| Report Year: 2009 |
| Pleasant Creek Lake, Linn County |
| Summary Data Table |
| Parameter | 6/23/2009 | 7/28/2009 | 2009 | 2007 | 2006 | 2005 | 2004 | 2003 | 2002 | 2001 | 2000 |
| Lake Depth (m) | 14.0 | 15.6 | 14.8 | 14.8 | 14.7 | 16.4 | 15.3 | 14.4 | 15.3 | 15.4 | 15.6 |
| Thermocline Depth (m) | 1.6 | 3.4 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A |
| Secchi Disk Depth (m) | 4.8 | 0.8 | 2.8 | 1.6 | 1.9 | 1.3 | 1.0 | 3.5 | 4.3 | 3.4 | 1.5 |
| Temperature(oC) | 27.4 | 24.6 | 26.0 | 24.7 | 24.4 | 26.3 | 24.3 | 23.8 | 25.6 | 24.3 | 25.2 |
| Dissolved Oxygen (mg/L) | 9.2 | 8.0 | 8.6 | 7.9 | 7.7 | 9.0 | 9.5 | 9.0 | 8.7 | 7.7 | 9.6 |
| Dissolved Oxygen Saturation (%) | 117 | 96 | 106.3 | 94.3 | 91.6 | 111.4 | 113.8 | 106.8 | 106.9 | 99.0 | 118.3 |
| Specific Conductivity (μS/cm) | 320.0 | 300.0 | 310.0 | 287.9 | 327.2 | 299.2 | 377.2 | 302.6 | 345.7 | 253.4 | 317.9 |
| Turbidity (NTU) | 0.9 | 8.4 | 4.6 | 7.5 | 7.1 | 9.9 | 10.7 | 4.5 | 7.8 | 6.2 | 34.9 |
| Chlorophyll a (μg/L) | 4.0 | 24.0 | 14.0 | 18.1 | 13.3 | 37.5 | 23.3 | 10.5 | 5.7 | 4.1 | 11.0 |
| Total Phosphorus as P (μg/L) | 19 | 52 | 36 | 39 | 31 | 43 | 46 | 40 | 49 | 22 | 60 |
| SRP as P (μg/L) | 1 | - | 1 | 1 | 1 | 1 | 4 | 1 | 1 | - | - |
| Total Nitrogen as N (mg/L) | 0.65 | 1.06 | 0.86 | 0.81 | 0.84 | 0.83 | 0.76 | 0.72 | 0.84 | 0.63 | 1.02 |
| (Phenate)Ammonia Nitrogen (NH3 + NH4+) as N (μg/L) | 16 | 16 | 16 | 16 | 17 | 87 | 42 | - | - | - | - |
| (Phenate)Ammonia Nitrogen (NH3) as N (un-ionized)(μg/L) | 2.1 | 1.2 | 1.7 | 1.1 | 2.3 | 9.6 | 7.1 | - | - | - | - |
| Nitrate + Nitrite (NO3 + NO2) as N (mg/L) | 0.12 | 0.12 | 0.12 | 0.12 | 0.12 | 0.12 | 0.12 | 0.12 | 0.13 | 0.19 | 0.12 |
| TN:TP ratio | 34 | 20 | 27 | 22 | 30 | 20 | 17 | 20 | 22 | 34 | 62 |
| pH | 8.8 | 8.9 | 8.8 | 8.7 | 8.6 | 8.6 | 8.7 | 8.3 | 8.5 | 8.5 | 7.4 |
| Alkalinity as CaCO3 (mg/L) | 150 | 147 | 149 | 131 | 145 | 130 | 128 | 89 | 129 | 128 | 137 |
| Silica as Si (mg/L) | - | - | - | - | - | 1.64 | 2.15 | 0.88 | 1.05 | - | - |
| Dissolved Organic Carbon (mg/L) | 4.61 | 4.99 | 4.80 | 5.52 | 5.45 | 6.64 | 4.58 | 7.89 | 8.65 | - | - |
| Inorganic Suspended Solids (mg/L) | 1 | 3 | 2 | 1 | 4 | 3 | 3 | 3 | 4 | 2 | 3 |
| Volatile Suspended Solids (mg/L) | 2 | 7 | 4 | 5 | 3 | 6 | 5 | 4 | 2 | 2 | 3 |
| Total Suspended Solids (mg/L) | 2 | 10 | 6 | 6 | 5 | 8 | 8 | 6 | 7 | 3 | 6 |
| Carlson Trophic State Index (Secchi)* | 37 | 63 | 45 | 54 | 51 | 57 | 60 | 42 | 39 | 43 | 54 |
| Carlson Trophic State Index (Chl a)* | 44 | 62 | 56 | 59 | 56 | 66 | 61 | 54 | 48 | 44 | 54 |
| Carlson Trophic State Index (TP)* | 47 | 61 | 56 | 57 | 53 | 58 | 59 | 57 | 60 | 49 | 63 |
| *Index values generally range between 0 and 100, with increasing values indicating more eutrophic conditions. |