| Report Year: 2009 |
| George Wyth Lake, Black Hawk County |
| Summary Data Table |
| Parameter | 6/24/2009 | 7/29/2009 | 2009 | 2007 | 2006 | 2005 | 2004 | 2003 | 2002 | 2001 | 2000 |
| Lake Depth (m) | 4.6 | 4.5 | 4.6 | 4.1 | 3.7 | 4.6 | 4.5 | 4.4 | 4.7 | 4.4 | 4.6 |
| Thermocline Depth (m) | 3.0 | 3.1 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A |
| Secchi Disk Depth (m) | 0.9 | 0.5 | 0.7 | 0.8 | 1.2 | 1.2 | 1.6 | 1.4 | 1.1 | 2.1 | 0.9 |
| Temperature(oC) | 25.5 | 23.8 | 24.7 | 25.4 | 25.5 | 26.4 | 24.4 | 24.4 | 26.0 | 24.7 | 24.7 |
| Dissolved Oxygen (mg/L) | 9.4 | 7.9 | 8.6 | 11.1 | 10.5 | 10.7 | 9.7 | 11.1 | 11.7 | 6.9 | 11.3 |
| Dissolved Oxygen Saturation (%) | 115 | 93 | 103.9 | 135.5 | 128.1 | 132.8 | 116.8 | 133.7 | 145.0 | 90.2 | 135.8 |
| Specific Conductivity (μS/cm) | 440.0 | 430.0 | 435.0 | 550.4 | 617.4 | 570.8 | 660.4 | 553.6 | 545.1 | 376.8 | 447.4 |
| Turbidity (NTU) | 9.0 | 18.0 | 13.5 | 13.6 | 120.8 | 44.5 | 8.6 | 16.4 | 17.1 | 6.0 | 139.2 |
| Chlorophyll a (μg/L) | 36.0 | 15.0 | 25.5 | 34.1 | 25.3 | 48.2 | 16.2 | 19.3 | 16.7 | 11.0 | 9.5 |
| Total Phosphorus as P (μg/L) | 57 | 84 | 71 | 36 | 35 | 35 | 40 | 43 | 50 | 24 | 64 |
| SRP as P (μg/L) | - | - | - | 1 | - | 1 | 3 | 2 | 1 | - | - |
| Total Nitrogen as N (mg/L) | 1.03 | 1.50 | 1.27 | 0.95 | 1.08 | 0.88 | 0.67 | 1.25 | 1.11 | 1.01 | 1.21 |
| (Phenate)Ammonia Nitrogen (NH3 + NH4+) as N (μg/L) | - | 16 | 16 | 16 | 31 | 71 | 62 | - | - | - | - |
| (Phenate)Ammonia Nitrogen (NH3) as N (un-ionized)(μg/L) | - | 0.8 | 0.8 | 1.8 | 2.3 | 7.0 | 9.5 | - | - | - | - |
| Nitrate + Nitrite (NO3 + NO2) as N (mg/L) | 0.12 | - | 0.12 | 0.12 | 0.12 | 0.13 | 0.23 | 0.38 | 0.31 | 0.38 | 0.20 |
| TN:TP ratio | 18 | 18 | 18 | 27 | 33 | 26 | 18 | 30 | 26 | 51 | 25 |
| pH | 8.6 | 8.7 | 8.7 | 8.5 | 8.4 | 8.4 | 8.4 | 8.4 | 8.4 | 8.4 | 7.4 |
| Alkalinity as CaCO3 (mg/L) | 126 | 129 | 128 | 152 | 135 | 127 | 141 | 95 | 117 | 122 | 125 |
| Silica as Si (mg/L) | - | - | - | - | - | 2.55 | 1.75 | 2.10 | 2.67 | - | - |
| Dissolved Organic Carbon (mg/L) | 4.53 | 5.47 | 5.00 | 4.36 | 4.27 | 4.86 | 3.84 | 7.98 | 7.56 | - | - |
| Inorganic Suspended Solids (mg/L) | 1 | 2 | 1 | 3 | 4 | 2 | 3 | 3 | 2 | 5 | 3 |
| Volatile Suspended Solids (mg/L) | 8 | 14 | 11 | 6 | 7 | 7 | 4 | 4 | 5 | 5 | 5 |
| Total Suspended Solids (mg/L) | 8 | 15 | 12 | 9 | 10 | 9 | 7 | 7 | 7 | 10 | 8 |
| Carlson Trophic State Index (Secchi)* | 62 | 70 | 65 | 64 | 57 | 57 | 53 | 55 | 59 | 49 | 61 |
| Carlson Trophic State Index (Chl a)* | 66 | 57 | 62 | 65 | 62 | 69 | 58 | 60 | 58 | 54 | 53 |
| Carlson Trophic State Index (TP)* | 62 | 68 | 66 | 56 | 55 | 55 | 57 | 58 | 61 | 50 | 64 |
| *Index values generally range between 0 and 100, with increasing values indicating more eutrophic conditions. |