2017-2018 Annual Outfall Screening Plan

FY2017-2018 Outfall Screening Plan
Summer 2017
Third Fork Creek will be targeted during FY2017-2018 because of high geometric means for fecal
coliform results at several ambient monitoring sites in the Third Fork Creek watershed. Summer outfall
screening will begin with the highest priority subwatershed within Third Fork Creek, which is located
upstream of the City's ambient monitoring site (TF5.6TC) at Forest Hills Park on University Drive. TF5.6TC
had fecal coliform geometric means of 1790 in 2014 and 1505 in 2016. Summer outfall screening goals
will require a total of 25 outfalls during July and August.
The summer outfall screening plan is as follows:
1. Screen priority outfalls in the subwatershed upstream of ambient monitoring site TF5.6TC
a. Screen the medium -low to high priority outfalls in TF5.6TC until the summer goal is
reached (25 outfalls screened in July and August).
b. If there are low priority outfalls near higher ranking outfalls that you plan to screen,
then screen the low priority outfalls if it makes sense to group them together and is
more efficient in the field.
c. Use the Outfall Database and the following files to plan out summer screening days:
i. Priority outfall spreadsheet created by John Cox: 2017 TFC Outfalls FacIDs
Selected for Screening v7
ii. GIS mxd file created by John Cox: Outfall Screening Selection 2017 TFC
Winter 2017-2018
Winter outfall screening will focus on the remaining Third Fork Creek subwatersheds, which will start
where the summer outfall screening finished. If all medium -low to high priority outfalls in TF5.6TC are
screened in July and August, then winter outfall screening will move to the subwatershed with the next
highest number of priority outfalls, and so on. Winter outfall screening goals will require a total of at
least 225 (exceeds goal of 275) outfalls between October to March.
The winter outfall screening plan is as follows:
1. Screen the remaining priority outfalls in Third Fork Creek subwatersheds in this order:
a.
TF5.6TC
b.
TF2.5TCTC
c.
TF5.1RC
d.
TF4.4TC
e.
TF3.4TC
f.
TFO.7TC
g.
TF2.OTCTC
h.
TF6.5RCUT
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2. Screen any low to very high priority outfalls in the Third Fork Creek subwatersheds listed
above. If we subtract 25 outfalls completed during July and August, it leaves 230 outfalls in Third
Fork Creek to be screened.
3. Another watershed will need to be screened to reach 275 or more outfalls. I recommend using - - commented []Al]: we have decided that this Watershed Will
a similar approach to prioritize outfalls in the Ellerbe Creek subwatersheds. Calculate geometric be Northeast Creek, with first priority of focusing on finding and
eliminating sources of fecal coliform bacteria (due to the stream
means for fecal coliform data from 2016 and the first half of 2017 to prioritize which TMDLfor FCB).
subwatersheds upstream of ambient stream monitoring sites should be targeted. Also include
hotspot areas for zinc and conductivity (i.e. upstream of Club Blvd at South Ellerbe Creek and
west/northwest side of Duke East Campus near Markham and Broad)
4. Use the Outfall Database and the following files to plan out winter screening days:
a. Priority outfall spreadsheet created by John Cox: 2017 TFC Outfalls FacIDs Selected for
Screening v7
b. GIS mxd file created by John Cox: Outfall Screening Selection 2017 TFC
5. For daily screening routes, include outfalls within close proximity of each other in order to
make field work more efficient.
6. Create screening maps and booklets to help make screening more efficient.
a. Booklets should include necessary information to assist in finding outfalls (example)
i. Table with Facility ID, address, important notes.
ii. Screen shots of GIS/CutfallDB maps showing drainage system.
iii. Google streetview images of outfall locations.
Industrial Outfall Screening
1. Start with the 8 industrial outfalls prioritized in the Third Fork Creek subwatershed upstream of
ambient monitoring site TF5.1RC. Refer to the outfall spreadsheet created by John Cox: 2017
TFC Outfalls FaclDs Selected for Screening v7
2. The industrial outfall screener (Patrick Hogan) and the outfall screening program supervisor will
need to decide on other facilities to target in Third Fork Creek and Ellerbe Creek.
Conductivity Triggers
The conductivity threshold for FY2017-2018 will be changed to account for seasonal differences
between summer and winter screening. The conductivity results should be tracked throughout the
screening season and the thresholds should be evaluated again at the end of the winter screening
season. The procedures for conducting investigations and taking laboratory samples related to
conductivity results are listed below.
1. The new conductivity thresholds areas follows:
a. > 800 [tS/cm during summer screening months (July -August)
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b. > 1000 NS/cm during winter screening months (October -March)
2. If there is only an exceedance of the conductivity threshold, then it does not immediately trigger
an investigation. At a minimum, the exceedance will trigger laboratory samples and be analyzed
for the following parameters:
a. Fecal coliform bacteria
b. Fluoride
c. MBAS (Methylene Blue Active Substances)
d. Copper
e. Zinc
3. If the laboratory results of the sample(s) exceed thresholds for other parameters or an illicit
discharge is suspected, then this will trigger an investigation
4. Staff will need to pay attention to winter storms and the application of brine and salt to roads
and sidewalks for public safety purposes. Snow and ice melt will generally produce runoff over a
longer period than a typical rain event. If field teams detect high conductivity measurements
after a winter storm, then they will not need to collect a laboratory sample or initiate an
investigation, unless there are other parameters indicating a problem.) , — Commented [A32]: shouldteams wait until majorityof snow
has melted from drainage areas
Sample Collection for Lab Analysis
1. Sample collection for laboratory analysis
a. Discuss discharge type and proposed laboratory analyses with the outfall program
supervisor prior to collecting samples
b. Depending on type of discharge, the samples maybe analyzed for the following
parameters
i. Nutrients
ii. Fecal Coliform
iii. BODS (5-day biochemical oxygen demand)
iv. Metals (typically zinc and copper, but others may be requested depending on
source of discharge)
v. TSS (total suspended solids)
c. At a minimum, the following parameters should be analyzed for sewage discharges:
1. Fecal coliform bacteria
2. Ammonia (NH3-N)
3. Nitrate+Nitrite (NO2+ NO3)
4. Total Kjeldahl Nitrogen (TKN)
5. Total Phosphorus (TP)
Contact the appropriate laboratory in advance of collecting a sample:
i. All fecal coliform samples will be analyzed by the South Durham Water
Reclamation Facility (SDWRF) Laboratory
ii. All other laboratory parameters will be analyzed by the City's contract
laboratory (Meritech, Inc. in Reidsville, NC)
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e. Follow procedures on pages 22 and 23 of the draft version of the Dry Weather Outfall
Screening and Monitoring SOP
f. Focus on dry weather flows with low or high pH (<6.5 or>8.5) and high conductivity
(summer months > 800 µS/cm, winter months > 1000 µS/cm)
g. Focus on dry weather flows with high ammonia levels
h. If feasible, collect flow rates of the discharge during sample collection
IEstlmate Flow Rates[ - - Commented [A33]: Units? Need databasefeld.
1. When possible, estimate flow rates for )illicit discharges) - - commented [Al4]: when Possible at the moment of
2. Use the container method as described on page 23 of the draft version of the Dry Weather determination of anon Stormwater flow
Outfall Screening and Monitoring SOP
3. Use other flow estimation methods described in the following documents:
a. Pollution Volume Estimates presentation located in this folder: F:\SW\Division
Files\Quality\Docs\Investigations\Investigation Procedures\Measuring Flow & Load
b. Chapter 11: The Outfall Reconnaissance Inventory in the Center for Watershed
Protection's document Illicit Discharge Detection and Elimination: A Guidance Manual
for Program Development and Technical Assessments
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