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ENGI NEERI NG • AR CHI TECTURE • ENV IRO NM ENT AL
Ongoing Screening Summary Report
2015 Inspection Year
Illicit Discharge Detection and Elimination Program
City of Oshkosh
January 8, 2016
OMNNI Project No. N2029C15
Illicit Discharge Detection and Elimination
Conducted For
City of Oshkosh
Ongoing Screening Summary Report
2015 Inspection Year
Prepared by:
OMNNI Associates, Inc.
One Systems Drive
Appleton, WI 54914-1654
(T) 920/735-6900
(F) 920/830-6100
www.omnni.com
OMNNI Project Number N2029C15
January 8, 2016
Table of Contents
EXECUTIVE SUMMARY ................................................................................................................. 1
BACKGROUND ............................................................................................................................... 1
PURPOSE ...................................................................................................................................... 1
PROGRAM HISTORY ....................................................................................................................... 2
SCREENING METHODOLOGY .......................................................................................................... 3
RAINFALL AND FLOW ................................................................................................................... 5
RAINFALL ...................................................................................................................................... 5
FLOW ............................................................................................................................................ 7
SUBMERGED OUTFALLS ................................................................................................................. 8
PHYSICAL INDICATOR ASSESSMENT ........................................................................................ 9
FLOATABLES ................................................................................................................................. 9
ODOR ......................................................................................................................................... 10
TURBIDITY ................................................................................................................................... 10
COLOR ........................................................................................................................................ 10
VEGETATION ............................................................................................................................... 10
BENTHIC GROWTH ....................................................................................................................... 11
STAINS........................................................................................................................................ 11
GROSS SOLIDS............................................................................................................................ 12
OBSERVED CONDITIONS .............................................................................................................. 12
CHEMICAL ANALYSIS ................................................................................................................. 13
PH .............................................................................................................................................. 14
TEMPERATURE ............................................................................................................................ 15
CONDUCTIVITY ............................................................................................................................ 16
CHLORINE ................................................................................................................................... 18
AMMONIA .................................................................................................................................... 19
DETERGENTS .............................................................................................................................. 20
POTENTIAL ILLICIT DISCHARGES ............................................................................................. 22
UPSTREAM MANHOLES WITH SIGNIFICANT FLOATABLE DEBRIS ...................................................... 24
OUTFALL 16-1508 (N. W ESTFIELD STREET) ................................................................................. 25
OUTFALL 12-1328A (NOLTE AVENUE DETENTION BASIN) ............................................................... 26
OUTFALL CONDITION ASSESSMENTS ..................................................................................... 28
DAMAGE ..................................................................................................................................... 29
DEPOSITION ................................................................................................................................ 31
EROSION ..................................................................................................................................... 34
GRAFFITI ..................................................................................................................................... 34
2016 ONGOING SCREENING PROGRAM .................................................................................. 35
CONCLUSION ............................................................................................................................... 35
STANDARD OF CARE .................................................................................................................. 37
List of Appendices
MS4 OUTFALL MAP .................................................................................................................... A-1
2015 OUTFALL INSPECTION MAP............................................................................................. A-2
OUTFALL INSPECTION REPORTS ............................................................................................... B
LOCATIONS OF OUTFALLS WITH POTENTIAL ILLICIT DISCHARGES .................................. C-1
LOCATIONS OF OUTFALLS WITH DAMAGE ............................................................................ C-2
LOCATIONS OF OUTFALLS WITH DEPOSITION ...................................................................... C-3
LOCATIONS OF OUTFALLS WITH EROSION ........................................................................... C-4
LOCATIONS OF OUTFALLS WITH GRAFFITI ........................................................................... C-5
UPSTREAM MANHOLES WITH SIGNIFICANT FLOATABLE DEBRIS ...................................... D-1
OUTFALL 16-1508 (N. WESTFIELD STREET) INVESTIGATION .............................................. D-2
OUTFALL 12-1328A (NOLTE AVENUE DETENTION BASIN) INVESTIGATION ....................... D-3
MS4 OUTFALL SCREENING HISTORY/SCHEDULE .................................................................... E
List of Tables
TABLE 1 – IDDE POTENTIAL OF OUTFALLS WITH ELEVATED CONDUCTIVITIES ............... 18
TABLE 2 – IDDE POTENTIAL OF OUTFALLS WITH AMMONIA DETECTIONS ........................ 20
TABLE 3 – OUTFALLS WITH ELEVATED ILLICIT DISCHARGE CLASSIFICATIONS ............... 22
TABLE 4 – OUTFALLS W ITH DAMAGE ....................................................................................... 29
TABLE 5 – OUTFALLS W ITH DEPOSITION ................................................................................ 31
TABLE 6 – OUTFALLS W ITH GRAFFITI ...................................................................................... 34
List of Figures
FIGURE 1 – LOCATION OF WEATHER STATION FOR WEATHER HISTORY ........................... 5
FIGURE 2 – SUMMER 2015 WEATHER HISTORY (WEATHER UNDERGROUND) ................... 6
FIGURE 3 – RAINFALL HISTORY AND OUTFALL INSPECTIONS .............................................. 7
FIGURE 4 – FLOW INTENSITY AT OUTFALL ............................................................................... 8
FIGURE 5 – SUBMERGED STATUS OF OUTFALLS .................................................................... 9
FIGURE 6 – PHYSICAL INDICATOR OBSERVATIONS .............................................................. 13
FIGURE 7 – PH SAMPLE RESULTS ............................................................................................ 15
FIGURE 8 – TEMPERATURE SAMPLE RESULTS ..................................................................... 16
FIGURE 9 – CONDUCTIVITY SAMPLE RESULTS ...................................................................... 17
FIGURE 10 – AMMONIA SAMPLE RESULTS ............................................................................. 20
FIGURE 11 – TYPICAL MBAS DETERGENT TEST RESULTS .................................................. 22
FIGURE 12 – ILLICIT DISCHARGE POTENTIAL OF INSPECTED OUTFALLS ......................... 24
FIGURE 13 – OUTFALL 16-1508 (9/28/2015) .............................................................................. 25
FIGURE 14 – PARK RESTROOM BUILDING UPSTREAM OF 16-1504 (2013) ......................... 26
FIGURE 15 – OUTFALL 12-1328A (9/23/2015) ............................................................................ 27
FIGURE 16 – INLET 582A (9/28/2015) ......................................................................................... 28
FIGURE 17 – PIPE DISCHARGING INTO INLET 582A (9/28/2015) ........................................... 28
FIGURE 18 – SIGNIFICANT SETTLING AT OUTFALL 03-22 (SEVERE DAMAGE) .................. 29
FIGURE 19 – CORRODED METAL PIPE AT OUTFALL 12-890 (MODERATE DAMAGE) ......... 29
FIGURE 20 – BROKEN PVC PIPE AT OUTFALL 12-972 (MINOR DAMAGE) ............................ 30
FIGURE 21 – CORROSION AND CRUSHED PIPE AT OUTFALL 13-1106 (MINOR DAMAGE) 30
FIGURE 22 – CORRODED METAL PIPE AT OUTFALL 13-1283 (MINOR DAMAGE) ............... 30
FIGURE 23 – ERODED FLOWLINE IN MANHOLE 13-68 US1 (MINOR DAMAGE) ................... 30
FIGURE 24 – 4” JOINT DISPLACEMENT AT OUTFALL 14-999 (MODERATE DAMAGE) ........ 30
FIGURE 25 – CORRODED METAL PIPE AT OUTFALL WASH41_01 US1 (MINOR DAMAGE) 30
FIGURE 26 – MODERATE DEPOSITION IN MANHOLE 01-380 US1 ........................................ 31
FIGURE 27 – MODERATE DEPOSITION AT OUTFALL 02-105 ................................................. 31
FIGURE 28 – MINOR DEPOSITION IN MANHOLE 03-35 US1 ................................................... 32
FIGURE 29 – MINOR DEPOSITION IN MANHOLE 12-1795 US1 ............................................... 32
FIGURE 30 – MODERATE DEPOSITION AT OUTFALL 12-2034 ............................................... 32
FIGURE 31 – MINOR DEPOSITION AT OUTFALL 13-1106 ....................................................... 32
FIGURE 32 – MODERATE DEPOSITION AT OUTFALL 13-1283 ............................................... 32
FIGURE 33 – MODERATE DEPOSITION AT OUTFALL 13-1758 ............................................... 32
FIGURE 34 – SEVERE DEPOSITION AT OUTFALL 13-1766 ..................................................... 33
FIGURE 35 – SEVERE DEPOSITION AT OUTFALL 13-1769 ..................................................... 33
FIGURE 36 – MINOR DEPOSITION IN MANHOLE 13-1769 US1 ............................................... 33
FIGURE 37 – MODERATE DEPOSITION AT OUTFALL 14-1514 ............................................... 33
FIGURE 38 – MINOR DEPOSITION IN MANHOLE 15-146 US1 ................................................. 33
FIGURE 39 – MODERATE DEPOSITION AT OUTFALL 15-1093 ............................................... 33
FIGURE 40 – MINOR DEPOSITION AT OUTFALL 15-2477 ....................................................... 34
FIGURE 41 – GRAFFITI NEAR OUTFALL 12-569 ....................................................................... 34
FIGURE 42 – ILLICIT DISCHARGE POTENTIAL ......................................................................... 36
January 8, 2016 1 2015 Ongoing Screening Summary Report
City of Oshkosh
EXECUTIVE SUMMARY
During the summer of 2015, OMNNI Associates, Inc. (OMNNI) assisted the City of Oshkosh with
inspecting the outfalls in the City’s municipal separate storm sewer system (MS4) for potential
illicit discharges. Following the Illicit Discharge Ongoing Inspection Program that was revised in
2015, OMNNI inspected 98 of the approximately 425 MS4 outfalls identified in the City. The
inspections consisted of a visual screening along with a chemical analysis of any dry-weather
flow that was present. The inspections revealed 21 outfalls with evidence of potential or obvious
illicit discharges, primarily manholes with trapped floating litter.
The 2015 outfall screening was conducted using the draft 2015 revisions to the Ongoing
Screening Program. Based on the information collected during the screening, the proposed
ongoing screening program will undergo minor revisions, and can then be submitted to the
Wisconsin Department of Natural Resources (WDNR) for use in future screening programs.
BACKGROUND
Purpose
Under Section 2.3.2 of the Wisconsin Pollutant Discharge Elimination System (WPDES) Permit
No WI-S050075-2 (“permit”), the City of Oshkosh is required to conduct ongoing dry weather
field screening of all outfalls during the term of the permit to detect potential illicit discharges.
Under the MS4 permit, an outfall is defined as “the point at which storm water is discharged to
waters of the state or leaves one municipality and enters another.” The MS4 is defined as “a
conveyance or system of conveyances including roads with drainage systems, municipal streets,
catch basins, curbs, gutters, ditches, constructed channels or storm drains, which meets all of
the following criteria:
1. Owned or operated by a municipality.
2. Designed or used for collecting or conveying storm water.
3. Which is not a combined sewer conveying both sanitary and storm water.”
When applied to the City of Oshkosh, the MS4 permit requires ongoing screening of the road
ditch or storm sewer outfalls where the outfalls discharge to a water of the state (i.e., a
navigable or non-navigable stream, lake, or wetland) or where they discharge into an adjacent
municipality or to a county or state highway right-of-way.
Each outfall is classified as “major” or “minor.” A “major outfall,” as defined by the MS4 permit,
is an MS4 outfall that meets one of the following criteria:
1. A single pipe with an inside diameter of 36 inches or more or equivalent conveyance
(cross sectional area of 1,018 square inches) which is associated with a drainage area of
more than 50 acres.
2. A municipal separate storm sewer system that receives storm water runoff from lands
zoned for industrial activity that is associated with a drainage area of more than 2 acres
or from other lands with 2 or more acres of industrial activity, but not land zoned for
industrial activity that does not have any industrial activity present.
Outfalls not meeting the definition of a major outfall are considered “minor outfalls.”
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OMNNI has also worked with the WDNR to develop a third class of outfalls – “supplemental”
outfalls. Supplemental outfalls are storm sewer outfalls which may not meet the legal definition
of an outfall according to the MS4 general permit, but should be included in an ongoing field
screening program. The majority of the supplemental outfalls are detention basin inlets, which
do not discharge directly to a water of the state, and therefore are not technically outfalls.
However, sampling the detention basin inlets is an important component of the overall
screening process, as illicit discharges are more likely to be discovered at the detention basin
inlets rather than at the detention basin outfall.
The current MS4 map for the City of Oshkosh consists of 425 outfalls, including:
95 major outfalls
237 minor outfalls
93 supplemental outfalls
These numbers are updated each year as outfalls are located during the ongoing field screening
program and modifications are made to the MS4. A map showing the MS4 outfalls is included in
Appendix A.
Program History
The activities that have taken place with the Illicit Discharge Program for the City of Oshkosh are
summarized below:
September 2009 – Initial Screening (major outfalls)
109 major outfalls screened, with 23 potential and one obvious illicit discharge identified.
City of Oshkosh Initial Field Screening Summary Report (May 18, 2010)
December 2009 – Ongoing Field Screening Program
348 MS4 outfalls identified, screened over a four-year inspection cycle.
City of Oshkosh IDDE Ongoing Field Screening Program (May 19, 2010)
August 2010 – 2010 Ongoing Screening
93 outfalls screened, with 26 potential illicit discharges identified.
City of Oshkosh Ongoing Screening Summary Report – 2010 Inspection Year (March 28, 2011)
June 2, 2011 – USEPA Audit
Assisted with questions concerning the IDDE program
October 2011 – 2011 Ongoing Screening
121 outfalls screened, with 15 potential and one obvious illicit discharge identified.
City of Oshkosh Ongoing Screening Summary Report – 2011 Inspection Year (March 6, 2012)
October 2012 – 2012 Ongoing Screening
100 outfalls screened, with 12 potential illicit discharges identified.
City of Oshkosh Ongoing Screening Summary Report – 2012 Inspection Year (March 25, 2013)
July 2013 – 2013 Ongoing Screening
95 outfalls screened, with 7 potential illicit discharges identified.
City of Oshkosh Ongoing Screening Summary Report – 2013 Inspection Year (February 20, 2014)
October 2014 – 2014 Ongoing Screening
42 outfalls screened (prior potential illicit discharges), with 17 potential illicit discharges
identified.
City of Oshkosh Ongoing Screening Summary Report – 2014 Inspection Year (February 23, 2015)
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September 2015 – Ongoing Field Screening Program Revision (draft)
425 MS4 outfalls identified, with 60 priority outfalls.
City of Oshkosh IDDE Ongoing Field Screening Program – 2015 Revision (September 16, 2015)
September 2015 – 2015 Ongoing Screening
98 outfalls screened, with 20 potential and one obvious illicit discharge identified.
City of Oshkosh Ongoing Screening Summary Report – 2015 Inspection Year (January 8, 2016)
The 2015 revision to the Ongoing Screening Program implemented the “priority outfall” concept
that was introduced by the WDNR in a March 2012 guidance document. These priority outfalls
are outfalls that have the highest likelihood of a potential illicit discharge based on the
characteristics of the drainage basins for each outfall. The priority outfalls are scheduled to be
screened annually, while the non-priority outfalls are screened less frequently (every five years
for major outfalls, every ten years for non-major outfalls). The current version of the program
includes 60 priority outfalls.
The 2015 outfall screening followed the 2015 revision to the Ongoing Screening Program. The
priority outfalls were screened, along with a subset of the non-priority outfalls. Based on the
field observations during the screening, the Ongoing Screening Program will be modified slightly
for future years.
The outfalls that were included in the 2015 screening program are shown in Appendix A, and the
associated outfall inspection reports are included in Appendix B. The City may need to include
these results in the annual report required by the MS4 permit due March 31, 2016.
Screening Methodology
OMNNI’s outfall screening methodology loosely follows the procedures outlined in ILLICIT
DISCHARGE DETECTION AND ELIMINATION : A GUIDANCE MANUAL FOR PROGRAM DEVELOPMENT AND
T ECHNICAL ASSESSMENTS (Center for Watershed Protection / Robert Pitt, October 2004). The
procedures were modified to comply with the MS4 permit requirements, and have evolved after
several years of experience and discussions with the WDNR.
Outfalls that have been previously inspected are located with the assistance of GPS. For outfalls
that have not been previously inspected, the available MS4 mapping is used to physically locate
the outfall, and then the GPS location is recorded to assist with future inspections. The physical
properties of the outfall are then recorded – type of outfall, dimensions, material, and discharge
location. A photograph of the outfall is taken to show the general location and configuration.
After the physical properties have been recorded, the outfall and surrounding area are screened
for indicators of current or past illicit discharges. Sample indicator parameters include floatable
material, gross solids, odors, stains, color of water, turbidity, abnormal vegetation and benthic
growth. If any of these physical indicators are observed, they are further described and
quantified. A close-up photograph is taken of the actual discharge of the outfall, showing any
indicator parameters or flow from the outfall. A short video of the flow is also taken to
document the magnitude of the flow or the lack of flow at the time of inspection.
The MS4 permit specifies that the outfalls be screened during periods of dry weather. Outfall
inspections are typically conducted in the summer months to avoid the effects of snowmelt
runoff in the storm sewer system. OMNNI generally waits for a minimum of 72 hours following a
runoff-producing rainfall event to conduct the outfall screening. This typically allows sufficient
time for the stormwater to discharge through the drainage area and outfall. If, after 72 hours,
the outfall still has flow, a sample is collected and screened for chemical indicators of an illicit
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City of Oshkosh
discharge. While the actual list of chemical parameters is specific to each outfall, most flowing
outfalls are screened for the following parameters:
pH
Chlorine (total chlorine and free chlorine)
Detergents
Ammonia
Temperature
Conductivity
In some cases, outfalls can be either partially or fully submerged. A partially submerged outfall is
an outfall where the elevation of the invert is below the water level of the receiving water. A
fully submerged outfall is a pipe that is entirely below the water surface. In either condition, the
receiving water is “backed up” into the discharging pipe or channel, and is not free-flowing.
Under these conditions, if a sample is collected at the outfall point, the sample could consist
almost entirely of the receiving water.
In the case of partially or fully submerged outfalls, OMNNI developed a sampling procedure that
was approved by WDNR. The submerged outfall is screened for physical indicators. However,
the flow sample is collected from the first access point (i.e., manhole, catchbasin, curb inlet)
upstream of the outfall. This reduces the influence of the receiving water. Typically, if there is no
flow or pooled water at the upstream location, then no sample is collected. For all upstream
sampling, a note is made of the distance and land use of the area between the outfall and the
upstream area to assess the potential for illicit connections between the outfall and the
upstream location.
In the event that the physical or chemical indicators show that there is a potential ongoing illicit
discharge, the Illicit Discharge Coordinator of the municipality is contacted. If requested, OMNNI
then assists the municipality with attempting to identify the source of the discharge, usually by
inspecting and/or sampling additional upstream points to attempt to isolate a particular branch
of the MS4 network.
While not explicitly required by the MS4 permit, OMNNI also conducts a physical condition
assessment for each outfall. The inspector identifies any graffiti, damage, erosion or deposition
present at the outfall and assigns a severity. This information is provided to the municipality to
assist with maintenance activities.
A detailed outfall report is generated for each outfall that is inspected. The outfall report
includes the general outfall information that was collected, along with detailed inspection
results for each inspection conducted at the outfall. This provides a comprehensive history of
the inspection results for the outfall as multiple inspections are performed over the life of the
outfall.
Detailed inspection reports for each outfall are included in Appendix B. Some general
observations from the field screening are noted in the following sections.
January 8, 2016 5 2015 Ongoing Screening Summary Report
City of Oshkosh
RAINFALL AND FLOW
Rainfall
Weather data was obtained from the Weather Underground website. Personal weather station
KWIOSHKO16 (“Scott54902Wx”) is located on W 6th Avenue between Sawyer Street and Knapp
Street in the City of Oshkosh. The conditions at this weather station were considered
representative of the weather in the City of Oshkosh for the 2015 ongoing screening. The
location of the weather station is shown in Figure 1.
Figure 1 – Location of weather station for weather history
The weather history from August 1 through October 1, 2015 from this weather station is shown
in Figure 2.
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City of Oshkosh
Figure 2 – Summer 2015 weather history (Weather Underground)
Outfall inspections were conducted in the City of Oshkosh on September 22-24 and 28, 2015.
Those inspection dates (red), along with the daily rainfall history (blue), are shown in Figure 3.
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City of Oshkosh
Figure 3 – Rainfall history and outfall inspections
The rainfall on September 19 ended at approximately 1:30 a.m., providing more than 72 hours
of dry weather before the start of the inspections. The rainfall on September 28 occurred after
the inspections were completed.
Flow
To meet the requirement of dry weather screening, outfalls were typically screened at least 72
hours after the previous runoff-producing rainfall event. Because the outfalls that were
screened in 2015 were primarily submerged outfalls, flow could only be assessed at 20 of the
outfalls.
Submerged outfalls, along with the observed flow patterns, are described in the next section.
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City of Oshkosh
The distribution of the flow intensity of the outfalls is shown in Figure 4.
Figure 4 – Flow intensity at outfall
If dry weather flow was found during the field screening, a sample was collected and analyzed
for the presence of indicator parameters. The analysis conducted is discussed in a later section.
Not all flow is an indicator of an illicit discharge. Following a significant rainfall event, surface
water and groundwater elevations can be higher than normal. Much of the observed flow may
originate from sump pump discharges, detention basin discharges, permitted discharges, and
infiltration into the storm sewer system.
Submerged Outfalls
Most of the outfalls in the City were located at or below the normal levels of their respective
receiving waters. Of the 98 inspected outfalls, 24 were partially submerged, and 52 were fully
submerged (Figure 5). Of the 52 fully submerged outfalls, 47 could not be physically located.
January 8, 2016 9 2015 Ongoing Screening Summary Report
City of Oshkosh
Figure 5 – Submerged status of outfalls
Submerged outfalls were screened at a representative upstream location (i.e., first upstream
manhole), if one was available. If flow or a submerged pool was present in the upstream
location, a sample was collected. If a representative upstream location was not available, a
sample was collected from the submerged pool at the outfall. Sampling locations are noted on
the individual outfall inspection reports.
PHYSICAL INDICATOR ASSESSMENT
All outfalls, regardless of whether they exhibited dry-weather flow at the time of inspection,
underwent an extensive assessment for physical indicators of past or current illicit discharges.
The physical indicators are grouped into eight categories, and each category is assigned a
severity rating based on the observed conditions, along with a qualitative description, if
applicable. The eight categories of physical indicators are described below.
Floatables
Floatables include petroleum sheens, suds, algae, and evidence of raw sewage. These conditions
would typically be observed in an area of stagnant water, such as a downstream pool or an
upstream manhole, although some may be observed in the actual flow. Some conditions
(petroleum sheens and sewage) are almost always the result of an illicit discharge. Other
floatables, like suds and algae, can have non-illicit sources, but their presence can also indicate
the potential for an illicit discharge, and the source should be traced.
Vegetative debris and solid waste (litter) can also float, but these substances are included in the
Gross Solids category, and are not considered floatables.
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City of Oshkosh
A slight severity for floatables indicates isolated occurrences of the substance in the pool or
flow. A moderate severity indicates a broader coverage, including distinct pockets of the
substance. A severe classification typically describes total coverage of the water surface.
Odor
Clean stormwater should have no odor. Odors may be caused by the presence of chemicals,
which can indicate a potential illicit discharge. The classification of odor is somewhat subjective,
and may vary depending on the inspector. Some of the odor classifications are chemical-based,
and include petroleum, VOC/solvent, chlorine, and sulfur. Other odor classifications are even
more subjective, and include musty, fishy, sewage, and fragrant.
Odor can be difficult to quantify. As a result, the severity is based on the method that it can be
detected. A slight severity for odor indicates that the odor can be detected in the sample bottle.
A moderate severity indicates that the odor can be detected in the flow itself. A severe
classification indicates that the odor can be detected from a distance.
Turbidity
Turbidity is a measure of the clarity of a water sample, reflecting the amount of suspended
solids present in the water. As turbidity increases, the water becomes cloudy and eventually
opaque. Turbidity has a negative impact on aquatic life, as it prevents sunlight from penetrating
the water.
Turbidity is frequently caused by soil erosion that occurs upstream of the outfall. The soil
erosion can be accelerated by poor erosion control management practices. Active construction
sites and highly eroded areas are common sources of turbidity.
While turbidity can be measured directly using an instrument like a turbidimeter, the relative
turbidity of each outfall sample was assessed qualitatively. A slight severity for turbidity
indicates that the sample appeared slightly cloudy in the sample bottle. A moderate severity
indicates that the sample exhibits significant cloudiness. A severe classification was used for a
sample that was opaque in the sample bottle.
Color
Stormwater typically should be clear, with no apparent color. Certain tints and colors can
indicate the presence of substances that could be a potential illicit discharge. Some tints can be
caused by natural substances, such as tannins in leaves and vegetative debris causing a slight
brown tint. High concentrations of suspended solids can cause orange tints (clay), brown tints
(loam) or gray-black tints (organic materials). Certain colors (i.e., red, blue and green) are almost
never naturally-occurring, and likely indicate an illicit discharge.
Color is most easily assessed in the sample bottle. The sample bottle can be compared to a
bottle of deionized water as a standard. The general color of the sample is noted, along with the
relative severity. A slight severity for color indicates that the color is faint in the sample bottle. A
moderate severity indicates that the color is easily detected in the sample bottle. A severe
classification indicates that the color can be observed in the actual flow or pool, outside of the
sample bottle.
Vegetation
The health of the vegetation in the area surrounding the outfall can be an indicator of potential
illicit discharges from the outfall. Various chemicals in an illicit discharge can inhibit or kill the
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City of Oshkosh
vegetation in the areas surrounding the outfall. Discharges with high nutrient levels –
particularly fertilizer runoff – can significantly increase the amount of vegetation around the
outfall.
Because outfalls provide a water source, the vegetation around outfalls is typically more
productive than areas farther from the outfall, particularly during dry periods. It is important to
distinguish between increased vegetation due to available water and excessive vegetation due
to nutrients in the runoff. True vegetation impacts due to chemicals or nutrients appear to be
rare compared to other physical indicator parameters.
The “vegetation” indicator parameter does not apply to vegetation growing inside the outfall
pipe or on the pipe apron. This condition is evaluated under the “benthic growth” parameter.
Vegetation effects were classified as either “inhibited” or “excessive.” The severity was
subjectively assigned based on the extent of the vegetation impact that was observed, ranging
from slight to severe.
Benthic Growth
Due to the presence of nutrients, organic materials and moisture, outfall pipes and aprons can
commonly host vegetation that grows on the sides and bottoms of the structures. This is
particularly common in concrete pipes, which are more porous, but can occur on nearly all pipe
materials. The vegetation encountered is typically algae, moss and lichens.
Some degree of benthic growth is present on nearly all storm sewer outfall pipes, and appears
to increase with age. The presence of benthic growth alone is not typically a reason to classify an
outfall as a potential illicit discharge. However, severe cases of benthic growth, especially when
combined with other indicators, can be used to classify and trace illicit discharges.
The color of the benthic growth is noted on the inspection report. Green benthic growth is most
common in outfalls with sunlight. Brown benthic growth is more common in outfalls with
limited sunlight. Other colors, such as orange, can sometimes be present.
The severity of the benthic growth is determined by a subjective analysis of the thickness of the
vegetation. A slight severity for benthic growth indicates a thin layer, usually a film or the dried
stains of former growth. A moderate severity is used when an actual depth of vegetation can be
observed, typically up to one-half inch deep. A severe classification is used when the vegetation
changes from a short, “fuzzy” layer to longer, more defined plants with stems and leaves.
Stains
Stains inside pipes, aprons, riprap and channels can be good indicators of past illicit discharges.
Clean stormwater typically would not cause stains. However, some non-illicit discharges can
cause stains, including tannins from vegetation (brown), road salt (white), minerals (various
colors) and suspended solids (gray or brown). Most storm sewer pipes will have some degree of
staining due to natural causes, and the stains tend to increase with the age of the structure.
These stains are typically found at either the normal or the high flowline for the pipe.
Abnormal stains are typically indicators of past illicit discharges. Common types of stains in this
category include oil and grease, paint, concrete washout, and iron discharges (rust). It is
important to distinguish between actual iron discharges and normal pipe corrosion, which can
occur in metal pipes, and is not an illicit discharge. Corrosion typically occurs along the invert of
the pipe, where water may collect and corrode the pipe. Rust stains are typically darker streaks,
often originating from a lateral or other incoming pipe.
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Stains are useful indicators, since they tend to be persistent, and can often be used to trace the
flow path upstream to a source, even after the original illicit discharge has ended. By screening
outfalls on a regular basis and documenting the stains with photographs, it is possible to
compare the severity of the stains to determine if a discharge is ongoing.
Stains are classified according to the type of stain present (i.e., oil, paint, rust, etc.), as well as
their relative severity. The severity is subjectively assigned based on the extent of the staining
that was observed, ranging from slight to severe. Because of the subjective nature of this rating,
photographs are extremely helpful for documentation.
Gross Solids
The Center for Watershed Protection adopted the concept of Gross Solids in regards to illicit
discharge detections. Gross solids are materials that are larger than fine solids (silt and clay) and
coarse solids (fine sand, fine gravel, and detritus). Gross solids consist primarily of litter (human
derived trash larger than 4.75 mm), organic debris (leaves, branches, seeds, twigs and grass
clippings larger than 4.75 mm), and coarse sediments (inorganic breakdown products from soils,
pavement or building materials greater than 0.075 mm).
The type of gross solid most frequently encountered during outfall inspections appears to be
litter (garbage). These materials typically enter the storm sewer from an upstream catchbasin or
inlet. Paper, plastic and foam are frequently encountered in manholes, where they can become
trapped as they float on the surface. These materials can also travel down storm sewer pipes
and swales, ultimately discharging at the outfall.
Vegetative debris, including leaves and grass clippings, can also enter the storm sewer through
catchbasins and inlets and travel to the outfall. As with litter, an attempt is made to determine if
the vegetative debris traveled through the storm sewer or was deposited at the outfall in
another manner.
Coarse sediment is encountered less frequently than litter and vegetative debris. Most of the
sediment encountered during outfall inspections is fine sediment that travels through the storm
sewer and is deposited at the outfall. This sediment is included in the “Deposition” category of
the Physical Condition Assessment on the report, and the sediment depth is recorded. Sediment
is typically only considered a Gross Solid physical indicator parameter if it appears that the
sediment was illicitly dumped into the storm sewer through a catchbasin, inlet or manhole.
Gross solid severity is similar to the method used for floatables. A slight severity for gross solids
indicates isolated occurrences of the substance in the pool or flow. A moderate severity
indicates a broader coverage, including distinct pockets of the substance. A severe classification
typically describes total coverage of the water surface or manhole.
Observed Conditions
The presence of any physical indicators in the pipe or channel, flow, downstream pool, and
surrounding area were recorded at the time of the inspection. Certain physical indicators, such
as color and turbidity, can only be evaluated if flow or downstream pools are present. (Because
the inspection criteria for physical indicator parameters have evolved over the past several
years, some of the parameters included in the current year’s inspections may not have been
evaluated in previous years, and those parameters may appear as blank or missing data on
earlier reports.)
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The presence of one or more physical indicator parameters does not necessarily indicate that an
illicit discharge is occurring or has occurred in the past. Certain physical indicators, such as the
presence of solid waste or oil sheens in the flow, strongly suggest an illicit discharge has recently
occurred. Other indicators, such as staining of the pipe or channel, may indicate that an illicit
discharge occurred in the past, although the exact time is not known. Still other physical
indicators may have natural or non-illicit causes, and the presence of these parameters alone
should not be the grounds for assuming an illicit discharge.
Physical indicators can also be valuable aids when tracing a suspected illicit discharge upstream
to the source. Certain physical indicators – pipe and channel stains in particular – are persistent
and can be used to trace the flow well after the actual flow has stopped.
The physical indicators observed during the outfall inspections are summarized in Figure 6.
Figure 6 – Physical indicator observations
Benthic growth (green and/or brown) and flowline stains were prevalent at many of the outfalls.
These conditions are fairly common, and are not typically considered strong indicators of
recurring illicit discharges unless they are particularly severe, or occur in conjunction with other
indicators.
In 2015, 19 outfalls were classified as potential illicit discharge because of the presence of
moderate or severe gross solids in their upstream manholes. These outfalls are discussed in
more detail in the Potential Illicit Discharges section of this report. No other outfalls were
classified as potential illicit discharge solely due to physical indicators.
CHEMICAL ANALYSIS
When dry-weather flow is present at an outfall or upstream manhole, chemical indicator
parameters can provide valuable information about whether the flow is an illicit discharge, as
well as providing clues about the potential sources of the flow. Section 2.3.2.2 of the general
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permit requires that outfalls with dry-weather flow be sampled for pH, total chlorine, total
copper, total phenol and detergents for the initial screening of major outfalls, unless detergent,
ammonia, potassium and fluoride were used as alternate parameters.
Under section 2.3.3, the ongoing screening of all outfalls could be modified to include other
parameters. For the ongoing screening program, OMNNI tested for the following chemical
indicators, based on the 2015 revision to the ongoing screening program:
pH
Temperature
Conductivity
Chlorine (total and free)
Ammonia
Detergents
Flow samples were collected at all outfalls that exhibited dry-weather flow at the time of the
inspection. For partially-submerged or fully-submerged outfalls, a sample was collected from the
flow or submerged pool at the first upstream sampling location, or from the outfall pool if an
upstream location was not available. A total of 79 stormwater samples were collected and
analyzed as part of the ongoing screening process in 2015 – 9 were from flow streams, and 70
were from pools.
The indicator parameters, testing methods, and results are explained in the sections that follow.
pH
Background
The pH of a stormwater sample can be used to detect the presence of illicit substances in the
flow. Neutral water has a pH of 7.0. However, unpolluted rainwater commonly has a pH of 5.0 to
6.0, due to the conversion of carbon dioxide in the atmosphere to carbonic acid. The presence
of pollutants in the atmosphere can cause the formation of additional hydrochloric and/or nitric
acid in the rainwater, which will further lower pH. The pH of the runoff is typically raised as it
reacts with carbonates and other alkaline materials in the rocks and soil. Contact with concrete
pipes and channels also raises the pH of the runoff.
The typical pH range for stormwater runoff is from 6.0 to 9.0. Samples with a pH lower than 6.0
or higher than 9.0 would be suspect for illicit discharges. Possible sources of high or low pH
include industrial discharges and concrete truck washout.
Testing Method
During the ongoing screening program, OMNNI tested the pH of the outfall samples with a Hach
Pocket Pro+ Multi 2 Tester handheld pH/conductivity/temperature meter, which displays the pH
reading to 0.01 pH units. The probe was periodically calibrated at 4.01, 7.00 and 10.01 pH
values. The pH reading was taken in the sample bottle as soon as possible after the sample was
collected from the outfall, as the pH of the sample can change over time.
Results
The pH results for the pH samples are shown in Figure 7.
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Figure 7 – pH sample results
The pH values ranged from 7.10 to 11.66. One sample (12-1328a) was outside of the 6.0-9.0
normal range. Because the sample also had elevated ammonia and conductivity, the outfall was
classified as an obvious illicit discharge, and is discussed in more detail in the Potential Illicit
Discharges section of this report.
Temperature
Background
While not included in the list of parameters required by the general permit, the temperature of
a stormwater sample can be useful in determining if the flow is originating from an illicit source.
Because most stormwater is conveyed in underground pipes, the temperature of the flow at the
outfall is typically expected to be similar to the ground temperature which is often cooler than
the ambient temperature in summer. However, stormwater that passes through open channels
or ponds upstream of the outfall can be heated directly by the sun, and may be close to ambient
temperature or even slightly warmer. Temperature is normally only a consideration when the
runoff is significantly lower than the ground temperature or higher than the ambient
temperature, which can indicate the presence of an industrial discharge. For example, cooling
water or process water is typically significantly warmer than the ambient temperature.
Ground temperatures were typically 55 °F or warmer in summer. As a result, the “normal”
temperature range was set at 55 °F to 90 °F. Any samples outside of this range could contain
flow other than stormwater runoff.
Testing Method
During the ongoing screening program, OMNNI recorded the temperature of the outfall samples
with a Hach Pocket Pro+ Multi 2 Tester handheld pH/conductivity/temperature meter, which
displays the temperature reading to 0.1 °F. The temperature reading was taken in the sample
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bottle at the same time the pH was tested, as soon as possible after the sample was collected
from the outfall, as the temperature of the small volume of the sample container will rapidly
change.
Results
The temperature results for the samples are shown in Figure 8.
Figure 8 – Temperature sample results
The temperature values ranged from 65 to 77 °F. The samples with the highest temperatures
were collected from locations that could be influenced by solar heating, so the upper values
were not considered suspect. None of the samples exhibited abnormal temperatures, so none
of the samples were considered suspect due to temperature.
Conductivity
Background
While not included in the list of parameters required by the general permit, the conductivity of a
stormwater sample can be useful in determining if the flow is originating from an illicit source,
and identifying potential sources of the discharge. Conductivity is a measure of the ability of
water to pass an electrical current. The presence of inorganic dissolved solids (chloride, nitrate,
sodium, calcium, iron, etc.) can increase the conductivity of a water sample. Organic compounds
(oil, alcohol, sugar, etc.) are not good conductors, and therefore have relatively low
conductivities.
Conductivity in surface water is influenced by the local geology. Streams that run through
granite bedrock tend to have lower conductivity because granite is composed of more inert
materials that do not ionize when washed into the water. However, streams that run through
areas with clay soils tend to have higher conductivity because of the higher ionizing potential of
clay. Sanitary sewage can raise the conductivity due to increased levels of chloride, phosphate
and nitrate.
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Conductivity is typically measured in siemens, with a typical unit of microsiemens per
centimeter (µS/cm). Distilled water has a conductivity in the range of 0.5 to 3 µS/cm, while
rivers typically have conductivities ranging from 50 to 1500 µS/cm. Conductivity readings above
2000 µS/cm can sometimes be associated with industrial discharges.1
Conductivity values under 2000 µS/cm would be considered to be normal. Samples with
conductivities over 2000 µS/cm would be identified as suspicious, but the discharge would not
be considered a potential illicit discharge unless other indicator parameters (physical or
chemical) were observed.
Testing Method
During the ongoing screening program, OMNNI recorded the conductivity of the outfall samples
with a Hach Pocket Pro+ Multi 2 Tester handheld pH/conductivity/temperature meter, which
displays the conductivity reading to 0.01 µS/cm. The conductivity reading was taken in the
sample bottle as soon as possible after the sample was collected from the outfall, as the
conductivity of the sample can change with temperature.
Results
The conductivity results for the samples are shown in Figure 9.
Figure 9 – Conductivity sample results
The conductivity values ranged from 328 to 2,470 µS/cm. Two samples exceeded the 2,000
µS/cm action limit. Based on other factors, those outfalls may or may not have been classified as
potential illicit discharges. The illicit discharge potential of the outfalls with elevated
conductivities are summarized in Table 1.
1 USEPA: Water-Monitoring & Assessment – Conductivity (http://water.epa.gov/type/rsl/monitoring/vms59.cfm)
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Table 1 – IDDE potential of outfalls with elevated conductivities
Outfall
Conductivity
(µS/cm) IDDE Potential Reason
12-1328a 2,470 Obvious
Elevated ammonia, pH and conductivity;
abnormal chlorine result.
13-68 US1 2,100 Unlikely
No other significant chemical or physical
indicators identified.
The outfalls that were considered potential or obvious illicit discharges are discussed in more
detail in the Potential Illicit Discharges section of this report.
Chlorine
Background
The presence of chlorine in a stormwater sample usually demonstrates the presence of
substances other than stormwater runoff. Chlorine is typically an indicator of either potable
water (from a chlorinated municipal water supply) or an industrial discharge. It can also be
caused by leaking or draining swimming pools. However, chlorine can also be present in non-
illicit discharges (as defined by the general permit and the City’s illicit discharge ordinance),
including residential car washing, lawn irrigation, hydrant flushing, water main breaks, and
industrial discharges regulated under a WPDES permit. Therefore, the presence of chlorine in a
sample indicates the presence of a non-stormwater source; however, the source should be
identified to determine if it is an illicit discharge.
Dissolved chlorine is measured using three different values: free chlorine, combined chlorine,
and total chlorine. Free chlorine represents the “unbound” chlorine molecules in solution, which
are the most effective for disinfecting. Combined chlorine represents the chlorine molecules
that are bound to other organic molecules, such as chloramines, which are also commonly used
in drinking water disinfection. Total chlorine represents the sum of the free chlorine and the
combined chlorine. The general permit requires sampling for total chlorine.
Action levels were established by OMNNI for most chemical indicators. A test result that
exceeds the action level warrants follow-up investigation. In general, the action level for total
chlorine is set at 0 mg/L. Any detection of chlorine indicates the presence something other than
stormwater in the sample. Depending on the source, it may or may not be an illicit discharge.
Testing Method
During the ongoing screening program, OMNNI tested the outfall samples for total chlorine and
free chlorine using Hach Free & Total Chlorine Test Strips, 0-10 mg/L. These test strips had result
steps of 0, 0.5, 1, 2, 4 and 10 mg/L. The chlorine tests were taken in the sample bottle as soon as
possible after the sample was collected from the outfall, as chlorine can dissipate over time.
Results
None of the samples tested positive for free chlorine or total chlorine, so none of the samples
were considered suspect due to chlorine.
One sample (12-1328a US1) produced an abnormal result on the chlorine test strips. Instead of
turning a shade of purple, the test strip turned yellow. This behavior typically results when
exposed to certain chemicals other than chlorine. This sample also had elevated ammonia, pH
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and conductivity, which caused it to be classified as an obvious illicit discharge, regardless of the
chlorine result.
Ammonia
Background
While not included on the list of required parameters in the general permit, ammonia is a
valuable test parameter to identify potential illicit discharges. Besides being present in industrial
discharges, ammonia can also be an indicator of wastewater or washwater discharges, which are
often indicators of sanitary sewer cross-connections. When tested along with potassium, it is
possible to use the ratio of ammonia to potassium to distinguish between wastewater and
washwater. However, since both typically originate from sanitary sewer, this determination is
not usually required to identify an illicit discharge.
It should be noted that there are also several natural sources of ammonia which do not
constitute an illicit discharge. Waste from pets and wildlife can cause ammonia in the runoff,
particularly if wildlife frequently inhabit the storm sewer pipes and manholes. Storm sewers
connected to stagnant water or wetlands frequently have elevated ammonia levels due to
microbial decay of plant and animal proteins. In addition, ammonia may be present in industrial
discharges with a WPDES permit. Ammonia is also sometimes present in HVAC condensate,
which is allowed to be discharged under the MS4 general permit.
Because of the natural sources of ammonia, the action level for ammonia detections was set at
greater than 1 ppm. Samples with ammonia concentrations of 1 ppm or lower were not
investigated unless additional chemical or physical indicator parameters were present.
Testing Method
During the ongoing screening program, OMNNI tested the outfall samples for ammonia using
Hach Ammonia (Nitrogen) Test Strips, 0-6.0 ppm. These test strips had result steps of 0, 0.25,
0.5, 1, 3, and 6 ppm NH3-N. The ammonia tests were conducted in a separate vial of stormwater
taken from the sample bottle as soon as possible after the sample was collected from the
outfall, as the ammonia concentration can dissipate over time.
Results
The ammonia results for the samples are shown in Figure 10.
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Figure 10 – Ammonia sample results
The ammonia values ranged from 0 to 3 ppm. Five samples were at or above the 1 ppm action
limit. Based on other factors, those outfalls may or may not have been classified as potential
illicit discharges. The illicit discharge potential of the outfalls with ammonia detections are
summarized in Table 2.
Table 2 – IDDE potential of outfalls with ammonia detections
Outfall
Ammonia
(ppm) IDDE Potential Reason
03-81 US1 1 Unlikely
Previous petroleum sheen and odor in
manhole; not observed in 2015.
03-381 US1 1 Potential
Floating gross solids (litter) in manhole; no
prior ammonia detections.
12-890 US1 3 Unlikely
Ammonia likely from stagnant pool in manhole
with decaying vegetation. No flow observed in
upstream manhole.
12-1328a US1 1 Obvious
Elevated pH, conductivity and ammonia, with
abnormal chlorine test results.
16-1508 US1 3 Potential Past ammonia detections.
The outfalls that were considered potential or obvious illicit discharges are discussed in more
detail in the Potential Illicit Discharges section of this report.
Detergents
Background
The presence of detergents in the outfall sample is usually an indication of the presence of
wastewater and/or washwater. This is typically the result of a sanitary sewer cross connection
or washwater dumped in or near a stormwater inlet. However, detergent can also be present in
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non-illicit discharges (as defined by the general permit and the municipality’s illicit discharge
ordinance), including runoff from residential car washing. Therefore, the presence of detergent
in a sample indicates the presence of a non-stormwater source; however, the source should be
identified to determine if it is an illicit discharge.
There are four main classes of detergents:
Anionic detergents (negatively charged) – Common in dishwasher detergents, liquid and
powdered laundry detergents, carwash detergents, and shampoo. Anionic detergents
have excellent cleaning properties and high sudsing potential.
Cationic detergents (positively charged) – Used for germicides, fabric softeners and
emulsifiers. Cationic detergents have poor cleaning properties by themselves, but can
help anionic detergents be more effective.
Nonionic detergents (ionically inert) – Common in hand dishwashing liquids, household
cleaners, and laundry detergents (especially in combination with anionic detergents).
Nonionic detergents are excellent grease removers.
Amphoteric detergents (negatively or positively charged, based on pH) – Found in
shampoo and cosmetic products due to their mild chemical nature. Amphoteric
detergents are also found in hand dishwashing liquids due to their high sudsing
potential.
Unfortunately, due to the diverse classes of detergents, there is no single test to detect the
presence of all detergents. The most common test – the Methylene Blue Active Substances
(MBAS) test – is only effective in identifying the presence of anionic detergents.
The general permit requires sampling for detergents. In general the action level for detergents is
set at 0 mg/L. Any detection of detergent indicates the presence something other than
stormwater in the sample. Depending on the source, it may or may not be an illicit discharge.
Testing Method
During the ongoing screening program, OMNNI tested the outfall samples for detergents using
MBAS method with the equipment and reagents provided in the Hach Stormwater Test Kit. This
is a colorimetric test method in which the intensity of the color in the reagent can be used to
estimate the anionic detergent concentration. In most cases, a clear result indicates no
detergent in the sample, and a blue tint indicated a positive detection of detergent.
In some samples with high turbidity, the MBAS test method results in foam or bubbles in the
solution. These bubbles have no impact on the overall test result, and if the bubbles and
solution are clear, the result is a negative test for detergent.
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No Detergent Present Detergent Present Turbidity Bubbles,
No Detergent Present
Figure 11 – Typical MBAS Detergent Test Results
Because of the equipment and reagents (including chloroform) used in the MBAS test, the
detergent test was conducted in the office at the end of the day. OMNNI’s experience with
samples that have tested positive for detergent show that little dissipation occurs within 48
hours of testing, so same-day testing for detergents was an acceptable approach.
Results
None of the samples tested positive for detergents, so none of the samples were considered
suspect due to detergent.
POTENTIAL ILLICIT DISCHARGES
After examining the presence of physical indicators at each outfall and any chemical indicators
present in the stormwater samples, each outfall was assigned one of the following
classifications, in order of increasing likelihood of the presence of current or past illicit
discharges:
Unlikely – no significant physical or chemical evidence of current or past illicit discharge
Potential – presence of physical and/or chemical indicators, but no strong visible
evidence
Obvious – visible and/or strong chemical evidence of current or past illicit discharge
Of the 98 inspected outfalls, 77 were classified as unlikely, 20 were classified as potential, and
one was classified as “obvious.” The outfalls that were classified as anything other than
“unlikely” are summarized in the table below and discussed in more detail in the following
sections. A map showing the locations of these outfalls is included in Appendix C.
Table 3 – Outfalls with elevated illicit discharge classifications
Outfall Classification Reason
01-318 Potential Persistent gross solids in upstream manhole.
01-520 Potential Persistent gross solids in upstream manhole (also present in 2009,
2010, 2011, 2012, 2013 and 2014).
01-642 Potential Persistent gross solids in upstream manhole.
02-309 Potential Persistent gross solids in upstream manhole (also present in 2011).
02-357 Potential Persistent gross solids in upstream manhole (also present in 2011,
2012 and 2014).
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Outfall Classification Reason
03-22 Potential Persistent gross solids in upstream manhole (also present in 2009,
2010, 2011, 2012, 2013 and 2014).
03-35 Potential Persistent gross solids in upstream manhole (also present in 2009,
2010, 2011, 2012 and 2013).
03-173 Potential Persistent gross solids in upstream manhole (also present in 2010,
2011 and 2014).
03-381 Potential Persistent gross solids in upstream manhole (also present in 2010,
2011 and 2014).
05-14 Potential Persistent gross solids in upstream manhole.
06-52 Potential Persistent gross solids in upstream manhole (also present in 2010,
2011 and 2014).
08-284 Potential Persistent gross solids in upstream manhole (also present in 2010,
2011 and 2014).
08-347 Potential Persistent gross solids in upstream manhole (also present in 2010,
2011 and 2014).
08-364 Potential Persistent gross solids in upstream manhole (also present in 2011).
11-376 Potential Persistent gross solids in upstream manhole (also present in 2009,
2011 and 2014).
11-512 Potential Persistent gross solids in upstream manhole (also present in 2011,
2012 and 2014).
12-569 Potential Persistent gross solids in upstream manhole (also present in 2010
and 2014).
16-142 Potential Persistent gross solids in upstream manhole (also present in 2010,
2011, 2012 and 2014).
16-533 Potential Persistent gross solids in upstream manhole (also present in 2010,
2011 and 2014).
16-1508 Potential Ammonia in upstream manhole (also present in 2013 and 2014).
12-1328a Obvious Elevated pH, conductivity and ammonia traced to upstream
property.
A chart showing the number of outfalls inspected over the past seven years (starting with the
initial screening in 2009) and the number of potential or obvious illicit discharges is shown in
Figure 12.
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Figure 12 – Illicit discharge potential of inspected outfalls
Upstream Manholes with Significant Floatable Debris
During the 2015 ongoing screening program, 19 upstream manholes contained significant
amounts of floatable debris (gross solids), including plastic bottles, foam packaging, and other
solid waste, and were classified as potential illicit discharges. This effect was most pronounced
at manholes upstream of a fully-submerged outfall, where the storm sewer pipes within the
manhole were also fully-submerged. In these cases, any floatable debris traveling along the top
of the storm sewer pipe will enter the manhole, and will remain trapped on the surface of the
manhole pool, as they are not able to escape through the submerged outlet pipe. In these cases,
the submerged manhole acts as a trap for much of the floatable debris.
While some may not consider gross solids a true illicit discharge, it does meet the definition of
an illicit discharge, since it is a substance present in the discharge that is not comprised entirely
of stormwater. In most cases, there will be one or more access points which allow the debris to
enter the MS4. Because of this, the presence of significant floatable debris in upstream
manholes caused the illicit discharge potential of the outfall to be raised to “potential.”
Upstream manholes with isolated solid waste or debris (generally three or fewer pieces) are not
included in this list, and were not considered potential illicit discharges.
Note that in some cases, sediment and/or vegetation falls into the manhole when the manhole
cover is removed, and those materials also appear in the photos. The severity of the floatable
debris is based on the presence of the original debris and solid waste.
Upstream manholes that were classified as “potential” sources of illicit discharge due to
significant floatable debris during the 2009-2014 screening programs are shown in the table in
Appendix D-1. The 2015 screening results are also shown.
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The outfalls with continuing observations of significant floatable debris were classified as
priority outfalls in the revised ongoing screening program. This designation will cause them to
be screened annually. These manholes should be cleaned several months prior to the scheduled
outfall screening. By doing this, it will be possible to determine if the debris is from a prior
discharge, or if the problem is ongoing. If it is determined that it is an ongoing problem,
upstream inlets, especially those located near dumpsters or other solid waste storage areas,
should be closely examined in an attempt to locate the source of the discharge. These areas
could then be targeted for public education campaigns.
A map showing the locations of the manholes with floatable debris is included in Appendix D-1.
Outfall 16-1508 (N. Westfield Street)
Outfall 16-1508 consists of a 54-inch reinforced concrete pipe that discharges to Sawyer Creek
from the south. The outfall is located approximately 60 feet east of the Westfield Street bridge.
The outfall was previously named 16-487 before it was reconstructed in 2011.
Figure 13 – Outfall 16-1508 (9/28/2015)
The outfall was initially screened on May 30, 2012 as part of the gross solids prescreening.
Because the outfall was partially submerged, the upstream manhole was screened. A sample
was collected from the submerged pool in the manhole, and the sample had an ammonia
concentration of 1 ppm. The Illicit Discharge Coordinator was informed of the detection on May
30, 2012.
Samples were collected from the upstream manholes and inlets during subsequent outfall
screening events. Ammonia was typically detected in manholes 16-1508 and 16-1504. However,
at the next upstream manhole (16-430), no ammonia was detected. It appeared that the
ammonia was being introduced between manholes 16-460 and 16-1504.
The land use in this area consists of multifamily residential property on the west side of
Westfield Street, and Red Arrow Park on the east side of the street. A building housing the
restrooms for the park is located immediately to the east of this segment. Based on the elevated
ammonia levels in the segment adjacent to the park restroom building, this was identified as a
potential source. Additionally, Red Arrow Park is a former landfill site, and infiltration of
groundwater from the site could be another potential source.
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Figure 14 – Park restroom building upstream of 16-1504 (2013)
During the tracking, several sanitary sewer manholes were observed in the impacted area. The
City may want to televise the storm sewer and/or sanitary sewer lines to determine if there are
any leaks or improper connections.
The ammonia concentrations of the samples collected from the first upstream manhole
(16-1508) are summarized in the table below:
Date Ammonia (ppm)
5/30/2012 1
6/6/2012 0
9/27/2012 3
9/5/2013 0.5
10/7/2014 3
9/28/2015 3
Because of the continued presence of ammonia in the stormwater samples, this outfall was
classified as a priority outfall in the revised Ongoing Screening Program. This will result in annual
screenings for the outfall, unless the source of the ammonia can be identified as a non-illicit
source. OMNNI recommends that the City televise this segment of storm sewer to investigate
whether the source of the ammonia is the former landfill, park restrooms, nearby sanitary
sewer, or another source.
Additional maps and information related to this investigation are included in Appendix D-2.
Outfall 12-1328a (Nolte Avenue detention basin)
Outfall 12-1328a consists of a 42-inch reinforced concrete pipe that discharges the northeast
corner of the detention basin located between W. Snell Road and Algoma Blvd. This segment of
storm sewer was reconstructed in 2014 as part of the I-41 /Algoma Blvd (USH 45) overpass. This
outfall replaces former outfall 12-1328, which was located at the west end of Fernau Avenue.
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Figure 15 – Outfall 12-1328a (9/23/2015)
The outfall was screened on September 23, 2015. During the screening, a trickle discharge was
observed, with a white, silty substance. The silt was observed inside the pipe, on the apron, and
on the riprap downstream of the apron. The sample that was collected from the flow had the
following chemical indicator parameters outside of normal range:
Ammonia: 1 ppm
pH: 11.66
Conductivity: 2,470 µS/cm
In addition, the sample reacted with the chlorine test strips to turn yellow, rather than their
typical graduated shades of purple. This typically indicates that another chemical is present in
the sample that interferes with the test strips.
The Illicit Discharge Coordinator was notified of the discharge on September 25, 2015. The
construction plans for the updated storm sewer were requested to aid with the tracking of the
discharge.
OMNNI traced the discharge on September 28, 2015. A sample from the outfall had a pH of
9.73. Upstream tracing was conducted primarily using visible flow and white staining, and
supplemented with pH samples. The discharge was traced to a 6-inch pipe that was tapped into
a curb inlet (582A) near the intersection of Walter Street and Fernau Avenue. The pipe appeared
to be coming from the Carew concrete plant. A sample collected from this pipe had a pH of
12.28, and white staining was present in the pipe, confirming that it was the source of the
discharge.
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Figure 16 – Inlet 582A (9/28/2015)
Figure 17 – Pipe discharging into inlet 582A (9/28/2015)
The Illicit Discharge Coordinator was notified of this pipe on September 28, 2015, and OMNNI
and City personnel met with a representative of Carew Concrete on September 29, 2015 to
attempt to identify the source of the discharge. No upstream inlets or catchbasins were located
on the property. City personnel inserted a temporary plug in the end of the pipe to stop the
discharge. If no adverse impacts are seen upstream, the City will permanently plug the pipe to
eliminate the discharge.
OMNNI recommends that the City continue to investigate the history of this pipe and confirm
that it can be plugged. Because of the industrial nature of the drainage basin and the identified
illicit discharge, outfall 12-1328a will be classified as a priority outfall, and will be screened
annually.
Additional maps and information related to this investigation are included in Appendix D-3.
OUTFALL CONDITION ASSESSMENTS
While not required for the illicit discharge field screening, OMNNI inspectors noted the presence
of any structural damage, significant deposition or erosion, or graffiti at the outfalls. This
information can be passed along to the appropriate personnel for any necessary action.
January 8, 2016 29 2015 Ongoing Screening Summary Report
City of Oshkosh
Damage
Eight outfalls showed signs of damage that may require attention in the near future. Observed
damage included corrosion on corrugated metal pipes, pipe joint displacement, and settling
around pipes.
The outfall damage that was observed during the ongoing screening program is summarized in
Table 4.
Table 4 – Outfalls with damage
Outfall Severity Description
03-22 Severe Significant sinking above suspected pipe location.
12-890 Moderate Corrosion of corrugated metal pipe below flowline.
12-972 Minor End of PVC pipe broken.
13-1106 Minor Corrugated metal pipe corroded and slightly crushed at end.
13-1283 Minor Corrosion of corrugated metal pipe.
13-68 US1 Minor Eroded concrete flowline in manhole.
14-999 Moderate 4” joint displacement at end section of pipe.
Wash41_01 US1 Minor Corrosion of corrugated metal pipe.
The outfall damage is shown in the photos that follow. The locations of the damaged outfalls are
shown on the map in Appendix C.
Figure 18 – Significant settling at outfall 03-22 (severe
damage)
Figure 19 – Corroded metal pipe at outfall 12-890 (moderate
damage)
January 8, 2016 30 2015 Ongoing Screening Summary Report
City of Oshkosh
Figure 20 – Broken PVC pipe at outfall 12-972 (minor damage)
Figure 21 – Corrosion and crushed pipe at outfall 13-1106
(minor damage)
Figure 22 – Corroded metal pipe at outfall 13 -1283 (minor
damage)
Figure 23 – Eroded flowline in manhole 13-68 US1 (minor
damage)
Figure 24 – 4” joint displacement at outfall 14-999 (moderate
damage)
Figure 25 – Corroded metal pipe at outfall Wash41_01 US1
(minor damage)
January 8, 2016 31 2015 Ongoing Screening Summary Report
City of Oshkosh
Deposition
A total of 15 outfalls showed minor, moderate or severe deposition at the end of the outfall pipe
or channel, or inside the upstream screening location. As deposition increases, flow may
become restricted in the pipe or downstream channel. Outfalls with moderate or severe
deposition may need to undergo maintenance to remove the deposited sediment and debris
and maintain proper flow.
The outfall deposition that was observed during the ongoing screening program is summarized
in Table 5.
Table 5 – Outfalls with deposition
Outfall Severity Description
01-380 US1 Moderate 14” of sediment in manhole.
02-105 Moderate 12” of rocks and sediment at end of pipe.
03-35 US1 Minor 1” of sediment in manhole.
12-1795 US1 Minor 1” of gravel in manhole.
12-2034 Moderate 6” of sediment on apron.
13-1106 Minor 2” of sediment in end of pipe.
13-1283 Moderate 18” of sediment in end of pipe.
13-1758 Moderate 8” of sediment on apron.
13-1766 Severe 18” of sediment at end of pipe.
13-1769 Severe 4” of sediment on apron.
13-1769 US1 Minor 1” of gravel in manhole.
14-1514 Moderate 10” of stone in pipe.
15-146 US1 Minor 1” of gravel in manhole.
15-1093 Moderate 6” of sediment at end of pipe.
15-2477 Minor 7” of sediment at end of pipe.
The outfall deposition is shown in the photos that follow. The locations of the outfalls with
deposition are shown on the map in Appendix C.
Figure 26 – Moderate deposition in manhole 01-380 US1
Figure 27 – Moderate deposition at outfall 02-105
January 8, 2016 32 2015 Ongoing Screening Summary Report
City of Oshkosh
Figure 28 – Minor deposition in manhole 03-35 US1
Figure 29 – Minor deposition in manhole 12-1795 US1
Figure 30 – Moderate deposition at outfall 12-2034
Figure 31 – Minor deposition at outfall 13-1106
Figure 32 – Moderate deposition at outfall 13-1283
Figure 33 – Moderate deposition at outfall 13-1758
January 8, 2016 33 2015 Ongoing Screening Summary Report
City of Oshkosh
Figure 34 – Severe deposition at outfall 13-1766
Figure 35 – Severe deposition at outfall 13-1769
Figure 36 – Minor deposition in manhole 13-1769 US1
Figure 37 – Moderate deposition at outfall 14-1514
Figure 38 – Minor deposition in manhole 15-146 US1
Figure 39 – Moderate deposition at outfall 15-1093
January 8, 2016 34 2015 Ongoing Screening Summary Report
City of Oshkosh
Figure 40 – Minor deposition at outfall 15-2477
Erosion
No erosion was observed near any of the outfalls that were screened under the 2015 screening
program.
Graffiti
Graffiti was observed in or around one outfall. The graffiti was not severe, but should probably
be monitored to make sure that it does not become more severe.
The graffiti that was observed during the ongoing screening program is summarized in Table 6.
Table 6 – Outfalls with graffiti
Outfall Severity Description
12-569 Moderate Graffiti on bridge abutment adjacent to outfall.
The graffiti is shown in the photos that follow. The locations of the outfalls with graffiti are
shown on the map in Appendix C.
Figure 41 – Graffiti near outfall 12-569
January 8, 2016 35 2015 Ongoing Screening Summary Report
City of Oshkosh
2016 ONGOING SCREENING PROGRAM
The 2015 outfall screening was conducted using the revised Ongoing Screening Program as a
guide. All of the outfalls that had been identified as priority outfalls had been screened, along
with a subset of the non-priority outfalls. Because some of the outfalls in the program had not
been previously screened, this initial screening was used to verify the priority status of the
outfalls. Based on the field observations, the overall outfall classification was revised to:
48 priority outfalls
80 non-priority major outfalls
297 non-priority non-major outfalls
Using the screening frequency specified in the Ongoing Screening Program, the following
number of outfalls are recommended to be screened for the 2016 outfall screening program:
48 priority outfalls
16 non-priority major outfalls
30 non-priority non-major outfalls
In addition, the six non-priority outfalls that had potential or obvious illicit discharges will also
be rescreened, bringing the 2016 total to 100 outfalls.
The outfalls that are proposed to be screened under the 2016 outfall screening program are
included in Appendix E.
CONCLUSION
OMNNI assisted the City of Oshkosh with the 2015 ongoing screening of the MS4 outfalls, as
required by the MS4 permit. A total of 98 outfalls were screened, along with upstream
monitoring locations when necessary. Of those 98 outfalls, 77 exhibited unlikely potential of
past illicit discharges, 20 were classified as “potential,” and one was classified as “obvious.”
These results are summarized in Figure 42:
January 8, 2016 36 2015 Ongoing Screening Summary Report
City of Oshkosh
Figure 42 – Illicit discharge potential
Those outfalls classified as “potential” or “obvious” should be given special attention in the
ongoing screening program.
The ongoing screening also identified 8 outfalls with structural damage, 15 with deposition, and
1 with graffiti. While none of these posed an immediate danger, the City will likely want to
address these issues as part of the regular storm sewer system maintenance.
Minor changes will be made to the 2015 revision to the Ongoing Screening Program based on
the information collected during the outfall screening. After the Ongoing Screening Program has
been updated, it should be submitted to the WDNR, and subsequent outfall screening programs
should follow the structure of this program.
January 8, 2016 37 2015 Ongoing Screening Summary Report
City of Oshkosh
STANDARD OF CARE
The conclusions presented in this report were arrived at using generally accepted engineering
practices. The conclusions presented herein represent our professional opinions, based on data
collected at the time of the inspections, at the specific inspection locations discussed in this
report. Conditions at other locations in the City or at different times may be different than
described in this report. The scope of this report is limited to the specific project and the
inspection locations described herein.
Prepared By:
Jason Weis, P.E.
Project Engineer
Reviewed By: Brian D. Wayner, P.E.
Project Manager
Appendix A
MS4 Outfall Maps
A-1 MS4 Outfall Map
A-2 2015 Outfall Inspection Map
C:\SyncFolders\IDDE_GIS\MS4Map_11x17_Oshkosh.mxd
PROJECT NO.N2029C15
FIGURE NO.A-1
SCALE:1 " = 3,620 'Project Manager:BDWProject Engineer:JCWDrawn By:JCWChecked By:BDW
2015 IDDE ONGOING SCREENING PROGRAM
CITY OF OSHKOSHWINNEBAGO COUNTY, WISCONSIN
MS4 OUTFALL MAP
ONE SYSTEMS DRIVEAPPLETON, WI 54914 PHONE (920) 735-6900FAX (920) 830-6100 Date:1/6/2016
Legend
Municipal BoundaryOutfalls
Major Outfall (95)
Minor Outfall (237)
Supplemental Outfall (93)
0 10.5 Miles
C:\SyncFolders\IDDE_GIS\InspectedOutfalls_Oshkosh.mxd
PROJECT NO.N2029C15
FIGURE NO.A-2
SCALE:1 " = 5,047 'Project Manager:BDWProject Engineer:JCWDrawn By:JCWChecked By:BDW
2015 IDDE ONGOING SCREENING PROGRAM
CITY OF OSHKOSHWINNEBAGO COUNTY, WISCONSIN
2015 OUTFALL INSPECTION MAP
ONE SYSTEMS DRIVEAPPLETON, WI 54914 PHONE (920) 735-6900FAX (920) 830-6100 Date:1/6/2016
Weather Station
Screened Outfalls
Priority (48)
Non-Priority Major (16)
Non-Priority Non-Major (34)
Appendix B
Outfall Inspection Reports
Appendix C
Outfall Condition Summary Maps
C-1 Outfalls with Potential Illicit Discharges
C-2 Outfalls with Damage
C-3 Outfalls with Deposition
C-4 Outfalls with Erosion
C-5 Outfalls with Graffiti
C:\SyncFolders\IDDE_GIS\IDDEpot_Oshkosh.mxd
PROJECT NO.N2029C15
FIGURE NO.C-1
SCALE:1 " = 5,047 'Project Manager:BDWProject Engineer:JCWDrawn By:JCWChecked By:BDW
2015 IDDE ONGOING SCREENING PROGRAM
CITY OF OSHKOSHWINNEBAGO COUNTY, WISCONSIN
OUTFALLS WITH POTENTIALILLICIT DISCHARGESONE SYSTEMS DRIVEAPPLETON, WI 54914 PHONE (920) 735-6900FAX (920) 830-6100 Date:1/6/2016
Illicit Discharge Potential
Potential
Obvious
C:\SyncFolders\IDDE_GIS\Cond_Damage_Oshkosh.mxd
PROJECT NO.N2029C15
FIGURE NO.C-2
SCALE:1 " = 7,000 'Project Manager:BDWProject Engineer:JCWDrawn By:JCWChecked By:BDW
2015 IDDE ONGOING SCREENING PROGRAM
CITY OF OSHKOSHWINNEBAGO COUNTY, WISCONSIN
OUTFALLS WITH DAMAGE
ONE SYSTEMS DRIVEAPPLETON, WI 54914 PHONE (920) 735-6900FAX (920) 830-6100 Date:1/6/2016
Damage Severity
Minor (5)
Moderate (2)
Severe (1)
C:\SyncFolders\IDDE_GIS\Cond_Deposition_Oshkosh.mxd
PROJECT NO.N2029C15
FIGURE NO.C-3
SCALE:1 " = 7,000 'Project Manager:BDWProject Engineer:JCWDrawn By:JCWChecked By:BDW
2015 IDDE ONGOING SCREENING PROGRAM
CITY OF OSHKOSHWINNEBAGO COUNTY, WISCONSIN
OUTFALLS WITH DEPOSITION
ONE SYSTEMS DRIVEAPPLETON, WI 54914 PHONE (920) 735-6900FAX (920) 830-6100 Date:1/6/2016
Deposition Severity
Minor (6)
Moderate (7)
Severe (2)
C:\SyncFolders\IDDE_GIS\Cond_Erosion_Oshkosh.mxd
PROJECT NO.N2029C15
FIGURE NO.C-4
SCALE:1 " = 7,000 'Project Manager:BDWProject Engineer:JCWDrawn By:JCWChecked By:BDW
2015 IDDE ONGOING SCREENING PROGRAM
CITY OF OSHKOSHWINNEBAGO COUNTY, WISCONSIN
OUTFALLS WITH EROSION
ONE SYSTEMS DRIVEAPPLETON, WI 54914 PHONE (920) 735-6900FAX (920) 830-6100 Date:1/6/2016
Erosion Severity
Minor (0)
Moderate (0)
Severe (0)
No Erosion Observedat Screened Outfalls
C:\SyncFolders\IDDE_GIS\Cond_Graffiti_Oshkosh.mxd
PROJECT NO.N2029C15
FIGURE NO.C-5
SCALE:1 " = 7,000 'Project Manager:BDWProject Engineer:JCWDrawn By:JCWChecked By:BDW
2015 IDDE ONGOING SCREENING PROGRAM
CITY OF OSHKOSHWINNEBAGO COUNTY, WISCONSIN
OUTFALLS WITH GRAFFITI
ONE SYSTEMS DRIVEAPPLETON, WI 54914 PHONE (920) 735-6900FAX (920) 830-6100 Date:1/6/2016
Graffiti Severity
Minor (0)
Moderate (1)
Severe (0)
Appendix D
Illicit Discharge Investigation Reports
D-1 Upstream Manholes with Significant Floatable Debris
D-2 16-1508 (N. Westfield Street) Investigation
D-3 12-1328a (Nolte Avenue Detention Basin) Investigation
APPENDIX D-1
Upstream Manholes with Significant Floatable Debris
Table 1 - History of manholes with significant gross solids
Manhole
(City ID) 2009 Initial Screening
(September 2009)
2010 Ongoing
Screening
(October 2010)
2011 Manhole
Prescreening
(May 2011)
2011 Ongoing
Screening
(October 2011)
2012 Ongoing
Screening
(June 2012)
2012 Repeat
Screening
(September 2012)
2013 Ongoing
Screening
(July 2013)
2014 Ongoing
Screening
(July 2013)
2015 Ongoing
Screening
(September 2015)
2015 IDDE Potential
01-132 US1
(01-132)
Not screened due to
traffic
Not screened due to
traffic
Not screened due to
traffic
Not screened due to
traffic N/A
01-520 US1
(01-520)
Potential
02-357 US1
(02-357)
Potential
03-173 US2
(03-170)
Potential
03-22 US1
(03-22)
Potential
03-35 US1
(03-35)
Potential
Manhole
(City ID) 2009 Initial Screening
(September 2009)
2010 Ongoing
Screening
(October 2010)
2011 Manhole
Prescreening
(May 2011)
2011 Ongoing
Screening
(October 2011)
2012 Ongoing
Screening
(June 2012)
2012 Repeat
Screening
(September 2012)
2013 Ongoing
Screening
(July 2013)
2014 Ongoing
Screening
(July 2013)
2015 Ongoing
Screening
(September 2015)
2015 IDDE Potential
03-381 US1
(03-381)
Potential
03-81 US1
(03-81)
Unlikely
05-264 US1
(05-264)
06-1694 US1
06-221 US1
(06-221)
06-52 US1
(06-52)
Potential
Manhole
(City ID) 2009 Initial Screening
(September 2009)
2010 Ongoing
Screening
(October 2010)
2011 Manhole
Prescreening
(May 2011)
2011 Ongoing
Screening
(October 2011)
2012 Ongoing
Screening
(June 2012)
2012 Repeat
Screening
(September 2012)
2013 Ongoing
Screening
(July 2013)
2014 Ongoing
Screening
(July 2013)
2015 Ongoing
Screening
(September 2015)
2015 IDDE Potential
06-560 US1
(06-560)
(outfall removed and
replaced with outfall
06-2241)
06-829 US1
(06-831)
08-284 US1
(08-284)
Potential
08-347 US1
(08-347)
Potential
09-101c US1
(09-47)
Not screened due to
traffic
11-376 US1
(11-376)
Potential
Manhole
(City ID) 2009 Initial Screening
(September 2009)
2010 Ongoing
Screening
(October 2010)
2011 Manhole
Prescreening
(May 2011)
2011 Ongoing
Screening
(October 2011)
2012 Ongoing
Screening
(June 2012)
2012 Repeat
Screening
(September 2012)
2013 Ongoing
Screening
(July 2013)
2014 Ongoing
Screening
(July 2013)
2015 Ongoing
Screening
(September 2015)
2015 IDDE Potential
11-465 US1
(11-465)
(outfall removed and
replaced with pump
station/outfall
11-465a)
11-512 US1
(11-512)
Potential
12-569 US1
(12-569)
Potential
12-576 US1
(12-576)
Unlikely
14-1075 US1
(14-1075)
16-142 US1
Potential
Manhole
(City ID) 2009 Initial Screening
(September 2009)
2010 Ongoing
Screening
(October 2010)
2011 Manhole
Prescreening
(May 2011)
2011 Ongoing
Screening
(October 2011)
2012 Ongoing
Screening
(June 2012)
2012 Repeat
Screening
(September 2012)
2013 Ongoing
Screening
(July 2013)
2014 Ongoing
Screening
(July 2013)
2015 Ongoing
Screening
(September 2015)
2015 IDDE Potential
16-201 US1
16-396 US1
(16-396)
(Behind locked fence
– manhole not
screened)
16-436 US1
(16-436)
(Behind locked fence
– manhole not
screened)
16-463 US1
16-533 US1
(16-533)
Potential
16-551 US1
(16-551)
C:\SyncFolders\IDDE_GIS\Floatables_Oshkosh.mxd
PROJECT NO.N2029D15
FIGURE NO.D-1
SCALE:1 " = 5,047 'Project Manager:BDWProject Engineer:JCWDrawn By:JCWChecked By:BDW
2015 IDDE ONGOING SCREENING PROGRAM
CITY OF OSHKOSHWINNEBAGO COUNTY, WISCONSIN
MANHOLES WITH FLOATABLEGROSS SOLIDSONE SYSTEMS DRIVEAPPLETON, WI 54914 PHONE (920) 735-6900FAX (920) 830-6100 Date:1/6/2016
Gross Solids Severity
Minor
Moderate
Severe
APPENDIX D-2
16-1508 (N. Westfield Street) Investigation
1
Jason Weis
From:Jason Weis
Sent:Friday, October 10, 2014 11:31 AM
To:James Rabe (jrabe@ci.oshkosh.wi.us)
Cc:Brian Wayner
Subject:2014 outfall screening summary
Attachments:16-1508.pdf
James:
I was able to screen the outfalls that were included in the 2014 screening program on 10/7 and 10/9. I notified you
about the potential petroleum at outfall 03‐81 on Thursday, since it seemed like a new development, or at least an
increase in severity. Below are the other items that I encountered, which consisted of more of an ongoing nature:
Outfall 16‐1508 (N Westfield Dr / Red Arrow Park) had an ammonia concentration of 1‐3 mg/L in the upstream
manhole, similar to 2012. I did some quick tracking upstream, and as in 2012, there was no ammonia at
manhole/inlet 16‐430 (upstream of park restroom), but 3 ppm at inlet/manhole 16‐1504 (just downstream of
the restroom). The restrooms were closed for the season, so they are probably not the source. There are
several sanitary manholes near 16‐1504, so perhaps there is a leak that is getting into the storm
sewer. However, there was no detergent detected, so perhaps it is infiltration from the former landfill, as was
previously suggested. I’ve attached the map from 2012, since the results were essentially the same.
Outfall 02‐184 (Legion Place): The upstream manhole was significantly cleaner than in previous years (no sludge
or odor) – I’m assuming it was vacuumed out at some point. The incoming and outgoing pipes could actually be
seen. The sample that was collected from the manhole pool did not have an odor. However, it had an ammonia
concentration of 3 ppm, a detergent concentration of 0.7 mg/L, and a conductivity of 1030 uS, which could
indicate potential sanitary sewage. I know that this branch of storm sewer is on the City’s radar from previous
years.
Most of the outfalls that were screened because of gross solids in the upstream manholes still had some degree
of gross solids present. In some cases, they seemed similar to previous years, and in other cases, there were
less. I’m assuming that some of them were not vacuumed out due to access issues. I will work on putting
together a comprehensive list of manholes and photos over the years, so we can determine which manholes
appear to have an ongoing issue (to be potentially listed as priority outfalls).
Outfalls 16‐396 and 16‐436 were inside a locked gate at a marina. During previous screening events, at least one
gate was open, but since it was later in the season this year, I was not able to obtain access. Both of those
outfalls had been included because of gross solids in upstream manholes. I recommend skipping those two
outfalls for 2014, and addressing them in the revised ongoing screening program.
I will work on getting formal outfall reports put together in the upcoming weeks, as well as the overall summary
report. I will also be finishing up the drainage basins and modeling for the revised ongoing screening program, and will
likely have some questions about specific drainage areas at some point.
Jason Weis, P.E., GISP, CPESC
Project Manager / GIS Manager OMNNI Associates, Inc. (920) 735-6900 (920) 830-6100 FAX jason.weis@omnni.com
Manhole 16-1508Ammonia: 3 ppm
Inlet 16-1504Ammonia: 3 ppm
Inlet 16-430Ammonia: 0 ppm
Manhole 16-469Ammonia: 0 ppm
Inlet 16-429Ammonia: 0 ppm
Manhole 16-470Ammonia: 0 ppm
Manhole 16-xxxAmmonia: 0 ppm
SuspectedSegment
Red Arrow Park
16-487
16-488
16-514
N
W
E
S
T
F
I
E
L
D
S
T
TAFT AVE
16-430
16-429
16-46916-470
16-618
16-471
16-514
16-1179
16-1180
16-1504
16-1505
16-1506
16-1508
16-1509
16-151016-1511
16-1512
C:\SyncFolders\IDDE_GIS\_Oshkosh\16-487.mxd
PROJECT NO.N2029B12
FIGURE NO.A-1
SCALE:1 " = 150 'Project Manager: BDWProject Engineer: JCWDrawn By: JCWChecked By: BDW
OSHKOSH 2012 IDDE ONGOING SCREENING
CITY OF OSHKOSHWINNEBAGO COUNTY, WISCONSIN
MANHOLE 16-487 DETECTION9/27/2012ONE SYSTEMS DRIVEAPPLETON, WI 54914 PHONE (920) 735-6900FAX (920) 830-6100 Date: 9/28/2012
0 150 300Feet
1
Jason Weis
From:Brian Wayner
Sent:Wednesday, June 06, 2012 1:00 PM
To:Rabe, James E.
Cc:Jason Weis
Subject:RE: Ammonia detection - outfall 16-487
Jason rescreened 16-487. No ammonia detections (or any of the other field parameters detected) this time. The initial
ammonia detection was likely from a natural source(s), but we will check it again when we are in the area and update
you.
Brian D. Wayner, P.E.
Environmental Manager
OMNNI Associates, Inc.
One N. Systems Drive, Appleton, WI 54914-1654
800.571.6677, 920.830.6141 (D), 920.830.6100 (F)
bwayner@omnni.com
From: Rabe, James E. [mailto:jrabe@ci.oshkosh.wi.us]
Sent: Thursday, May 31, 2012 3:41 PM
To: Jason Weis
Cc: Brian Wayner
Subject: RE: Ammonia detection - outfall 16-487
Jason,
Only the outfall in this location has been recently reconstructed. This outfall was reconstructed with the Westfield Street
Bridge project last year. The new storm sewer extends only about 175 feet to the south along Westfield Street. The next
upstream manhole now has a new designation (since it was replaced last year). We’ll have to get you some new
information. We should follow up on this as soon as possible.
James
From: Jason Weis [mailto:Jason.Weis@omnni.com]
Sent: Thursday, May 31, 2012 3:24 PM
To: Rabe, James E.
Cc: Brian Wayner
Subject: Ammonia detection - outfall 16-487
James:
I started screening some of Oshkosh’s outfalls on Wednesday. I focused on the outfalls that discharged to Sawyer
Creek. Because it had been 72 hours since the previous rainfall, we treated this as a normal outfall screening event,
rather than our typical spring “pre-screening.” That way, it will not be necessary to revisit these outfalls again in fall,
unless manhole cleaning or other maintenance activities are required. We will make sure that all outfalls and upstream
manholes are visited before the end of June, in case any manholes need to be cleaned out and rescreened.
One outfall that was inspected on Wednesday had a slightly elevated level of ammonia in the upstream
manhole. Outfall 16-487 is located on N Westfield St, and discharges into Sawyer Creek from the south (south of Robin
Ave). The outfall pipe was partially submerged, so a sample was collected from the upstream manhole (16-487). The
ammonia concentration of this sample was 1 mg/L. No other chemical indicators were out of range, and no physical
2
indicators were observed. (It appeared that the storm sewer had been recently reconstructed, so it appeared fairly
clean.)
1 mg/L is what we usually use as the threshold for follow-up investigation, especially if no other indicators are
present. Since the sample was collected from a pool sample, natural sources of ammonia (decaying vegetation, etc.)
could all cause slightly elevated ammonia levels. However, to be proactive, we will collect an additional sample the next
time we are screening in Oshkosh (next week) to determine if the ammonia is still present, and if any additional
investigation is warranted.
If you have any questions or concerns about this outfall or the screening program in general, feel free to contact Brian or
me.
Jason Weis, P.E., CPESC
GIS Manager / Municipal Project Manager
OMNNI Associates, Inc.
(920) 735-6900
(920) 830-6100 FAX
jason.weis@omnni.com
This email is subject to OMNNI Associates, Inc. Electronic File Disclaimer.
For full disclaimer see http://wwwomnni.com/legal/OMNNI_Email_Disclaimer.pdf
This email is subject to OMNNI Associates, Inc. Electronic File Disclaimer.
For full disclaimer see http://www.omnni.com/legal/OMNNI_Email_Disclaimer.pdf
1
Jason Weis
From:Jason Weis
Sent:Friday, September 28, 2012 8:40 AM
To:James Rabe (jrabe@ci.oshkosh.wi.us)
Cc:Brian Wayner
Subject:Ammonia in manholes on N Westfield St (Outfall 16-487 / 16-1508)
Attachments:16-487.pdf
James:
Brian and I finished the outfall inspections in Oshkosh on Thursday. The follow-up inspections consisted mainly of the
manholes in which we had previously identified gross solids issues, and outfalls/manholes that had previous chemical
indicator parameter detections. One of these was the outfall on N Westfield St, near Red Arrow Park (previously 16-487
before the recent reconstruction).
The upstream manhole (16-1508) had an ammonia detection of 1 ppm during the spring pre-screening. A subsequent
inspection showed no ammonia. During Thursday's inspection, the ammonia in this manhole was 3 ppm. Due to
construction in the receiving stream and vegetation inside the grate of the outfall pipe, flow was restricted, and the sample
was collected from the submerged pool in the upstream manhole.
Because of the elevated ammonia and the previous history of ammonia, we attempted to trace the ammonia
upstream. All upstream manholes (up to and including Taft Ave) were partially-submerged, with no free-flowing
stormwater. Samples were collected from the pools in several manholes/curb inlets upstream of the outfall. Based on the
samples, it appears that the source of the discharge may be between manhole/inlet 16-1504 and 16-430. The ammonia
at inlet 16-1504 was approximately 3 ppm, but no ammonia was detected at the next upstream inlet (16-430). It was
noted that the restroom facility for Red Arrow Park was located in this stretch of storm sewer, which could be a potential
ammonia source.
It should be noted that, since the manholes were partially submerged and the samples were collected from submerged
pools, the isolation of the suspect segment is not as precise as in a free-flowing storm sewer, since it is possible for the
ammonia to disperse in the pooled stormwater. However, based on the sample results, this would probably be the first
segment that should be investigated.
The City may want to televise this segment of storm sewer to determine if there are any cross connections or other
sources of ammonia infiltration. If you would like us to conduct any additional testing in the area, please let us know.
I will send you a summary of the gross solids follow-up early next week. Many of the manholes had significantly less
gross solids compared to the previous inspection. However, a few appeared to be similar, and may not have been
cleaned. I should have the table updated on Monday or Tuesday.
Jason Weis, P.E., CPESC
GIS Manager / Municipal Project Manager
OMNNI Associates, Inc.
(920) 735-6900
(920) 830-6100 FAX
jason.weis@omnni.com
APPENDIX D-3
12-1328a (Nolte Avenue Detention Basin) Investigation
1
Jason Weis
From:Jason Weis
Sent:Friday, September 25, 2015 12:50 PM
To:James Rabe (jrabe@ci.oshkosh.wi.us); Steve Gohde (sgohde@ci.oshkosh.wi.us)
Cc:Brian Wayner
Subject:Potential illicit discharge - Nolte Avenue detention basin
Attachments:IMGP4848.JPG; IMGP4849.JPG; IMGP4851.JPG; IMGP4852.JPG; 12-1328a_.pdf
James/Steve:
I conducted outfall inspections on Tuesday, Wednesday and Thursday this week. I am approximately 80% complete. I
plan on finishing the scheduled outfalls on Monday of next week.
So far, I have identified only one potential illicit discharge, and I’ll need you to confirm if it is actually a city outfall. I was
investigating the area around W Fernau Ave and Walter St. The city’s storm sewer mapping still shows the old storm
sewer, from before the Fernau/Algoma roundabout. This storm sewer originally discharged at outfall 12-1328, which no
longer exists. I decided to spend a few minutes in the field attempting to determine the layout of the new storm sewer
and the location of the new outfall.
I identified an outfall in the northeast corner of the detention basin near Nolte Ave and Algoma Blvd. Based on the
configuration of the manholes and curb inlets, it appeared that this might be the replacement for outfall 12-1328, so I
did an initial screening.
During the screening, I noticed a white discharge coming from the outfall. The trickle discharge appeared to have a fine
sediment in it, similar to chalk or silt. The white color was present in the flow, and had stained the pipe, apron, and
downstream riprap. There were also pools of the white discharge in the riprap channel leading to the detention basin.
A sample was collected and tested for chemical indicator parameters:
• Ammonia was 1 ppm (at the threshold for a potential illicit discharge).
• The chlorine test strips turned bright yellow, rather than a shade of purple. This typically is a result of another
dissolved chemical interfering with the test strips.
• No detergent was detected.
• Conductivity was 2470 µS/mS, which shows a fairly high concentration of dissolved ionic material. (Anything
over 2000 µS/mS is suspect for wastewater/washwater.)
• The pH was 11.66, which is extremely high. (Typical outfall samples have a pH of 6-9.)
I located the curb inlet at the southwest corner of Nolte Avenue and Walter Street, which appeared to be the first
upstream structure. I did not observe a flow in this structure, but it was difficult to see the flowline from the south.
At this time, I have a few questions for the City:
1. Can you confirm that this is the City’s outfall (not County, State, etc.)?
2. Is this outfall the replacement for outfall 12-1328, which was relocated due to the roundabout construction?
3. Is there any updated storm sewer mapping available for this area?
4. After I finish the scheduled outfall screening on Monday, would you like me to spend some time attempting to
track the discharge (based on flow and/or stains)?
5. Are you aware of any facilities along Walter or Fernau (west of the Fernau detention basin) that might be a
source for this white alkaline material?
2
Jason Weis, P.E., GISP
Project Manager / Geospatial Manager
OMNNI Associates, Inc.
(920) 735-6900
(920) 830-6100 FAX
jason.weis@omnni.com
1
Jason Weis
From:Jason Weis
Sent:Monday, September 28, 2015 3:15 PM
To:Gohde, Steven M.; Rabe, James E.
Cc:Brian Wayner; Lyons, Kris
Subject:RE: Potential illicit discharge - Nolte Avenue detention basin
Attachments:Tracking_150928_.pdf; IMGP5142.JPG; IMGP5143.JPG; IMGP5145.JPG; IMGP5146.JPG;
IMGP5126.JPG; IMGP5119.JPG; IMGP5124.JPG
I have attached a map that summarizes the tracking activities from today. The staining and elevated pH discharge was
observed at the outfall, and a surface water sample from the detention basin also had an elevated pH (9.73). The white
stain was present at the upstream inlet on Walter Road, and clearly came from the south. The white stain in the
manhole near Walter Road and Walter Court reinforced that the discharge was coming from the direction of Fernau Ave.
The new storm sewer branches to the northeast and southwest at Fernau Ave. Due to traffic issues, the manhole at the
intersection of Walter and Fernau could not be inspected to determine which branch was contributing the stain. Several
of the inlets and manholes from the “original” Fernau Avenue storm sewer (northeast branch) were inspected, and
there were no signs of white stains. The first “new” manhole northeast of the intersection was inspected, and there
were also no signs of white stains, suggesting that the discharge was coming from the southwest branch.
The first manhole southwest of the intersection (#562) was wet and had some of the white substance in it. The stain
appeared to come from the inlet to the east. The inlet on the west side of Fernau (582B) was dry and clean. The inlet on
the east side of Fernau (582A) was wet and had the white substance. Upon further inspection of the inlet, a 6” pipe was
identified protruding through the back side (east/south) of the structure, with white staining and a trickle flow. This pipe
appeared to originate from the property to the east (Carew). A sample was collected from this trickle flow, and the pH
was 12.23. The elevated pH, along with the white staining from the pipe, indicate that this is the likely source of the
discharge.
As a confirmation, the next set of inlets upstream (south) of this manhole were inspected (immediately north of Stillman
Road). The inlet on the east side of the road had water in the sump. A sample was collected from this pool, and the pH
was 7.4, which is in the typical range for stormwater. This seems to indicate that the discharge is limited to the area
around manhole 562, and specifically from the 6” pipe in inlet 562A.
I have attached a few additional photos to this email, along with a map showing the general layout and investigation
findings. It is recommended that the City investigate the origin of this 6” pipe, along with any potential sources of the
illicit discharge on the Carew property. If the City needs assistance with this tracking, OMNNI would be happy to help.
Please keep OMNNI updated on any investigation activities for this discharge, along with any findings or resolutions, so
we can include them in the Summary Report that we will prepare later this year.
If you have any questions, please let me know.
Jason Weis, P.E., GISP
Project Manager / Geospatial Manager
OMNNI Associates, Inc.
(920) 735-6900
(920) 830-6100 FAX
jason.weis@omnni.com
2
From: Jason Weis
Sent: Monday, September 28, 2015 12:42 PM
To: Gohde, Steven M.; Rabe, James E.
Cc: Brian Wayner; Lyons, Kris
Subject: RE: Potential illicit discharge - Nolte Avenue detention basin
The probable source of the white alkaline discharge has been located. There is a 6" pipe stubbed into the back of
curb inlet 582A (from the plan sheet you sent me). The inlet is on the east side if Fernau, just south of Walter.
The pipe appears to come from the Carew property.
A sample collected from this pipe had a pH of 12.23. There was also white staining coming from this pipe.
Therefore, this should be the location where the discharge is entering the MS4. The City will likely need to
determine the source of this pipe on the Carew property. OMNNI can assist if needed.
Note that the pH of the water in the downstream detention basin was 9.73, which is very high for surface water.
I have attached a few pbotos. I will send more detailed information once I get back to the office this afternoon.
Feel free to call if you have any questions.
Jason
Sent from my U.S. Cellular® Smartphone
-------- Original message --------
From: "Gohde, Steven M." <sgohde@ci.oshkosh.wi.us>
Date: 09/25/2015 4:05 PM (GMT-06:00)
To: Jason Weis <Jason.Weis@omnni.com>, "Rabe, James E." <jrabe@ci.oshkosh.wi.us>
Cc: Brian Wayner <Brian.Wayner@omnni.com>, "Lyons, Kris" <KLyons@ci.oshkosh.wi.us>
Subject: RE: Potential illicit discharge - Nolte Avenue detention basin
Jason,
Attached is a sheet from the DOT project that reconstructed the storm sewer in this area. The plans did not show the
section of the storm sewer being reconnected to the east. I am unsure how it was reconnected but suspect it was one
of the two red dashed lines I drew on the attached. The plans also do not show storm sewer for Walter Ct, but inlet
exist.
My best suspect for a source is Carew Concrete located on the south/east side of Fernau Ave at the Walter Rd
intersection.
Please investigate this discharge. If you need any City staff assistance please let us know.
Thanks,
Steve
From: Jason Weis [mailto:Jason.Weis@omnni.com]
Sent: Friday, September 25, 2015 12:50 PM
To: Rabe, James E.; Gohde, Steven M.
Cc: Brian Wayner
Subject: Potential illicit discharge - Nolte Avenue detention basin
3
James/Steve:
I conducted outfall inspections on Tuesday, Wednesday and Thursday this week. I am approximately 80% complete. I
plan on finishing the scheduled outfalls on Monday of next week.
So far, I have identified only one potential illicit discharge, and I’ll need you to confirm if it is actually a city outfall. I was
investigating the area around W Fernau Ave and Walter St. The city’s storm sewer mapping still shows the old storm
sewer, from before the Fernau/Algoma roundabout. This storm sewer originally discharged at outfall 12-1328, which no
longer exists. I decided to spend a few minutes in the field attempting to determine the layout of the new storm sewer
and the location of the new outfall.
I identified an outfall in the northeast corner of the detention basin near Nolte Ave and Algoma Blvd. Based on the
configuration of the manholes and curb inlets, it appeared that this might be the replacement for outfall 12-1328, so I
did an initial screening.
During the screening, I noticed a white discharge coming from the outfall. The trickle discharge appeared to have a fine
sediment in it, similar to chalk or silt. The white color was present in the flow, and had stained the pipe, apron, and
downstream riprap. There were also pools of the white discharge in the riprap channel leading to the detention basin.
A sample was collected and tested for chemical indicator parameters:
• Ammonia was 1 ppm (at the threshold for a potential illicit discharge).
• The chlorine test strips turned bright yellow, rather than a shade of purple. This typically is a result of another
dissolved chemical interfering with the test strips.
• No detergent was detected.
• Conductivity was 2470 µS/mS, which shows a fairly high concentration of dissolved ionic material. (Anything
over 2000 µS/mS is suspect for wastewater/washwater.)
• The pH was 11.66, which is extremely high. (Typical outfall samples have a pH of 6-9.)
I located the curb inlet at the southwest corner of Nolte Avenue and Walter Street, which appeared to be the first
upstream structure. I did not observe a flow in this structure, but it was difficult to see the flowline from the south.
At this time, I have a few questions for the City:
1. Can you confirm that this is the City’s outfall (not County, State, etc.)?
2. Is this outfall the replacement for outfall 12-1328, which was relocated due to the roundabout construction?
3. Is there any updated storm sewer mapping available for this area?
4. After I finish the scheduled outfall screening on Monday, would you like me to spend some time attempting to
track the discharge (based on flow and/or stains)?
5. Are you aware of any facilities along Walter or Fernau (west of the Fernau detention basin) that might be a
source for this white alkaline material?
Jason Weis, P.E., GISP
Project Manager / Geospatial Manager
OMNNI Associates, Inc.
(920) 735-6900
(920) 830-6100 FAX
jason.weis@omnni.com
This email is subject to OMNNI Associates, Inc. Electronic File Disclaimer. For full disclaimer see
http://www.omnni.org/legal/OMNNI_Email_Disclaimer.pdf
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1
Jason Weis
From:Rabe, James E. <jrabe@ci.oshkosh.wi.us>
Sent:Tuesday, September 29, 2015 10:01 AM
To:Jason Weis; Gohde, Steven M.
Cc:Brian Wayner; Lyons, Kris
Subject:RE: Potential illicit discharge - Nolte Avenue detention basin
Jason,
Thank you for the summary. To confirm our phone conversation, we will meet Mike Tews from Carew Concrete onsite at
1:00 p.m. to review this, and see if the source can be located. Please bring your gear to assist. Please charge on the
“tracking” task.
Streets Division will meet us at the intersection of Fernau and Walter with the push camera to assist in looking up the line
tapped into the back of the inlet.
Thank you,
James
From: Jason Weis [mailto:Jason.Weis@omnni.com]
Sent: Monday, September 28, 2015 3:15 PM
To: Gohde, Steven M.; Rabe, James E.
Cc: Brian Wayner; Lyons, Kris
Subject: RE: Potential illicit discharge - Nolte Avenue detention basin
I have attached a map that summarizes the tracking activities from today. The staining and elevated pH discharge was
observed at the outfall, and a surface water sample from the detention basin also had an elevated pH (9.73). The white
stain was present at the upstream inlet on Walter Road, and clearly came from the south. The white stain in the
manhole near Walter Road and Walter Court reinforced that the discharge was coming from the direction of Fernau Ave.
The new storm sewer branches to the northeast and southwest at Fernau Ave. Due to traffic issues, the manhole at the
intersection of Walter and Fernau could not be inspected to determine which branch was contributing the stain. Several
of the inlets and manholes from the “original” Fernau Avenue storm sewer (northeast branch) were inspected, and
there were no signs of white stains. The first “new” manhole northeast of the intersection was inspected, and there
were also no signs of white stains, suggesting that the discharge was coming from the southwest branch.
The first manhole southwest of the intersection (#562) was wet and had some of the white substance in it. The stain
appeared to come from the inlet to the east. The inlet on the west side of Fernau (582B) was dry and clean. The inlet on
the east side of Fernau (582A) was wet and had the white substance. Upon further inspection of the inlet, a 6” pipe was
identified protruding through the back side (east/south) of the structure, with white staining and a trickle flow. This pipe
appeared to originate from the property to the east (Carew). A sample was collected from this trickle flow, and the pH
was 12.23. The elevated pH, along with the white staining from the pipe, indicate that this is the likely source of the
discharge.
As a confirmation, the next set of inlets upstream (south) of this manhole were inspected (immediately north of Stillman
Road). The inlet on the east side of the road had water in the sump. A sample was collected from this pool, and the pH
was 7.4, which is in the typical range for stormwater. This seems to indicate that the discharge is limited to the area
around manhole 562, and specifically from the 6” pipe in inlet 562A.
2
I have attached a few additional photos to this email, along with a map showing the general layout and investigation
findings. It is recommended that the City investigate the origin of this 6” pipe, along with any potential sources of the
illicit discharge on the Carew property. If the City needs assistance with this tracking, OMNNI would be happy to help.
Please keep OMNNI updated on any investigation activities for this discharge, along with any findings or resolutions, so
we can include them in the Summary Report that we will prepare later this year.
If you have any questions, please let me know.
Jason Weis, P.E., GISP
Project Manager / Geospatial Manager
OMNNI Associates, Inc.
(920) 735-6900
(920) 830-6100 FAX
jason.weis@omnni.com
From: Jason Weis
Sent: Monday, September 28, 2015 12:42 PM
To: Gohde, Steven M.; Rabe, James E.
Cc: Brian Wayner; Lyons, Kris
Subject: RE: Potential illicit discharge - Nolte Avenue detention basin
The probable source of the white alkaline discharge has been located. There is a 6" pipe stubbed into the back of
curb inlet 582A (from the plan sheet you sent me). The inlet is on the east side if Fernau, just south of Walter.
The pipe appears to come from the Carew property.
A sample collected from this pipe had a pH of 12.23. There was also white staining coming from this pipe.
Therefore, this should be the location where the discharge is entering the MS4. The City will likely need to
determine the source of this pipe on the Carew property. OMNNI can assist if needed.
Note that the pH of the water in the downstream detention basin was 9.73, which is very high for surface water.
I have attached a few pbotos. I will send more detailed information once I get back to the office this afternoon.
Feel free to call if you have any questions.
Jason
Sent from my U.S. Cellular® Smartphone
-------- Original message --------
From: "Gohde, Steven M." <sgohde@ci.oshkosh.wi.us>
Date: 09/25/2015 4:05 PM (GMT-06:00)
To: Jason Weis <Jason.Weis@omnni.com>, "Rabe, James E." <jrabe@ci.oshkosh.wi.us>
Cc: Brian Wayner <Brian.Wayner@omnni.com>, "Lyons, Kris" <KLyons@ci.oshkosh.wi.us>
Subject: RE: Potential illicit discharge - Nolte Avenue detention basin
Jason,
3
Attached is a sheet from the DOT project that reconstructed the storm sewer in this area. The plans did not show the
section of the storm sewer being reconnected to the east. I am unsure how it was reconnected but suspect it was one
of the two red dashed lines I drew on the attached. The plans also do not show storm sewer for Walter Ct, but inlet
exist.
My best suspect for a source is Carew Concrete located on the south/east side of Fernau Ave at the Walter Rd
intersection.
Please investigate this discharge. If you need any City staff assistance please let us know.
Thanks,
Steve
From: Jason Weis [mailto:Jason.Weis@omnni.com]
Sent: Friday, September 25, 2015 12:50 PM
To: Rabe, James E.; Gohde, Steven M.
Cc: Brian Wayner
Subject: Potential illicit discharge - Nolte Avenue detention basin
James/Steve:
I conducted outfall inspections on Tuesday, Wednesday and Thursday this week. I am approximately 80% complete. I
plan on finishing the scheduled outfalls on Monday of next week.
So far, I have identified only one potential illicit discharge, and I’ll need you to confirm if it is actually a city outfall. I was
investigating the area around W Fernau Ave and Walter St. The city’s storm sewer mapping still shows the old storm
sewer, from before the Fernau/Algoma roundabout. This storm sewer originally discharged at outfall 12-1328, which no
longer exists. I decided to spend a few minutes in the field attempting to determine the layout of the new storm sewer
and the location of the new outfall.
I identified an outfall in the northeast corner of the detention basin near Nolte Ave and Algoma Blvd. Based on the
configuration of the manholes and curb inlets, it appeared that this might be the replacement for outfall 12-1328, so I
did an initial screening.
During the screening, I noticed a white discharge coming from the outfall. The trickle discharge appeared to have a fine
sediment in it, similar to chalk or silt. The white color was present in the flow, and had stained the pipe, apron, and
downstream riprap. There were also pools of the white discharge in the riprap channel leading to the detention basin.
A sample was collected and tested for chemical indicator parameters:
• Ammonia was 1 ppm (at the threshold for a potential illicit discharge).
• The chlorine test strips turned bright yellow, rather than a shade of purple. This typically is a result of another
dissolved chemical interfering with the test strips.
• No detergent was detected.
• Conductivity was 2470 µS/mS, which shows a fairly high concentration of dissolved ionic material. (Anything
over 2000 µS/mS is suspect for wastewater/washwater.)
• The pH was 11.66, which is extremely high. (Typical outfall samples have a pH of 6-9.)
I located the curb inlet at the southwest corner of Nolte Avenue and Walter Street, which appeared to be the first
upstream structure. I did not observe a flow in this structure, but it was difficult to see the flowline from the south.
At this time, I have a few questions for the City:
1. Can you confirm that this is the City’s outfall (not County, State, etc.)?
4
2. Is this outfall the replacement for outfall 12-1328, which was relocated due to the roundabout construction?
3. Is there any updated storm sewer mapping available for this area?
4. After I finish the scheduled outfall screening on Monday, would you like me to spend some time attempting to
track the discharge (based on flow and/or stains)?
5. Are you aware of any facilities along Walter or Fernau (west of the Fernau detention basin) that might be a
source for this white alkaline material?
Jason Weis, P.E., GISP
Project Manager / Geospatial Manager
OMNNI Associates, Inc.
(920) 735-6900
(920) 830-6100 FAX
jason.weis@omnni.com
This email is subject to OMNNI Associates, Inc. Electronic File Disclaimer. For full disclaimer see
http://www.omnni.org/legal/OMNNI_Email_Disclaimer.pdf
This email is subject to OMNNI Associates, Inc. Electronic File Disclaimer. For full disclaimer see
http://www.omnni.org/legal/OMNNI_Email_Disclaimer.pdf
Appendix E
MS4 Outfall Screening History/Schedule
City of Oshkosh
MS4 Outfall Screening History and Schedule
Priority Outfall ID 2015 2016 2017 2018 2019
P 01-20 U x
P 01-35 U x
P 01-278 U x
P 01-520 P x
P 02-357 P x
P 03-22 P x
P 03-35 P x
P 03-81 U x
P 03-119 U x
P 03-173 P x
P 03-381 P x
P 05-241 U x
P 06-52 P x
P 06-253 U x
P 06-810 U x
P 08-284 P x
P 08-347 P x
P 08-937 U x
P 09-101a U x
P 11-376 P x
P 11-512 P x
P 12-569 P x
P 12-576 U x
P 12-1313 U x
P 12-2297 U x
P 12-2299 U x
P 13-1098 U x
P 13-1588 U x
P 13-1716 U x
P 13-1718 U x
P 13-1758 U x
P 13-2957 U x
P 13-3774 U x
P 14-582 U x
P 14-999 U x
P 14-1514 U x
P 15-143 U x
P 15-146 U x
P 15-1093 U x
P 15-1108 U x
P 15-1237 U x
P 15-2409 U x
P 15-2477 U x
P 16-142 P x
P 16-533 P x
P 16-844 U x
P 16-1205 U x
P 16-1508 P x
NPM 01-360 U
NPM 01-642 P r
NPM 03-293 x
Page 1
City of Oshkosh
MS4 Outfall Screening History and Schedule
Priority Outfall ID 2015 2016 2017 2018 2019
NPM 05-155 U
NPM 05-216 U
NPM 06-489
NPM 06-1132
NPM 06-1136
NPM 06-1601
NPM 06-1746
NPM 06-2241
NPM 06-2380 U
NPM 09-32
NPM 09-84
NPM 09-101b
NPM 11-173 x
NPM 11-400 x
NPM 11-465a x
NPM 11-479 x
NPM 12-890 U
NPM 12-925 U
NPM 12-2042 U
NPM 12-2064
NPM 13-68 U
NPM 13-101
NPM 13-337
NPM 13-471
NPM 13-875
NPM 13-1106 U
NPM 13-1174 U
NPM 13-1242
NPM 13-1283 U
NPM 13-1769 U
NPM 13-2332
NPM 13-2382
NPM 13-2611
NPM 13-2613
NPM 13-2736
NPM 13-2822b
NPM 13-2872b
NPM 14-188 x
NPM 14-331 x
NPM 14-400 x
NPM 14-595
NPM 14-635
NPM 14-644
NPM 14-645
NPM 14-659
NPM 14-670
NPM 14-676
NPM 14-766
NPM 14-996
NPM 14-1007
NPM 15-636 x
Page 2
City of Oshkosh
MS4 Outfall Screening History and Schedule
Priority Outfall ID 2015 2016 2017 2018 2019
NPM 15-744 x
NPM 15-787 x
NPM 15-910 x
NPM 15-940 x
NPM 15-959 x
NPM 15-1032
NPM 15-1067
NPM 15-1095
NPM 15-1219
NPM 15-1248
NPM 15-1263
NPM 15-1277 x
NPM 15-1817 x
NPM 15-1889
NPM 15-2108
NPM 15-2243
NPM 15-2404a
NPM 15-2790
NPM 16-295 U
NPM 16-389 U
NPM 16-436
NPM 16-646b
NPM 16-1610
NPM FernauPond U
NPM OakwoodPondOut
NPM WashAller01
NPNM 01-132
NPNM 01-318 P r
NPNM 01-380 U
NPNM 02-105 U
NPNM 02-309 P r
NPNM 02-322 U
NPNM 02-324 U
NPNM 03-306
NPNM 03-379
NPNM 03-382
NPNM 03-385
NPNM 03-387
NPNM 03-392
NPNM 05-14 P r
NPNM 05-264a U
NPNM 06-3
NPNM 06-65
NPNM 06-154
NPNM 06-216
NPNM 06-221 x
NPNM 06-471
NPNM 06-473
NPNM 06-478
NPNM 06-494
NPNM 06-588
Page 3
City of Oshkosh
MS4 Outfall Screening History and Schedule
Priority Outfall ID 2015 2016 2017 2018 2019
NPNM 06-602
NPNM 06-610
NPNM 06-622a
NPNM 06-729
NPNM 06-745
NPNM 06-795
NPNM 06-798
NPNM 06-829
NPNM 06-880
NPNM 06-961
NPNM 06-968
NPNM 06-977
NPNM 06-1028 x
NPNM 06-1083
NPNM 06-1090
NPNM 06-1149
NPNM 06-1159
NPNM 06-1161
NPNM 06-1210
NPNM 06-1211
NPNM 06-1477
NPNM 06-1495
NPNM 06-1562
NPNM 06-1619
NPNM 06-1633
NPNM 06-1636
NPNM 06-1694
NPNM 06-1814
NPNM 06-1816
NPNM 06-1986
NPNM 08-55
NPNM 08-100 U
NPNM 08-162 U
NPNM 08-270 U
NPNM 08-271 U
NPNM 08-279 U
NPNM 08-285 U
NPNM 08-350 U
NPNM 08-364 P r
NPNM 08-369 U
NPNM 08-395 U
NPNM 08-1042 U
NPNM 09-101c
NPNM 11-46
NPNM 11-64
NPNM 11-69
NPNM 11-71
NPNM 11-75
NPNM 11-79
NPNM 11-118
NPNM 11-177
Page 4
City of Oshkosh
MS4 Outfall Screening History and Schedule
Priority Outfall ID 2015 2016 2017 2018 2019
NPNM 11-225
NPNM 11-244
NPNM 11-247
NPNM 11-318
NPNM 11-515
NPNM 11-801
NPNM 11-803
NPNM 11-805
NPNM 12-889 U
NPNM 12-972 U
NPNM 12-997 U
NPNM 12-1245
NPNM 12-1261
NPNM 12-1328a O r
NPNM 12-1414
NPNM 12-1604
NPNM 12-1676
NPNM 12-1676a
NPNM 12-1682
NPNM 12-1692
NPNM 12-1700
NPNM 12-1711
NPNM 12-1781 U
NPNM 12-1793 U
NPNM 12-1795 U
NPNM 12-1916
NPNM 12-2026 U
NPNM 12-2034 U
NPNM 12-2075
NPNM 12-2079
NPNM 12-2089
NPNM 12-2092a
NPNM 12-2093
NPNM 12-2273
NPNM 13-95
NPNM 13-546
NPNM 13-819
NPNM 13-948
NPNM 13-1109
NPNM 13-1552
NPNM 13-1554 U
NPNM 13-1673
NPNM 13-1715
NPNM 13-1760
NPNM 13-1766 U
NPNM 13-1870
NPNM 13-1957
NPNM 13-2031
NPNM 13-2135
NPNM 13-2156
NPNM 13-2387 U
Page 5
City of Oshkosh
MS4 Outfall Screening History and Schedule
Priority Outfall ID 2015 2016 2017 2018 2019
NPNM 13-2390 U
NPNM 13-2455
NPNM 13-2464
NPNM 13-2527
NPNM 13-2557
NPNM 13-2559
NPNM 13-2561
NPNM 13-2563
NPNM 13-2564
NPNM 13-2596
NPNM 13-2666
NPNM 13-2768
NPNM 13-2822
NPNM 13-2860
NPNM 13-2867
NPNM 13-2872
NPNM 13-2886
NPNM 13-3097
NPNM 13-3099
NPNM 13-3119
NPNM 13-3127
NPNM 13-3130
NPNM 13-3162
NPNM 13-3194
NPNM 13-3204
NPNM 13-3204b
NPNM 13-3224
NPNM 13-3243
NPNM 13-3427
NPNM 13-3431
NPNM 13-3488
NPNM 13-3497
NPNM 13-3509
NPNM 13-3636
NPNM 13-3706
NPNM 14-124
NPNM 14-327
NPNM 14-368
NPNM 14-517
NPNM 14-615
NPNM 14-660
NPNM 14-675
NPNM 14-759
NPNM 14-789
NPNM 14-1075
NPNM 14-1130
NPNM 14-1133
NPNM 14-1136
NPNM 14-1138
NPNM 14-1139
NPNM 14-1218
Page 6
City of Oshkosh
MS4 Outfall Screening History and Schedule
Priority Outfall ID 2015 2016 2017 2018 2019
NPNM 14-1220
NPNM 14-1222
NPNM 14-1227
NPNM 14-1253
NPNM 14-1253b
NPNM 14-1387
NPNM 14-1515
NPNM 15-027
NPNM 15-349
NPNM 15-350
NPNM 15-378
NPNM 15-399
NPNM 15-488
NPNM 15-571
NPNM 15-573
NPNM 15-687
NPNM 15-690
NPNM 15-692
NPNM 15-693
NPNM 15-798
NPNM 15-804
NPNM 15-835
NPNM 15-840
NPNM 15-858
NPNM 15-863
NPNM 15-865
NPNM 15-895
NPNM 15-905
NPNM 15-965
NPNM 15-1018
NPNM 15-1020
NPNM 15-1106
NPNM 15-1110
NPNM 15-1125
NPNM 15-1127
NPNM 15-1129
NPNM 15-1132
NPNM 15-1135
NPNM 15-1137
NPNM 15-1185
NPNM 15-1187
NPNM 15-1188
NPNM 15-1217
NPNM 15-1225
NPNM 15-1239
NPNM 15-1287
NPNM 15-1348
NPNM 15-1494
NPNM 15-1702
NPNM 15-1734
NPNM 15-1746
Page 7
City of Oshkosh
MS4 Outfall Screening History and Schedule
Priority Outfall ID 2015 2016 2017 2018 2019
NPNM 15-1749
NPNM 15-1806
NPNM 15-1807
NPNM 15-1856
NPNM 15-1891
NPNM 15-1903
NPNM 15-1983
NPNM 15-2242
NPNM 15-2292
NPNM 15-2295
NPNM 15-2297
NPNM 15-2375
NPNM 15-2394
NPNM 15-2404
NPNM 15-2412
NPNM 15-2475
NPNM 15-2527
NPNM 15-2528
NPNM 15-2690
NPNM 16-28 x
NPNM 16-47 x
NPNM 16-71 x
NPNM 16-93 x
NPNM 16-119 x
NPNM 16-155 x
NPNM 16-164 x
NPNM 16-201 x
NPNM 16-289 x
NPNM 16-328 x
NPNM 16-334 x
NPNM 16-351 x
NPNM 16-358 x
NPNM 16-362 x
NPNM 16-368 x
NPNM 16-381 x
NPNM 16-386 x
NPNM 16-396
NPNM 16-463 x
NPNM 16-488 x
NPNM 16-514 x
NPNM 16-532 x
NPNM 16-551 x
NPNM 16-587 x
NPNM 16-594 x
NPNM 16-622
NPNM 16-629
NPNM 16-646a
NPNM 16-660
NPNM 16-663
NPNM 16-719 x
NPNM 16-826
Page 8
City of Oshkosh
MS4 Outfall Screening History and Schedule
Priority Outfall ID 2015 2016 2017 2018 2019
NPNM 16-828
NPNM 16-869
NPNM 16-871 x
NPNM 16-873 x
NPNM 16-941
NPNM 16-995
NPNM 16-1074 x
NPNM 16-1204
NPNM 16-1207
NPNM 16-1213
NPNM 16-1628
NPNM 16-1633
NPNM EdgePond1out
NPNM EdgePond2in
NPNM Osh0944
NPNM Wash41_01 U
NPNM Wash41_02 U
U Unlikely 77 0 0 0 0
P Potential 20 0 0 0 0
O Obvious 1 0 0 0 0
98 0 0 0 0
x Scheduled 0 94 0 0 0
r Reinspect 0 6 0 0 0
0 100 0 0 0
Priority
P Priority Outfall (annual)48
NPM Non-Priority Major Outfall (5 years)80
NPNM Non-Priority Non-Major Outfall (10 years)297
425
Page 9