HomeMy WebLinkAbout05.b. Receive information on a Southern California study conducted on the exfiltration of sewer lines Page 1 of 57
Item 5.b.
CENTRAL SAN
October 12, 2020
TO: REAL ESTATE, ENVIRONMENTAL AND PLANNING COMMITTEE
FROM: LORI SCHECTEL, ENVIRONMENTALAND REGULATORY COMPLIANCE
DIVISION MANAGER
PAUL SEITZ, COLLECTION SYSTEM OPERATIONS DIVISION MANAGER
REVIEWED BY: JEAN-MARC PETIT, DIRECTOR OF ENGINEERING AND TECHNICAL
SERVICES
ROGER S. BAILEY, GENERAL MANAGER
SUBJECT: RECEIVE INFORMATION ON A SOUTHERN CALIFORNIA STUDY
CONDUCTED ON THE EXFILTRATION OF SEWER LINES
Staff will present information on the comprehensive study of 15 agencies in Southern California regarding
the exfiltration of sewer lines (Attachment 1). The California Water Environment Association (CW EA)
Sewer System Exfiltration Webinar was held on August 6, 2020 (Attachment 2).
Strategic Plan Tie-In
GOAL TWO: Environmental Stewardship
Strategy 2—Anticipate and prepare for potential regulatory changes
ATTACHMENTS:
1. Presentation
2. CW EA Webinar Presentation
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 31 of 100
Page 2 of 57
Attachment 1
r�
SEWER LINES EXFILTRATION
REAL ESTATE, ENVIRONMENTAL & PLANNING COMMITTEE
OCTOBER 12, 2020
Lori Schectel
Environmental & Regulatory Compliance
Division Manager
Paul Seitz
Collection System Operations
Division Manager -'
WHAT IS EXFILTRATION?
Flow out of a collection system (sewer) through breaks or cracks
in the pipe wall, defective pipe joints or connections, eroded pipe
due to corrosion, openings caused by root growth, and breaks in
access port (manhole) connections and walls
cracking
failing
c
ground
2
1
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 32 of 100
Page 3 of 57
KEY REGULATION
State Water Resources Control Board (SWRCB) Order
No. 2006-0003-DWQ; Statewide General Waste
Discharge Requirements for Sanitary Sewer Systems
E 3
CURRENT EXFILTRATION INTEREST
• Bacteria are a frequent constituent of concern in watersheds
• Interest in exfiltration has increased
• Increasingly included in Non-Governmental Organization (NGO)
lawsuits
• Water Board concern about site-specific impacts on surface
water quality
LSoolme stormwater permittees indicating exfiltration as potential
ution source
! '
00117-11N.ME
2
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 33 of 100
Page 4 of 57
SAN DIEGO REGIONAL INVESTIGATIVE ORDER
• Investigative Order No. R9-2019-0014 (Adopted June 12, 2019):
• Requires the Submittal of Technical and Monitoring Reports to
Identify and Quantify the Sources and Transport Pathways of
Human Fecal Material to the Lower San Diego River Watershed
• Directs agencies in the San Diego River Watershed to identify and
quantify the sources and pathways of human fecal material
discharges to the San Diego River and its tributaries
• In response to a Surfer Health Study and other studies that have
identified human fecal matter in the San Diego Watershed
I!s
CENTRALSAN
EXFILTRATION MEASUREMENT METHODS
• The initial exfiltration measurement device consisted of pumps,
flowmeter, tank, temperature and humidity sensors.
• A metered amount of water was pumped into a sewer segment.
The water was then pumped to a tank and the volume was
measured.
• The theory is the difference between the volume introduced and
the volume captured was exfiltrated.
• Testing was being performed during the week of September
14th in EI Cajon using new testing equipment.
• Pumped 40 gallons per minute for 30 minutes into sewer
segment. Removed water with Hydro Vac truck and measured
the volume.
• Used potable water for test that may have removed culmination
layer and Hydro Vac truck being used had minor leakage.
6
CENTRALSAN
3
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 34 of 100
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STATE & REGIONAL COORDINATION
• California Association of Sanitation Agencies (CASA)
Collections System Workgroup
• Summit Partners
• Bay Area Clean Water Agencies (BACWA)
•Webinars
• CASA Library for Information Sharing
l
CENTRALSAN
I!
--
HOW WILL THIS IMPACT CENTRAL SAN?
• Central San expects revised Waste Discharge
Requirements (WDR) with language regarding exfiltration.
Proposed language was to "Perform Exfiltration Analysis".
• The State has completed their in-house draft.
• Central San is anticipating the draft will be issued for public
comments in Calendar Year (CY) 2021 and the final WDR
update to be issued in CY 2022.
8
CENTRALSAN
4
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 35 of 100
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Questions?
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5
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 36 of 100
Page 7 of 57
Attachment 2
I& EA
Sewer System Exfiltration -
Understanding the Basics
Webinar, August 6, 2020, 11 am - 1 pm
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October 12, 2020 REEP Committee Meeting Agenda Packet- Page 37 of 100
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October2020 REEP Committee • Agenda Packet- '.•- 39 of 11
Page 10 of 57
Today's Purpose
• Exfiltration A ground surface BI I C I
o Sewage leaving thet sanita
sewer system into sanitary sewer sanitary
the ground sewer % sewer
f
VV
• Other words used vadose zone go V 4 0
o Leakage9
o Sub-surface
release saturated zone
Conceptual models of sewage exfiltration and groundwater infiltration from USEPA's"Evaluation of Sanitary Sewers as a Source of Pathogen
Contamination of Municipal Water Supply Wells"
https://cfpub.epa.gov/ncer abstracts/index.cfm/fuseaction/display.abstractDetail/abstract/9454/report/2012
Today's Purpose
• Start statewide conversation
• Topic of interest for decades
o Lawsuits against dry cleaners
• Solvents disposed into sewer
o EPA studies in early 2000s
• EPA/600/R-01/034 n united States
EFA Environmental Prolection
• NTIS#:PB2003-103053 Agency
Project Summary
Exfiltration in Sewer
Systems
Robert S.Amick and Edward Burgess
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 40 of 100
Page 11 of 57
Today's Purpose
• Interest in exfiltration has increased BAYKEEPER.
o Increasingly included in Non-Governmental
Organization (NGO) lawsuits ` 0, �F_ --1V .
Soma 9aCHANNELKEEPER' at�h
o Regional Board existing and proposed actions
for site-specific impacts on surface water quality
• San Francisco Bay Regional Water Board Sewer
• San Diego Regional Water Board Agencies
o Some stormwater MS4 NPDES permittees
indicating exfiltration as potential pollution Stormwater
source Agencies
Water Boards
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fid► `1� � �
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October 12, 2020 REEP Committee Meeting Agenda Packet- Page 41 of 100
Page 12 of 57
Agenda for Today & Speaker Introductions
• Part 1 —Why is there a Focus on Exfiltration Today? — Michael Flores, Senior #
Consultant, HDR
• Part 2 — Exfiltration: Some Basic Concepts — Dr. George Tchobanoglous,
Professor Emeritus, UC Davis
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• Part 3 —A Talk About Sewer Exfiltration Theory (and the San Diego ; .
"Exfiltration" Investigative Order") — Steve Jepsen, Executive Director, SCAP ,
Learning Expectations
• Why we have a specific focus on sewer system performance
• How exfiltration occurs
• Where sewer system exfiltration causes water quality impacts
• Learn ways to identify, assess and mitigate potential exfiltration where it may impact
water quality
• Learn how sewer exfiltration fits into current regulatory discussions
THMETOLE . -
o—,%
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 42 of 100
Page 13 of 57
Part 1 - Why is there a
Focus on Exfiltration
Today?
A Little Sewer History fromROWN ACRES
"Brown Acres"
• Book by Anna Sklar _
lk.ZIL
. 1.
o NPR reporter 0
q JAL
o Public Affairs Director for Los Angeles Dept of Public Works AN
o Avid historian OF THE
LOS
• Details Los Angeles sewer history
a Politics
o Decisions `
o Details issues and challenges solved over time
angelcitypress.com/products/brac07- , -
Anna.
https://angelcitypress.com/cart/450100389:1?channel=buy button
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 43 of 100
Page 14 of 57
"0
Strategies to Deal with Sewage
40
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Sell as fertilizer
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October 12, 2020 REEP Committee Meeting Agenda Packet- Page 44 of 100
Page 15 of 57
Key Regulations for California Sewer Systems
Foderal
Wastewater - Federal Clean Water Act Capacity,Management,Operations and Maintenance
(1972} (CMOM)(Early 2000's-Nat Promulgated)
Regulations
Prohibi�s son r.3ry ser•.r r cvor`laws into
Surfar:r r,alrrs r.l tFe LJn r.rd.Sl ales
California Porter-Cologne State Water Resources Regional Water Quality
Water (CA Water Cade, Control Board Control Boards
Quality Chapter 7) Waste Discharge Basin Plans and
Regulations (1969) Requirements J2006) Regian-specific Orders
Prohibits sanitary sewer overflows into Regional watershec-specific criteria
surface waters of the United States
Waterbncy specific criteria
Prohibits discharges creasing nuisance per CA
Water Code 130�C'm
Includes 1 Provisicrs,incll.dirg requirement
fci Sewer System Management Plan
Federal Clean Water Act
Regulates pollutant discharges from point sources into the waters
of the US
Clean Water Act o NPDES permit for point sources as discrete conveyances
Regulates quality standards for surface waters
Discharges from a point source into waters of the US prohibited
unless discharged per an NPDES permit
Point sources are discrete conveyances such as pipes or man-made ditches.
tEQ 57ATfiS
• USEPA develops national water quality for surface waters
< Y�
C w
z z o Requires State and Regional Water Boards to develop state-
?a�yTQt PROZEG{�O specific water quality criteria
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 45 of 100
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Federal Clean Water Act and Safe Drinking Water Act
• Regulates pollutant discharges from point sources into the waters
of the US and drinking water supplies
Cl titer Act . NPDES permit for point sources as discrete conveyances
Drinking water permits for treatment of drinking water
• Regulates quality standards for surface waters and drinking water
supplies I
• Discharges from a point source into waters of the US prohibited
unless discharged per an NPDES permit
Point sources are discrete conveyances such as pipes or man-made ditches. on
J�,,�ea SrA�s
• USEPA develops national water quality and drinking water
<� rW pollutant criteria for surface waters
ao Requires State and Regional Water Boards to develop state-
specific water quality criteria and drinking water criteria
q[PROZrc�'•
California Water Code
0 • Provides State and Regional Water Boards authority and
responsibility to regulate and protect beneficial uses of the
0 71 41 1 WO waters of the State
"' o Surface waters, including waters of the United States
Water Boards o Groundwater
§ 113. It is the policy of the state that groundwater
Porter-Cologne resources be managed sustainably for long-term reliability
Water{duality Control Act and multiple economic, social, and environmental benefits
Wa[erCode Division 7 and Related Sections for current and future beneficial uses.
IAs amended.incl Wino sialuees 20181
U'P-11-1
Provides that "Beneficial uses" of the waters of the state be
protected against quality degradation
JANUARY 2019
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 46 of 100
Page 17 of 57
Beneficial Uses Directly or Indirectly Impacted by Sewage
DomesticMunicipal&® Community, military,or individual water supply systems;
includes drinking water supply
Farming, horticulture, or ranching; includes to, irrigation,
Agricultural Supply stock watering,or support of vegetation for range grazing
Recreational® Direct . Recreational activities with body contact
® indirect Recreational Contact Recreational activities with close proximity to water
Various Fish and Wildlife- Supports cold and warm water ecosystems, preservation or
enhancement of aquatic habitats, marine life,vegetation,
related Uses fish,or wildlife, including invertebrates
Regional Water Board
Water Quality Control Plans (Basin Plans)
Federal regulations require States to have state-
specific water quality control plans
Each Regional Water Quality Control Board in
g Y
California has a region-specific Basin Plan
o Specifies water quality objectives for surface and
ground waters
• Beneficial uses of the water
• Water quality criteria to uphold the beneficial uses
'- • Antidegradation
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 47 of 100
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State Water Board Resolutions Addressing
Statewide Protection of MUN Use
• Sources of Drinking Water— Resolution 88-63
o All surface and ground waters of the State:
• Considered to be suitable for MUN uses
• Should be designated for MUN uses by the Regional Boards(with specific
exception)
https://www.waterboards.ca.gov/board decisions/adopted orders/resolutions/2006/rs20
06 0008 rev rs88 63.pdf
• Human Right to Water— Resolution 2016-1010
o Human right to water is a core value
o Adopted as a top priority for the Water Boards.
o Encourages consideration of human right to safe water in all activities
and regulatory actions that could affect existing or potential sources of
drinking water(MUN)
https://www.waterboards.ca.gov/board decisions/adopted orders/resolutions/2016/rs20
16 0010.pdf
State Water Board Resolutions Addressing
Statewide Protection of MUN Use Mal
• Sources of Drinking Water— Resolution 88-63
o All surface and ground waters of the State:
• Considered to be suitable for MUN uses
• Should be designated for MUN uses by the Regional Boards(with specific
exception)
https://www.waterboards.ca.gov/board decisions/adopted orders/resolutions/2006/rs200
6 0008 rev rs88 63.pdf
• Human Right to Water— Resolution 2016-1010
o Human right to water is a core value
o Adopted as a top priority for the Water Boards.
o Encourages consideration of human right to safe water in all activities
and regulatory actions that could affect existing or potential sources of
drinking water(MUN)
https://www.waterboards.ca.gov/board decisions/adopted orders/resolutions/2016/rs201
6 0010.pdf
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 48 of 100
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Sewer System Exfiltration Concerns are System-Specific
• Localized geographical and
• System-Specific Causes
hydrological conditions o Pipe condition
o Proximity to surface water o Pipe material
body o Pipe construction
o Groundwater aquifer levels • Pipe sags
• Defective joints
o Soil types o Localized ground movement
o Watershed hydrology (i.e. (i.e. earthquake, mudslides, subsidence)
connectedness of
groundwater to surface o Operation and maintenance practices
waters) • Pipe degradation accelerated by high
pressure or mechanical
• Excessive tree roots
The Big Picture
• We collectively own 100,000* miles of r
mainline sewers in California worth
—$1006
o What are the issues to address with this
infrastructure?
o To what extent is exfiltration one of those NI
issues?
o When is it worth spending money to
address potential exfiltration?
*Based on analysis of sewer agency data in CIWQS
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 49 of 100
Page 20 of 57
Y
lA
ExHitration: Some Basic Concepts
CWEA Webinar
SEWER SYSTEM EXFILTRATION
August 6, 2020
George Tchobanoglous
Professor Emeritus
Department of Civil and Environmental Engineering
University of California, Davis
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 50 of 100
Page 21 of 57
Topics
• Definition of exfiltration
• Types of wastewater sewers
• Where does exfiltration occur
• Background information on sewer
pipe materials and joints
• Estimating exfiltration
• The movement of exfiltrated water
• Assessment and maintenance of sewers
Definition of Exfiltration
Flow out of a collection system (sewer)
through breaks or cracks in the pipe wall,
defective pipe joints or connections, eroded
pipe due to corrosion, openings caused by
root growth, and breaks in access port
(manhole) connections and walls
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 51 of 100
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Some Historical Facts and
Observations Concerning Exfiltration
1 . The early sewers were constructed in the
Eastern United States where high groundwater
conditions are common. As a result, exfiltration
was not considered a serious issue.
2. In fact, some writers noted that infiltration would
help flush the sewers and dilute the wastewater
3. There were no acceptance standards, rather
quality control during construction was stressed.
Definition Sketch for Combined
and Separate Wastewater Collection Systems
Sanitary wastewater
Cdlectidn lateral Residential houses,
apartments_office
buildings,commercial
Stormwater establishments,etc. Slormwater Impervious
surface
catch basin overFaw to
I nfillration basin. Access port
storage basin,
or surface water
Combined sewer
overflow to basin
or surface water d
Wastewater
collection main to
l treatment Facility
Combined wastewater Stormw Aer collectlon system
Surface and stormwater cpbecbon to separate or combined
water main to treatment raraldy treatment banality or storage
Regulating basin nor su hsequent Irealment
structure and
access pod
(aY Ib,
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 52 of 100
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Classification of Sewers in
Separate Wastewater Collection System
Building(such as an Building
individual family dwelling) sewer
Lateral sewers
(75 to 80%of all sewers)
Main sewer
Trunk sewers
IF
Access ports Junction Intercepting sewer
(manholes) chamber
Definition Sketch for Exfiltration from
Separate Wastewater Collection System
Defective service
lateral connection p'
Brokenicracked
- service lateral
Defective joint in
service lateral
w under street
Broken/ pipe, E
defective joints,noot
intrusion,corroded pipe
Defective access port
connection and or defective _
access port casing t
1•
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 53 of 100
Page 24 of 57
.
-MAP—
Criteria for Selection of
Wastewater Collection Pipes
Criteria Requirement
Strength Ability to withstand dally stresses
Durability Must resist deterioration due to weather,moisture,or
chemicals found in wastewater
Imperviousness Must be impervious to admission of groundwater or
exfiltration of wastewater
Smoothness To enhance the flow of wastewater and to avoid the
accumulation of deposits
Hardness To resist erosion from grit in wastewater
Uniformity To avoid projections and irregularities at joints
Joints Must remain watertight
cost Must be cost effective with respect to other sewer
components
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 54 of 100
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Types of Materials Used for
Wastewater Collection Systems, Part 1
Sewer material Comment
Clay pipe used throughout the world,but of varying quality.
Vitrified day pipe Relatively inexpensive resist corrosion and abrasion are smooth and
{VCP} durable but are bulky and difficult to transport and handle.Brittleness
can make It more prone to cracking and root Intrusion. Joints are
susceptible to chemical attack.Modem VCP plpe is nothing like the
day pipe used in the 1950s and 1960s,prim a d I y because of the new
joint materials[see slide No.13].
Steel(cast iron, Cast iron pipes are most Commonly found in older homes,Steel is
ductile iron,and much heavier and more expensive than other materials- Because of
galvanized iron) weight,short sections are required and leading to more opportunity for
joint failure.Electrolytical and other types of corrosion are common.
Wood pipes Wood stave or hollowed out pipes were used for both water and
wastewater In the ninetieth century.Wood pipes are still found as
sewer lines are being replaced.
Bituminized fiber Made of cellulose wood fiber held together with water-resistant
pipe(Orangeburg adhesive and impregnated with liquified coal tar pitch{most common
pipe} color of pipe is black).Lightweight and easy to work with,but weak and
prone to failure.Most of the Orangeburg sewers have been replaced
due to failure of partial collapse.
Masonry(bricks) The first brick and mortar sewer constructed in the Indus Valley in
northwestem regions of South Asia,ca 2500 BC.
Types of Materials Used for
Wastewater Collection Systems, Part 2
Sewer material Comment
Concrete Strong,smooth,and light weight must be reinforced in beyond 600 mm.
Requires careful installation to avoid cracking
Asbestos cement Made with a mixture of asbestos fiber,silica,and cement.First
manufactured in the early 1930s.Brittle and subject to deterioration with
the release of asbestos fibers.More commonly used in water supply.It is
estimated that more than 400,000 miles of asbestos cement may still be
in use.No longer used for sewers.
Reinforced concrete Strong,smooth,and light weight must be reinforced in beyond 600 mm.
These pipes are subject to corrosion where acid discharges are carried
in the Sewer and where hydrogen sulfide can form under septic
conditions
Cast in place Where conditions require the use of non-standard sections of sewer
reinforced concrete pipe
Plastic(PVC and Smooth surface,excellent carrying capacity resistant to tree root
ABS) intrusion,must be supported properly to to avoid bending and or
collapse.
High density Used increasingly because of its durability,flexibility and corrosion
polyethylene (NUPE) resistance.The most common material used for sewer repair.The
material of choice for force mains.Used extensive€y in Europe.
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 55 of 100
Page 26 of 57
�ti t
Construction of a
Cast-In-Place and a Brick
Egg-Shaped Sewer
I_�4
Types of Joint Materials and Methods
in Use Over the Past 150 Years for VCP
Joint material Comment
Cement Used in early sewers in England and Germany in the 1800s. Cement joint
offered no flexibility.
Sulfur,tar,and First used in England and widely adopted for use in the United States without
sand the tar.Joint is rigid once formed.
Asphalt and tar Used extensively in Germany;also,some usage in the United States. Joint
material melts where hot water is discharged to sewer.
Oakum and Oakum is a rope-like material made from oiled jute or hemp fibers.Cement
cement mortar mortar is applied after hemp in packed into bell of pipe.Joints were rigid and not
resistant to earth movement.In common use until after Word War ll.
Hot pour Bitumastic compounds,GK(Vulcanized linseed oil and anhydrous day which
compounds served as the binder)and JC-60 a plastic based compound have all been used
Prefabricated Polyurethane attracted to bell and spigot.Polyester and O-ring joint for bell and
compression spigot pipes.Polyester resin cast onto the bell portion of the pipe and the spigot
joints end is cast with a grove or gland.During the late 1950s to the mid 1960s,PVC
was also used for joint material.
Flexible rubber Use for coupling VCP to each other and to other types of pipe.Most commonly
coupling used for repairing broken pipes.
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 56 of 100
Page 27 of 57
Most Commonly Used Joints for Vitrified Clay
Pipe Since the Passage of the CWA in 1972
Bead cast in polyurethane
material attached to Gell Flexible P-ring
i
Flexible polyurethane compression joint Polyester comprsssion joint with flexible o-ring
factory applied factory applied
Adapted from the National Clay Pipe Institute
Maximum Allowable Leakage for Exfiltration
• In the early 1900s, a leakage (exfiltration) rate of
50,000 gal/mi-d, without regard to size, was
common. There was no standard for exfiltration at
the time
• By 1980, an exfiltration rate of 200 gal/in-dia•mi•d
was in use for new sewers
• In the 21St century an exfiltration rate of 50 gal/in-
dia•mi•d is now in common use for new sewers
"The total exfiltration, as determined by a hydrostatic head test,
shall not exceed 50 gallons per inch diameter per mile of pipe
per 24 hours at a minimum test head of 2 feet above the crown
of the pipe at the upstream manhole or 2 feet above the
groundwater elevation, whichever is greater."Courtesy City of Galveston,TX
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 57 of 100
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Public Health and the Environment
Impact of Defective Pipe Joint Material
Consider the effects of using PVC formed with varying
amounts plasticizer for clay pipe joint material (circa 1958 -
1965)
With the passage of time.
the removal of plasticizer was
Initially,as installed accelerated by the presence
with new PVC gaskets of dry cleaning chemicals
PVC gaskets Narrowing of
Untreated gasket allows
wastewater water to escape
Most Commonly Used Joints for Concrete Pipe
Since the Passage of the CWA in 1972
Joint material Comment
Rubber gasket A rubber gasket is utilized for concrete joints with a grove or offset on
the spigot and or bell joints
Perform flexible Bitumen and butyl sealants are applied to the tongue or spigot and
joint sealants inserted into the bell or grove
Mortar tongue and A layer of cement paste or mastic mortar is placed in the lower portion of
groove the bell or groove of the installed pipe and on the upper portion of the
tongue or spigot of the pipe section to be installed.
External sealing Sealing bands are designed to be wrapped around the exterior of the
bands joint to provide resistance to infiltration and/or e0tration.
Grout
. �space
1i
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 58 of 100
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Factors Effecting Exfiltration from
Separate Wastewater Collection Systems
Physicallbiological Environmental
Age of sewer Type of bedding material
Size of sewer Colmation in bedding material
Materials of construction Type of soil (coefficient of permeability)
Construction quality, type Root growth into sewers, especially
of pipe joint during draught conditions
Location of sewer damage Damage in the upper portion of the
(defect) sewer pipe may not lead to exfiltration
Depth of flow in sewer Depth to groundwater
Accumulations in sewer Location of frost line
Wastewater constituents Average rainfall
External loading conditions Intensity of rainfall events
AL
�
POLL
QUESTION CWEA
i
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 59 of 100
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Public Health and the Environment
Potential Impact of a Leaky Sewer
• Consider a sewer leak of 600 gal/d caused by
small crack (e.g., 1/4 in diameter hole with a
water head 0.5 ft (see later computation)
• If the coliform count is 109/100 mL and the water
quality requirement for a water body is 240/100
mL
• Then, hypothetically, 2,500,000,000 gal/d of
water can be contaminated
Estimating Exfiltration from a Sewer
DISCHARGE THROUGH AN ORIFICE
Q=C,C,M2gh
h Where C,=coefficient of contraction,unitless
C,=coefficient of velocity,unitless
A=area of orifice,ft2
g=acceleration due to gravity,ftls2
h=head of water,ft
Estimate the discharge through a crack with an
equivalent open area corresponding to a circle with
a diameter of/,in subject to a head of 0.5 ft
Assumptions:
Cc=0.60
C,=0.8 due to unevenness of the cracked perimeter
0_(0.6)(0.8)((3.1414)[0.25112)2]4(2X32.2)(0.5)
Q=(4.6)(0.8)(3.41 x 10-4)(5.67)=9.28 x 10-4 Wis
Q=(9.28 x 10-4 ft31sX86,400 sld)=80 ft31d
h Q=(80 ft31d)(7.48 gaVW)=600 galld
Q=(600 galld)(365 dlyr)=219,000 gallyr
Note:Applies to newly broken pipe,or broken pipe not
subject to continuous inundation and solids accumulation
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 60 of 100
Page 31 of 57
Limitations in Estimating
Exfiltration from a Sewer
200
FACTORS IN ASSESSING EXFILTRATION
ts0 1.Hourly variation in wastewater flow as
a function of community size and size of sewers
2.Long-term flowrate reduction due to conservation
Inlarmediate size city 3.Type of leak(crack in pipe wall,broken pipe,leak
aso at pipe joint,root growth,leaks at access part)and
Small carnmunity
dimensions of leak
00 4 a 12 is 20 24 4.Accumulation of solids,grease,and biological material
Midnignl Noon Micnight in the bottom of sewer forming a low permeability layer
Time of day 5.Nature of the bedding material and whether periodic
l� water barriers were used
6.Biological growth in bedding material forming a low
permeability colmation layer
Taken together these factors can reduce the computed
gA, i rate of exfiltration,using the orifice equation,from cracks
!a in the sewer by a factor varying from 50 to 80 percent.
Typical reductions for broken pipe and joints can vary
from 25 to 60 percent.
Pi
4P� PI 01 4� 0.1 0.5 06 RT W Pf N LI 11 w7
Moe ei n,d,eela rhmmp dAikd Srgmarro�e.FhniR3cM�
Impact of Water Conservation on Solids Deposition, H2S
Formation, and Downstream Corrosion and Exfiltration
H2S wrr ed
downstream Large concrete
by friction with wastewaler Corrosion of
moving water mtereeplor sewer crown
Lateral From and sides
household Insufficient flow
to scour solids
deposited on
bottom o}pipe
Wastewater H2S
collection O
system
Exfiltration due to brokeNcracked pipe,detectivejoints.
corroded pipes,tree root intrusion,pipe corrosion,
Solids deposition and grease accumulation,due
to water conservation and drought conditions,tend
to limit exhltration from small breaks and cracks
Direction located below the typical depth of flow
offic'w Air H2$+202—H2S0,
H2S H2SO4+CaCO3—CaSO4+HZCOy
H2S H2S partitions into mcsture that has
H28 condensed on inside of pipe.
HZ5 forms under anaerobic conditions Thiobaclllus bacteria present in
in settled solids and bioflrns,where sulfur condensate oxidize the H2S
containing conslduents,e.g.sulfate,are to form H2Soy
reduced by sulfate reducing bacteria
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 61 of 100
Page 32 of 57
Where Does Exfiltrated Wastewater Go?
Ground Bedding Groundwater level
surface material above head In pipe
Leak at
joint
t 1 1 + 1
High groundwater
prevents exfiltration
Wastewater constituents
may be attenuated in Deep
unsaturated zone groundwater
Shallow and intermediate
0 1 groundwater contaminated
by exfiltration
[a) {b} c}
Note: In some cases where exfiltration occurs,
wastewater may travel horizontally in the bedding trench
similar to effluent distribution in a septic tank leach field
Darcy's Equation for Estimating Flow
Through a Permeable Medium
Darcys Equation
Q h2-hi
=-KA L
L Where Q=discharge,ft'Is
h, K=coefficient of permeability,ftls
=h 2 A=area,ft2
h2=hydraulic head at cutlet,ft
h2=hydraulic head at inlet,ft
L=length of soil sample,It
The minus sign is used to denote that the
flow is from a higher to a lower potential
hu Permeability range
Porous medium _ cm/s fus
Gravel 102-104 3,25-3.25x10-2
L h Sand 10°-10-2 3.25x10'-3.25x104
Fine sand,silt, 10.10-3 3.25x10 -3.25x10-5
lasses
h2=0 Silty Gay 10'-10$ 3.25x10-s-3.25x10-7
Clay c10-6 c3,25x10-1
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 62 of 100
Page 33 of 57
Estimating Flow Through Layered Soil
Pipe bedding DARCY FLOW EXAMPLE
material,Ki
h2 -hl
hL Q=-KAL
0177Z Lt Referring to the figure on the left
I i
I Ki =3.25 x 10-4 ftls(bedding layer)
I { ht
K2=3.25 x 10-6 fus(native soil,silty clay)
ht.=1ft
L2 Li=1ft
L2=5ft
L=6ft
iLj] A=1.0 ft�
h'=g
Native soil,Kz K= 1 1+5
5 =3.89 x 10"fus
For flow perpendicular to a layered soil, 3.25 x10"4 3.25
the average coeffieient of permeability K=(3.89 x 10-6 fUs)x(86,400 sldy= 0.34 ftld
can be computed using the following
expression0-(6+1)ft
L Q=--(0.34 ft/d)[1 ft2] C,—+5)ft =0.40 ft'/d
K j',�) 0=(0+4 ft31d)(7.48 gallft3)=3.0 galld
What is the Reality of Estimating Exfiltration:
Mission Impossible
�7 Wastewater depth in sewer
L
Accumulated residual organic matter.
grease,grit,and residual organic matter
from biological growth, Kt
K7
_ Accumulated grit,grease,residual
Broken section in pipe organic matter,and residual organic
matter from biological growth,K2 K3
Accumulated residual organic matter. K4
and residual organic matler from biological
growth in the bedding mats nu 1,K3 Bedding material,Kd
(also known as a coloration layer)
K5
Native Sail,KS
Note:All three types of accumulation contribute to
self healing,reducing the extent of exfltation
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 63 of 100
Page 34 of 57
Typical Steps in the Assessment and Maintenance
of Wastewater Collection Systems
(Discussed further in Part 3)
1 . Program development
2. Asset inventory (GIS based systems)
3. Asset Assessment/inspection
a. Selecting and prioritizing assets for inspection
(e.g., age, type of pipe material, joint material,
external loading, contamination potential, etc.)
b. Asset inspection
4. Data management
5. Data analysis
6. Decision making
7. Implementation schedule for maintenance
Adapted from US EPA
Typical Setup for Televising A Sewer Between
Access Ports (Manholes) to Assess Condition
rl
rcy rr«r c.,,nw
0-q'V
a
M•
uw
end. �r
wM...meh -- w�rawawr
Courtesy:Avami,P.,A.Coghill,S.Gifford,and J.Schertig(2005)Sewer
Exfiltration Test Method for Sub-Subface Discharge Evaluation,A report
prepared for Brown and Caldwell,Project Manager for Orange County
Sanitation District,Water Quality and Treatment Laboratory,Civil and
Environmental Engineering,University of California,Irvine,CA.
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 64 of 100
Page 35 of 57
Typical Setup for Exfiltration and Air
Testing of Collection Systems
Exfiltration Testing (Avami et al., 2005)
1.Special Exfiltrometer was developed.
2.Unique feature of"Ex0rometer is the ability to control the
_ water level in the test section to any level between one
inch water depth and a full pipe."
- 3.By controlling the depth, the exfiltration test can be
conducted at the normal operation depth in the sewer
4.Sewer defects in one OCSD sub-area, based on CCTV:
• Cracks 483
• Broken holes 64
• °�-•• Roots 374 (increasing with draught conditions)
5.Rates of exfiltration varied from non-detect to 2,100 gal/yr
per test location. Considerably lower than those predicted
or measured with a conventional exfiltration test(see
previous definition)
Avami,P.,A.Coghill,S.Gifford,and J.Scherfig(2005)Sewer Exfiltration Test Method for Sub-Subface Discharge
Evaluation,A report prepared for Brown and Caldwell,Project Manager for Orange County Sanitation District,Water
Quality and Treatment Laboratory,Civil and Environmental Engineering,University of California,Irvine,CA.
Use of Damage Severity Index (DSI) for
Analyzing Data and Prioritizing Sewer Repairs
1100,000 DSI example, based on
CCN assessment
d
a 80,000 - 051- Sum of event ratings,er Length of pipe inspected,200 ft
Length of line inspected,ft
s0,000 Event ratings(Sewer problem or
a condition observed with CCN)
Broken pipe,longitudinal,er=500
40,000 Roots,difficult or impossible to
pass,er=400
Corrosion,native soil is visible,
20.000 er=5D0
E
U
500+400+500
U o_ n o m o m o m o m o n o n o o o p$J= 200
=TO
V N N M M Y] u'1 (O (O A m m o
O V v V V V V V V V V V V V N V V V_ V V
N Y1 O YI O I1 O N O Y1 O N O rIl O u7 O !] O
N r N N AI N AI Y AI AI M AJ n M W AI M M
N N N N AI AI AI AI AI AI N N N N N N At Al
Al
Damage severity index,DSI,damage ratinglft
Courtesy:Stege Sanitary District
Note:DSI is one of many approaches used to analyze and Larry Rugaard
CCTV and other sewer system data including contamination
potential,pipe material,type of joint,age,etc.
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 65 of 100
Page 36 of 57
Closing Thoughts
1 . Exfiltration is a more serious issue in the Western
United States, especially with climate change
2. Techniques are available for identifying whether
there is a problem
3. To protect and maintain collection systems
assets, condition assessment must be an
ongoing activity
4. Maintaining a collection system maintenance
program is difficult in today's economic
environment
5. Be well!
mom
r
A,
APG-
ly
SOUTHERN CALIFORNIA ALLIANCE OF
PUBLICLY OWNED TREATMENT WORKS
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 66 of 100
Page 37 of 57
A Talk About Sewer Exfiltration
Theory
and the San Diego Region
"Exfiltration" Investigative Order
sewer
storm
dry soil drain
August 6,2020 to creek
6W Steve Jepsen (Serou et al.2011.ES&T)
sjepsen@scapl.org
What Will Be Covered
11. What is the problem?
The Sewer "Exfiltration"
Investigative Order in San Diego
3. Exfiltration theories and
investigation approaches
4. Why should we care about
exfiltration
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 67 of 100
Page 38 of 57
What's the Problem?
Water Quality from Urban Runoff
continues to be an issue
There are little direct funding sources for r .
stormwater quality programs ''
Leaking sewer collection systems are _
considered a likely source by the public, . .
regulators and NGOs despite a lack of _
evidence
Are Sewers a Bacteria Source? No?
UC Irvine, OCSD, Brown and Caldwell
Study zoos — ;
Quantifying Sub-surface discharges
from Individual Sewer Defects
Metcalf& Eddy Water Treatment Book has a chapter dedicated to how natural
treatment systems, in the soil, effectively treat bacteria and viruses
TABLE 14.7
Treatment performance pf onsite system components and intermltteM or recRcu ,
1.0 n b*10W S.9 It WOW-
bottom of bottom of
Septtc lank 4ewhfWd 1
each7iaka
Raw wade alHuenl trench trench
III {21 I31 I41
parametx
210-530 I4o-200 0 0
SOD,,m9A- 50-90 a ❑
SS,nVt 237-GM
fftrogen,rrmATQIW
NH {-40 20-00 2o°y 40°
10-27 10-30 10° 1 ■
TOW phosphorus.mg+L
to°-1D0
109-706r 90-10O9
F� MN700 mL 105-1 g406,
Vioges.PFLVmL' Ur&rbDwe
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 68 of 100
Page 39 of 57
Are Sewers a Bacteria Source? Yes?
City of Santa Barbara Studies 604 .m m
sewer
■ Bacteria found in storm drains
■ Dogs used to identify sources d �;, � - strain
dry drain
■ Human specific HF 183 tests positive =or"k
■ Sewers shown to be a source Awi
(Sercu et al.2o11,ES&T)
■ Dye tests confirm sewer exfiltration
into storm drain occurring
Ir
San Diego Regional Investigative Order
Investigative Order No. 119-2019-0014 (Adopted June 12, 2019):
An Investigative Order Requiring the Submittal of Technical and
Monitoring Reports to Identify and Quantify the Sources and Transport
Pathways of Human Fecal Material to the Lower San Diego River
Watershed.
• The order directs agencies in the San Diego River Watershed to
identify and quantify the sources and pathways of human fecal
material discharges to the San Diego River and its tributaries.
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 69 of 100
Page 40 of 57
Here is the Proof?
i
1
The order is in response to a Surfer Health Study
prepared by SCCWRP and other studies that have
identified human fecal matter in the San Diego
Watershed
SCCWRP — Surfer Health Study
In the winters of 2013/2014 and 2014/2015, a Surfer Health Study (SHS)
was conducted by the Southern California Coastal Water Research
Project (SCCWRP), at Ocean Beach and Tourmaline Beach.
The study measured illness rates of surfers after ocean exposure.
Results indicated an increased rate of GI illness following ocean
exposure compared with not entering the water (25 illnesses/l000
swimmers, vs. 18 illnesses/l000 swimmers). This illness rate increased
even further following wet weather(up to 3o illnesses/l000
swimmers).
USEPA criteria for recreational waters is 32-36 illnesses/loo
swimmers.
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 70 of 100
Page 41 of 57
SDR @
Channel
Eucalyptus Los(ches Concentrations of Human Marker
Hills @ (HF183) In San Diego River
5D
Carlton Hills
` Sycar're Ck — Ck
5
Miss rails
AlvaAdo C
SDR @
Mission Rd
—M
SDI @
Fa n
Valley
Morena Blvd
SDk@ Drain
Ingra am
Storm Date: 1/31-2/1/2016
The San Diego Investigative Order
Footnote in the Order:
12 Exfiltration refers to the leakage of sewage wastewater through minute cracks,gaps or breaks in
sanitary sewer collection system infrastructure or private laterals to the surrounding environment.or
through the material making up the system itself(e.g.vitrified clay pipe(VCP). For regulatory purposes
any sewage exfiltration release from a public sanitary sewer system is defined as a sanitary sewer
overflow(SSO)and any sewage exfiltration release from a private lateral is defined as a private lateral
sewage discharge(PLSD). Exfiltration may be related to construction practices and/or materials,
infrastructure deterioration,inadequate preventive maintenance programs, or insufficient planned
system rehabilitation or replacement programs which have resulted in deteriorated pipes,manholes
and pump stations that allow sewage containing high levels of suspended solids, pathogenic
organisms,toxic pollutants, nutrients,oil,and grease to exit the systems and contaminate adjacent
ground and surface waters,and/or enter the storm drain.
Repeated in the Order:
a.Exfiltration-The(agency name here)has not reported to the San Diego Water Board any estimation
regarding the exfiltration of wastewater from the sanitary sewer collection system to the Lower San
Diego River Watershed.
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 71 of 100
Page 42 of 57
The San Diego Investigative Order Requires
The ten agencies in the watershed shall:
* Identify and quantify relative contributions of suspected sources of
human fecal material in wet weather discharges to the San Diego Rive
* Determine the transport pathways of such discharges
* Determine how this information will be used by each Discharger to
assess the effectiveness of current management measures in
preventing discharges of human fecal matter into the San Diego River
�. -among
--
SCCWRP Work Plan Tasks
1. Steering Committee and Technical Advisory Committee
z. GIS Foundation
3. Human Fecal Contamination from Exfiltration of Publicly Owned Collection
Systems
• Microbial Community Profilin
4. Human Fecal Contamination from Exfiltration of Private Laterals
5. Human Fecal Contamination from Homeless Encampments
6. Human Fecal Contamination from Septic Systems
7. Human Fecal Contamination from Dry Weather Illicit Connections/Illicit Discharge
8. Frequency and Magnitude of Sanitary Sewer Overflows
g. Reporting and Data Management
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 72 of 100
Page 43 of 57
Microbial Community Profiling
Aj-w Hfdhtr
AbWldMt
Corm Pipe#1
Sewer
#2
Sewer
#1
I I
Unique to Storm Unique to Sewer f Unique Uni
Pipe #i *2 to Sewer Sewer#i
Exfiltration Measurement Device
FN. review pipe test segments for
&slope of pipe.
of water required for test is a
,variables include size,slope,
gment should not have
1
W, m
Weirldiffusing Additional plug
device to release
[Mechanical plug inflow at controlled
rate
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 73 of 100
Page 44 of 57
Colmation Layer
a • Colmation Layer
Flow (clogging layer)
Grits and heavy • Accumulation of
'"a` h - suspended solids an
biomass
6eddinglayer • 1 to 5 cm thick
• Reduces K and
erlx� porosity
• Exfiltration
h Area of the leak Flaw Pam 8 decreased or
eliminated
,: rhw I • Referenced in several
publications:
• UK study
• German study
• OCSD/UC Irvine study
Colmation Layer
Exfiltration and
physical and chemical physical,chemical and formation of
processes,pore clogging biological processes
Colmation layer
1.E-02 • Study related K� to
■ unsaturated
1.E-03 ! saturated capillary pressure
1.E-04 • and colmation layer
. . • i
1.E-05 A A • • As colmation layer
A AAY 1.E-06 , , develops,
1.E-07 decrease in KL
1.E-08 • 1 to 2 orders
1.E-09 magnitude in 3
1 3 5 7 9 11 13 15 17 19 21 23 25
timed I days
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 74 of 100
Page 45 of 57
Sewer Construction
CUT&COVER
I ,
30'TO"'WIDE DEPENDING
ON SITE CONDITIONS
H
nu-TRUCH
i EXCAVATOR PIPE
STRING
41�
SPI
PILL
- -. _ s .--� - �- � - � YID'=11 - .. .. .... _ .� - -_ - •- - .-: -.
I�TIn TRENCH
14111�/
u+ ul-
411�I
INS7ALLE6 PIPE
Trench Bottom and Pipe Zone
nwN [RAGE FOA 3'—nSP -T
DNPAlED MEhB FOI PALED MEAS
EMST.IA.
4{ �F T!M(AH ACCRI E
71411071» C
7
KD�1 WUDEAL
OIATIYE 9EL]
•■lO1CATES WH.IIELRTILE DOYPACT101!
1PPAb�[O Br
DLit N0.
D V DE K PIPE TRENCH I 0-906
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 75 of 100
Page 46 of 57
Normal Open Channel Sewer -
Headspace Air Travels with Sewage
•Sewers Flow Partially
Full
•"Headspace" = Air
Above Water Surface -EXISTINGGRADE
•"Headspace" Conducts
Foul Air
•Creating Negative GRAVITYSEWFR
Pressure •
AIR r �
.. .-
. WASTEWATER
Dwyer Instruments - Magnehelic
Pressure and Vacuum Gauges
1
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 76 of 100
Page 47 of 57
Conditions Preventing Wiltration
Negative
• Colmation layer pressure
• Gravity sewer at zero or negative pressure
• Half full is maximum design flow
Moist pipe wall
• Normal peak flow is less than half full
• Diurnal flow patterns create daily low flow Sewer atmosphere
periods far below half full
• High groundwater creates positive pressure into
pipe favoring infiltration Bulk wastewater
• Compacted trench bottom not conducive to
percolation Biofilms
• Declining flow=higher grease and suspended
solids Content Sediments
• Modern joints and pipe materials
• Effective natural treatment occurs in soil
• Finally the sewage must push through soil and '� Colmation
through the stormdrain pipe Layer
e
110
r
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 77 of 100
Page 48 of 57
Desktop GIS Approach
507 pipes
93,000 ft (18
miles) '_ Y'
Watershed
Study Area
Collection System
Desktop GIS Investigation
•Contributing Factors '
• Pipe Crossings
•Vertical Separation
•Sewer Pipe Material/Age/Condition =°
• Sewer Flow
•Storm Drain Material/Age
•Soil Type -
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 78 of 100
Page 49 of 57
Desktop GIS Priority Ratings
• Scoring matrix-based
• 19 of 507 (4%) sewer pipe segments above storm drain
• 12 of 19 (2%) also cross storm drain
• 6 of 12 (1%) also have defect
• 2 of 6 (0.3%) also in sandy soil --> highest rating
Spatial Relationship Ground Water Sewer Pipe Priority Rating Storm Drain Pipe Priority Rating Soil Priority Rating FINAL
Site ID g y P g P g Age Avg Total Perm.(in/hr) Avg Total SCORE Rank
Vert.Dist. Hon.Dist Av To[al In Valley?Swr Depth Vert.Dist. Avg Total Flow De th Defect EMA Avg Total SD Mat'I Size
116 5 1 3.0 9.0 3 3 5 3.7 3.7 1 0 0 0.3 1.7 2 3 2 2.3 2.3 3 3.0 6.0 22.7 S
176 5 3 4.0 12.0 3 2 5 3.3 3.3 2 2 0 1.3 6.7 2 5 2 3.0 3.0 1 1.0 2.0 27.0 3
223 5 3 4.0 12.0 3 1 5 3.0 3.0 1 0 0 0.3 1.7 2 5 2 3.0 3.0 1 1.0 2.0 21.7 10
225 5 2 3.5 10.5 3 2 5 3.3 3.3 2 0 0 0.7 3.3 2 5 2 3.0 3.0 1 1.0 2.0 22.2 9
257 4 3 3.5 10.5 3 1 5 3.0 3.0 1 2 0 1.0 5.0 3 3 2 2.7 2.7 1 1.0 2.0 23.2 7
277 5 3 4.0 12.0 3 1 1 5 3.0 3.0 1 2 0 1.0 5.0 2 3 2 2.3 2.3 1 1.0 2.0 24.3 5
302 5 3 4.0 12.0 1 1 5 2.3 2.3 0 3 0 1.0 5.0 2 2 2 1 2.01 2.0 1 1.0 2.0 23.3 6
333 5 1 3 4.0 12.0 3 2 5 3.3 3.3 2 4 0 2.0 10.0 3 4 3 3.3 3.3 3 3.0 6.0 34.7 1
368 5 1 3.0 9.0 3 2 5 3.3 3.3 1 4 0 1 1.71 8.3 1 4 1 3 2.7 2.7 1 1.0 2.0 25.3 4
59 Villillilliftj 3.5 10.5 2.3 2.3 1.7 8.3 1 3 2 2 2.3 2.3 3.0 6.0 29.5 2
Field-based Approach
�i..r
• Approximate Bonn Locanons
•�Appro mare Stormwater PWe Lombon9
ApproRlmale Sewer,
,,
an Lo atlons
3S3 •�Appro%ima[e Sewer L"Mi Locations
Apponurnale Water Unites LoUlhWa
Gardena Avenue and Gardena p4C•
e�^le Gy Gardena F'6aee and Vane Way
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 79 of 100
Page 50 of 57
Field-based Approach Preparation
awe _
[.A0.�ENh
PL�
r
soman wrr"ssua� ,y Enyn,..v,p
SIOX RPAER10•IOOH INCF 11wi ".,pay i�¢w`
tAAER•6]tt9N11 iyx ,•XOS iD w...^ �'vH F�sIOM��wrvcws�. 8m W0.cA
Traffic Control Plan Water Pollution Control Plan
Field-based Approach
i
Excavated Hole
Air Knife Technology - —
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 80 of 100
Page 51 of 57
Field-based Approach
J
i
's3
Direct Push Rig - Processing Sample Collectio
What are the Drivers?
.Z .
Priority = Bacteria �.
Priority = Nutrients
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 81 of 100
Page 52 of 57
San Diego Region
WQIP Strategies
Page 557 of 1,368
lmpfWWftton Jlp~ JhuledKewnel ImplemenletWn Polluum;Addnard R..PornMl.
IB-3-L.11XtA w Cwawcuw hplamenuuon C�BePi°11eM
(Fregrwncy of lnspetnMe.5-$.b.0 Xe1[NII Tear Seheduk Source end Odler
$VnegJ lFurx6hstaeowue.B.1.b i MAIM.a.-IDI DXwll a I �t Cdleborefgg
f7rlggen-8.1.6.[1X6](vV] [B.3B k.[1Xb}I (9.3L.[3Nexq; IB]-6.11Xe1IN11 3 IB.1L[txeXl[) O.par�rrrLa
{Inrarxary BMPe,B-Ab.11X•XIIA B-1-b41NeXH11 p'B"ede1
6.3 t�
1fSl Ahfnefruebrn
Role,foIMP$ed-7Tae MSi vw atayevypacWd
by Putk6c Wake alai M W*l once per Yew Esw el on
�4 krplenerdab_ W..b oad marMrahce aokd- the W".f the nepedw.tre"Podomn q..d Pink Wake and
12 le�hec6ahend oieaahglfor Mata ad reladd arachim ad proper doea
apl d —t-al Jued (ri mrd NIS X X X X HU Clean W.I.latch bnm,,alwm San rash,del~bmru,.k I R*=4 d IN coiedad W31,and debna prayai s to Prcaram
mam.eb imm berg Pu.W"the s,alern and eto
the from mmk
Pubic Wo 1p end
121 Pedam catch beau chwx^9 Mghed and clam wkh baavu=W* Jaaddmal "16X X X >< MCf 1'l Wale,
P
DM- Rapur end CpepP =P-.=.-
ade.-.GX.d ldlm pmacbhe eemuoa 6 npmi9- Jundmonel N16X X MS7 X X lean WalaraM
122 protidesource from Mia edraattm-ko a and k444 Q*N P
Refs d.X ° m4 wNlhe Cl,re$aNWY s Works and
Lthe MSl lmm leaWg/tnNX{Jf.eeas and jim". r JuudriorW FY
13 15 X MS1 clean Wear
13 aRodrvnly operau-marcxan,r�and repleca aexen for Ova"
le�cs and ereasxwueraroe_;_--- manhaka and aCibom Progran
"Implement controls to prevent infiltration of sewage into
the MS4 from leaking sanitary sewers and identify sewer
leaks and areas for sewer pipe replacement."
Los Angeles
LA River eWMP Strategies
• Page 92 of 694
BMP effectiveness with respect Agenry -
to WQPS
o
WCM z
X CategnryAO WCM 5 3
15 MCM•PIP•1 StormwaterresourtesonOtywebsite
Public Apncy Activltles ..
16 MCM-PAA-1 E n h anted BMP requirements for fixed 0 0 ® ^ ® +x 'Y x � � X X X
facility/field activities 17
17 MCM-PAA•2 Repriontizatronofcatchbasesand ♦ . ♦ , 0 8 X X X X X X X
clean•aut frequent ms
18 MCM-PAA•3 Ineegraled Pest Management
Program V V
19 MCM-PAA-d E nh anted measure+lo on,rol O 0 0 g, g. x % % X x X
rn li l,rat.on Irom Wnrt ary;pvrn ry V
"Enhanced measures to control infiltration from sanitary sewers"
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California City Liable for Contamination Spread by
Leaky Sewers
Posted feh.6,2019,11:04 AM
By Petcr Hayes -- —— --
Defects'in~ewers spread Curiumination
City sph-[N cleanup culls with dry c:lerrlter
The city of 4'isalia.Calif.,i,un 1}w hook rnr lialf of all future Supertund cleanup costs for C0111M inarion that
Uriginatcd from a shy-dCM1119 bclsirtell llve.jd l5ecaure of the city's poorly maintained cewcr system,the
Eastern Dislrict of California ruled.
While the cuntaininmio,l ariginarcd on a commercial sundry facility uperalcd by UrLen Supply,the
city Contributed to 111c releases of peechlnroethylenc and uthcr hk1ZJFlUUE subslarlxe,,frm Ort,ewcr system,the
iuurt stiitl.
The Scwv.,ll[1VC rl[[1l)C:0U.j"d4feL tm,- including holes,broken pipes,cxpu�ctl ti{1il.crack-5,lugs,separated joints,
]M.,M ftg FroFtioll�nt tYllk,[17n1 IntrUSinj%debris,and hlockugt's,111e COt114 40.
The Cnnlar9l, trtion.;pre td to ground Water and conlarnioawd drinking wate+'we11ti,the Court said.
rn 2oio,the['alifornia Department or Toxic 5ubllanCc4 CU11MIl ordered ivfik•ion Linen to conduct
enwirnnntental studies anti cooNjatc in rlcanup cffurts.
Rfiseinn Linen in May 2015 filed a Superfund cuutribulian diflin apaimt the city-
JN-court held a bench trial to allocate liability belween rhe city Md Nlisvinn Linen.Follmlving the trial,rhe
patties engaged in 5citicmcnt utlhs fur mono Iltar.a your,bol failed to reach a rescAution.
Mission Linen and tate city will cveniy%Ilii;111 Int1:r1.1'eNpol:tie costs incurred by Mission relaled to the K14,
Plume,the court ruled.
The city il rctiptlnsiblc run 1 til}Peft 0-11 X11:1 IV repAiM 10 the ticwcrs that may be ncceaaary.
7udyc Anthony W.Ishii issued thx i il iaL,.
Groben&ASbLWLLXeti repre�.n1,[1%'.Lwon Linen Supply.
I[v r Pedersen h Bughtnd,L1,11 and blond Stnith Henning&Bcnuan LLP Tepresemed the c[ty-
Thr case is Al,,itm I-inert Suppiv v.City Vkrdia,2019 BL 37490,E.D.CA,No-L-5-c'V-0672.21Sll9
Conclusions
* Bacteria are a frequent constituent of concern in watersheds
* Stormwater quality practitioners and scientists don't always understand
collection systems
* Sewer Exfiltration to MS4 Infiltration is a prime suspect, there are rare but
documented cases were it has occurred
* Sometimes there is a rush to judgement based on a lack of understanding of
collection system operation/construction
* We need to get out in front of this issue and:
* Educate the public, regulators and stormwater quality practitioners
* Design focused exfiltration investigation and remediation practices FF 'our
collection systems
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I�
� 1
a
�.. .
• • What Can
an Agency Do to be
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Things an Agency Can Do ffAV
to be Proactive
1. Get educated and prepare for conversations
o Understand how exfiltration happens and where it _
might be an issue Ge
o Understand local and regional regulatory issues
pertaining to exfiltration
2. Build collaborative relationship with stormwater
agencies in areas you serve
o Communicate information needs to support risk
assessment (i.e. stormwater system mapping)
Things an Agency Can Do to be Proactive
3. Identify which pipe segments might have impacts
o Close proximity to:
• surface water body or drainage channel
• lower elevation unprotected stormwater pipe
o Over shallow groundwater basin with beneficial uses and without
adequate distance for soil treatment
o Pipes conveying industrial waste streams moDERATe
iPA
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Things an Agency Can Do PLAN
to be Proactive
4. Assess condition of pipes in
U
locations with potential impact
o Identify defects having leakage potential UNMEN
5. Address defects with potential saffkp*vim
lmayesofsewerfines Sh6wMgbrokePW.""MIC*UVEIE.~jwnna► IBM&
impact MENEM
o Repair plans or 5-year/10-year capital
improvement plans
- r s
Co- ntact H" u
•
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WEA
Thank You !
Please complete the participant survey:
www.surveymonkey.com/r/sewer8620
October 12, 2020 REEP Committee Meeting Agenda Packet- Page 87 of 100