| Report Year: 2009 |
| Easter Lake, Polk County |
| Summary Data Table |
| Parameter | 7/20/2009 | 6/15/2009 | 2009 | 2007 | 2006 | 2005 | 2004 | 2003 | 2002 | 2001 | 2000 |
| Lake Depth (m) | 5.3 | 5.4 | 5.4 | 5.6 | 6.1 | 5.9 | 5.7 | 5.6 | 5.9 | 5.6 | 6.1 |
| Thermocline Depth (m) | Nil | 4.2 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A |
| Secchi Disk Depth (m) | 1.1 | 1.2 | 1.2 | 0.7 | 0.7 | 0.6 | 0.9 | 0.9 | 0.6 | 1.0 | 0.6 |
| Temperature(oC) | 23.6 | 21.6 | 22.6 | 26.7 | 26.2 | 27.0 | 23.7 | 25.3 | 28.0 | 25.1 | 24.5 |
| Dissolved Oxygen (mg/L) | 5.7 | 7.7 | 6.7 | 8.3 | 6.2 | 11.8 | 10.5 | 9.0 | 8.3 | 12.4 | 7.4 |
| Dissolved Oxygen Saturation (%) | 67 | 88 | 77.5 | 104.3 | 76.2 | 150.0 | 124.6 | 110.5 | 108.4 | 149.3 | 89.1 |
| Specific Conductivity (μS/cm) | 450.0 | 460.0 | 455.0 | 431.3 | 477.6 | 381.0 | 429.5 | 425.5 | 417.2 | 460.6 | 326.3 |
| Turbidity (NTU) | 8.8 | 6.6 | 7.7 | 15.0 | 20.3 | 30.4 | 19.2 | 19.5 | 33.0 | 18.0 | 28.5 |
| Chlorophyll a (μg/L) | 7.0 | 15.0 | 11.0 | 25.4 | 26.5 | 126.2 | 31.4 | 22.8 | 56.5 | 26.1 | 14.8 |
| Total Phosphorus as P (μg/L) | 61 | 50 | 56 | 59 | 58 | 74 | 50 | 59 | 76 | 88 | 106 |
| SRP as P (μg/L) | - | - | - | 1 | 1 | 1 | 3 | 3 | 1 | - | - |
| Total Nitrogen as N (mg/L) | 0.69 | 0.66 | 0.68 | 0.89 | 0.91 | 1.39 | 1.25 | 1.25 | 0.96 | 1.33 | 1.13 |
| (Phenate)Ammonia Nitrogen (NH3 + NH4+) as N (μg/L) | 56 | 61 | 59 | 48 | 53 | 35 | 47 | - | - | - | - |
| (Phenate)Ammonia Nitrogen (NH3) as N (un-ionized)(μg/L) | 7.8 | 5.0 | 6.4 | 4.1 | 3.7 | 2.8 | 4.6 | - | - | - | - |
| Nitrate + Nitrite (NO3 + NO2) as N (mg/L) | - | 0.12 | 0.12 | 0.21 | 0.12 | 0.21 | 0.21 | 0.37 | 0.13 | 0.44 | 3.03 |
| TN:TP ratio | 11 | 13 | 12 | 16 | 16 | 20 | 25 | 23 | 14 | 15 | 25 |
| pH | 8.5 | 8.3 | 8.4 | 8.3 | 8.1 | 8.5 | 8.4 | 8.3 | 8.4 | 8.2 | 7.5 |
| Alkalinity as CaCO3 (mg/L) | 151 | 153 | 152 | 129 | 122 | 107 | 119 | 81 | 100 | 124 | 112 |
| Silica as Si (mg/L) | - | - | - | - | - | 4.15 | 2.47 | 2.58 | 3.23 | - | - |
| Dissolved Organic Carbon (mg/L) | 4.04 | 3.86 | 3.95 | 4.08 | 4.66 | 5.44 | 3.80 | 7.80 | 9.31 | - | - |
| Inorganic Suspended Solids (mg/L) | 10 | 6 | 8 | 6 | 8 | 8 | 8 | 6 | 6 | 7 | 7 |
| Volatile Suspended Solids (mg/L) | - | 3 | 3 | 5 | 5 | 12 | 7 | 6 | 11 | 7 | 4 |
| Total Suspended Solids (mg/L) | 9 | 9 | 9 | 11 | 13 | 20 | 15 | 13 | 16 | 13 | 11 |
| Carlson Trophic State Index (Secchi)* | 59 | 57 | 58 | 64 | 65 | 68 | 62 | 62 | 67 | 60 | 68 |
| Carlson Trophic State Index (Chl a)* | 50 | 57 | 54 | 62 | 63 | 78 | 64 | 61 | 70 | 63 | 57 |
| Carlson Trophic State Index (TP)* | 63 | 61 | 62 | 63 | 63 | 66 | 61 | 63 | 67 | 69 | 71 |
| *Index values generally range between 0 and 100, with increasing values indicating more eutrophic conditions. |