
| Silica as Si (mg/L) | - | - | - | - | - | 17.52 | 14.57 | 7.83 | 9.07 | - | - |
| Dissolved Organic Carbon (mg/L) | 8.15 | 8.29 | 8.22 | 10.73 | 7.09 | 9.49 | 9.60 | 12.03 | 14.15 | - | - |
| Inorganic Suspended Solids (mg/L) | 1 | 2 | 1 | 16 | 21 | 13 | 21 | 23 | 22 | 19 | 23 |
| Volatile Suspended Solids (mg/L) | 6 | 11 | 8 | 17 | 39 | 21 | 15 | 17 | 16 | 21 | 15 |
| Total Suspended Solids (mg/L) | 7 | 12 | 10 | 33 | 60 | 35 | 36 | 40 | 38 | 40 | 38 |
| Carlson Trophic State Index (Secchi)* | 48 | 56 | 51 | 75 | 74 | 74 | 64 | 69 | 81 | 80 | 85 |
| Carlson Trophic State Index (Chl a)* | 66 | 63 | 65 | 75 | 79 | 83 | 73 | 57 | 75 | 81 | 74 |
| Carlson Trophic State Index (TP)* | 70 | 73 | 71 | 77 | 92 | 94 | 89 | 78 | 86 | 87 | 89 |
| *Index values generally range between 0 and 100, with increasing values indicating more eutrophic conditions. |