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

Ambient Stream Monitoring

Since October 1999, the Iowa Department of Natural Resources has maintained a network of stations to monitor ambient water quality in the state. Currently, a total of stream sites are sampled. However, the total number of stations monitored each year has varied. The most stations sampled were a total of 84 stream sites and 1 spring from 2003 to 2006.

Sites in this statewide ambient stream network have been sampled on a monthly basis since October 1999 for a variety of parameters. These data are used for a number of purposes, such as determining status and trends, to determine if Iowa’s rivers support beneficial uses for which they are designated, to calculate nutrient loads, and to support development of new or revised water quality standards.

Program Details

Sampling Results (2000 to 2021) 257,946
# of Sites

Current Ambient Stream Sites

SiteID Site County

Stream Water Quality Summary 2000 to 2021

Summary statistics last calculated 3/11/2022 1:49:41 PM
Analyte Units # Results Min 10th Percentile 25th Percentile Median 75th Percentile 90th Percentile Max Max Sample Date % Non-detection
Alkalinity, total mg/l CaCO3 3,391 55 150 180 220 270 300 460 12/2/2014 0.00
Ammonia-nitrogen mg/l 13,635 Not calculated when non-detections exceed 50% 78.48
Calcium mg/l 3,320 15 53 64 77 90 110 150 12/2/2014 0.00
Carbonaceous biochemical oxygen demand, standard conditions mg/l 13,453 Not calculated when non-detections exceed 50% 77.51
Chloride mg/l 13,152 <1 11 15 19 25 34 180 9/4/2013 0.02
Chlorophyll a, free of pheophytin ug/l 10,714 <1 2 4 8 22 60 870 8/9/2006 3.53
Dissolved oxygen (DO) mg/l 13,718 <0.9 7.7 8.7 10.5 12.6 13.9 20.3 1/10/2012 0.01
Escherichia coli MPN/100ml 13,492 <10 10 41 140 500 2300 920000 10/2/2002 7.73
Hardness, carbonate mg/l 13,481 3 200 240 290 350 410 820 1/13/2004 0.00
Inorganic nitrogen (nitrate and nitrite) mg/l 13,635 <0.05 0.62 2.7 5.4 7.8 11 30 5/8/2013 4.97
Kjeldahl nitrogen mg/l 13,634 <0.05 0.2 0.4 0.69 1.1 1.7 28 5/5/2003 4.64
Magnesium mg/l 3,320 2.9 15 21 26 32 37 68 12/2/2014 0.00
Organic Carbon mg/l 3,366 <0.5 1.5 2 2.7 3.7 5 25 3/6/2018 0.33
Orthophosphate mg/l 13,590 <0.02 <0.02 0.05 0.08 0.14 0.23 5.9 1/14/2013 16.46
pH None 13,667 5.8 7.7 8 8.2 8.3 8.5 10.9 1/6/2009 0.00
Phosphate-phosphorus mg/l 13,634 <0.02 0.07 0.11 0.19 0.32 0.57 10 6/4/2002 2.83
Potassium mg/l 3,320 <0.88 1.6 2.1 2.9 4.1 6 23 3/6/2018 0.66
Sodium mg/l 3,320 1.8 6.3 8 10 14 21 240 10/6/2021 0.00
Sulfate mg/l 12,955 <2.3 17 21 30 49 88 480 10/6/2021 0.07
Temperature, water deg C 13,748 -1.9 0.2 2.1 12.1 20.3 24.3 34.3 7/10/2000 0.00
Total dissolved solids mg/l 13,631 4 260 300 350 420 500 2580 5/3/2021 0.00
Total suspended solids mg/l 13,635 <1 4 11 36 99 260 17000 5/5/2003 0.68
Turbidity NTU 13,586 <0.1 2.7 6.2 17 45 115 8500 5/5/2003 0.93
Volatile Suspended Solids mg/l 10,549 <1 2 3 8 17 35 2100 4/1/2008 1.90
Project Codes in this Program

Code Description