Iowa DNR
AQuIA
Water Quality Monitoring
Surface Waters - Groundwater
Physical - Chemical - Fish Tissue

Ambient Lake Monitoring

The Ambient Lake Monitoring program samples lakes in Iowa over the summer recreational season. Each lake is sampled three times between May and September: once in early summer, once in mid-summer, and once in late summer/early fall. Data from this project are used to assess the health of our lakes and target individual lakes for restoration and watershed improvement activities. Monitoring is currently completed through a partnership with the Iowa State University Limnology Laboratory.

Program Details

Sampling Results (2000 to 2022) 171,291
# of Sites

Current Ambient Lake Sites

SiteID Site County

Lake Water Quality Summary 2000 to 2022

Summary statistics last calculated 8/23/2023 9:07:44 AM
Analyte Units # Results Min 10th Percentile 25th Percentile Median 75th Percentile 90th Percentile Max Max Sample Date % Non-detection
Ammonia mg/l 7,391 Not calculated when non-detections exceed 50% 50.62
Ammonia-nitrogen mg/l 8,594 <0 <0.008265 <0.016 0.05 0.13 0.21 1.734 8/11/2004 44.46
Calcium carbonate mg/l 4,272 9 81 97 124 157 192 485 8/6/2018 0.00
Chlorophyll a ug/l 8,363 <0 3.5 8.1135 23 47 89.98 743 8/3/2005 6.37
Depth, Secchi disk depth m 10,138 0 0.3 0.48 0.77 1.4 2.55 10 7/21/2015 0.00
Dissolved oxygen (DO) mg/l 9,949 0.3 5.88379 7.22 8.7 10.31 12.5 30.2 5/23/2011 0.00
Dissolved oxygen saturation % 7,921 4 69 86 103 123.5 152 322 8/3/2005 0.00
Escherichia coli MPN/100ml 792 <1 <1 <1 3 10 20 6130 5/27/2020 46.46
Fixed suspended solids mg/l 10,013 <0 <1.2 <2.6 4 8.7 17 378 5/31/2011 25.33
Kjeldahl nitrogen mg/l 6,624 <0.1 0.5386 0.83246 1.18 1.7 2.35 12.92 8/8/2011 6.91
Microcystin ug/l 2,091 Not calculated when non-detections exceed 50% 62.75
Nitrate + Nitrite mg/l 10,019 <0 <0.04 <0.06 0.16 0.67 3.84932 24.53 5/14/2013 48.76
Orthophosphate mg/l 9,206 Not calculated when non-detections exceed 50% 63.01
pH None 10,048 6.5 7.89 8.14 8.4 8.7 9 11.3 8/17/2020 0.00
Phycocyanin ug/l 2,301 <1.8 <7 17.29 51.09104 110.2 181.14304 11107.53 6/28/2022 11.82
Specific conductance uS/cm 10,074 0.202 220 270 351.01667 458 565.7 1361 7/11/2000 0.00
Temperature, water deg C 10,104 7 17.8 21.3 24.1 26.3 27.8 33.8 7/9/2002 0.00
Total dissolved solids mg/l 6,300 0.3 140 170 218 290 349.07 800 9/14/2020 0.00
Total Phosphorus, mixed forms mg/l 9,770 <0 0.0274 0.0446 0.076 0.13 0.2177 2.8 7/25/2007 1.98
Total suspended solids mg/l 10,155 <0 3.6 6 11 20 34 452 5/31/2011 6.08
Turbidity NTU 9,868 <0 2.6 6 13 27 53 2333 8/7/2000 1.32
Volatile Suspended Solids mg/l 7,298 <0 <2 4 8 11 19.3 196 7/25/2006 14.14
Project Codes in this Program

Code Description

Additional Summary Calculations

Parameter Value
TSI (ChlA) 66
TSI (Secchi) 58
TSI (TP) 72