Iowa DNR
AQuIA

Water Quality Monitoring

Surface Waters - Groundwater
Physical - Chemical

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.

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

Project Type Description

Program Details

Results (2000 to 2019) 147,153
Sites

Additional Summary Calculations

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