| Report Year: 2011 |
| Ingham Lake, Emmet County |
| Summary Data Table |
| Parameter | 5/31/2011 | 7/18/2011 | 8/29/2011 | 2011 | 2010 | 2009 | 2007 | 2006 | 2005 | 2004 | 2003 | 2002 | 2001 | 2000 |
| Lake Depth (m) | 2.8 | 2.6 | 2.4 | 2.6 | 2.7 | 2.7 | 2.6 | 2.3 | 2.8 | 2.9 | 2.8 | 2.8 | 3.1 | 2.9 |
| Thermocline Depth (m) | Nil | 1.7 | 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) | 0.4 | 0.3 | 0.3 | 0.3 | 0.2 | 0.4 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.4 | 0.9 | 0.4 |
| Temperature(oC) | 20.2 | 28.5 | 23.3 | 24.0 | 22.9 | 23.2 | 23.5 | 24.8 | 24.1 | 22.3 | 21.2 | 23.7 | 24.4 | 24.9 |
| Dissolved Oxygen (mg/L) | 10.6 | 12.2 | 10.1 | 11.0 | 7.9 | 10.2 | 7.8 | 11.7 | 10.0 | 9.6 | 9.1 | 9.7 | 8.6 | 8.6 |
| Dissolved Oxygen Saturation (%) | 117 | 158 | 118 | 131.0 | 90.0 | 119.6 | 92.4 | 142.1 | 118.1 | 110.0 | 101.7 | 114.6 | 102.4 | 104.0 |
| Specific Conductivity (μS/cm) | 360.0 | 360.0 | 340.0 | 353.3 | 413.3 | 433.3 | 407.0 | 428.0 | 421.6 | 461.5 | 446.2 | 545.0 | 545.9 | 446.3 |
| Turbidity (NTU) | 36.4 | 46.2 | 63.1 | 48.6 | 26.3 | 23.2 | 36.2 | 56.5 | 83.3 | 78.3 | 67.4 | 41.7 | 35.8 | 52.2 |
| Chlorophyll a (μg/L) | 112.9 | 166.7 | 226.6 | 168.8 | 100.0 | 44.3 | 74.2 | 53.1 | 362.5 | 135.9 | 31.0 | 86.0 | 72.4 | 60.5 |
| Total Phosphorus as P (μg/L) | 131.7 | 152.4 | 180.8 | 154.9 | 189.4 | 145.2 | 168 | 158 | 132 | 161 | 140 | 100 | 187 | - |
| SRP as P (μg/L) | <11 | <11 | <11 | <11 | <8 | <9 | <1 | <1 | <1 | <1 | <1 | <1 | - | - |
| TKN (mg/L) | 0.8 | 1.5 | 4.1 | 2 | 2 | - | - | - | - | - | - | - | - | - |
| Total Dissolved Solids (g/L) | 0.2 | 0.2 | 0.2 | 0.2 | - | - | - | - | - | - | - | - | - | - |
| Total Nitrogen as N (mg/L) | - | - | - | - | - | 2.5 | 2.01 | 2.83 | 2.74 | 2.77 | 3.15 | 2.29 | 2.15 | 2.82 |
| (Phenate)Ammonia Nitrogen (NH3 + NH4+) as N (μg/L) | <145 | <145 | <145 | <145 | <136 | <130 | <26 | <26 | 44 | <26 | - | - | - | - |
| (Phenate)Ammonia Nitrogen (NH3) as N (un-ionized)(μg/L) | <PQL | <PQL | <PQL | <PQL | <PQL | <130 | 1 | -2 | 6 | 6 | - | - | - | - |
| Nitrate + Nitrite (NO3 + NO2) as N (mg/L) | <0.4 | <0.4 | <0.4 | <0.4 | <0.5 | - | 0.12 | 0.12 | 0.18 | 0.22 | 0.18 | 0.24 | 0.32 | 0.30 |
| TN:TP ratio | - | - | - | - | - | 17 | 13 | 20 | 21 | 19 | 23 | 23 | 13 | - |
| pH | 8.8 | 8.7 | 9.0 | 8.8 | 8.7 | 8.9 | 8.7 | 9.0 | 8.7 | 8.9 | 8.6 | 8.8 | 8.3 | 8.2 |
| Alkalinity as CaCO3 (mg/L) | 126 | 132 | 114 | 124 | 131 | 145 | 103 | 137 | 124 | 121 | 96 | 134 | 157 | 156 |
| Silica as Si (mg/L) | - | - | - | - | - | - | - | - | 9.93 | 8.76 | 10.47 | 8.76 | - | - |
| Dissolved Organic Carbon (mg/L) | <7.6 | <7.6 | 9.08 | <7.6 | 9 | 12 | 13.96 | 11.34 | 8.80 | 19.59 | 21.21 | 9.28 | - | - |
| Inorganic Suspended Solids (mg/L) | 5 | 15 | <5 | 7 | 8 | 9 | 9 | 16 | 8 | 17 | 11 | 11 | 4 | 83 |
| Volatile Suspended Solids (mg/L) | 23 | 32 | 42 | 32 | 17 | 25 | 30 | 30 | 30 | 35 | 29 | 25 | 11 | 42 |
| Total Suspended Solids (mg/L) | 28 | 47 | 42 | 39 | 26 | 34 | 41 | 48 | 35 | 51 | 40 | 24 | 14 | 126 |
| Carlson Trophic State Index (Secchi)* | 75 | 77 | 80 | 77 | 83 | 74 | 78 | 78 | 77 | 79 | 78 | 74 | 61 | 75 |
| Carlson Trophic State Index (Chl a)* | 77 | 81 | 84 | 81 | 76 | 68 | 73 | 70 | 88 | 79 | 64 | 74 | 73 | 71 |
| Carlson Trophic State Index (TP)* | 75 | 77 | 79 | 77 | 80 | 76 | 78 | 77 | 75 | 77 | 75 | 71 | 80 | - |
| *Index values generally range between 0 and 100, with increasing values indicating more eutrophic conditions. |