| Report Year: 2009 |
| Rathbun Reservoir, Appanoose County |
| Summary Data Table |
| Parameter | 6/17/2009 | 7/21/2009 | 2009 | 2007 | 2006 | 2005 | 2004 | 2003 | 2002 | 2001 | 2000 |
| Lake Depth (m) | 13.3 | 12.7 | 13.0 | 12.7 | 12.8 | 14.2 | 14.4 | 12.9 | 12.9 | 13.6 | 13.0 |
| Thermocline Depth (m) | Nil | 12.2 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A |
| Secchi Disk Depth (m) | 0.4 | 0.5 | 0.5 | 0.9 | 1.0 | 1.0 | 0.8 | 1.2 | 0.9 | 0.7 | 1.2 |
| Temperature(oC) | 19.8 | 23.1 | 21.5 | 24.7 | 24.1 | 23.7 | 22.2 | 23.7 | 25.0 | 20.8 | 24.0 |
| Dissolved Oxygen (mg/L) | 8.1 | 7.3 | 7.7 | 6.9 | 6.2 | 8.1 | 7.2 | 7.8 | 8.4 | 7.2 | 7.7 |
| Dissolved Oxygen Saturation (%) | 88 | 85 | 86.5 | 82.6 | 73.0 | 95.2 | 82.0 | 92.0 | 101.3 | 79.7 | 91.5 |
| Specific Conductivity (μS/cm) | 240.0 | 240.0 | 240.0 | 254.4 | 302.4 | 281.5 | 280.3 | 273.6 | 399.4 | 216.8 | 249.7 |
| Turbidity (NTU) | 39.9 | 26.2 | 33.1 | 11.9 | 17.2 | 13.3 | 60.2 | 17.2 | 12.5 | 39.3 | 50.3 |
| Chlorophyll a (μg/L) | 3.0 | 1 | 2.0 | 17.5 | 15.1 | 18.8 | 17.3 | 16.4 | 6.5 | 2.6 | 5.2 |
| Total Phosphorus as P (μg/L) | 97 | 62 | 80 | 65 | 35 | 37 | 41 | 49 | 44 | 85 | 114 |
| SRP as P (μg/L) | 22 | 18 | 20 | 29 | 1 | 4 | 1 | 2 | 6 | - | - |
| Total Nitrogen as N (mg/L) | 2.18 | 2.08 | 2.13 | 1.84 | 0.69 | 0.98 | 1.25 | 0.81 | 1.10 | 1.96 | 1.50 |
| (Phenate)Ammonia Nitrogen (NH3 + NH4+) as N (μg/L) | 16 | - | 16 | 16 | 26 | 45 | 51 | - | - | - | - |
| (Phenate)Ammonia Nitrogen (NH3) as N (un-ionized)(μg/L) | 0.3 | - | 0.3 | 1.6 | 1.7 | 1.8 | 2.9 | - | - | - | - |
| Nitrate + Nitrite (NO3 + NO2) as N (mg/L) | 1.60 | 1.68 | 1.64 | 1.06 | 0.12 | 0.46 | 0.58 | 0.15 | 0.59 | 1.50 | 0.16 |
| TN:TP ratio | 22 | 33 | 28 | 34 | 20 | 27 | 31 | 17 | 28 | 26 | 15 |
| pH | 8.0 | 8.1 | 8.1 | 8.3 | 8.2 | 8.1 | 8.1 | 8.4 | 8.0 | 7.4 | 7.3 |
| Alkalinity as CaCO3 (mg/L) | 85 | 88 | 87 | 95 | 115 | 103 | 99 | 71 | 96 | 86 | 133 |
| Silica as Si (mg/L) | - | - | - | - | - | 2.84 | 2.29 | 2.09 | 3.05 | - | - |
| Dissolved Organic Carbon (mg/L) | 5.62 | 5.18 | 5.40 | 6.87 | 5.42 | 6.82 | 5.57 | 8.16 | 9.06 | - | - |
| Inorganic Suspended Solids (mg/L) | 6 | 4 | 5 | 6 | 6 | 8 | 7 | 7 | 5 | 17 | 3 |
| Volatile Suspended Solids (mg/L) | 1 | 3 | 2 | 2 | 3 | 5 | 3 | 6 | 4 | 5 | 1 |
| Total Suspended Solids (mg/L) | 8 | 7 | 7 | 8 | 9 | 13 | 10 | 13 | 9 | 21 | 4 |
| Carlson Trophic State Index (Secchi)* | 73 | 70 | 72 | 62 | 60 | 61 | 63 | 57 | 62 | 65 | 57 |
| Carlson Trophic State Index (Chl a)* | 41 | 31 | 37 | 59 | 57 | 59 | 59 | 58 | 49 | 40 | 47 |
| Carlson Trophic State Index (TP)* | 70 | 64 | 67 | 64 | 55 | 56 | 58 | 60 | 59 | 68 | 72 |
| *Index values generally range between 0 and 100, with increasing values indicating more eutrophic conditions. |