| Report Year: 2011 |
| Meyers Lake, Black Hawk County |
| Summary Data Table |
| Parameter | 6/6/2011 | 7/25/2011 | 9/6/2011 | 2011 | 2010 | 2009 | 2007 | 2006 | 2005 | 2004 | 2003 | 2002 | 2001 | 2000 |
| Lake Depth (m) | 5.7 | 5.8 | 5.7 | 5.7 | 6.1 | 6.1 | - | - | 5.7 | 6.2 | 5.9 | 5.9 | 5.8 | 5.7 |
| Thermocline Depth (m) | 3.9 | 2.5 | 3.5 | 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) | 0.9 | 0.6 | 0.4 | 0.6 | 1.4 | 0.5 | - | - | 0.5 | 0.9 | 0.7 | 2.6 | 0.9 | 0.6 |
| Temperature(oC) | 24.0 | 29.5 | 21.5 | 25.0 | 24.5 | 27.5 | - | - | 26.5 | 24.8 | 24.4 | 25.6 | 23.5 | 24.7 |
| Dissolved Oxygen (mg/L) | 14.6 | 10.9 | 4.0 | 9.8 | 11.8 | 11.0 | - | - | 9.1 | 10.0 | 13.2 | 7.9 | 7.9 | 9.1 |
| Dissolved Oxygen Saturation (%) | 173 | 143 | 45 | 120.6 | 141.4 | 139.8 | - | - | 113.5 | 121.7 | 157.5 | 96.3 | 98.9 | 109.8 |
| Specific Conductivity (μS/cm) | 610.0 | 590.0 | 400.0 | 533.3 | 520.0 | 413.3 | - | - | 401.7 | 527.9 | 369.8 | 447.5 | 350.6 | 388.8 |
| Turbidity (NTU) | 6.4 | 77.3 | 42.5 | 42.1 | 6.2 | 17.1 | - | - | 28.8 | 12.1 | 26.1 | 16.1 | 16.7 | 83.2 |
| Chlorophyll a (μg/L) | 42.3 | 71.1 | 71.6 | 61.7 | 17.3 | 58.7 | - | - | 137.8 | 30.8 | 24.8 | 4.9 | 15.8 | 14.7 |
| Total Phosphorus as P (μg/L) | 89.0 | 106.5 | 211.5 | 135.7 | 114.2 | 167.0 | - | - | 144 | 91 | 134 | 101 | 135 | - |
| SRP as P (μg/L) | <11 | <11 | 12.6 | 12.6 | 12.2 | 31.2 | - | - | <1 | 3.1 | 3.8 | 77.9 | - | - |
| TKN (mg/L) | - | 3.1 | 2.9 | 3 | <0.5 | - | - | - | - | - | - | - | - | - |
| Total Dissolved Solids (g/L) | 0.4 | 0.4 | 0.3 | 0.4 | - | - | - | - | - | - | - | - | - | - |
| Total Nitrogen as N (mg/L) | - | - | - | - | - | 1.8 | - | - | 1.70 | 1.00 | 1.60 | 0.86 | 1.80 | 1.33 |
| (Phenate)Ammonia Nitrogen (NH3 + NH4+) as N (μg/L) | 340.98 | <145 | 500.89 | 284 | <136 | <130 | - | - | 79 | 95 | - | - | - | - |
| (Phenate)Ammonia Nitrogen (NH3) as N (un-ionized)(μg/L) | 32 | <PQL | 10 | <PQL | <PQL | <130 | - | - | 7 | 7 | - | - | - | - |
| Nitrate + Nitrite (NO3 + NO2) as N (mg/L) | <0.4 | <0.4 | <0.4 | <0.4 | <0.5 | - | - | - | 0.13 | 0.12 | 0.12 | 0.14 | 0.12 | 0.14 |
| TN:TP ratio | - | - | - | - | - | 12 | - | - | 12 | 11 | 12 | 14 | 17 | - |
| pH | 8.3 | 9.1 | 7.7 | 8.4 | 8.5 | 9.5 | - | - | 8.4 | 8.4 | 8.7 | 8.7 | 7.8 | 7.2 |
| Alkalinity as CaCO3 (mg/L) | 137 | 83 | 74 | 98 | 143 | 94 | - | - | 95 | 113 | 60 | 91 | 96 | 99 |
| Silica as Si (mg/L) | - | - | - | - | - | - | - | - | 5.05 | 2.48 | 2.85 | 2.35 | - | - |
| Dissolved Organic Carbon (mg/L) | <7.6 | <7.6 | <7.6 | <7.6 | <6.4 | 6 | - | - | 8.18 | 6.47 | 10.23 | 10.67 | - | - |
| Inorganic Suspended Solids (mg/L) | <5 | <5 | <5 | <5 | 6 | <4 | - | - | 1 | 3 | 3 | 4 | 4 | 4 |
| Volatile Suspended Solids (mg/L) | 9 | 12 | 19 | 13 | <9 | 15 | - | - | 14 | 6 | 9 | 4 | 6 | 10 |
| Total Suspended Solids (mg/L) | 12 | 16 | 20 | 16 | 11 | 18 | - | - | 15 | 9 | 12 | 7 | 11 | 14 |
| Carlson Trophic State Index (Secchi)* | 62 | 68 | 75 | 67 | 55 | 69 | - | - | 70 | 62 | 66 | 46 | 62 | 66 |
| Carlson Trophic State Index (Chl a)* | 67 | 72 | 72 | 71 | 59 | 71 | - | - | 79 | 64 | 62 | 46 | 58 | 57 |
| Carlson Trophic State Index (TP)* | 69 | 71 | 81 | 75 | 72 | 78 | - | - | 76 | 69 | 75 | 71 | 75 | - |
| *Index values generally range between 0 and 100, with increasing values indicating more eutrophic conditions. |