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Bacteria Monitoring Reports

DMRWQN Bacteria Reports

These reports are preliminary. See monthly reports for any corrections. Bacteria monitoring is seasonally performed (mid-May-mid-September) at the regular riverine and surface reservoirs stations (see map).  During this time samples are collected weekly at the swimming beaches at both reservoirs, as described below (also see sampling protocol). All bacteria tests are now performed by 18 hour Coliert method (2013 on). Prior to 2013 a membrane filtration method was used.

The swimming beach data from OGB, SPB, NOB and WBB refer to composite samples collected along Oak Grove and Sandpiper beaches at Saylorville Reservoir and North Overlook and Whitebreast beaches at Red Rock Reservoir. At each beach nine samples were collected and composited (ankle depth, knee depth and chest depth at three locations along the beach).

Beach Posting/Closing Criteria

A beach will be posted with a "Swimming is Not Recommended" notice if the geometric mean of five consecutive samples exceeds 126 organisms/100 ml. The notice will remain in effect until the geometric mean of five consecutive samples is less than or equal to 126 organisms/100 ml.

A beach will also be posted with a "Swimming is Not Recommended" notice if the result from a resampling exceeds 235 organisms/100 ml. The notice will be removed when the concentration is less than or equal to the one time maximum of 235 organisms/100 ml and the geometric mean of 126 organisms/100 ml.

At the beginning of the monitoring season, prior to the collection of five samples, any beach with an E. coli concentration greater than 235 organisms/100 ml will be resampled. If the E. coli concentration exceeds 235 organisms/100 ml upon resampling, the beach will be posted with a "Swimming is Not Recommended" notice. The beach will remain posted until the concentration falls below 235 organisms/100 ml, or until five samples have been collected and the geometric mean concentration is less than or equal to
126 organisms/100 ml.

The reservoir manager reserves the right to close a beach in the event of a documented health risk, such as outbreak of an infectious disease, wastewater by-pass, spill from animal waste storage facility, hazardous chemical spill, etc. In most instances, this decision will be made following consultation with local public health agency officials and/or ED-HQ staff.

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Contract Period 44 (2013)

| 5/20/13 regular stations / beaches | 5/6/13 regular stations |

Contract Period 43 & extension (2012)

| 9/17/12 regular stations | 9/10/12 beaches | 9/4/12 regular stations / beaches | 8/27/12 beaches | 8/20/12 regular stations / beaches | 8/13/12 regular stations/ beaches / resampling | 8/6/12 regular stations / beaches / resampling | 7/30/12 beaches / resampling | 7/23/12 regular stations / beaches | 7/16/12 regular stations / beaches / resampling | 7/11/12 regular stations / beaches / resampling | 7/4/12 beaches | 6/25/12 regular stations / beaches | 6/18/12 regular stations / beaches | 6/11/12 regular stations / beaches / resample | 6/4/12 beaches | 5/29/12 beaches | 5/21/12 beaches / resample | 5/14/12 beaches |

Contract Period 43 (2011)

| 9/12/11 beaches | 9/6/11 beaches | 8/29/11 regular stations / beaches | 8/15/11 regular stations / beaches | 8/5/11 beaches | 8/1/11 regular stations / beaches | 7/25/11 regular stations / beaches | 7/18/11 regular stations / beaches | 7/11/11 regular stations / beaches | 7/5/11 beaches | 6/27/11 regular stations / beaches | 6/13/11 regular stations | 6/6/11 regular stations / beaches / beach resampling | 5/31/11 beaches | 5/23/11 beaches | 5/16/11 beaches |

Contract Period 42 (2010)

The beaches at both reservoirs are now flooded and closed;
therefore there is no longer any bacteria monitoring

| 8/30 regular stations | 8/16/10 regular stations | 8/10/10 regular stations | 7/26/10 regular stations | 7/19/10 regular stations | 7/14/10 regular stations || 6/28/10 regular stations | 6/14/10 regular stations / beaches | 6/7/10 regular stations / beaches| 6/1/10 / beaches | 5/24/10beaches | 5/17/10 beaches |

Contract Period 41 (2009)

| 9/15/09 beaches | 9/8/09 beaches | 9/1/09 beaches | 8/25/09 regular stations / beaches | 8/19/09 resampling beaches | 8/17/09 regular stations / beaches | 8/5/09 resampling beaches | 8/3/09 regular stations / beaches | 7/27/09 regular stations / beaches | 7/20/09 regular stations / beaches | 7/13/09 beaches | 7/6/09 regular stations / beaches | 6/29/09 regular stations / beaches | 6/22/09 beaches / resample | 6/15/09 regular stations / beaches | 6/8/09 beaches| 6/1/09 regular stations / beaches | 5/26/09 beaches | 5/18/09 beaches | 5/11/09 beaches |

Contract Period 40 (2008)

| 9/9/08 beaches | 9/2/08 beaches | 8/26/08 beaches | 8/18/08 regular stations / beaches / beach resample | 8/11/08 regular stations / beaches | 8/4/08 regular stations / beaches | 7/28/2008 beaches / beach resample | 7/21/2008 regular stations / beaches | 7/14/08 regular stations / beaches | 7/7/08 regular stations / beaches | 6/30/08 beaches | 6/23/08 regular stations | 6/9/08 regular stations | 6/2/08 regular stations / beaches | 5/27/08 beaches | 5/19/08 beaches |

Contract Period 39 (2007)

| 9/11/07 beaches | 9/4/07 regular stations / beaches | 8/28/07 beaches | 8/21/07 regular stations / beaches | 8/13/07 regular stations / beaches | 8/8/07 beach resampling | 8/6/07 regular stations / beaches | 7/30/07 beaches | 7/23/07 regular stations / beaches | 7/18/07 beach resampling | 7/16/07 regular stations / beaches | 7/9/07 regular stations / beaches | 7/02/07 beaches | 6/25/07 regular stations / beaches | 6/18/07 beaches | 6/11/07 regular stations / beaches flooded | 6/4/07 regular stations / beaches flooded | 5/21/07 regular stations / beaches flooded | 5/14/07 regular stations / beaches flooded |

Information

Fecal coliform bacteria information from the latest Annual Report

Cyanobacteria and Microcystin at Recreational Areas from latest Annual Report

Historical Review of Bacteria Concentrations at Sayl/RR Swimming Beaches (1985-2008)

Information regarding Iowa DNR beach closing and warning policies

Methods

Sampling Protocol

CCEE/EERL Laboratory Method Synopsis

Counting Rules

Using Geometric Mean to Evaluate Fecal Coliform Bacteria Concentrations

Webmaster: Donna S. Lutz