| Report Year: 2011 |
| Rock Creek Lake, Jasper County |
| Summary Data Table |
| Parameter | 6/20/2011 | 8/10/2011 | 9/19/2011 | 2011 | 2010 | 2009 | 2007 | 2006 | 2005 | 2004 | 2003 | 2002 | 2001 | 2000 |
| Lake Depth (m) | 4.7 | 4.6 | 4.2 | 4.5 | 4.8 | 4.7 | 5.0 | 4.9 | 5.0 | 5.1 | 5.0 | 4.9 | 5.3 | 5.1 |
| Thermocline Depth (m) | 2.3 | Nil | Nil | 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) | 1.4 | 0.6 | 0.6 | 0.9 | 0.6 | 0.7 | 0.8 | 0.7 | 1.0 | 0.8 | 0.9 | 0.7 | 1.4 | 1.2 |
| Temperature(oC) | 23.3 | 26.7 | 17.8 | 22.6 | 23.8 | 23.2 | 25.9 | 26.2 | 25.3 | 22.2 | 24.7 | 26.7 | 23.5 | 25.4 |
| Dissolved Oxygen (mg/L) | 8.9 | 5.6 | 10.8 | 8.4 | 10.7 | 8.0 | 9.4 | 9.9 | 10.3 | 9.8 | 9.8 | 8.5 | 12.6 | 8.0 |
| Dissolved Oxygen Saturation (%) | 105 | 70 | 113 | 95.9 | 126.9 | 93.2 | 116.6 | 121.5 | 125.6 | 112.8 | 116.8 | 105.2 | 148.4 | 97.5 |
| Specific Conductivity (μS/cm) | 380.0 | 280.0 | 300.0 | 320.0 | 360.0 | 356.7 | 361.5 | 360.0 | 374.6 | 392.4 | 389.9 | 388.4 | 343.8 | 309.5 |
| Turbidity (NTU) | 4.8 | 16.9 | 39.4 | 20.4 | 11.1 | 15.1 | 16.7 | 89.8 | 29.1 | 23.4 | 19.2 | 17.1 | 14.0 | 12.6 |
| Chlorophyll a (μg/L) | 9.2 | 12.6 | 75.2 | 32.3 | 23.1 | 32.7 | 24.2 | 36.0 | 87.9 | 25.4 | 30.3 | 26.8 | 28.6 | 14.8 |
| Total Phosphorus as P (μg/L) | 28.0 | 105.9 | 122.3 | 85.4 | 73.6 | 79.2 | 68 | 123 | 71 | 75 | 57 | 59 | 69 | - |
| SRP as P (μg/L) | <11 | 28.7 | <11 | <11 | <8 | 28.6 | <1 | 109.3 | 44.7 | 4.5 | 3.8 | 1.8 | - | - |
| TKN (mg/L) | <0.5 | <0.5 | 1.5 | 1 | 2 | - | - | - | - | - | - | - | - | - |
| Total Dissolved Solids (g/L) | 0.3 | 0.2 | 0.2 | 0.2 | - | - | - | - | - | - | - | - | - | - |
| Total Nitrogen as N (mg/L) | - | - | - | - | - | 2.4 | 4.70 | 3.33 | 4.00 | 5.78 | 4.42 | 3.34 | 6.89 | 2.23 |
| (Phenate)Ammonia Nitrogen (NH3 + NH4+) as N (μg/L) | <145 | <145 | <145 | <145 | 179 | <130 | 118 | <26 | 203 | 88 | - | - | - | - |
| (Phenate)Ammonia Nitrogen (NH3) as N (un-ionized)(μg/L) | <PQL | <PQL | <PQL | <PQL | <PQL | <130 | 16 | 3 | 16 | 14 | - | - | - | - |
| Nitrate + Nitrite (NO3 + NO2) as N (mg/L) | 5.51 | <0.4 | <0.4 | 2 | 2 | - | 3.82 | 2.14 | 2.91 | 4.68 | 3.37 | 2.57 | 6.08 | 0.62 |
| TN:TP ratio | - | - | - | - | - | 35 | 70 | 52 | 84 | 84 | 92 | 63 | 99 | - |
| pH | 8.2 | 8.6 | 8.9 | 8.6 | 8.3 | 8.6 | 8.5 | 8.6 | 8.3 | 8.6 | 8.4 | 8.3 | 8.4 | 7.8 |
| Alkalinity as CaCO3 (mg/L) | 168 | 128 | 108 | 135 | 160 | 155 | 149 | 144 | 151 | 144 | 110 | 143 | 140 | 141 |
| Silica as Si (mg/L) | - | - | - | - | - | - | - | - | 5.27 | 5.61 | 2.96 | 3.17 | - | - |
| Dissolved Organic Carbon (mg/L) | <7.6 | <7.6 | <7.6 | <7.6 | <6.4 | <6.2 | 3.60 | 3.68 | 2.98 | 3.18 | 6.49 | 9.27 | - | - |
| Inorganic Suspended Solids (mg/L) | 5 | 15 | 10 | 10 | 9 | 12 | 9 | 7 | 7 | 13 | 9 | 9 | 5 | 4 |
| Volatile Suspended Solids (mg/L) | <8 | 9 | 14 | 8 | <9 | <8 | 9 | 7 | 4 | 6 | 7 | 8 | 4 | 4 |
| Total Suspended Solids (mg/L) | 7 | 23 | 25 | 18 | 15 | 18 | 18 | 15 | 12 | 18 | 16 | 16 | 9 | 8 |
| Carlson Trophic State Index (Secchi)* | 56 | 68 | 67 | 62 | 68 | 65 | 64 | 65 | 60 | 63 | 62 | 65 | 56 | 57 |
| Carlson Trophic State Index (Chl a)* | 52 | 55 | 73 | 65 | 61 | 65 | 62 | 66 | 75 | 62 | 64 | 63 | 63 | 57 |
| Carlson Trophic State Index (TP)* | 52 | 71 | 73 | 68 | 66 | 67 | 65 | 74 | 66 | 66 | 63 | 63 | 65 | - |
| *Index values generally range between 0 and 100, with increasing values indicating more eutrophic conditions. |