HomeMy WebLinkAboutOshkosh_Summary_Report_2014_Final
ENGI NEERI NG • AR CHI TECTURE • ENV IRO NM ENT AL
Ongoing Screening Summary Report
2014 Inspection Year
Illicit Discharge Detection and Elimination Program
City of Oshkosh
February 23, 2015
OMNNI Project No. N2029C14
Illicit Discharge Detection and Elimination
Conducted For
City of Oshkosh
Ongoing Screening Summary Report
2014 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 N2029C14
February 23, 2015
Table of Contents
EXECUTIVE SUMMARY ................................................................................................................. 1
BACKGROUND ............................................................................................................................... 1
PURPOSE ...................................................................................................................................... 1
OUTFALL IDENTIFICATION AND MAPPING ......................................................................................... 2
INITIAL SCREENING PROGRAM ........................................................................................................ 2
DEVELOPMENT OF ONGOING SCREENING PROGRAM ....................................................................... 3
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
COPPER ...................................................................................................................................... 19
AMMONIA .................................................................................................................................... 19
DETERGENTS .............................................................................................................................. 20
PHENOLS .................................................................................................................................... 22
POTENTIAL ILLICIT DISCHARGES ............................................................................................. 23
UPSTREAM MANHOLES WITH SIGNIFICANT FLOATABLE DEBRIS ...................................................... 25
OUTFALL 02-184 (LEGION PLACE) ............................................................................................... 25
OUTFALL 03-81 (PIONEER DRIVE) ................................................................................................ 28
OUTFALL 16-1508 (N. W ESTFIELD STREET) ................................................................................. 32
OUTFALL CONDITION ASSESSMENTS ..................................................................................... 35
DAMAGE ..................................................................................................................................... 35
DEPOSITION ................................................................................................................................ 36
EROSION ..................................................................................................................................... 39
GRAFFITI ..................................................................................................................................... 39
CONCLUSION ............................................................................................................................... 40
STANDARD OF CARE .................................................................................................................. 40
List of Appendices
MS4 OUTFALL MAP .................................................................................................................... A-1
2014 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 02-184 (LEGION PLACE) INVESTIGATION .............................................................. D-2
OUTFALL 03-81 (PIONEER DRIVE) INVESTIGATION ............................................................... D-2
OUTFALL 16-1508 (N. WESTFIELD STREET) INVESTIGATION .............................................. D-3
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 ............... 23
TABLE 4 – OUTFALLS WITH DAMAGE ....................................................................................... 35
TABLE 5 – OUTFALLS WITH DEPOSITION ................................................................................ 36
TABLE 6 – OUTFALLS WITH GRAFFITI ...................................................................................... 39
List of Figures
FIGURE 1 – LOCATION OF WEATHER STATION FOR WEATHER HISTORY ........................... 5
FIGURE 2 – SUMMER 2014 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 .................................................. 21
FIGURE 12 – DETERGENT SAMPLE RESULTS ........................................................................ 22
FIGURE 13 – ILLICIT DISCHARGE POTENTIAL OF INSPECTED OUTFALLS ......................... 24
FIGURE 14 – SUDS ALONG SHORELINE NORTH OF OUTFALL 02-184 (2012) ..................... 26
FIGURE 15 – POOL IN UPSTREAM MANHOLE 02-184 US1 (2012) .......................................... 26
FIGURE 16 – POOL IN UPSTREAM MANHOLE 02-184 US1 (2013) .......................................... 27
FIGURE 17 – POOL IN UPSTREAM MANHOLE 02-184 US1 (2014) .......................................... 27
FIGURE 18 – UPSTREAM MANHOLE 03-81 US1 (2009) ........................................................... 28
FIGURE 19 – FLOATABLE DEBRIS AND GREASE IN UPSTREAM MANHOLE 03-81 US1
(2009) ............................................................................................................................................ 28
FIGURE 20 – SAMPLE CONTAINER FROM UPSTREAM MANHOLE 03-81 US1 (2009) .......... 29
FIGURE 21 – FLOATABLE DEBRIS IN UPSTREAM MANHOLE 03-81 US2 (2009) .................. 29
FIGURE 22 – OIL SHEEN IN UPSTREAM MANHOLE 03-81 US4 (2009) .................................. 30
FIGURE 23 – OIL SHEEN AND DEBRIS IN MANHOLE 03-81 US1 (2014) ................................ 31
FIGURE 24 – OIL SHEEN AND DEBRIS IN MANHOLE 03-81 US1 AFTER VACUUMING (2014)
....................................................................................................................................................... 31
FIGURE 25 – UPSTREAM MANHOLE 03-81 US4 (2014) ........................................................... 32
FIGURE 26 – PETROLEUM SHEEN IN UPSTREAM MANHOLE 03-81 US4 (2014) .................. 32
FIGURE 27 – OUTFALL 16-1508 (5/30/2012) .............................................................................. 33
FIGURE 28 – OUTFALL 16-1508 (9/27/2012) .............................................................................. 33
FIGURE 29 – PARK RESTROOM BUILDING UPSTREAM OF 16-1504 (2013) ......................... 34
FIGURE 30 – CORRODED METAL PIPE AT OUTFALL 08-284 (MINOR DAMAGE) ................. 35
FIGURE 31 – CORRODED METAL PIPE AT OUTFALL 12-890 (MODERATE DAMAGE) ......... 35
FIGURE 32 – CORRODED METAL PIPE AT OUTFALL 12-890X (MINOR DAMAGE) ............... 36
FIGURE 33 – MINOR DEPOSITION IN MANHOLE 02-322 US1 ................................................. 37
FIGURE 34 – MINOR DEPOSITION IN MANHOLE 03-35 US1 ................................................... 37
FIGURE 35 – MINOR DEPOSITION IN MANHOLE 03-381 US1 ................................................. 37
FIGURE 36 – MINOR DEPOSITION IN MANHOLE 03-81 US1 ................................................... 37
FIGURE 37 – MODERATE DEPOSITION IN INLET 06-1694 US1 .............................................. 37
FIGURE 38 – MINOR DEPOSITION IN MANHOLE 06-221 US1 ................................................. 37
FIGURE 39 – MINOR DEPOSITION AT OUTFALL 08-284 ......................................................... 38
FIGURE 40 – MINOR DEPOSITION AT OUTFALL 12-890 ......................................................... 38
FIGURE 41 – MODERATE DEPOSITION AT OUTFALL 13-1758 ............................................... 38
FIGURE 42 – MINOR DEPOSITION AT OUTFALL 13-3099 ....................................................... 38
FIGURE 43 – MODERATE DEPOSITION IN MANHOLE 15-1093 US1 ...................................... 38
FIGURE 44 – MINOR DEPOSITION IN INLET 16-119 US1 ........................................................ 38
FIGURE 45 – MINOR DEPOSITION IN INLET 16-142 US1 ........................................................ 39
FIGURE 46 – GRAFFITI NEAR OUTFALL 12-569 ....................................................................... 39
FIGURE 47 – ILLICIT DISCHARGE POTENTIAL ......................................................................... 40
February 23, 2015 1 2014 Ongoing Screening Summary Report
City of Oshkosh
EXECUTIVE SUMMARY
During the summer of 2014, 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 developed
in 2009, OMNNI inspected 42 of the approximately 362 MS4 outfalls identified in the City. The
screened outfalls were selected based on evidence of potential illicit discharges in previous
screening years. The inspections consisted of a visual screening along with a chemical analysis of
any dry-weather flow that was present. The inspections revealed 17 outfalls with evidence of
potential illicit discharges.
The 2013 inspection year completed the first four-year cycle that was outlined in the original
2009 Ongoing Screening Program. The 2014 inspection year was used to conduct an additional
screening of the outfalls that showed evidence of potential illicit discharges in the previous
screening years, to determine if the discharge had been remedied. The City will review and
update the Ongoing Screening Program to include the Priority Outfall concept recommended by
the Wisconsin Department of Natural Resources (WDNR) in the March 15, 2012 IDDE guidance
document. After the updated plan is implemented, annual outfall screenings will resume
according to the revised schedule.
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.
OMNNI assisted the City of Oshkosh with developing a four-year ongoing screening program in
2009, and completed the ongoing screening program for the first set of outfalls in 2010. The first
four-year inspection cycle was completed in 2013. The 2014 screenings were conducted with
the purpose of determining if suspected illicit discharges from previous years were ongoing. The
City may need to include these results in the annual report required by the MS4 permit due
March 31, 2015.
February 23, 2015 2 2014 Ongoing Screening Summary Report
City of Oshkosh
Outfall Identification and Mapping
In 2009, the City of Oshkosh identified major and minor outfalls within the city as part of the
MS4 mapping process required by the permit. Outfalls were identified at the locations where
the City’s MS4 discharged to a water of the state, to an adjacent municipality, or outside the
permitted area. Approximately 348 potential outfalls were identified during this process in 2009.
(The number has changed since then, due to construction of stormwater detention basins,
reconfiguration of the City’s storm sewer system, and reevaluation of existing outfalls.)
Topographic information was also used to define approximate drainage basins for each outfall.
Based on this information, each outfall was 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.” 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 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.
When necessary, field verification was used to determine outfall sizes or drainage patterns. The
current outfall map includes 100 major outfalls, 230 minor outfalls, and 32 “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.
Initial Screening Program
Per Section 2.3.2 of the MS4 general permit, the City was required to conduct an initial field
screening at all major outfalls during dry weather periods. This initial field screening was
required to be conducted within 36 months of the date that the permit was issued. The minor
and supplemental outfalls should be included in the ongoing field screening to be conducted in
future years.
OMNNI conducted the initial field screening for the City of Oshkosh during the summer of 2009.
During the initial field screening, 109 major outfalls throughout the City were inspected. (There
has been a net decrease of nine major outfalls since the initial field screening due to changes in
the storm sewer system and field confirmation of measurements.) The initial field screening
revealed 24 major outfalls that showed evidence of a potential illicit discharge. The results of
the initial field screening were presented to the City in the City of Oshkosh Initial Field
Screening Summary Report (May 18, 2010).
February 23, 2015 3 2014 Ongoing Screening Summary Report
City of Oshkosh
Development of Ongoing Screening Program
Section 2.3.3 of the MS4 permit requires municipalities to develop an ongoing screening
program and submit it to the WDNR within 36 months of the date that the permit was issued.
The ongoing screening program was to include provisions to include all outfalls (major, minor
and supplemental) at least once during the 5-year permit cycle. In developing the program,
consideration was to be given to the hydrological conditions, total drainage area, population
density, traffic density, age of the structures or buildings in the area, history of the area, and
land use types.
Based on the MS4 permit requirements and other information obtained from WDNR, OMNNI
developed a proposed ongoing screening program for the City of Oshkosh. The permitted area
was divided into four inspection districts, each with approximately the same number of outfalls.
One district would be inspected each year, resulting in a four-year inspection cycle. At the end
of the first inspection cycle, the inspection results were to be evaluated to determine if the
inspection cycle for each outfall should be adjusted.
The proposed ongoing screening program was presented to the City in the CITY OF OSHKOSH
IDDE O NGOING FIELD SCREENING PROGRAM (May 19, 2010). OMNNI conducted the first round of
ongoing screening inspections during the summer of 2010. The first four-year inspection cycle
was completed in 2013. Outfalls that had potential illicit discharges identified during the 2010-
2013 inspection years were screened during the 2014 ongoing screening program. The outfalls
that were included in the 2014 screening program are shown in Appendix A.
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
February 23, 2015 4 2014 Ongoing Screening Summary Report
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)
Copper
Detergents
Phenols (for outfalls in basins with industrial sources)
Ammonia
Temperature
Conductivity
The list of chemical parameters was developed using the parameters that were required for the
initial field screening in the MS4 permit (listed in bold), and supplemented with additional
parameters that are useful for tracking illicit discharges.
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.
February 23, 2015 5 2014 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 2014 inspection area. The location
of the weather station is shown in Figure 1.
Figure 1 – Location of weather station for weather history
February 23, 2015 6 2014 Ongoing Screening Summary Report
City of Oshkosh
The weather history from August 1 through October 15, 2014 from this weather station is
shown in Figure 2.
Figure 2 – Summer 2014 weather history (Weather Underground)
February 23, 2015 7 2014 Ongoing Screening Summary Report
City of Oshkosh
Outfall inspections were conducted in the City of Oshkosh on October 7 and 9, 2014. Those
inspection dates (red), along with the daily rainfall history (blue), are shown in Figure 3.
Figure 3 – Rainfall history and outfall inspections
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 2014 were primarily submerged outfalls, no flow was observed at any of the
outfalls.
Submerged outfalls, along with the observed flow patterns, are described in the next section.
February 23, 2015 8 2014 Ongoing Screening Summary Report
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 42 inspected outfalls, 12 were partially submerged, and 30 were fully
submerged (Figure 5). Of the 30 fully submerged outfalls, 24 could not be physically located.
February 23, 2015 9 2014 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.
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.
February 23, 2015 10 2014 Ongoing Screening Summary Report
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
February 23, 2015 11 2014 Ongoing Screening Summary Report
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.
February 23, 2015 12 2014 Ongoing Screening Summary Report
City of Oshkosh
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.)
February 23, 2015 13 2014 Ongoing Screening Summary Report
City of Oshkosh
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 2014, 14 outfalls were classified as potential illicit discharge because of the presence of gross
solids in their upstream manholes. One outfall (03-81) was classified as an obvious illicit
discharge because of the observed petroleum sheen and odor. 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
February 23, 2015 14 2014 Ongoing Screening Summary Report
City of Oshkosh
well as providing clues about the potential sources of the flow. Section 2.3.2.2 of the general
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:
pH
Temperature
Conductivity
Chlorine (total and free)
Copper
Ammonia
Detergents
Phenols (for drainage basins with industrial areas)
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 39 stormwater samples were collected and
analyzed as part of the ongoing screening process in 2014 – none were from flow streams, and
all were from pools. Depending on the specific conditions for the outfall, not all tests were run
for all samples.
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 an
Oakton PC-10 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
February 23, 2015 15 2014 Ongoing Screening Summary Report
City of Oshkosh
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.
Figure 7 – pH sample results
The pH values ranged from 7.22 to 8.34. None of the samples were outside of the standard 6.0
to 9.0 pH range, so none of the samples were considered suspect due to pH.
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.
February 23, 2015 16 2014 Ongoing Screening Summary Report
City of Oshkosh
Testing Method
During the ongoing screening program, OMNNI recorded the temperature of the outfall samples
with an Oakton PC-10 handheld pH/conductivity/temperature meter, which displays the
temperature reading to 0.1 °C. The temperature reading was taken in the sample 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 53 to 62 °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. Due to a malfunction of the field testing equipment, 16 samples
could not be analyzed for temperature. 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
February 23, 2015 17 2014 Ongoing Screening Summary Report
City of Oshkosh
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.
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 an Oakton PC-10 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 310 to 2,360 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
1 USEPA: Water-Monitoring & Assessment – Conductivity (http://water.epa.gov/type/rsl/monitoring/vms59.cfm)
February 23, 2015 18 2014 Ongoing Screening Summary Report
City of Oshkosh
potential illicit discharges. The illicit discharge potential of the outfalls with elevated
conductivities are summarized in Table 1.
Table 1 – IDDE potential of outfalls with elevated conductivities
Outfall
Conductivity
(µS/cm) IDDE Potential Reason
15-1093 US1 2,030 Unlikely
No other significant chemical or physical
indicators identified.
15-1095 US1 2,630 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.
February 23, 2015 19 2014 Ongoing Screening Summary Report
City of Oshkosh
Copper
Background
The presence of copper in stormwater runoff is usually due to discharge from industries that
manufacture copper-based products or use copper-containing chemicals in their manufacturing
process. In some cases, copper can leach from plumbing systems and enter the water. Copper
concentrations as low as 0.1 mg/L can be toxic to aquatic vegetation and wildlife.
The general permit requires sampling for total copper. In general the action level for total
copper is set at 0 mg/L. Any detection of copper indicates the presence something other than
stormwater in the sample.
Testing Method
During the ongoing screening program, OMNNI tested the outfall samples for total copper using
Hach Copper Test Strips, 0-3 mg/L. These test strips had result steps of 0, 0.2, 0.5, 1, and 3 ppm.
The copper tests were taken in the sample bottle as soon as possible after the sample was
collected from the outfall.
Results
None of the samples tested positive for total copper, so none of the samples were considered
suspect due to copper.
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.
February 23, 2015 20 2014 Ongoing Screening Summary Report
City of Oshkosh
Results
The ammonia results for the samples are shown in Figure 10.
Figure 10 – Ammonia sample results
The ammonia values ranged from 0 to 3 ppm. One sample was at or below 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 0.5 Obvious Petroleum sheen and odor in manhole.
02-184 US1 3 Potential
0.7 mg/L detergent in sample. Past ammonia
and detergent detections.
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
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
February 23, 2015 21 2014 Ongoing Screening Summary Report
City of Oshkosh
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.
Figure 11 – Typical MBAS Detergent Test Results
February 23, 2015 22 2014 Ongoing Screening Summary Report
City of Oshkosh
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
The detergent results for the samples are shown in Figure 12.
Figure 12 – Detergent sample results
The detergent values ranged from 0 to 0.7 mg/L, with one sample having estimated detergent
concentration of 0.7 mg/L. This sample – 02-184 US1 – is located on an old branch of storm
sewer on Legion Place. The sample also had an ammonia concentration of 3 ppm, so it was
considered a potential illicit discharge. This outfall is discussed in more detail in the Potential
Illicit Discharges section of this report.
Phenols
Background
The presence of phenol in stormwater runoff is usually due to discharge from industries that use
phenol-containing chemicals in their manufacturing process. These industries include chemical,
textile, paint, resin, tire, plastic, electronics and pharmaceutical manufacturing. Phenol can also
occur naturally in the groundwater in some areas.
The general permit requires sampling for phenol. Because of its limited sources, the Ongoing
Screening Program submitted to the WDNR proposed that phenol only be tested for outfalls
with industrial sources in the drainage basin. In general the action level for phenol is set at
0 mg/L. Any detection of phenol indicates the presence something other than stormwater in the
sample.
February 23, 2015 23 2014 Ongoing Screening Summary Report
City of Oshkosh
Testing Method
During the ongoing screening program, OMNNI tested the outfall samples for phenol using 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 phenol
concentration. In most cases, a clear result indicates no phenol in the sample, and an orange tint
indicated a positive detection of phenol.
Because of the equipment and reagents used in the phenol test, the phenol test was conducted
in the office at the end of the day. No dissipation of the phenol was expected within 24-48 hours
of collecting the sample.
Results
None of the samples tested positive for phenol, so none of the samples were considered suspect
due to phenol.
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 42 inspected outfalls, 25 were classified as unlikely, 16 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
01-520 Potential Persistent gross solids in upstream manhole (also present in 2009,
2010, 2011, 2012 and 2013).
02-184 Potential Detergent and ammonia in upstream manhole (also present in 2012
and 2013). Storm sewer supposedly abandoned.
02-357 Potential Persistent gross solids in upstream manhole (also present in 2011
and 2012).
03-22 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
and 2011).
06-52 Potential Persistent gross solids in upstream manhole (also present in 2010
and 2011).
February 23, 2015 24 2014 Ongoing Screening Summary Report
City of Oshkosh
Outfall Classification Reason
08-284 Potential Persistent gross solids in upstream manhole (also present in 2010
and 2011).
08-347 Potential Persistent gross solids in upstream manhole (also present in 2010
and 2011).
11-376 Potential Persistent gross solids in upstream manhole (also present in 2009
and 2011).
11-512 Potential Persistent gross solids in upstream manhole (also present in 2011
and 2012).
12-569 Potential Persistent gross solids in upstream manhole (also present in 2010).
12-576 Potential Persistent gross solids in upstream manhole (also present in 2009).
13-1758 Potential Persistent gross solids in upstream manhole (also present in 2013).
Former petroleum release.
16-142 Potential Persistent gross solids in upstream manhole (also present in 2010,
2011 and 2012).
16-533 Potential Persistent gross solids in upstream manhole (also present in 2010
and 2011).
16-1508 Potential Ammonia in upstream manhole (also present in 2013).
03-81 Obvious Petroleum odor and sheen in upstream manhole, with slightly
elevated ammonia (also present in 2009).
A chart showing the number of outfalls inspected over the past five years (starting with the
initial screening in 2009) and the number of potential or obvious illicit discharges is shown in
Figure 13.
Figure 13 – Illicit discharge potential of inspected outfalls
February 23, 2015 25 2014 Ongoing Screening Summary Report
City of Oshkosh
Upstream Manholes with Significant Floatable Debris
During the 2014 ongoing screening program, 14 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 2009-2013 screening programs are shown in the table in
Appendix D-1. The 2014 screening results are also shown.
It is recommended that the outfalls with continuing observations of significant floatable debris
be 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 02-184 (Legion Place)
The City contacted OMNNI on December 4, 2012 with a request to investigate a report of suds in
Lake Winnebago near outfall 02-184. A concerned citizen contacted the City about suds along
the shoreline near Legion Place on November 9, 2012. The resident had stated that the suds
were common during the summer of 2011, and that they were again present. The City
investigated the report, but no suds were observed during the investigation. The caller was
advised to notify the City if the suds reappeared. The resident contacted the City again on
November 30, 2012 to report that the suds were present again at that time.
OMNNI investigated the area around the outfall on December 6, 2012. Outfall 02-184 consists of
an 8-inch clay pipe that is fully submerged and could not be located. The first upstream manhole
February 23, 2015 26 2014 Ongoing Screening Summary Report
City of Oshkosh
(02-184) is located directly west of the outfall on Legion Place, and has two short segments to
the north and south of the manhole. The actual drainage basin only consists of five residential
parcels along the shoreline. A separate storm sewer pipe runs parallel to this branch in Legion
Place, and discharges at outfall 02-357, north of outfall 02-184.
OMNNI met with the resident that reported the suds to the City. Some suds were present on the
shoreline near the outfall. Samples of the suds and lake water were collected near the outfall
and at two locations along the shoreline north of the outfall. Because the outfall was
submerged, a sample was also collected from the pool in the upstream manhole.
Figure 14 – Suds along shoreline north of outfall 02-184 (2012)
Figure 15 – Pool in upstream manhole 02-184 US1 (2012)
The suds observed on December 6 were consistent with the appearance of the suds that can be
formed by natural surfactants in surface water. However, the sample that was collected from
the pool in the upstream manhole had a detergent concentration of 0.2 mg/L, and an ammonia
concentration of 3-6 ppm. These chemical indicators suggest that sanitary sewage may be
present in the storm sewer, which could be causing the suds in the lake.
Based on the sample results, OMNNI recommended that the City televise the entire storm
sewer branch to locate any potential sanitary cross connections. An email was sent to the Illicit
Discharge Coordinator on December 6 summarizing the results and the recommended action.
February 23, 2015 27 2014 Ongoing Screening Summary Report
City of Oshkosh
After the storm sewer was televised, it appeared that the storm sewer outfall had been
abandoned.
The outfall and upstream manhole were re-screened on September 5, 2013. At that time, a
strong sewer odor was present in the upstream manhole. In addition, the sample had an
ammonia concentration in excess of 6 ppm, and a detergent concentration of 1.3 mg/L. Both of
these concentrations were higher than the 2012 screening. An update was provided to the Illicit
Discharge Coordinator on September 6, 2013.
Figure 16 – Pool in upstream manhole 02-184 US1 (2013)
Because of the potential illicit discharges in prior years, the outfall was included in the 2014
screening program. During the 2014 screening, it was noted that the manhole appeared to be
cleaner, with less sludge at the bottom. The sewage odor that was detected in previous years
was not detected.
Figure 17 – Pool in upstream manhole 02-184 US1 (2014)
However, the stormwater sample collected from the manhole pool had an ammonia
concentration of 3 ppm, and a detergent concentration of 0.7 mg/L. While these concentrations
are approximately half of the 2013 concentrations, they are still significant.
Based on these results, it appears that there may be sanitary sewage in this branch of storm
sewer. The City should verify that it is indeed abandoned, and also check for cross-connections
February 23, 2015 28 2014 Ongoing Screening Summary Report
City of Oshkosh
from the nearby residences. This outfall will likely be classified as a priority outfall in the revised
Ongoing Screening Plan, which will result in annual inspections.
Additional information and maps related to this investigation are included in Appendix D-2.
Outfall 03-81 (Pioneer Drive)
Outfall 03-81 discharges near the railroad trestle at the north end of Pioneer Drive. The outfall is
fully-submerged, and the MS4 mapping suggests that the end of the pipe may be 90 feet past
the shoreline. As a result, the outfall is screened at the first upstream manhole.
The outfall was first screened in 2009. The first upstream manhole was located on the south side
of Pioneer Drive, behind the railroad control shed. When the manhole was opened, a strong
smell of diesel fuel was detected inside the manhole. The manhole was also submerged, and
had a significant amount of floatable debris, which appeared to be coated with oil and grease.
Figure 18 – Upstream manhole 03-81 US1 (2009)
Figure 19 – Floatable debris and grease in upstream manhole 03-81 US1 (2009)
A sample was collected from upstream manhole 03-81 US1. The sample had a grayish-black
color, and had a strong odor of diesel fuel. The sampling equipment and container were coated
in grease from penetrating the floatable debris. None of the typical sampling parameters tested
February 23, 2015 29 2014 Ongoing Screening Summary Report
City of Oshkosh
positive. Because of the obvious odor of diesel fuel and appearance of grease, no additional VOC
or oil/grease tests were run. The railroad track ballast in the area showed no signs of stains or
other leaks, so a railroad spill seemed unlikely.
Figure 20 – Sample container from upstream manhole 03-81 US1 (2009)
After receiving authorization from the City to use the contingency funds set aside for the
project, additional upstream manholes were screened in an attempt to determine the extent of
the contamination and the possible source. The first upstream manhole could not be located, as
it was buried under the ballast in the railroad right-of-way. The second upstream manhole was
located, also in the railroad right-of-way. This manhole (03-81 US2) also had oil-covered
floatables, but the diesel odor was not as significant as in 03-81 US1.
Figure 21 – Floatable debris in upstream manhole 03-81 US2 (2009)
Additional upstream manholes were sampled along E. 10th Avenue. The manholes on 10th
Avenue did not have the floatable debris or the diesel odor. However, they did have a reddish-
brown tint to the submerged pool, and showed a slight oil sheen. The property on the south side
of 10th Avenue is a steel fabrication facility, and the property on the north side is a metal salvage
facility. Both could be potential sources of oil and grease.
February 23, 2015 30 2014 Ongoing Screening Summary Report
City of Oshkosh
Figure 22 – Oil sheen in upstream manhole 03-81 US4 (2009)
The drainage area for this storm sewer branch includes the properties along E. 10th Avenue, as
well as properties on W. 10th Avenue, west of Main Street. The upstream manholes west of
Main Street were also screened, and were found to be dry, with significant amounts of dry
sediment inside the manholes. It appeared that the most likely sources of the illicit discharge
would be east of Main Street.
The City and OMNNI believed that the illicit discharge evidence for this outfall was not caused
by one significant event. Rather, it was likely caused by a gradual buildup of diesel fuel and
oil/grease over many years, which became trapped in the downstream manholes. Upon
discovering the problem, the City vacuumed the upstream manholes. A follow-up inspection of
manhole 03-81 US1 revealed that the manhole was still fully-submerged, but the sample
collected from the pool did not have a detectable odor.
The 2010 follow-up screening showed no petroleum sheen or floatable debris, but a slight
petroleum odor. No abnormal chemical indicators were noted. The 2011 screening had a slight
amount of floatable debris and 0.25 ppm ammonia, but no petroleum sheen or odor. The outfall
was not screened in 2012 or 2013.
The outfall was screened on October 9, 2014 as part of the 2014 ongoing screening program due
to the past illicit discharge. During this inspection, the manhole once again had moderate
floatable debris, a visible petroleum sheen on the water and debris, and a faint petroleum odor.
The stormwater sample collected from the manhole also contained an ammonia concentration
of 0.5 ppm. The Illicit Discharge Coordinator was contacted on October 9 and notified of the
reappearance of the petroleum.
February 23, 2015 31 2014 Ongoing Screening Summary Report
City of Oshkosh
Figure 23 – Oil sheen and debris in manhole 03-81 US1 (2014)
The City vacuumed the debris from the manhole on October 9. The manhole was rescreened on
October 22, 2014. There was no debris present in the manhole, but the petroleum sheen and
odor was still present.
Figure 24 – Oil sheen and debris in manhole 03-81 US1 after vacuuming (2014)
Based on the 2009 tracking, the suspected source(s) came from E 10th Avenue. The manhole at
the east end of E 10th Avenue was opened for a visual inspection. There was a small submerged
pool in this manhole, and a slight petroleum sheen and odor were detected. There were also
some darker stains above the flowline of the manhole, possibly from petroleum.
February 23, 2015 32 2014 Ongoing Screening Summary Report
City of Oshkosh
Figure 25 – Upstream manhole 03-81 US4 (2014)
Figure 26 – Petroleum sheen in upstream manhole 03-81 US4 (2014)
There appears to be an ongoing intermittent discharge of petroleum from a source on E. 10th
Street. OMNNI recommends that the City televise the storm sewer branches along this segment
to identify any potential cross connections. It may also be necessary for City inspectors to
inspect the areas where the storm sewer crosses private property to check for potential sources
of industrial runoff that may enter the storm sewer system.
This outfall will likely be classified as a priority outfall in the revised Ongoing Screening Program,
which will result in annual screenings. The annual screenings will assist in identifying these
intermittent discharges if no obvious source is found.
Additional information and maps related to this investigation are included in Appendix D-3.
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.
February 23, 2015 33 2014 Ongoing Screening Summary Report
City of Oshkosh
Figure 27 – Outfall 16-1508 (5/30/2012)
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.
The manhole was resampled on June 6, 2012. The sample collected on this date did not have
ammonia. No additional investigation was conducted for this outfall at that time, but it was
decided that the outfall should be checked one more time before the end of the year.
The outfall was rescreened on September 27, 2012. At that time, the Sawyer Creek stream
channel was under construction. The outfall was still partially submerged, and a sample was
collected from the upstream manhole.
Figure 28 – Outfall 16-1508 (9/27/2012)
The sample collected from the upstream manhole had an ammonia concentration of 3 ppm,
which was higher than the May 30 sample, and warranted tracing of the source. The various
manholes upstream of the outfall were sampled in an attempt to isolate the segment of the
storm sewer where the ammonia was being introduced.
After collecting samples from the various upstream manholes, it was determined that the
ammonia concentration was 3 ppm at manholes 16-1508 and 16-1504. However, at the next
February 23, 2015 34 2014 Ongoing Screening Summary Report
City of Oshkosh
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.
Figure 29 – Park restroom building upstream of 16-1504 (2013)
The Illicit Discharge Coordinator was notified of the findings on September 28, 2013. At that
time, OMNNI recommended that the storm sewer segment between manholes 16-460 and
16-1504 be televised to inspect for potential leaks or cross connections, particularly in the area
of the restroom building.
The outfall was screened on October 7, 2014 as part of the 2014 ongoing screening program due
to the past illicit discharge. During this inspection, the upstream manhole once again had an
ammonia concentration of 3 ppm. As in 2012, the ammonia was traced back to inlet 16-1504,
just downstream of the park restrooms, and there was no ammonia detected in the next
upstream inlet (16-430). It was noted that the park restrooms were closed for the season at the
time of the inspection, so they are less likely to be the source of the ammonia.
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 Illicit Discharge Coordinator was provided an update about the continued presence of the
ammonia on October 10.
Because of the continued presence of ammonia in the stormwater samples, this outfall will likely
be 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.
Additional maps and information related to this investigation are included in Appendix D-4.
February 23, 2015 35 2014 Ongoing Screening Summary Report
City of Oshkosh
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.
Damage
Three outfalls showed signs of damage that may require attention in the near future. All three
cases consisted of various degrees of corrosion on corrugated metal 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
08-284 Minor Corrosion on submerged pipe
12-890 Moderate Corrosion on sides and bottom of CMP
12-890x Minor Minor corrosion of CMP
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 30 – Corroded metal pipe at outfall 08 -284 (minor
damage)
Figure 31 – Corroded metal pipe at outfall 12-890 (moderate
damage)
February 23, 2015 36 2014 Ongoing Screening Summary Report
City of Oshkosh
Figure 32 – Corroded metal pipe at outfall 12 -890x (minor
damage)
Deposition
A total of 13 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
02-322 US1 Minor 1” deposition in upstream manhole
03-35 US1 Minor 1” deposition in upstream manhole
03-381 US1 Minor 2” deposition in upstream manhole
03-81 US1 Minor 2” deposition in upstream manhole
06-1694 US1 Moderate 3” deposition in upstream inlet
06-221 US1 Minor 3” deposition in upstream manhole
08-284 Minor 3” deposition in end of submerged pipe
12-890 Minor 3” deposition and stones at end of pipe
13-1758 Moderate 8” deposition in end of submerged pipe
13-3099 Minor 4” deposition/gravel in end of submerged pipe
15-1093 US1 Moderate 3” deposition in upstream manhole
16-119 US1 Minor 1” deposition in upstream inlet
16-142 US1 Minor 1” deposition in upstream inlet
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.
February 23, 2015 37 2014 Ongoing Screening Summary Report
City of Oshkosh
Figure 33 – Minor deposition in manhole 02-322 US1
Figure 34 – Minor deposition in manhole 03-35 US1
Figure 35 – Minor deposition in manhole 03-381 US1
Figure 36 – Minor deposition in manhole 03-81 US1
Figure 37 – Moderate deposition in inlet 06-1694 US1
Figure 38 – Minor deposition in manhole 06-221 US1
February 23, 2015 38 2014 Ongoing Screening Summary Report
City of Oshkosh
Figure 39 – Minor deposition at outfall 08-284
Figure 40 – Minor deposition at outfall 12-890
Figure 41 – Moderate deposition at outfall 13-1758
Figure 42 – Minor deposition at outfall 13-3099
Figure 43 – Moderate deposition in manhole 15-1093 US1
Figure 44 – Minor deposition in inlet 16-119 US1
February 23, 2015 39 2014 Ongoing Screening Summary Report
City of Oshkosh
Figure 45 – Minor deposition in inlet 16-142 US1
Erosion
No erosion was observed near any of the outfalls that were screened under the 2014 screening
program.
Graffiti
Graffiti was observed in or around one outfall. The graffiti was relatively minor, 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 46 – Graffiti near outfall 12-569
February 23, 2015 40 2014 Ongoing Screening Summary Report
City of Oshkosh
CONCLUSION
OMNNI assisted the City of Oshkosh with the 2014 ongoing screening of the MS4 outfalls, as
required by the MS4 permit. A total of 42 outfalls were screened, along with upstream
monitoring locations when necessary. Of those 42 outfalls, 25 exhibited unlikely potential of
past illicit discharges, 16 were classified as “potential,” and one was classified as “obvious.”
These results are summarized in Figure 47:
Figure 47 – 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 3 outfalls with structural damage, 13 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.
The City will review and update the Ongoing Screening Program to include the Priority Outfall
concept recommended by the WDNR in the March 15, 2012 IDDE guidance document. After the
updated plan is implemented, annual outfall screenings would resume according to the revised
schedule.
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
25
16
1
Illicit Discharge Potential of Inspected Outfalls
Unlikely
Potential
Obvious
February 23, 2015 41 2014 Ongoing Screening Summary Report
City of Oshkosh
described in this report. The scope of this report is limited to the specific project and the
inspection locations described herein.
Project Engineer
Project Manager
Appendix A
MS4 Outfall Maps
A-1 MS4 Outfall Map
A-1 2014 Outfall Inspection Map
C:\SyncFolders\IDDE_GIS\MS4Map_11x17_Oshkosh.mxd
PROJECT NO.N2029C14
FIGURE NO.A-1
SCALE:1 " = 3,620 'Project Manager:BDWProject Engineer:JCWDrawn By:JCWChecked By:BDW
2014 IDD E ONG OING SCREEN ING PROG RAM
CITY OF OSHKOSHWINNEBAGO COUNTY, WISCONSIN
MS4 OUTFALL MAP
ONE SYSTEMS DRIVEAPPLETON, W I 54914 PHO NE (920) 735-6900FAX (920) 830-6100 Date:12/11/2014
Legend
Municipal BoundaryOutfalls
Major Outfall
Minor Outfall
Supplemental Outfall
0 10.5 Miles
C:\SyncFolders\IDDE_GIS\InspectedOutfalls_Oshkosh.mxd
PROJECT NO.N2029C14
FIGURE NO.A-2
SCALE:1 " = 5,047 'Project Manager:BDWProject Engineer:JCWDrawn By:JCWChecked By:BDW
2014 IDDE ONG OING SCREEN ING PROG RAM
CITY OF OSHKOSHWINNEBAGO COUNTY, WISCONSIN
2014 OUTFALL INSPECTION MAP
ONE SYSTEMS DRIVEAPPLETON, W I 54914 PHONE (920) 735-6900FAX (920) 830-6100 Date:12/11/2014
Weather Station
Screened Outfalls
Major Outfall
Minor Outfall
Supplemental Outfall
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.N2029C14
FIGURE NO.C-1
SCALE:1 " = 5,047 'Project Manager:BDWProject Engineer:JCWDrawn By:JCWChecked By:BDW
2014 IDDE ONG OING SCREEN ING PROG RAM
CITY OF OSHKOSHWINNEBAGO COUNTY, WISCONSIN
OUTFALLS WITH POTENTIALILLICIT DISCHARGESONE SYSTEMS DRIVEAPPLETON, W I 54914 PHONE (920) 735-6900FAX (920) 830-6100 Date:12/11/2014
Illicit Discharge Potential
Potential
Obvious
C:\SyncFolders\IDDE_GIS\Cond_Damage_Oshkosh.mxd
PROJECT NO.N2029C14
FIGURE NO.C-2
SCALE:1 " = 7,000 'Project Manager:BDWProject Engineer:JCWDrawn By:JCWChecked By:BDW
2014 IDDE ONG OING SCREEN ING PROG RAM
CITY OF OSHKOSHWINNEBAGO COUNTY, WISCONSIN
OUTFALLS WITH DAMAGE
ONE SYSTEMS DRIVEAPPLETON, W I 54914 PHONE (920) 735-6900FAX (920) 830-6100 Date:11/13/2014
Damage Severity
Minor (2)
Moderate (1)
Severe (0)
C:\SyncFolders\IDDE_GIS\Cond_Deposition_Oshkosh.mxd
PROJECT NO.N2029C14
FIGURE NO.C-3
SCALE:1 " = 7,000 'Project Manager:BDWProject Engineer:JCWDrawn By:JCWChecked By:BDW
2014 IDDE ONG OING SCREEN ING PROG RAM
CITY OF OSHKOSHWINNEBAGO COUNTY, WISCONSIN
OUTFALLS WITH DEPOSITION
ONE SYSTEMS DRIVEAPPLETON, W I 54914 PHONE (920) 735-6900FAX (920) 830-6100 Date:11/13/2014
Deposition Severity
Minor (10)
Moderate (3)
Severe (0)
C:\SyncFolders\IDDE_GIS\Cond_Erosion_Oshkosh.mxd
PROJECT NO.N2029C14
FIGURE NO.C-4
SCALE:1 " = 7,000 'Project Manager:BDWProject Engineer:JCWDrawn By:JCWChecked By:BDW
2014 IDDE ONG OING SCREEN ING PROG RAM
CITY OF OSHKOSHWINNEBAGO COUNTY, WISCONSIN
OUTFALLS WITH EROSION
ONE SYSTEMS DRIVEAPPLETON, W I 54914 PHONE (920) 735-6900FAX (920) 830-6100 Date:11/12/2014
Erosion Severity
Minor (0)
Moderate (0)
Severe (0)
No Erosion Observed
C:\SyncFolders\IDDE_GIS\Cond_Graffiti_Oshkosh.mxd
PROJECT NO.N2029C14
FIGURE NO.C-5
SCALE:1 " = 7,000 'Project Manager:BDWProject Engineer:JCWDrawn By:JCWChecked By:BDW
2014 IDDE ONG OING SCREEN ING PROG RAM
CITY OF OSHKOSHWINNEBAGO COUNTY, WISCONSIN
OUTFALLS WITH GRAFFITI
ONE SYSTEMS DRIVEAPPLETON, W I 54914 PHONE (920) 735-6900FAX (920) 830-6100 Date:11/12/2014
Graffiti Severity
Minor (0)
Moderate (1)
Severe (0)
Appendix D
Illicit Discharge Investigation Reports
D-1 Upstream Manholes with Significant Floatable Debris
D-2 02-184 (Legion Place) Investigation
D-3 03-81 (Pioneer Drive) Investigation
D-4 16-1508 (N. Westfield Street) 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)
2014 IDDE
Potential
01-132 US1
(01-132)
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)
Unlikely
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)
2014 IDDE
Potential
03-381 US1
(03-381)
Unlikely
03-81 US1
(03-81)
Obvious*
05-264 US1
(05-264)
Unlikely
06-1694
US1
Unlikely
06-221 US1
(06-221)
Unlikely
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)
2014 IDDE
Potential
06-560 US1
(06-560)
(outfall removed and
replaced with outfall
06-2241)
N/A
06-829 US1
(06-831)
Unlikely
08-284 US1
(08-284)
Potential
08-347 US1
(08-347)
Potential
09-101c
US1
(09-47)
Not screened due to
traffic
Unlikely
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)
2014 IDDE
Potential
11-465 US1
(11-465)
(outfall removed and
replaced with pump
station/outfall 11-465a)
N/A
11-512 US1
(11-512)
Potential
12-569 US1
(12-569)
Potential
12-576 US1
(12-576)
Potential
14-1075
US1
(14-1075)
Unlikely
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)
2014 IDDE
Potential
16-201 US1
Unlikely
16-396 US1
(16-396)
(Behind locked fence –
manhole not screened) N/A
16-436 US1
(16-436)
(Behind locked fence –
manhole not screened) N/A
16-463 US1
Unlikely
16-533 US1
(16-533)
Potential
16-551 US1
(16-551)
Unlikely
C:\SyncFolders\IDDE_GIS\Floatables_Oshkosh.mxd
PROJECT NO.N2029C14
FIGURE NO.D-1
SCALE:1 " = 5,047 'Project Manager:BDWProject Engineer:JCWDrawn By:JCWChecked By:BDW
2014 IDDE ONG OING SCREEN ING PROG RAM
CITY OF OSHKOSHWINNEBAGO COUNTY, WISCONSIN
MANHOLES WITH FLOATA BLEGROSS SOLIDSONE SYSTEMS DRIVEAPPLETON, W I 54914 PHONE (920) 735-6900FAX (920) 830-6100 Date:11/12/2014
Gross Solids Severity
Minor
Moderate
Severe
APPENDIX D-2
02-184 (Legion Place) Investigation
North of outfall
South of outfall02-184
02-357
02-348
02-349
02-29702-296
02-289
02-183
02-184
02-185
02-357
LEGION PL
WINNEBAGO AVE
121206-09
121206-10
121206-04
121206-72
F:\ENVIRO\N2029C14 (Oshkosh IDDE 2014)\GIS\Legion.mxd
PROJECT NO.N2029C14
FIGURE NO.D-2
SCALE:1 " = 100 'Project Manager:BDWProject Engineer:JCWDrawn By:JCWChecked By:BDW
OSHKOSH 2014 IDDE O NGOING SCREENING
CITY OF OSHKOSHWINNEBAGO COUNTY, WISCONSIN
OUTFALL 02-184 (LEGION PL)INVESTIGATION (12/6/2012)ONE SYSTEMS DRIVEAPPLETON, W I 54914 PHONE (920) 735-6900FAX (920) 830-6100 Date:12/15/2014
0 100 200Feet
Parcels
Drainage Basins
Storm Sewer
Storm Manhole
Outfalls
Minor Outfall
Minor Outfall - Alternate Location
12/6/2012 Samples
12/6/2012 Samples
Sample Location Ammonia (ppm)Detergent (mg/L)Conductivity (μS/cm)
121206-72 Manhol e 02-184 3-6 0.2 1091121206-10 Near outfall 0.50 0 429121206-09 North of outfall 0.25 0 N/A121206-04 Control 0.25 0 420
130905-16 Manhol e 02-184 6+1.3 1036
141009-13 Manhol e 02-184 3 0.7 1030
2012
2013
2014
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
1
Jason Weis
From:Brian Wayner
Sent:Friday, September 06, 2013 11:52 AM
To:jrabe@ci.oshkosh.wi.us
Cc:Jason Weis
Subject:Oshkosh IDDE
Attachments:13-1716.pdf; Legion.pdf
James,
Jason and I finished up the outfall inspections yesterday. Samples from two of the re-inspections (detections from the
previous year) indicated detergent in the stormwater.
The manhole upstream from the pond (13-1716 attachment) had a high detergent detection. We didn’t observe water
coming from pipe from the carwash. The sample was taken from the water below/adjacent to the carwash pipe
discharge. Based on previous inspection work, we assume the detergent came from the carwash even though there was
no flow coming from the carwash at the time the sample was collected.
We also had a high detergent detection from a sample collected from the manhole (121206-72) in Legion Place (Legion
attachment). There were no notable suds in the lake (this inspection area originated from a lake resident contact last
year). The sample collected from the manhole also had a strong septic odor. Our understanding is the storm line in
Legion was abandoned, which makes the observed detergent detection and septic odor difficult to explain.
Please note, the attached maps are from last year’s inspections. I included them for reference. Jason and I should be in
the office on Monday if you want to discuss these finding further.
Have a great weekend!
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
This email is subject to OMNNI Associates, Inc. Electronic File Disclaimer.
For full disclaimer see http://www.omnni.com/legal/OMNNI_Email_Disclaimer.pdf
APPENDIX D-3
03-81 (Pioneer Drive) Investigation
1
Jason Weis
From:Rabe, James E. <jrabe@ci.oshkosh.wi.us>
Sent:Friday, October 10, 2014 11:07 AM
To:Jason Weis; Brian Wayner
Subject:FW: Outfall 03-81 petroleum
FYI
From: Burns, Todd
Sent: Thursday, October 09, 2014 12:54 PM
To: Rabe, James E.; Hintz, Andrew
Subject: RE: Outfall 03-81 petroleum
Will be done this afternoon. Todd
From: Rabe, James E.
Sent: Thursday, October 09, 2014 11:21 AM
To: Burns, Todd; Hintz, Andrew
Subject: FW: Outfall 03-81 petroleum
Todd / Andy,
Can you have a vac truck clean this manhole so we can check again?
Thank you,
James
From: Jason Weis [mailto:Jason.Weis@omnni.com]
Sent: Thursday, October 09, 2014 10:19 AM
To: Rabe, James E.
Cc: Brian Wayner
Subject: Outfall 03-81 petroleum
James:
While screening the upstream manhole for outfall 03-81 (east end of Pioneer by the RR bridge), I found a fair
amount of floatable debris and a petroleum sheen. The petroleum could be residual from the 2009 incident, or it
could be a new release.
It's something we'll want to keep an eye on. This outfall will definitely be included in the list of priority outfalls.
I hope to finish the screening today. I'll let you know of any other issues.
Sent from my U.S. Cellular® Smartphone
This email is subject to OMNNI Associates, Inc. Electronic File Disclaimer. For full disclaimer see
http://www.omnni.com/legal/OMNNI_Email_Disclaimer.pdf
S.
PIONEER
DR.
AVE.
AVE.
AVE.
AVE.
AVE.
MAIN
E. 11TH AVE.
E. 9TH AVE.
E. 8TH AVE.
E. 10TH AVE.
03-387
03-385
03-382
03-381
03-81
C:\SyncFolders\IDDE_GIS\_Oshkosh\03-81.mxd
1 " = 150 '
Project Manager:
BDW
Project Engineer:
JCW
Drawn By:
JCW
Checked By:
BDW
2014 IDDE ONGOING SCREENING PROGRAM
CITY OF OSHKOSH
ONE SYSTEMS DRIVE
APPLETON, WI 54914
PHONE (920) 735-6900
FAX (920) 830-6100
PROJECT NO.N2029C14
FIGURE NO.D-3
SCALE:
OUTFALL 03-81 INVESTIGATION (10/22/2014)
0 200100Feet
Date:
10/23/2014
Upstream ManholeUpstream Manhole
Manhole - east end of 10th AveManhole - east end of 10th Ave
Parcels
MS4 basins
Storm sewer
Storm manholes
Storm inlets
MS4 outfalls
Sadoff Iron & Metal
Alro Steel
Reinke & CoMonuments
SerwasWindowCleaning
KalmertonWeldingSupplies
G&BProducts
City of Oshkosh Redevelopment Authority
Buckstaff Company
CanteenVendingService
LuckyPenny
APPENDIX D-4
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 p pm
Manhole 16-xxxAmmonia: 0 ppm
SuspectedSegment
Red Arrow Park
16-487
16-488
16-514
N WESTFIELD ST
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 O NGOING SCREENING
CITY OF OSHKOSHWINNEBAGO COUNTY, WISCONSIN
MANHOLE 16-487 D ETECTION9/27/2012ONE SYSTEMS DRIVEAPPLETON, W I 54914 PHONE (920) 735-6900FAX (920) 830-6100 Date:9/28/2012
0 150 300 Feet
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