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Report Year: 2016
Mitchell Lake, Black Hawk County
Summary Data Table
Parameter6/7/20167/25/20169/7/20162016201520142013201220112010200920072006200520042003200220012000
Lake Depth (m)16.716.816.316.615.014.616.915.816.817.016.2--15.114.814.011.912.310.4
Thermocline Depth (m)2.23.51.3N/AN/AN/AN/AN/AN/AN/AN/AN/AN/AN/AN/AN/AN/AN/AN/A
Secchi Disk Depth (m)0.50.60.80.60.90.90.70.60.70.81.3--1.00.80.80.81.51.1
Temperature(oC)21.426.823.824.025.523.127.524.824.125.124.5--25.724.323.124.623.324.2
Dissolved Oxygen (mg/L)10.48.710.79.910.810.38.711.411.29.77.6--9.810.811.37.75.47.4
Dissolved Oxygen Saturation (%)118109126117.5132.2119.7109.5136.3132.7118.191.7--120.3131.0133.392.867.287.9
Specific Conductivity (μS/cm)530.0510.0540.0526.7536.7486.7460.0646.7533.3433.3390.0--426.6436.7597.5646.4559.8554.3
Turbidity (NTU)14.810.24.49.85.44.813.15.28.94.83.2--11.717.510.67.510.731.3
Chlorophyll a (μg/L)40.653.939.244.627.931.514.232.134.510.317.7--47.546.525.919.712.14.2
Total Phosphorus as P (μg/L)29.350.146.942.1414644.835.243.743.642.5--42102505049-
SRP as P (μg/L)<2.8<2.8<2.8<2.8<4.3<5.6<14<10<11<8<9--<1<1<1<1--
TKN (mg/L)0.990.970.940.960.871.521.011.341.101.26---------
Total Dissolved Solids (g/L)0.30.30.40.30.40.30.30.40.4----------
Total Nitrogen as N (mg/L)----------0.9--0.951.571.311.081.260.90
(Phenate)Ammonia Nitrogen (NH3 + NH4+) as N (μg/L)318.70<0.6<0.694<26<26<10<14<145<136<130--------
(Phenate)Ammonia Nitrogen (NH3) as N (un-ionized)(μg/L)25-8-25-22<PRL<PQL<PQL<PQL<130--------
Nitrate + Nitrite (NO3 + NO2) as N (mg/L)<0.07<0.07<0.07<0.070.120.12<0.14<0.06<0.42---0.280.360.120.240.210.18
TN:TP ratio----------21--2416312131-
pH8.38.88.88.68.58.58.58.58.37.98.1--8.39.08.38.38.07.2
Alkalinity as CaCO3 (mg/L)141137143140141132132131121146138--136107120153192174
Silica as Si (mg/L)-------------2.084.314.391.62--
Dissolved Organic Carbon (mg/L)27.7626.0932.9828.9414.3355.516<7.6<6.4<6.2--5.466.237.797.18--
Inorganic Suspended Solids (mg/L)23333363<5<4<4--355443
Volatile Suspended Solids (mg/L)121010118861310<9<8--877633
Total Suspended Solids (mg/L)1413141311111215128<5--1112121077
Carlson Trophic State Index (Secchi)*6968636662616667646356--616364645558
Carlson Trophic State Index (Chl a)*6770676863645765655359--686863605545
Carlson Trophic State Index (TP)*5361605858595955595958--5871606160-
*Index values generally range between 0 and 100, with increasing values indicating more eutrophic conditions.
       
 
 
 
Water Column Profiles
6/7/20167/25/20169/7/2016

Contact Limnology Laboratory, Iowa State University