Inflow Source Identification Program
EXECUTIVE SUMMARY
The summer of 1999 marked the sixth successful year of the High School Inflow Source
Identification Program established by Louisville and Jefferson County Metropolitan Sewer
District (MSD). High school students were used to assist MSD in investigations of the
sources of wet weather sewer problems. This program represents a public/private
partnership between MSD, Waggener High School, the Louisville Education Employment
Partnership (LEEP), Jefferson County Public Schools (JCPS) and several consultants
including PDR Engineers, Inc.
This 1999 program consisted of downspout
testing, smoke testing, sump pump testing, and CSO-area testing.
Downspout and Sump Pump Investigation
The 1999 investigation concentrated in several areas:
- Cardinal Hill PS
- East Rockford PS
- Falgate Court
- Garrs Lane PS
- Hazelwood PS
- Melody Lane PS
- Murray Heights PS
- Savage, Pioneer, and Fern Lea PS's
- Sonne PS
Each area is associated with a potential pump
site or documented sanitary sewer overflow (SSO). In each separate sewer area, the
collection system upstream of the MSD Facility was investigated.
In the course of the 1999 downspout program,
crews canvassed approximately 3,400 homes during 4 weeks of the program. This can be
translated into about 212 homes per crew day (canvassing 2 days per week). The
identification of connected downspouts the last four years has remained significantly low
when compared to the first two years of testing. The results can be found in Table E.1 and
the areas tested are expressed graphically in Figure
E.1.
Table E.1 Downspout and Sump
Pump Canvassing 1999
Item |
Number |
Fraction |
Originally
canvassed |
3384 |
--- |
Total responses |
585 |
17% |
Crew inspection |
84 |
42% of homes w/
sump pumps |
Self inspection |
83 |
14% of
respondents |
Positive tests |
20 |
10% of homes w/
sump pumps |
Sump pumps —
did not allow test and no self-test |
32 |
16% of homes w/
sump pumps |
Total sump pumps |
199 |
34% of
respondents |
Connected
downspouts |
0 |
--- |
Smoke Testing
Smoke testing using students and MSD's I&I field technicians was part of the program
again this year, and the partnership proved to be very effective. The weather for the 1999
smoke testing investigation could not have been better - only one significant rain event
occurred in late June. The lack of moisture created optimum ground conditions for allowing
smoke to escape through leaks in the pipe.
Smoke testing crews focused on nine areas;
- Falgate Court
- Garrs Lane PS
- Savage Lane PS (including Fern Lea PS and Pioneer
PS)
- East Rockford PS
- Murray Heights PS
- Hazelwood PS
- Melody Lane PS
- Cardinal Hill PS.
Crews were able to smoke test for approximately
six weeks (nearly the entire duration of the program). Due to the lack of time, Sonne Lane
PS was not tested. It is recommended that this be completed in the 2000 program. Two crews
tested more than 33 miles (174,200 LF) of mainline pipe in streets and easements. The
crews smoked a total of 22 days. Production rates can be translated into about 8000 LF of
sewer main per crew day. There were 891 pipe sections with a total of 80 leaks in the 33
miles of mainline pipe.
This data was compiled electronically in an
Access database. The Microsoft Access database structure that was created for this project
will allow data migration to MSD's Infrastructure Management System (IMS). The results of
smoke testing are shown in Table E.2.
Table E.2 Smoke Testing 1999
Item |
Number |
Total pipe sections tested |
891 |
Total pipe length tested |
174,200 linear feet |
Total number of defects identified |
80 |
CSO Area
Several houses in a CSO area just southwest of Cherokee Park (east of downtown Louisville)
were canvassed and downspouts and/or toilets were dye-water tested. This area has combined
sanitary and storm lines as well as separate sanitary lines. Testing was initiated to
determine downspout and toilet discharge locations. Results from dye tests indicate that
downspouts and toilets were connected correctly in this area. Figure E.1shows the location
of this area.
Summary
During the 1999 program, students identified sump pump inflow sources that could
theoretically contribute a peak 800,000 GPD*. This figure does not include an estimate of
smoke defect contributions, which would have a significant impact.
Continued identification of connected downspouts
& sump pumps coupled with elimination of illicit connections with help from the
Private Property Program will reduce treatment costs and help eliminate SSOs throughout
the county. The success of the smoke testing and home sump pump verification can continue
in similar areas to sustain this workforce concept in the future.
Potential Projects
- Private Source Disconnect Policy/Program Manual -
Actual Field Experiences will provide insight into the ongoing Private Property
Disconnection Study.
- Sump Pump Testing - The priority areas as
identified in SSO Sections of the MS4 Report are likely areas for future sump pump
testing.
- Downspout Testing - Continue program to close out
entire county
- Smoke Testing - Priority areas as identified in
SSO Sections of the MS4 Report
- Consider revisiting areas covered in the past for
the purpose of Q/A and to determine the effectiveness of rehabilitation.
- CSO Testing - Should be initiated as needed and
provide assistance with sewer separation projects (coordinate with CSO Engineer).
These areas could be canvassed in a manner
similar to this year's student program. The program could be expanded to a year-round
after-school student program to take advantage of homeowners' schedules by canvassing and
testing in evening hours, and to expand on school-to-work educational concept.
* This figure is based on two assumptions; 1) 20 GPM per sump pump; 2) 1 in 4 sump pumps is running
at any given time during the wet weather period.
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