Urban Stream Monitoring

Beginning in April of 2001, staff of the Water and Pollution Control Department began periodic monitoring of the five major urban streams in Ames for fecal coliform bacteria. Monitoring takes place approximately every month during the warm weather months of April through October. If obvious signs of pollution are discovered, or if significant degradation is observed, City staff will conduct more detailed water quality investigations. The results of the ongoing City monitoring are shown below. Note: The results shown prior to August 14, 2018 are for fecal coliform bacteria. The results from August 14, 2018 going forward are E. coli.

Sample Date Skunk River Ioway Creek  Clear Creek  College Creek  Worrell Creek 
July 23, 2025 839  959 683 1,670 -
June 18, 2025  933 727 683 4,352 1,081
May 21, 2025  5,475 4,352 683 1,046 4,611 
April 16, 2025  10 107 31 481 86
March 19, 2025  109 259 121 1,145 1,450
February 26, 2025  - 246 - - -
November 26, 2024   1,178  2,187  323  3,448  816
September 18, 2024  109  -  -  -  -
August 21, 2024  331  1,553  -  4,106  -
July 17, 2024  5,172  1,046  1,019  -  1,616
June 19, 2024  1,935  8,164  15,531  24,196  >24,196
May 17, 2024  132  238  313  487  146
April 17, 2024  292 1,722  573  910  987
March 27, 2024 <10 31 -  -  -
February 29, 2024  41  41  -  -  -
November 15, 2023  84 - -  - - 
October 18, 2023  238 1,314 - -   -
September 20, 2023  1,515 7,270 15,531 14,136 -
August 16, 2023 327 816 820 15,531 -
July 26, 2023  135 - 1,785 - -
June 21, 2023 573 1,850 1,333 2,603 1,396
May 17, 2023 313 771 414 504 345
April 19, 2023  30 336 20 355 96
March 22, 2023 <10 96 41 301 135
February 15, 2023 1,816 1,424 626 602 5,818
January 19, 2023 -  -  249 1,782 -
November 16, 2022 2,187 9,804 - 3,609 -
October 18, 2022 - 288 - - -
September 20, 2022 246 1,722 - - -
August 24, 2022 120 246 - - -
July 27, 2022 259 422 561 - -
June 15, 2022 8,704 10,344 15,402 9,222 22,398
May 18, 2022 109 345 2,143 9,208 7,270
April 26, 2022 10 41 63 1,860 52
March 18, 2022 41 52 - 410 20
December 17, 2021 10 185 96 3,130 -
November 17, 2021 620 52 84 - -
October 20, 2021 146 - - - -
September 15, 2021 41 - - - -
August 18, 2021 20 - - - -
July 21, 2021 98 441 - - -
June 16, 2021 805 904 - - -
May 21, 2021 121 455 110 1,396 187
April 21, 2021 31 33 - 908 51
March 17, 2021 20 173 - 318 613
January 21, 2021 - 20  - - -
December 16, 2020 - 82 - - -
November 18, 2020 85 173 - 3,076 -
October 21, 2020 40 394 - - 1,596
September 15, 2020 189 364 384 5,475 -
August 18, 2020 146 268 - 432 -
July 14, 2020 126 374 746 654 -
June 16, 2020 718 1,040 960 2,518 1,466
May 19, 2020 1,100 750 218 370 700
April 7, 2020 82 150 62 1,640 60
October 11, 2019 558 758 268 1,024 378
September 24, 2019 1,764 1,446 320 904 1,024
August 6, 2019 122 2,909 6,867 8,664 3,448
July 16, 2019 839 5,172  24,196 >24,196 2,098
June 11, 2019 173 374 414 583 594
May 16, 2019 63 231 189 265 384
April 9, 2019 122 158 85 2,909 448
October 16, 2018  187 187 171 298 282
September 18, 2018 479 105 50 261 -
August 14, 2018 275 529 1439 2,098 -
July 19, 2018 320 13,000 1,040 2,000 1,600
June 19, 2018 2,600 35,000 6,400 9,400 111,000
May 15, 2018 90 155 180 540 80
April 17, 2018 65 370 50 590 70
October 12, 2017 350 1,800 620 600 1,040
September 21, 2017 135 940 - 1,100 -
August 8, 2017 105 530 - 4,900 -
July 12, 2017 250 1,000 475 2,600 760
June 13, 2017 410 630 800 2,000 1,500
May 23, 2017  470 360 560 630 540
April 20, 2017  1,800 22,000 290 250 200
October 4, 2016 470 390 400 500 450
September 27, 2016 600 500 630 90 1,300
August 9, 2016 160  740 420 2,300 -
July 21, 2016 1,200 5,200 1,200 1,500 10,000
June 9, 2016  420 490 150 1,800 700
May 19, 2016 120 140 40 460 400
April 14, 2016  57 170 100 300 40
September 1, 2015 1,900 700 730 690 600
August 11, 2015 4,000 4,800 1,700 2,900 16,000
July 14, 2015 170 600 1,900 2,300 1,800
June 2, 2015 310 320 230 1,100 270
May 19, 2015 160 290 450 580 280
April 14, 2015  20 200 66 2,600 210
October 21, 2014 160 220 130 3,000 360
September 4, 2014 470 1,100  560 600 1,400
August 5, 2014 220 210 1,500 3,500 -
July 22, 2014 180 220 1,800 3,300 1,700
June 3, 2014 1,500 540 470 1,800 350
May 6, 2014 54 60 18 260 90
April 22, 2014 43 23 70 50 36
October 1, 2013 - -  - - -
September 12, 2013 160 - - - -
August 1, 2013 150 380 - - -
July 16, 2013 100 270 1,800 4,100 700
June 13, 2013 370 380 420 900 570
May 21, 2013 6,100 1,000 590 2,800 4,200
April 23, 2013 140 160 110 90 1,000
October 11, 2012 10 - - 190 -
September 5, 2012 500 33,000 - 75,000 68,000
August 9, 2012 680 8,000 5,000 2,000 2,200
July 19, 2012 40 200 210 - -
June 5, 2012 74 120 130  760 310
May 17, 2012  110 200 130  1,100 240
April 17, 2012 470 2,800 230 440 2,700
October 18, 2011 300 660 - 600 -
September 13, 2011 150 310 - 1,500 -
August 25, 2011 69 170 360 640 -
July 21, 2011 130 5,200 9,000 72,000 2,000
June 14, 2011 700 1,300 3,200 520 680
May 19, 2011 110 260 120 610 420
April 13, 2011 27 37 46 170 26
October 7, 2010 130 390 270 1,000 650
September 23, 2010  700 800 600 1,100 17,000
August 19, 2010  620 240 1,300 1,100 300
July 20, 2010 5,500 6,500 1,000 1,900 2,100
May 29, 2010 120 580 240 1,100 290
June 10, 2010  420 490 510 1,900 2,100
April 22, 2010 52 76 80 460 56
October 13, 2009  90 150 2,800 435 170
September 17, 2009  200 480 1,180 - -
August 20, 2009 800 2,800 4,100 6,300 4,400
July 16, 2009  700 800 6,200 2,200 1,200
June 23, 2009 1,700 1,200 1,300 700 2,500
May 27, 2009  14,800 25,600 3,100 3,300 >40,000
April 15, 2009  70 120 10 90 90

Samples are analyzed using the Membrane Filter Technique (SM 9222 D). The results of testing for fecal coliform when using this method are expressed in terms of the number of Colony-Forming Units (CFU) present in a 100 milliliter sample.

"Coliform density, together with other information obtained by engineering or sanitary surveys, provides the best assessment of the sanitary quality of water." -- Standard Methods for the Examination of Water and Wastewater

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