HomeMy WebLinkAbout8A Inflow and Infiltration Update�
EN H�LLS
Reques� for Council Action :
Prepared By_ Greg Hoag Council Meetir�g Date: June 9, 2008
lnflow and lnfiitration Update
Budgeted Amo�nt: Actual Amo�rnt: F�anding Source:
$'EQ0,10D NIA Sanitary Sewer FundNarious
Recommendatior�:
Rec�ive staff update on I� I project.
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Supporting Docum�nts:
1. Memorancfum dated June 9, 2008 frorr� Fublic Works �irector Greg Hoag and Ci�il Engineer
Kristine Giga.
2. Memorandurrt dated .Eune 4, 2008 fram Chuck Jar�ks�, Banestroo including a five year
schedule.
� E�T HII�L
5
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DATE: June 9, 2408
TO: Mayor and City Council
Ron Moarse, City Administrator
FROM: Greg Hoag, Public Warks Directar
Kristine Giga, Civil Engineer
SUBJECT: Inflow and Infiliratian (I&I) update
BACKGROUND
On March 31, 2008, staff presented the City Council with the Inflovcr and T�filtration (I&�) report
prepared by Bonestroo, which discussed initial results of the study and recomrraenc�ed n�xt steps.
Staff presented a work plan and requested approval of additional study on April 14, 2008. On
May 12, 2008 siaff presented the City Council with an upda�e af progress on the I& I praject, as
well as had Chuck 7anski frorn Bonestroo present to ansvver techz�ical questions.
UPDATE
Pro�ress to date:
Included as attachments to staffls memo is a working draft af a project schedule for the I& I
proj ect. This schedule was cornpleted by Bonestroo with assi�tance from staff Also attached is
a merno from Chuck Janski sul��tnarizing how a project of this magnitude is most efficiently
completed.
Lift station calibraiion:
Public Works staff is in the process of calibrating the fourteen lift stations (establishing pump
cycle times) so that the daily flow data retrieved can be better evaluated. To date we have
calibrated eight of the �ourteen lift stations. We expect this project to be complete in the next
two weeks.
11MetrainetlardenhillslPR&PW1EngineeringlI&116.9.08 Council Updafe16-9-08Memoll.doc
I&I
6/5/2008
Page 2
Lift station monitors:
Pump station monitors were insialled at Lift Stations 11 and 13 on Apri121, 2408 to further
break down t�e metershed to MCES meter 059 (on Wesi Round Lake Road). At the May 12`�'
Cify Cauncil Meeting Chuck Janski showed an example of the data tl�at these monitars are
collecting. On May 30, 2008 the pump siaiion monitor that was installed on lift siaiion 13 was
moved to Iift station 4. Weekly data from these manitors is being reviewed by Bonestroo.
Ternpora.ry flow metersT
Two flow meters were installed Wednesday, May 14. We anticipate the meters will be in place
for four to six weeks, depending an the weather. The �net�rs need to zxionitor "nortnal flaw" and
"high flow". High flow occurs when we receive signiiicant rain events. However, if we have a
drier than normal period, the length of time the meters are in place may need to be extended. To
date there has noi beEn a significant rain event to review iar "high flow".
Smoke testin�:
Smoke testzng is recommen�ed to occur in the sumniEr, after the streeis are swept and catc�
basins are cleared of leaves and debris. This allows the smoke to be mare visible to those
ca�npleting the tesiing. Staff �s working with Bonestroo to coordinate this work. In discussing
priorities for 2008, stafi and Bonestroo believe rnanhole rehabilitation is a higher priarity than
smoke tesiing. This item may be moved to the work plan for 2009.
At this tiane, the consultant recommends the following areas be included in sanoke testing: the
area flowing to the Glenarden neighborhood (proposed 2009 PMP), and the area flowing to Lift
Station #11 {northwest corner of the City.) Staff will keep the Cauncil updated on the schedule
far smoke testing.
Sanita Sewer televisin :
Staffls goal is to clean a�d televise approximately 30,040 feet (5.7 miles) in 2008.
Areas to be televised: In 2008, staff is focusing on televising sewer lines in low ar�d/or wet areas,
especially near ditch systems and lakes. 23,500 feet (4.5 miles) o#'televising is planned around
Round Lake, Lake Johanna, along Highway 10, and in the Vaientine Avenue neighborhood
(between Lake Valentine Road and 694.) Once these areas have been televised, staff will
continue to work on other areas of the City left to be televised To date we have cleaned
approximately 17,540 feet and televised approximately 9,200 feet.
Manhole ins �ction:
We have identif ed three areas in the City for manhole inspections in 200$; 165 manholes are
iocated in these areas. This wark is anticipated to be complete by mid J�une, To date we have
comple�ed 11 S oithe 165 manholes for 2008. When the 2008 inspections are cornplete,
approximateiy three quarters of the Citiy's manholes wili have been inspected. As we gather
additional information from other analysis such as flaw mefers, staff will i�entify the priority
areas where manhole inspections should be compleied next.
I&I
b/5/2008
Page 3
Additional seasonal staff position:
At the May �2, 2005 City Council meeting an additional seasonal employee was authorized. We
have filled this position from our pool of candidaies this year. The additional employee will
begin on June 9, 2008. It is anticipated tha� this employee wiil be available for fivvelve weeks.
Proposed imnrovement proiecf timeiines:
Sanita sewer linin ro�ec#s:
This will be a joint project with Roseville. Both Cities are currently zeviewing their records and
videos, identifying candidates for this projeci, and will coordinate to have areas determined in
3une, so the project ca� be advertised and a contract awarded in July. No new update at this
iirne.
Manhole rehabilitation project:
Manhole inspeciions have been completed for approximaiely one-half of the City. Of the
approximately 350 manhales, some level of repazr is needed to a�out 130. Needed repairs vary
fro�n replacing casting ri�gs and installing a chi�nney seal to regrouting manholes and repairing
structural cracks or leaks. Tn 2006 and 2007 staff completed 20 repairs. In addition to the
manhales inspected in 2006 and 20Q7 staff will review the results from the � 65 manholes
inspected in 2008 to prioritize a rehabilitaiion project for �ater this sirmrner.
In an effort to allow our staff to focus on identifying the source of I&I, we propose to assemble a
manhole rehabilitation project that incorporates all leveis of repair. Staff anticipates that this
project would be ready to advertise in July or August; this project will be brought back io council
ta award the contract.
Sum� Pump Inspeciion Pr�-am:
Our first step in developing a sump pump prograrn was to compile a spreadsheet of ihe results
from the 2000 inspection progxam to deiernune if there is an area in the city that should be
foc�sed on sooner rather tk�an Iater, and to determine how much of a potential issue suznp pumps
may actually be. The data from the 2000 inspeciion prograrn looks to be very pasitive for the
n�mber of properly installed sump p�.unp cannections in the city. However vcre only have
inspection records for about one third of the city. Staff has reviewed this information with
Bonestroo and is recorz�.mending a re-inspeciion prograrn in conjunction with a water meter
battery replacement progra�n to be cornpleted in ihe winter xzlonths ihe next three years. This
sununer we wiIl be working with Bonestroo io develap this program. Initial flow analysis has
pointed to an area in the city where sump pumps rnay be the cause oftk�e high flows. This area is
where vve will mosi likely start our inspection pragram. We wi11 carztinue to provide updates on
this item.
REC�MMENDED COUNCIL ACTI�N
Receive staff update on I& I project.
Memorandum
� Bones�roo
T0: KRIS GIGA & GREG HOAG PROJECT: ill A5SIS7ANCE PROJECT QATE; �iI�I2Q OS 2335 Highway 36 W
St Paul, MN 55113
FROM: CHUCK JANSKI CLIENT: CITY OF ARDEN HILLS TeE 651-636�60Q
Fax 651-636-1311
RE: I�I PLAN AN� DRAFT SCFiEDULE Fi�E No: 00353-07103-0 www.bonestroo.com
Problem: The City of Arden Hills is faced with an annual $100,100 s�archarge from the MCES due to
infiltration/inflow levels which exceed the MCE5 allowable peak fiaw rate for the community
Goal: The goaf of the program is to identify and remo�� sufficient I�T ta eliminate the current T/I surcharge
and reduce the annual treatment cost paid to the MCES.
Appraach: The approach will include an initial "big picture" review of the current situation, folfowed by more
detailed investiga�ions, data evaluation, rehabilitation and then Iong term follow-up. The plan provides a
basic guidefine far the anticipated project, but it must be flexible to adjust directian in response to actua[
situations or defects that accur or are identiFied during the course of the work. Rehabilitation is the step
that actually removes sources of I/I and should be consideret! an on-going task during �he project.
1. Initial r�view consists of compiling MCES ffow data, city maps, city investigation records, fift station
data, connection data, building type information,
A. Review MCES Flow data and precipitation data to understand MCES determination of peak
flow le�els
B. Review City Maps io understand sewer flaw patterns, high ground water areas, areas where
sanitary sewers are "off roadways" or on easements� [ift station locations and servic� areas,
C. Discuss and summarize Gity investigation effo�ts to further understand conditions of the
sani�ary sewer system
D. Compile lift statian pump data and review pump running times tfl determine �ariations
during wet weather conditions
E. Coliecf number af buifdir�g connections and types of buildings per drainage areas for data
evaluation and �urther understanding of the system
2. Analyze MCES flow data with respect to other system ir�formation to de�elo� "plan" for additianal
investigation e�Forts.
3. Identify locations for additional fEow monitoring to further subdivide the collection systern and
identify areas with little or no I/I flow. This will focus effor�s on those areas that actually contribute
to the I/I peak situation.
4. Collect flow cfata and review "flow respons�" to rainfall events.
A. The MCES data shou�d be regularly coliected and reviewed to monitar results of the
rehabiEitation efForts and determine benefits of the work.
g. Temporary flow metering (in manhofes} is typically a short term iask to identify sub-areas
requiring more or less investigation or rehabilitation efForts. The effectiveness of the
temporary metering is dependent on rainfall events.
C. The City lift station can also be used to monitor flows within their individual service areas.
Each station is equip�ed with a"r�n time" meter that records the number of hours that each
pump runs. These hourly data can be used in conjunction with the calibrated pu�-nping rate
��Metro-inet�ard�nhills�PR&PV4I�E�gineering�1&1�6.9.08 Council Update�City_CRJ^Memorandum re II Plan Ob 04 2408.doc
ta calculate the number of galfons that have passed through the site d�ring a particular
period af time. The firsi step in using these data is to calibrate the existing pumps to
determine an accurate pumping rate.
�. Projeck potential source(s) based on flow data to deiermine typ�s of additional investigation
methods ta use.
6. Cond�act additional investigation
A. Smoke testing. This pracedure is designed to icientify direct ir�flow type sources such as low
lying manhole covers, roof drains, catch basins and area drair�s.
B. Physical survey. This procedure invoives physically opening and 'mspecting each manhole
from the grnund surface to identify deficient adjusting rings, manhole barrel joints or wall
leakage, and pip� penetration joint leakage.
C. Internal tefe�ising. This procedure invoi�es cleaning the sanitary sewer segment to remove
as much debris and sediment as possibEe and then sending a speciaily designed television
camera down the line to view and video tape the condition of th� pipe under grour�d. The
tele�isian ir�spection typically identifes structural pipe probEems including open and leaking
joints, colEapsed pipes, poor quality service connections, and broken pEpes, in addition to I/T
defects such as leaking joints and leaking or running service conr�ections,
D. Surr�p pump inspection. This procedure involves actually entering each home or b�ilding in
the selected area ta inspect the baseme�t for sump purr�ps that may be connec�ed to the
sanitary sewer. The "inspector" campletes a standard form and �e[Is the bui�ding owner if
their s�mp pump is correctiy connected to discharge outside or illegally connected io the
sanitary sewer. If tf�e pump is i[legally connected, the property owner has an opportunity to
correct the siivation and ha�e the property re-inspected to appro�e the instaElation. Sump
pump inspections can require a significant labor effort to maice appointments and complete
ti�e ac�ual in E�ome inspeciion.
E. Foundation drain (or leaking service line) inspection. This procedure is difficult and can be
highly invasi�e in certain property cases. Faundation drains that are directly connected to
the sani�ary service la�eral or �eaking service la�eraE lines cannot be easily observed or
inspected. Small diameter television cameras have been de�eloped that can be pushed
down a 4 inch diameter sewer service pipe frorn t1�e b�ilding basement to the sewer main.
However, no� every buildir�g has plumbing t�at wi[I allow the entry of the tele�ision camera.
in some cases, a new cleanout must be i�tstalled to pro�ide access for tf�e camera. This can
require breaking a hole in the concrete basement floor to install the new cleanout.
Portions of the sewer service line can sometimes be inspected by a small rernote camera
that extends up the sewer service from t�e main inspeciian camera in the street sewer.
This remote camera can be effecti�e at viewing the pipe condition in a portion of the sewer
service lir�e, but the length af tra�el is limited and some defects can effectively block the
camera and preven� access for �iewing.
identification of directly connected foundation drains and leaking service lines on pri�ate
property is a difficuft and potentialfy expensive task that is appropriaiefy left to the end
investigatian list.
7. Throughout the project it is impartant to compile and update a data base of defects and projected
rehabilitation methods and costs to ultir►�ately prepare a priority listing of rehabiiitatior� req�ired to
correct the problems.
��Metro-inet�ardenhills�PR&P11J�Engineering�1&1�6.9.Q$ Council Update�Ciry_CR]^Memarandum re iT Plan Ob 04 2448.doc
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8. R�habilitation �f defects. Serious defects that are identified during the course af the investigation
should be rehabilitated as soon as possible to eliminate the I/I source. Howe�er, the majority of the
defects that are identified wiil be smaller and shou[d be compiled and evalua�ed before deciding
where ta expend funds for rehabilitation. As the list of defects is developed it should be regularly
re�iewed and prioritized to provide the most benefit for any rehabilitation expendiiure.
Rehabilitation methods include:
A. Catch basin rema�al
o Extend storm sewers to connect
o Disconnect and plug catch basin leads if possible
B. Roof drains
o Re-route ta ground or street surface or storm sewer if available
C. Manholes
o Raise cover to grade
o Seal co�er or replace with non-�ented type co�er
o Grout manhole barrel joints
o Cast in place manhole liner
o Replace deteriorated manhole
D. Pipe defects
o Test and seal joints
o Cured in place pipe liner (CIPP}
o Slip lining with new carrier pipe
o Pipe bursting to replace pipe "in place"
�. Private property sources
o Re-route sump pumps to discharge onto ground or street surface
o Provide aliernati�e outl�ts for sump pump discharge water
o Conduct regufar {e�ery two to three years) random re-inspection io assure tha� the
outside su�-Face discharge remain in place.
o Faundation drain r�moval typicalfy requires excavaiion near the building foundatian to
disconnect the direci connection and re-raute the flow from the drain tile to a new sump
pump. The sump pump is installed to lift the water from the foundation le�eE and
discharge it onto the ground surface away from the foundation.
o l.eaking service lines must be either replaced or slip IinecE to correct the leakage. Both
mett�ods �an be castiy and require extensi�� work at the praperty.
9. Annual Report
A. Summarize ef#orts and costs during past year.
B. iteview flow data and corr�pare to previaus year and MCES allowable flow rates.
C. Recomrr�end plan and work e�Forts for foflowing year.
��MeEro-inet�ardenhills�PR&PW�Engineering�1&1�6.9.08 Councif Update�City_CRJ^Memorandum re EI Pfan 06 04 2008.doc
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