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 2019) 147,153
# of Sites

Current Ambient Lake Sites

SiteID Site County

Lake Water Quality Summary 2000 to 2019

Summary statistics last calculated 8/28/2020 2:47:28 PM
Analyte Units # Results Min 10th Percentile 25th Percentile Median 75th Percentile 90th Percentile Max Max Sample Date % Non-detection
Ammonia mg/l 6,330 <0 <0 <0.001 0.01 0.015 0.018 0.433 7/17/2017 47.58
Ammonia-nitrogen mg/l 7,506 <0 <0.007825 <0.016 0.05 0.136 0.218 1.734 8/11/2004 48.80
Calcium carbonate mg/l 3,211 9 82 98 127 163 197 485 8/6/2018 0.00
Chlorophyll a ug/l 7,275 <0 3.314 8 22 45 85.96 743 8/3/2005 6.98
Depth, Secchi disk depth m 8,673 0.05 0.3 0.5 0.8 1.4 2.6 10 7/21/2015 0.00
Dissolved oxygen (DO) mg/l 8,533 0.3 5.9 7.3 8.8 10.5 12.7 30.2 5/23/2011 0.00
Dissolved oxygen saturation % 6,505 4 70 87 105 126.9 155.96 322 8/3/2005 0.00
Escherichia coli MPN/100ml 730 <1 <1 <1 2 10 19 2000 6/9/2005 44.52
Fixed suspended solids mg/l 8,925 <0 <1 2.1 4.2 9 17 378 5/31/2011 22.60
Inorganic nitrogen (nitrate and nitrite) mg/l 9,074 Not calculated when non-detections exceed 50% 50.02
Kjeldahl nitrogen mg/l 5,679 <0.1 0.51 0.8 1.2 1.71 2.4 12.92 8/8/2011 5.05
Microcystin ug/l 1,136 Not calculated when non-detections exceed 50% 64.79
Orthophosphate mg/l 8,118 Not calculated when non-detections exceed 50% 62.44
pH None 8,608 6.5 7.9 8.2 8.4 8.7 9.1 10.8 7/14/2005 0.00
Phosphate-phosphorus mg/l 8,682 <0 0.028 0.0452 0.077 0.13035 0.21799 2.8 7/25/2007 1.53
Phycocyanin ug/l 1,213 <1.8 <3.3 7 20.61 52 117.892 4733.81 6/11/2019 20.94
Specific conductance uS/cm 8,634 0.202 221 273 361 463 571 1361 7/11/2000 0.00
Temperature, water deg C 8,655 7 17.7 21.2 24.1 26.3 27.8 33.8 7/9/2002 0.00
Total dissolved solids mg/l 4,865 0.3 140 175 220 300 350 754 9/9/2019 0.00
Total suspended solids mg/l 9,067 <0 4 6 11.6 20 34 452 5/31/2011 4.55
Turbidity NTU 8,436 <0 3 6.755 14.2 29 57 2333 8/7/2000 0.49
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