| Report Year: 2011 |
| Hickory Grove Lake, Story County |
| Summary Data Table |
| Parameter | 6/20/2011 | 8/8/2011 | 9/19/2011 | 2011 | 2010 | 2009 | 2007 | 2006 | 2005 | 2004 | 2003 | 2002 | 2001 | 2000 |
| Lake Depth (m) | 10.1 | 10.1 | 9.8 | 10.0 | 10.4 | 10.2 | 10.3 | 10.1 | 10.4 | 10.5 | 10.5 | 8.8 | 11.1 | 10.7 |
| Thermocline Depth (m) | 1.4 | 3.6 | 6.5 | 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) | 1.7 | 0.9 | 0.8 | 1.1 | 0.7 | 1.0 | 1.3 | 2.0 | 2.9 | 1.0 | 2.7 | 3.1 | 1.9 | 1.4 |
| Temperature(oC) | 24.3 | 27.4 | 18.3 | 23.3 | 23.3 | 23.1 | 25.0 | 25.2 | 24.3 | 21.7 | 23.5 | 26.0 | 22.2 | 24.2 |
| Dissolved Oxygen (mg/L) | 14.6 | 13.1 | 6.6 | 11.4 | 11.3 | 11.4 | 10.5 | 9.8 | 10.8 | 9.8 | 10.6 | 9.2 | 9.7 | 11.8 |
| Dissolved Oxygen Saturation (%) | 174 | 165 | 71 | 136.5 | 133.4 | 134.1 | 126.5 | 118.9 | 128.8 | 111.6 | 124.9 | 112.5 | 109.9 | 140.7 |
| Specific Conductivity (μS/cm) | 440.0 | 340.0 | 370.0 | 383.3 | 373.3 | 380.0 | 403.0 | 512.3 | 521.8 | 360.1 | 438.2 | 470.6 | 435.9 | 407.5 |
| Turbidity (NTU) | 6.5 | 15.6 | 19.0 | 13.7 | 9.3 | 9.8 | 7.0 | 8.4 | 8.2 | 26.3 | 5.1 | 2.7 | 5.2 | 5.7 |
| Chlorophyll a (μg/L) | 19.1 | 23.4 | 36.4 | 26.3 | 22.4 | 37.3 | 17.8 | 6.9 | 15.6 | 19.8 | 17.1 | 7.2 | 15.3 | 6.6 |
| Total Phosphorus as P (μg/L) | 39.3 | 48.1 | 59.3 | 48.9 | 80.6 | 67.5 | 48 | 16 | 38 | 132 | 30 | 24 | 58 | - |
| SRP as P (μg/L) | <11 | <11 | <11 | <11 | 22.1 | <9 | <1 | <1 | <1 | <1 | 2.0 | <1 | - | - |
| TKN (mg/L) | 0.8 | <0.5 | 1.1 | 1 | 2 | - | - | - | - | - | - | - | - | - |
| Total Dissolved Solids (g/L) | 0.3 | 0.2 | 0.2 | 0.2 | - | - | - | - | - | - | - | - | - | - |
| Total Nitrogen as N (mg/L) | - | - | - | - | - | 4.3 | 9.08 | 6.42 | 9.04 | 7.44 | 9.09 | 9.46 | 12.24 | 3.24 |
| (Phenate)Ammonia Nitrogen (NH3 + NH4+) as N (μg/L) | <145 | <145 | 333.44 | 148 | 168 | <130 | 86 | 51 | 110 | 100 | - | - | - | - |
| (Phenate)Ammonia Nitrogen (NH3) as N (un-ionized)(μg/L) | <PQL | <PQL | 12 | <PQL | <PQL | <130 | 22 | 5 | 12 | 7 | - | - | - | - |
| Nitrate + Nitrite (NO3 + NO2) as N (mg/L) | 6.88 | 6.89 | 1.11 | 5 | 3 | - | 8.00 | 5.78 | 7.92 | 6.24 | 7.92 | 8.37 | 11.82 | 1.10 |
| TN:TP ratio | - | - | - | - | - | 65 | 189 | 515 | 275 | 96 | 323 | 414 | 263 | - |
| pH | 8.3 | 8.4 | 8.0 | 8.3 | 8.3 | 8.7 | 8.6 | 8.2 | 8.3 | 8.4 | 8.6 | 8.4 | 8.1 | 7.8 |
| Alkalinity as CaCO3 (mg/L) | 175 | 132 | 120 | 142 | 152 | 155 | 144 | 177 | 189 | 118 | 95 | 157 | 144 | 161 |
| Silica as Si (mg/L) | - | - | - | - | - | - | - | - | 5.43 | 7.77 | 2.47 | 1.55 | - | - |
| Dissolved Organic Carbon (mg/L) | <7.6 | <7.6 | <7.6 | <7.6 | <6.4 | <6.2 | 4.15 | 3.51 | 3.48 | 4.10 | 7.71 | 9.12 | - | - |
| Inorganic Suspended Solids (mg/L) | <5 | <5 | <5 | <5 | 4 | 9 | 3 | 4 | 4 | 10 | 3 | 6 | 2 | 2 |
| Volatile Suspended Solids (mg/L) | <8 | 10 | <8 | 8 | 9 | <8 | 4 | 3 | 4 | 5 | 4 | 4 | 2 | 4 |
| Total Suspended Solids (mg/L) | 9 | 14 | 9 | 10 | 14 | 12 | 7 | 7 | 8 | 15 | 7 | 10 | 5 | 6 |
| Carlson Trophic State Index (Secchi)* | 53 | 62 | 64 | 59 | 65 | 60 | 57 | 50 | 45 | 60 | 46 | 44 | 51 | 55 |
| Carlson Trophic State Index (Chl a)* | 60 | 62 | 66 | 63 | 61 | 66 | 59 | 50 | 58 | 60 | 58 | 50 | 57 | 49 |
| Carlson Trophic State Index (TP)* | 57 | 60 | 63 | 60 | 67 | 65 | 60 | 44 | 57 | 75 | 53 | 50 | 63 | - |
| *Index values generally range between 0 and 100, with increasing values indicating more eutrophic conditions. |