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 (2001 to 2020) 241,296
# of Sites

Current Ambient Stream Sites

SiteID Site County

Stream Water Quality Summary 2001 to 2020

Summary statistics last calculated 1/29/2021 9:55:09 AM
Analyte Units # Results Min 10th Percentile 25th Percentile Median 75th Percentile 90th Percentile Max Max Sample Date % Non-detection
Alkalinity, total mg/l CaCO3 2,683 55 150 190 230 270 300 460 12/2/2014 0.00
Ammonia-nitrogen mg/l 12,375 Not calculated when non-detections exceed 50% 78.48
Calcium mg/l 2,612 15 55 65 78 92 110 150 12/2/2014 0.00
Carbonaceous biochemical oxygen demand, standard conditions mg/l 12,193 Not calculated when non-detections exceed 50% 80.12
Chloride mg/l 12,444 <1 11 15 19 25 34 180 9/4/2013 0.02
Chlorophyll a, free of pheophytin ug/l 10,006 <1 2 4 8 21 57 870 8/9/2006 3.61
Dissolved oxygen (DO) mg/l 12,463 <0.9 7.7 8.7 10.5 12.5 13.9 20.3 1/10/2012 0.01
Escherichia coli MPN/100ml 12,298 <10 10 41 140 530 2500 920000 10/2/2002 7.73
Flow cfs 7,981 <0 12 74 260 770 2200 50000 5/1/2008 2.48
Hardness, carbonate mg/l 12,221 3 200 240 290 350 410 820 1/13/2004 0.00
Inorganic nitrogen (nitrate and nitrite) mg/l 12,375 <0.05 0.72 2.9 5.6 8 11 30 5/8/2013 4.63
Kjeldahl nitrogen mg/l 12,375 <0.05 0.2 0.4 0.7 1.1 1.7 28 5/5/2003 4.73
Magnesium mg/l 2,612 2.9 16 21 26 32 37 68 12/2/2014 0.00
Organic Carbon mg/l 2,672 <0.5 1.5 2 2.7 3.6 4.8 25 3/6/2018 0.19
Orthophosphate mg/l 12,330 <0.02 <0.02 0.05 0.08 0.14 0.23 5.9 1/14/2013 14.91
pH None 12,409 5.8 7.7 8 8.2 8.3 8.5 10.9 1/6/2009 0.00
Phosphate-phosphorus mg/l 12,375 <0.02 0.07 0.11 0.19 0.32 0.57 10 6/4/2002 1.94
Potassium mg/l 2,612 <0.88 1.6 2.075 2.8 4 6 23 3/6/2018 0.73
Sodium mg/l 2,612 1.8 6.2 7.8 9.9 13 19 110 9/6/2017 0.00
Sulfate mg/l 12,247 <2.3 17 21 30 49 88 400 10/2/2002 0.07
Temperature, water deg C 12,488 -1.9 0.2 2.1 12 20.2 24.2 33.2 8/1/2012 0.00
Total dissolved solids mg/l 12,371 4 260 300 350 420 500 1020 1/16/2001 0.00
Total suspended solids mg/l 12,375 <1 4 11 38 100 270 17000 5/5/2003 0.65
Turbidity NTU 12,326 <0.1 2.7 6.3 18 48 120 8500 5/5/2003 0.94
Volatile Suspended Solids mg/l 9,841 <1 2 3 8 18 36 2100 4/1/2008 2.02
Project Codes in this Program

Code Description