bonestroo, rosene, anderlik, & associates - sanitary sewer facility plan - 2002

8/9/2019 Bonestroo, Rosene, Anderlik, & Associates - Sanitary Sewer Facility Plan - 2002

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Village of Whitefish BaySanitary Sewer Facility Plan

September 12, 2002

Prepared by Bonestroo, Rosene, Anderlik & Associates

File No. 862-02-108


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Village of Whitefish Bay Sanitary Sewer Facility Plan

September 12, 2002

Bonestroo, Rosene, Anderlik & Associates, Inc. Page 2

Nevertheless, Village continues to benefit from three wet weather relief connections through the

MIS: two are bypasses that discharge into the Village storm sewer systems, and one connectionto the MMSD's 84-inch North Side High Level Relief Sewer. In addition, the sanitary sewersystem currently has sixteen overflow locations consisting of gravity connections to stormsewers, gated overflows to the storm sewers, and several locations where Department of PublicWorks staff are able to relieve sanitary sewer surcharging by pumping the flow into the stormsewers.

Despite the relatively high number of permanent and temporary overflow locations, the sanitarysewer system in Whitefish Bay continues to pose an unacceptable risk of basement backups tothe residents. Even when basement backups do not occur, the possibility of wet weatheroverflows exists, and consequently, the Village of Whitefish Bay is seeking aggressive anddecisive action to control and manage its sanitary sewer system operation and capacity.

1.2 - Description of Existing ProblemsThe very existence of numerous bypass locations throughout Whitefish Bays sewer system,along with the three bypasses in the MIS serving Whitefish Bay should be viewed as proof thatthe system is in serious need of repair and rehabilitation. In addition to these overflows, recentyears have seen a series of rain events that caused widespread basement backups in theVillage. As a result, the Village has initiated a methodical approach to reducing wet weathersewer overflows and minimizing basement backups.

Wet Weather OverflowsThe Village currently has a general permit for Bypasses or Overflows from Sewage CollectionSystems with an effective date of June 1, 2001. According to this permit, unscheduled

bypasses or overflows from the sewer system are prohibited. Unfortunately, the Villageexperienced two instances of bypassing in 2001, and one in 2002. All three of these recentbypasses occurred at existing permanent bypass locations.

In a letter dated August 16, 2002, the Department of Natural Resources sent a notice of permitviolation to Whitefish Bay; thereby acknowledging the latest bypass report dated June 4, 2002.Noting that the June 3, 2002 rainfall was about 3 inches and was not accompanied bywidespread flooding, we can conclude that the existing wet weather inflow and infiltrationproblems in sanitary sewers is the main cause of overflows in Whitefish Bay. Consequently, thepresent Facility Plan seeks solutions to the wet weather inflow and infiltration problem in orderto reduce bypassing and help Whitefish Bay remain in compliance with the general permit forbypasses or overflows from its sewer collection system.

Basement BackupsThe extent of property damage due to basement backups is well documented and can be foundin the 1999 SSES. Specifically, to establish the magnitude of basement flooding, a postcardsurvey was mailed to the Village residents. In order to obtain meaningful data, the survey waslimited to two heavy rainfall events that were known to have caused backups in the recentyears: June 20, 1997 and August 5, 1998.


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Section 2 Previous Studies of the System

The condition and performance of the Whitefish Bay sewer system has been previously studiedby MMSD in 1981 and later by the Village between 1998 and 2000. These efforts sought toidentify the sources of wet weather inflow and infiltration in the system in order to protectresidents from basement backups and to reduce the occurrence of sewer overflows into stormsewers or other receiving waters. As a result of these earlier studies, the Village took somecorrective measures.

2.1 - 1981 SSESIn 1981, the Milwaukee Water Pollution Abatement Program completed a Sanitary SewerEvaluation Survey and the present eight sewer drainage basins were defined. In general, thewet weather peak hourly flow rates in the eight basins range between 4 to 17 times normal dailyflows, indicating that severe surcharging in some basins was likely. Similar (or identical)conclusions are also found in the 2010 MMSD Facility Plan.

The 1981 MMSD SSES states that wet weather inflow and infiltration is predominantly attributedto the following sources:

Manhole defects: 5 % of totalDriveway drains, direct connected downspouts, and catch basins: 15 % of totalFoundation drains: 75 % of total

Based on the 1981 MMSD Private Property Infiltration/Inflow Pilot Project, of the 4,500 homes inWhitefish Bay, 3,500 have foundation drains connected to the sanitary sewer laterals (1999SSES, page 3-2). In other words, foundation drains are said to contribute a significant amountof wet weather inflow to sanitary sewers.

The General Report and the Village of Whitefish Bay Community Report from the 1981 SSESprovides data on historic problem areas, recognizes several deficiencies in the system, andrecommendations improvements.

2.2 - 1999 SSESThe 1999 SSES consisted of flow monitoring, manhole inspections, smoke testing. In addition,a complete hydraulic model of the sanitary sewer system was created and calibrated usingmonitored wet weather flows at eight locations throughout the Village. Details of the monitoring

and hydraulic model calibration are presented in the SSES Final Report by Earth Tech.Prior to commencing with the manhole inspection, flow monitoring, and smoke testing, a SurveyPlan was prepared, submitted to, and approved by the MMSD. The plan is a requirement for theMMSD survey cost-sharing program for Sewer System Evaluation Surveys.

For flow monitoring, ten (10) ISCO 4150 Area-Velocity flow meters were installed for a 10-weekperiod from September 1, 1998 through November 17, 1998, and set to record average flows on


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5-minute intervals. Based on the size and shape of the sewer, the flow rate was calculated bythe meter. During the ten-week monitoring period over 600,000 data points were collected.

The 1999 SSES utilized rain gauge data to correlate rainfall to sewer system inflow. An ISCO674L Tipping Bucket Rain Gauge was installed on the roof the Village Hall to record rainfall andset to record total rainfall on 5-minute periods.

The flow data was utilized to establish the base flow for each metered basin during periodswhen there was no rainfall for three days prior to and during a week of dry weather. Weekendflows were not used in the computation of the base flow. The base flow was then superimposedover the metered data for verification.

Calculated dry weather infiltration rates showed that the greatest dry weather infiltrationmeasured in any one basin is 6,844 gpd/in-dia/mile. Significant infiltration begins at rates

greater than 10,000 gpd/in-dia/mile. The 1999 SSES found that, in all basins, the wet weatherflow in the sewer system is greater than the dry weather base flow. In fact, in most cases wetweather flows are more than two times greater than the base flows. Since the basement backupproblems occur during rain events, it is clear that the major component of the problem inWhitefish Bay is due to wet weather inflow. Accessible manholes in the Village were physicallyinspected from the surface to identify and quantify infiltration/inflow (I/I) sources and thestructural condition. There are 942 manholes in the Village and, structurally speaking, less than5 percent (45 manholes) of the manholes were found to be in poor condition.

Smoke testing was performed on the entire sanitary sewer system in the Village of WhitefishBay (204,000 lineal feet). The testing was performed utilizing a portable smoke blower to blow anon-toxic smoke into the sanitary system. The surrounding area was then watched for the

presence of smoke, which would indicate a potential clear water entry point into the sanitarysystem. The smoke source was investigated further to determine if the source was an entrypoint. If so, the location and degree of smoke was documented and the source was videotaped.During the smoke testing program 136 defects were found. A total of 44 catch basins werefound smoking, 22 (50 percent) of which were due to a bypass connection between the sanitaryand storm sewer systems.The 1999 SSES inflow assignment (page 3-1, 3-2) suggests a slightly different assignmentdistribution as compared to the 1981 SSES, but the general pattern is the same:

Manhole defects: 5.5 % of totalDriveway drains, direct connected downspouts, and catch basins: 7.5 % of totalFoundation drains: 87 % of total

As stated earlier, the 1999 SSES found that, in all basins, the wet weather flow in the sewersystem is greater than the dry weather base flow. In fact, in most cases wet weather flows aremore than two times greater than the base flows. Since the basement backup problems occurduring rain events, it is clear that the major component of the problem in Whitefish Bay is due towet weather inflow.


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The SSES has identified several sources of inflow into the sanitary sewer system:

Surface connections of the sanitary sewer and the storm sewer systems (i.e.manholes). The inflow through manholes is contributed through two main sources:manhole covers and manhole frame to chimney interface. Please refer to section3.1.1 of the SSES for manhole inflow assignment calculations.

Connections to the sanitary sewer from homes in the Village. These connections areclassified as any connection that contributes storm water other than a defectivelateral. Connections of this type are foundation drain connections. The SSES hasfound that 73 percent of the homes in the Village have foundation drains connectedto the sanitary sewer. A small fraction of these homes (80 homes) have sump pumpsconnected to the foundation drain and an even smaller fraction of homes (fivehomes) have downspouts connected (as discovered through smoke testing).

2.3 - Other Studies since 1999In addition to the investigations carried out in developing the SSES, a number of other studieswere also conducted. The Village pursued these studies in order to evaluate various alternativesand identify solution alternatives that were the most cost effective.

A Village-wide dye water flooding study was performed starting February 2002.Storm sewers having a 24-ich diameter or less located above or parallel to thesanitary sewer system or the sanitary laterals were dye-water flooded. In thosesections of sanitary sewer that show positive dye water transference from the stormsewer, the dye water cross connections were confirmed by observation of sanitarysewer manholes.

Overall, it was found that most storm sewers leaked into either sanitary sewers ormore importantly, into the sanitary sewer laterals. Though it was not surprising thatstorm sewers exfiltrated water, the extent of clear water allowed to inflow throughdefects in laterals was significant. The dye water study report is included with thisFacility Plan as a supporting document.

A complete viewing of all available sewer main video inspections (approximately 95percent of the Village mains) was performed in February of 2002. The Village PublicWorks crews perform routine video inspections of nearly the entire sanitary sewersystem on a regular basis. As part of this facility Plan, Village staff viewed the tapesand noted the structural defects of various kinds, including sags, cracks, brokenpipes, holes in pipes, collapsed pipes, missing pipes, and defective or missing lateralconnections.

A significant amount of severe structural defects were identified. This effort stronglyand definitively refuted the statement regarding no structural deficiency finding inthe 1999 SSES. In fact, quite the opposite was seen, which brought the 1999 inflowassignment into question.

The present structural condition of the sewers in the Village indicated that, in additionto foundation drains, direct connections, and manhole defects, broken or missingpipes and lateral connections should be considered as important inflow sources.


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As a consequence, a new and revised inflow assignment was necessary because aportion of the inflows previously assigned to foundation drains clearly originated from

structural defects in the sewer system. Despite questions regarding the actualcontribution of foundation drains, the 1999 SSES seems to have overestimated themaximum possible contribution of foundation drains to the inflow problem. (Pleasesee Section 3.1.3 of the 1999 SSES.)

A comprehensive look at the hydraulic models for both the sanitary sewer systemand storm sewer system in the Village took place. Previously, each model had beendeveloped separately. When combined, the storm and sanitary sewer models wereable to describe the behavior and performance of the bypasses and crossconnections between the storm and sanitary pipes.

The hydraulic analysis clearly shows that at least six of the existing gravity bypasseshave the potential of backflow causing storm runoff to flow into the sanitary sewer

system. The remaining bypasses will gradually become obsolete as clear waterinflow is reduced from the system.

The following table summarizes the results of the hydraulic analysis of gravitybypasses.

Gravity Bypasses from Sanitary to Storm Sewers

Location of Bypass

10-year rainfall

Flow DirectionHGL in SanitarySewer

HGL inStormSewer

WB-20 at Lake Drive and Lake View 650.78 655.28 storm to sanitaryWB-1 at Montclaire and Kent 640.68 645.82 storm to sanitaryWB-6 at Montclaire and Bay Ridge 636.92 646.04 storm to sanitaryWB-7 at Montclaire and Santa Monica 647.05 643.35 sanitary to stormWB-9 at Montclaire and Berkeley 648.55 639.65 sanitary to stormWB-14 at Montclaire and Lake 650.50 633.57 sanitary to stormWB-13 at Monrovia and Lake Drive 654.59 663.57 storm to sanitaryWB-19 at Diversey and Lancaster 635.08 637.79 storm to sanitaryWB-26 at Sheffield and Hampton 639.55 637.96 sanitary to stormWB-18 at Newhall and Fairmount 656.91 619.39 sanitary to stormWB-23 at Oakland and Lake 658.19 661.58 storm to sanitaryWilshire and Cumberland 676.28 643.62 sanitary to stormNewhall and Chateau 660.60 655.35 sanitary to storm


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2.4 - Summary of Observed Structural Defects

Included in this Facility Plan are several maps that illustrate the structural defects identifiedduring and following the 1999 SSES:

Map 1: Dye Water Flooding Transference.This map is based on the dye water flooding study. It illustrates thelocations where water is transferred from the storm sewer system (stormsewer pipes 24 inches of diameter or greater) to the sanitary sewersystem. It distinguishes between various degrees of observedtransference between the systems.

Map 2: Sags in Pipes This map is based on the video inspections of the system. It illustrates thereaches of sewer main where sags were observed. Sags reduce pipecapacity and contribute to surcharging that results in basement backupsand bypassing.

Map 3: Cracked Pipes This map is based on the video inspections of the system. It illustrates thelocation in the where a sewer main is cracked, thus allowing infiltration.

Map 4: Broken Pipes, Holes in Pipes, & Collapsed PipesThis map is based on the video inspections of the system. It illustrates thevarious locations where a sewer main was found to be broken, have ahole in the pipe, or where sewer main pipes have completely collapsed,thus allowing inflow.

Map 5: Defective Lateral Connections This map is based on the video inspections of the system. It illustrates thestretches of sewer main where one or more sanitary sewer lateral has abroken connection to the main, thus allowing inflow.

Map 6: Bypass Locations This map is based on the result of the hydraulic analyses of sanitary andstorm sewers. It illustrates the locations of known bypasses in the Village.In addition, those bypasses where the flow direction could be from thestorm sewer to the sanitary sewer are shown.

2.5 - Identification of Additional Inflow SourcesBoth the 1999 and the 1981 SSES studies have identified foundation drains to be a majorsource of wet weather inflow. The 1999 SSES study assigns almost 90 percent of the inflow tofoundation drains, while MMSDs earlier study suggests 75 percent, not including wet weatherinfiltration from private sanitary sewer laterals. This information suggests that, if foundation


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drains can be disconnected from sanitary sewer laterals, we should expect significantreductions in wet weather inflows.

However, there is very little data correlating the number of foundation drain disconnection and acorresponding and predictable reduction in clear water inflows. This is because the actualcontribution of each foundation drain is unknown and cannot be realistically estimated. In fact,Bonestroo, Rosene, Anderlik & Associates, Inc., is currently verifying conventional assumptionsregarding foundation drain disconnection by conducting a study in the Village of Shorewood.Residents in the study area were encouraged to disconnect their foundation drains from thesanitary sewers through financial incentives. Flow monitors in the sewer mains, as well assump pump meters were installed at approximately 40 percent of the homes in the study area.Incidentally, the study area is served by a sewer system directly tributary to Basin 3 in WhitefishBay, meaning that conditions studied in this part of Shorewood are expected to be very similarto conditions in Whitefish Bay.

In the Shorewood study, a strong correlation was noted between the reported sump pumpactivity and the amount of monthly rainfall recorded at the Village rain gauge, i.e., the wettermonths have resulted in increased pumping from the sumps.

However, given the fact that the sewer flow response to rainfall is measured in tens ofthousands of gallons per day, and that the monthly sump pump activity amounts to thousands ofgallons per month, we conclude that other, as yet unidentified sources of wet weather inflow andinfiltration sources present a much bigger problem than the inflow from foundation drains. Infact, subsequent dyed water flooding of storm sewers in the study area has confirmed that clearwater transference between the storm sewers and sanitary sewer laterals is almost immediatein the area, and therefore, it was concluded that a very large portion of the wet weather flow

could be attributed to this source, rather than foundation drains.Therefore, significant inflow reduction due to foundation drain disconnection appears to bepossible in a very small number of cases. The current data suggests that most sump pumps willeither provide negligible or very modest inflow removal benefits. This conclusion is furthersupported by the fact that flow measurements taken downstream of the sump pumps have notrecorded any reduction in response to rainfall. In other words, despite the fact that sump pumpsremove some of the inflow into the sewer system, the amount of removal has not beensignificant enough to register in the flow measurements in the sewer pipes.

Given the results of the Shorewood study, it seems unreasonable to assign a very large portionof wet weather inflow to foundation drains, while ignoring structural defects and existing gravitybypasses as potential inflow sources.

Structural defects allow ground water to leak into the sewers by presenting unobstructedhydraulic paths for the ambient ground water. Since ground saturation closely follows rainfall,the broken or missing pipes, disconnected lateral connections, etc. represent wet weather inflowopportunities. In addition, structural defects play an important role in conveyance capacity ofsewers. Missing pipes, broken or collapsed sections impede flow and reduce performance.Sags in pipes usually result in reduced hydraulic capacity and cause surcharging in the system.


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We have shown that several of the existing gravity bypass connections to the storm sewershave the potential of backflow into the sewers, thus completely defeating the purpose of having

these bypasses. These direct connections to the storm sewers represent a real and substantialsource of clear water inflow into the sanitary system.

Therefore, for the purposes of this Facility Plan, a more comprehensive list of inflow sources toWhitefish Bays sanitary sewer system is presented as follows.

Inflow Source Estimated Contribution to totalwet weather flowManhole defects 5%Driveway drains, direct connected downspouts,and catch basins 15%

Foundation drains

80%Broken, collapsed, or missing pipesBroken lateral connectionsDefective sanitary lateralsExisting gravity connections to storm sewers


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Section 3 Solution Alternatives

The Facility Plan considered several alternatives to reduce bypassing and basement backupproblems in Whitefish Bay. The previously completed Sanitary Sewer Evaluation Survey (SSES)included some of these alternatives.

StoragePipe upsizingWet weather relief sewer constructionFoundation drain disconnectionDownspout extensionManhole rehabilitationRepair and rehabilitation of structural defectsSanitary sewer liningSanitary lateral repair and rehabilitationStorm sewer liningElimination of existing sanitary sewer bypassesStorm sewer and drainage improvements

It should be noted that the solution alternatives include improvements in both the public andprivate portions of the sanitary sewer collection system. While the structural defects in thepublic sewers certainly contribute to the current I/I problem, the condition of the private lateralsand the existence of foundation drain connections are important concerns. Therefore, thepresent Facility Plan seeks to combine improvements in both public and private sewercomponents to arrive at a realistic inflow and infiltration reduction expectation. Section 4 of thePlan describes each alternative in detail and presents the selected combination ofimprovements for the Village.

3.1 - Performance Criteria for Solution ImplementationThe 1999 SSES sought to provide solution alternatives that offered protection from basementflooding during storm events similar to the August 6, 1998 rainfall (2.9 inches in 16 hours, 217homes with sewer backups, estimated 932,000 gallons bypassed). This event was the mostsignificant storm event in recent history (excluding the June 1997 event, which would have beencost prohibitive to provide protection against).

Following the 1999 SSES and during the evaluation of the proposed improvements, the Villageof Whitefish Bay concluded that a reasonable protection level for residents would be against arainfall event with a 1 percent probability. The intent to provide this level of service waspresented to the Village Board and the public by the Village Engineer in March 2001 and allsubsequent evaluations of I/I reduction and sewer capacity management efforts targeted theprotection against a 1 percent probability (i.e., 100-year recurrence interval) rain event.

The present Facility Plan continues with this selected design objective of basement backupprotection during a 1 percent probability, 1-hour duration rainfall with a total depth of 2.64


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inches. This means that, with the proposed improvements in place, the total flow (consisting ofsanitary sewer, infiltration, and inflow) in the system during the 100-year, 1-hour rain should be

handled in such a way as to not cause sewer backups.During the 100-year, 1-hour rainfall, the hydraulic model estimates the presence of a total of1,430,000 cubic feet or 10.7 million gallons of clear water in the system. The same hydraulicmodel predicts that, during a 10-year, 1-hour duration rainfall (1.9 inches), the system will besurcharged at some locations, but will perform without backups or bypassing. The hydraulicanalysis indicates that, during a 10-year, 1-hour rainfall, a total of 845,577 cubic feet or 6.325million gallons of clear water move through the sanitary sewer system. In other words, there isno need to completely eliminate all inflow and infiltration to attain the target service level: if theinflow is limited to approximately 6.3 million gallons during a rain event (i.e., a 40 percentreduction from current levels), we would minimize basement backups and significantly reducethe frequency of sanitary sewer overflows.

Therefore, the present Facility Plan proposes to reduce wet weather inflow by 40 percent suchthat the improved systems performance during a 100-year rainfall is equivalent to the existingsystems performance during a 10-year rain. The Facility Plan further proposes that, toreasonable degree of engineering certainty, a 40 percent reduction in wet weather inflow isattainable.


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Section 4 Evaluation of Solution Alternatives

The overall objective of the Plan is to reduce wet weather inflow into the system by a minimumof 40 percent. The Facility Plan contains a series of rehabilitation and repair measures, which,when fully implemented, will reduce basement backups and sanitary sewer overflows. Therecommended measures include both the private and public components of the system:

On the public side, we have identified a number of severe structural defects in the form ofbroken and missing pipes, as well as a number of bypass locations where stormwater hasaccess to the sanitary sewers. By correcting these defects, the Facility Plan not onlyaddresses a basic infrastructure maintenance need, but also eliminates a great number ofgaping holes, each one of which is likely to be an important source of inflow into the system.

On the private side, we have found widespread evidence of clear water transference fromthe storm sewers into the sanitary sewer laterals. Village-wide dye water flooding of stormsewers indicated that defective sanitary laterals were an important and undisputed source ofstormwater inflow into the sewer system. While these defective laterals no doubt contributeto dry and wet weather infiltration, the Facility Plan seeks to address the wet weather inflowproblem first.

StorageThis alternative consists of building, in-line or parallel with, the existing sanitary sewer. To lowerthe hydraulic grade line significantly to reduce basement flooding, the storage would have to bebuilt below the existing sanitary system and pumped back into the system after the wet weatherevent had subsided. Storage would have to be constructed throughout the Village. The 1999SSES estimates that this alternative would have a probable cost of $17.7 million.

Storage was excluded from the recommended plan based on the basis of excessive cost, lackof a free outlet, and no protection from MIS surcharging.

Pipe UpsizingThis alternative would consist of replacing the existing sewer system with a larger and deepersystem to lower the hydraulic grade line. To provide protection from backflow during MISsurcharged conditions, a backflow prevention device would have to be installed at all Villageconnections to the MIS. It should be noted that replacing the majority of pipes in the Villagewould help reduce inflow and infiltration rates dramatically.

The 1999 SSES does not consider this to be a viable alternative, as it would be expected to costmore than the storage alternative. The cost of replacing the majority of sewers in Whitefish Baywith larger pipes can approach $30 million and since the Villages discharge volume and rateare limited by the MMSD, it is unlikely that such a grand project would even be possible toundertake. Therefore, this alternative is not included in the Facility Plan.

Wet Weather Relief Sewer ConstructionWet weather relief consists of constructing a deeper sewer system that would be tied into theexisting system at key locations to divert excess wet weather flows. The excess flows would be


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discharged into the MIS in Estabrook Parkway at the southwestern comer of the Village. Toprovide protection from MIS backflows during surcharged conditions, a backflow prevention

device would be installed at all Village connections to the MIS. Additionally, to provide freeoutlet during events greater than the design rainfall, an outfall to the Milwaukee River would beconstructed at the southwestern comer of the Village.

This alternative is expected to cost $10 million (the 1999 SSES cost estimate of $4.8 million wassubsequently revised by the authors of the SSES). Though it provides protection from MISsurcharging, this alternative requires the construction of a new sanitary sewer overflow to theMilwaukee River. Furthermore, the relief sewer, as opposed to pipe upsizing, would notaddress existing inflow and infiltration sources. Because of these reasons, this alternative wasnot included in the Facility Plan.

Foundation Drain Disconnection

This alternative consists of verifying every home with connected foundation drains. Each homeverified would then be disconnected and a sump pump installed. The cost for this alternativewould be approximately $3,500 per home or, a total of $12.3 million.

In addition, there is very little data correlating the number of foundation drain disconnection anda corresponding and predictable reduction in clear water inflows. This is because the actualcontribution of each foundation drain is unknown and cannot be realistically estimated. Adetailed description of a recent study supporting this argument has been presented in Section2.5 of this Facility Plan.

This alternative was not considered for the recommended plan due to excessive cost andunpredictable and uncertain benefits.

Downspout ExtensionAs an alternative to complete foundation drain disconnect, downspout extensions havesometimes been proven to be effective in the elimination of inflow. Downspout extensionconsists of extending the downspout a minimum of 6 to 8 feet from the foundation wall.

However, we note that the benefits of downspout extension diminish when dense and heavilycompacted backfill surrounds the foundation walls. As an established community where homesare sometimes more than seven or eight decades old, it would be reasonable to expect thatmost homes in Whitefish Bay are surrounded by heavily compacted soils, which may reduce theeffectiveness of the effort.

Nevertheless, the Village currently requires downspout discharges to be placed a minimum ofsix feet from the foundation wall. Downspout extension is closely related to establishing andmaintaining adequate storm sewer service in the Village. As previously discussed, there is ahigh potential for clear water leakage from storm sewers into sanitary laterals throughout theVillage. Under these circumstances, any additional runoff directed to the streets must first besafely and effectively collected by the drainage system. In addition, the transfer of runoff fromthe storm sewers into the sanitary laterals must be minimized either through sealing the stormsystem, or repairing and rehabilitating the private laterals.


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Manhole RehabilitationThe rehabilitation and repair of the approximately 720 defective manholes identified during the

1999 SSES inspection will be undertaken. The total estimated cost for this alternative is $0.8million, as detailed in Chapter 5 of the 1999 SSES.

It is estimated that approximately 5 percent of the total inflow would be removed from thesystem through this component.

Repair and Rehabilitation of Structural DefectsA number of potential inflow sources were identified during smoke testing as part of the 1999SSES. A detailed list of these defects is presented in Chapter 5 of the SSES report. Theimplementation of these repairs will be included in the overall improvements defined by thisFacility Plan. The estimated cost of repairs is $62,000.

Because of its immediate benefit and very low cost, this alternative is recommended andincluded in the Facility Plan. It is estimated that up to 5 percent of the total inflow would beremoved from the system through this component.

Sanitary Sewer ReplacementThis repair entails replacing the entire stretch of the sanitary main between two manholes wherea structural defect is found. For sags in pipes, broken pipes, holes in pipes, or missing pipes thisis the only course of action.

Construction of replacement sewers also helps in reducing the number of manholes in thesystem because current design practice and construction methods allow less frequent use ofmanholes than was the case when the Villages sewers were originally built. Fewer manholes

help fight I/I by reducing the number of locations ground and surface water can be introducedinto the system. Though the use of fewer manholes is not a specific component of the FacilityPlan, the concept will be applied in each case of sanitary main replacement.

The cost evaluation of sanitary pipe replacement includes the expected list of restoration itemsnormally encountered during utility construction:

Removal and replacement of asphalt and baseExcavation to existing mainRemoval of existing main and manholes by manhole to manhole segmentsInstallation of new sewer main and manholesReconnection of laterals along the new sewer mainBackfill of the excavationAny sanitary bypassing necessary to complete the construction

The following table represents the estimates of lineal feet of replacement per basin as shownthrough the various studies.


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Sanitary Sewer Replacement

Sanitary Sewer Basin Lineal Feet of SanitarySewer Replacement Cost per LF Cost per Basin

WB1 1,480

$ 70.00

$ 103,600.00WB2 2,660 $ 186,200.00WB3 2,690 $ 188,300.00WB4 2,020 $ 141,400.00WB5 2,840 $ 198,800.00WB6 7,570 $ 529,900.00WB7 8,230 $ 576,100.00WB8 6,330 $ 443,100.00Total 33,820 $ 2,367,400.00

Sanitary Sewer LiningWhere the structural defect on a sanitary main is limited to cracked pipes, pipe lining can beused to repair the source of inflow. The following table represents the estimates of lining persanitary sewer basin as shown through the various studies.

Sanitary Sewer Lining

Sanitary Sewer Basin Lineal Feet of SanitarySewer Lining Cost per LF Cost per Basin

WB1 2,190

$ 35.00

$ 76,650.00WB2 570 $ 19,950.00WB3 1,110 $ 38,850.00WB4 5,550 $ 194,250.00WB5 530 $ 18,550.00WB6 2,150 $ 75,250.00WB7 3,280 $ 114,800.00

WB8 530 $ 18,550.00Total 15,910 $ 556,850.00

It is estimated that approximately 10 to 20 percent of the wet weather flow would be removedfrom the system through sewer lining.

Sanitary Lateral Repair and RehabilitationSanitary sewer laterals are a known and documented source of inflow. The age of the laterals,original construction methods and materials all contribute to situations conducive to creatinginflow. For example, in the 2010 MMSD Sanitary Sewer Facility Plan, it is estimated thatbetween 20 to 60 percent of total inflow and infiltration may be due to defective sanitary sewerlaterals.

In addition to inflow potential, it is generally accepted that older laterals like the ones found inWhitefish Bay are also susceptible to collapse or root intrusions, thereby presenting serviceproblems for resident even during dry weather periods. In other words, the existence ofdefective laterals is a problem for both the public system and the individual homeowner.

We therefore recommend that lateral repairs be included in all sanitary sewer replacementprojects. Therefore, repairs and rehabilitation of the portion of the lateral between the sewermain and the property line is included in this Facility Plan.


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The following table presents and estimate of the number of laterals that would be replaced as

part of the public sewer main replacement component of the Plan.Private lateral repairs during public sewer replacement

Sanitary SewerBasin

Lineal Feet of SanitarySewer Replacement

Estimated Numberof Laterals Cost per Lateral Cost per Basin

WB1 1,480 30

$ 2,000.00

$ 59,200.00WB2 2,660 53 $ 106,400.00WB3 2,690 54 $ 107,600.00WB4 2,020 40 $ 80,800.00WB5 2,840 57 $ 113,600.00WB6 7,570 151 $ 302,800.00WB7 8,230 165 $ 329,200.00WB8 6,330 127 $ 253,200.00Total 33,820 677 $1,352,800.00

It is estimated that approximately 15 to 20 percent of the total inflow would be removed from thesystem through private lateral repairs. In addition to the private lateral rehabilitation andreplacement, the Facility Plan also includes consideration of private lateral repairs where stormsewers have been observed to leak into defective laterals.

We have previously shown that clear water transference between the storm sewers anddefective laterals presents a large problem for the Village. To address this situation, wepropose to rehabilitate private laterals in those areas where high transference was found even ifthe sanitary sewers are not recommended for replacement. In other words, we are proposing asecond group of private lateral rehabilitation in addition to the laterals addressed as part ofpublic main replacement projects. It is anticipated that this second group of private lateralswould be lined using remote control technology, and the main objective would be to seal theportion of the lateral in the immediate vicinity of the leaking storm sewer crossing.

Private lateral repairs to prevent storm sewer leakageSanitary Sewer

BasinLineal Feet of affected

storm sewerEstimated number oflaterals to be sealed Cost per Lateral Cost per Basin

WB1 -- --

$ 2,500.00

--WB2 1,450 16 $ 40,000.00WB3 2,200 22 $ 55,000.00WB4 2,020 20 $ 50,000.00WB5 -- -- --WB6 600 6 $ 15,000.00WB7 800 8 $ 20,000.00

WB8 8,000 800 $ 2,000,000.00Total 15,070 872 $ 2,180,000.00

Before including the second group of private laterals in the Facility Plan, we must first evaluatethe effectiveness of preventing clear water transference between storm sewers and privatelaterals through the sealing of storm sewers. This approach is already under investigation bythe Village and MMSD, and though it does not address the structural defects in the privatelaterals, some near term benefits may be obtained by lining storm sewers to prevent exfiltrationof clear water.


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Storm Sewer Lining

Recent dye water studies in Whitefish Bay show that storm sewers leak into the sanitary sewersand sanitary laterals. Lining the storm sewers can preventing exfiltration from the storm sewerand reduce this portion of the wet weather inflow. The following table represents cost estimatesof storm sewer lining per sanitary sewer basin as summarized from the Village dye waterflooding study.

Storm Sewer Lining

Sanitary Sewer Basin Lineal Feet of StormSewer Lining Cost per LF Cost per Basin

WB1 --

$ 50.00

--WB2 1,450 $ 72,500.00WB3 2,200 $ 110,000.00WB4 2,020 $ 101,000.00

WB5 -- --WB6 600 $ 30,000.00WB7 800 $ 40,000.00WB8 8,000 $ 400,000.00Total 15,070 $ 753,500.00

In locations where high water transference occurs, this method may be effective in the shortterm. However storm sewer lining does not address the continuing inflow and infiltrationproblems in the sanitary sewers and provides only a limited solution to the Villagespredicament.

The long-term inflow and infiltration reduction that can be obtained through storm sewer lining ispresently unknown, however, preventing exfiltration from the storm sewers has so far beenconsidered as an effective alternative to private sanitary laterals that transfer the leaking waterinto the sanitary sewers. In addition, the Village has already identified drainage improvementneeds, and the planned capacity increases and drainage improvements will address most of theleaking storm sewers, thereby reducing the need for storm sewer lining. More information onthe extent of drainage improvements, and the potential inflow and infiltration benefits ispresented in the following sections of this Facility Plan.

Elimination of Sanitary Sewer BypassesThis alternative consists of closing six bypasses immediately because they have been shown topose a risk of flow from the storm sewer into the sanitary sewers. As other inflow reducingmeasures are implemented, the remaining seven bypasses will be hydraulically evaluated andwhen found to be no longer necessary, closed permanently.

The estimated cost of bypass elimination is $5,000 per location. For planning purposes, theFacility Plan includes provisions to remove all existing bypasses for the estimated cost of$65,000 over the course of plan implementation period.

Because of its immediate benefit and low cost, this alternative is recommended and included inthe Facility Plan. Based on hydraulic modeling of the system, it is estimated that approximately5 percent of the total inflow would be removed from the system through this component.


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Storm Sewer and Drainage ImprovementsThe Village of Whitefish Bay has recognized the need for comprehensive Stormwater

Management and commissioned a Stormwater Management Plan in 1998. As a result ofdetailed hydraulic analysis, the stormwater management plan identified drainage problems andrecommended improvements to the storm sewer system throughout the Village. Overall, as thehydraulic and hydrologic analysis shows, the storm sewer system generally has the propercapacity to handle a 10-year rainfall event. However, pipe segments without the requiredcapacity also exist. An evaluation of the local topography suggests that these pockets ofdrainage problems are confined to the streets, or street right of ways, greatly reducing the risk offlood damage to property.

The close relationship between the storm sewers system and defective laterals has beendemonstrated and noted by the Village. In addition, practices such as down spout extension putincreased burdens on the storm drainage system. To this end, the Village continues to pursue

the improvements identified in the comprehensive stormwater management plan.Storm sewer capacity and drainage improvement is included in this Facility Plan because therelationship between poor drainage, leaking storm sewers, and Clearwater transference into thesanitary sewers has clearly been established. The Village is therefore proposing to includestorm sewer replacement and improvement projects as part of the overall effort to reduce andcontrol wet weather flows in the sanitary sewer system.

The following table presents the Village blocks and intersections where the hydraulic capacity ofthe storm sewer system is exceeded during the 10-year rainfall event.

Storm Sewer Capacity Improvement Needs Summary

Location Problem DescriptionRecommended Act ion to ensure 10

year storm capacityNorth of Santa MonicaBlvd. - Montclair Ave.intersection.

Undersized 24-inch pipe. Upsizing of this 280 ft. segment to a36-inch pipe.

Lydell Ave., betweenBelle Ave. and Montclair Ave.

Undersized 27-inch pipe segmentreceiving Lydell Ave. drainage in additionto storm sewer flows from mid-blockinlets on Kent and Shoreland Avenues.

Upsizing of this 400 ft. segment to a36-inch pipe.

Lydell Ave., betweenBelle Ave. and Montclair Ave.


Lydell Ave. north of DayAve. Undersized 18-inch pipe.


Birch Ave. between BayRidge and KentAvenues.


Birch Ave. between Kentand Shoreland Avenues. Undersized 30-inch pipe.


Santa Monica Bd.Between Henry Clay St.and Lexington Bd.



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Location Problem Description Recommended Act ion to ensure 10

year storm capacityIdlewild Ave. betweenFleetwood andBriarwood Pl.


Idlewild Ave. betweenBriarwood Pl. andLexington Bd.


Idlewild Ave. betweenLexington Bd. AndSylvan Ave.


Idlewil Ave. betweenSylvan Ave. and HenryClay St.


Cramer Ave. betweenWilshire Rd. andCumberland Bd.


Chateau Pl. betweenLarkin and Newhall St. Undersized 18-inch pipe.


Lake Dr. betweenFairmount and OaklandAve.


Fairmount Ave. betweenArdmore Ave. andWoodburn St.


North side of Silver Spring Dr. betweenLydell and Kent Ave.


South side of Silver Spring Dr. betweenLydell and Bay RidgeAve.


Lydell Ave. north andsouth of Fairmount Ave. Undersized 30-inch pipe.

Upsizing of this 1,420 ft. segment to a36-inch pipe.


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Location Problem Description Recommended Act ion to ensure 10

year storm capacity

North side of CourtlandPl. between MarlboroughAve. and Diversey Bd.

Undersized 36-inch pipe. The existing pipes will be adequatewhen downstream pipes are upgraded.

Undersized 30-inch pipe. Upsizing of this 40 ft. segment to a 42-inch pipe.





South side of CourtlandPl. between MarlboroughAve. and Diversey Bd.

Undersized 36x22-inch arch pipe. The existing pipe will be adequatewhen downstream pipes are upgraded.


Diversey Bd. betweenChateau and CourtlandPl.




Hampton Rd. betweenMarlborough Ave. andDiversey Bd.








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Storm Sewer Replacement

Sanitary Sewer Basin Street Estimated Construction Costby Basin

WB1Birch Ave. between Bay Ridge and Kent Avenues.

$ 55,000Birch Ave. between Kent and Shoreland Avenues.

WB2

North side of Silver Spring Dr. between Lydell and KentAve.

$ 285,000

South side of Silver Spring Dr. between Lydell and BayRidge Ave.

Lydell Ave., between Belle Ave. and Montclair Ave.

Lydell Ave., between Belle Ave. and Montclair Ave.

Lydell Ave. north of Day Ave.

Lydell Ave. one block north and south of Fairmount Ave.

WB3

North side of Courtland Pl. between Marlborough Ave.and Diversey Bd.

$ 570,000South side of Courtland Pl. between Marlborough Ave.and Diversey Bd.

Diversey Bd. between Chateau and Courtland Pl.

WB4Cramer Ave. between Wilshire Rd. and Cumberland Bd.

$ 80,000

Lake Dr. between Fairmount and Oakland Ave.

WB5 Hampton Rd. between Marlborough Ave. and DiverseyBd. $ 250,000

WB6Fairmount Ave. between Ardmore Ave. and Woodburn St.

$ 50,000Chateau Pl. between Larkin and Newhall St.

WB7

Idlewild Ave. between Fleetwood and Briarwood Pl.

$ 150,000Idlewild Ave. between Briarwood Pl. and Lexington Bd.

Idlewild Ave. between Lexington Bd. And Sylvan Ave.

Idlewild Ave. between Sylvan Ave. and Henry Clay St.

WB8 Santa Monica Bd. - North of Montclair Ave. $ 30,000

TOTAL $1,470,000.00


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Section 5 Facility Plan Implementation

5.1 Facility Plan SummaryThe proposed Facility Plan includes sewer replacement, private sanitary lateral repair whereversewer replacement occurs, private lateral rehabilitation where leakage from storm sewers arefound, sanitary sewer lining, bypass elimination, manhole rehabilitation, and othermiscellaneous repairs. The following table presents the anticipated I/I reduction benefits aspreviously discussed in Section 4 of this Plan.

Option 1: I/I Reduction Benefits (repair and rehabilitation of private sanitary laterals)

Option 1 Facility Plan ComponentEstimated I/IReduction

Benefit

Private Lateral Repair with (1) pipe replacement, and (2) rehabilitation of privatelaterals where stormwater transference has been found. Total estimated lateralsto be repaired, replaced or rehabilitated: 1,550

15% to 20%

Sanitary Sewer Replacement 5% to 10%Sanitary Sewer Lining 10% to 20%Storm Sewer Replacement 5%Elimination of Bypasses 5%Manhole Rehabilitation 5%Miscellaneous Repairs and Rehabilitation 0% to 5%TOTAL 45% to 70%

As an alternative to rehabilitating private laterals where stormwater leakage has been found,lining the storm sewers is considered as an alternative. Though this method does not addressthe structural defects in private laterals, it can nevertheless help reduce the amount ofstormwater transference between the storm sewers and the sanitary sewers.

Option 2: I/I Reduction Benefits (storm sewer lining and limited private sanitary sewer lateral repairs)

Option 2 Facility Plan ComponentEstimated I/IReduction

Benefit

Private Lateral Repair with pipe replacement only. Total estimated laterals to berepaired, replaced or rehabilitated: 680 5% to 10%

Sanitary Sewer Replacement 5% to 10%Sanitary Sewer Lining 10% to 20%Storm Sewer Replacement 5%Storm Sewer Lining 5% to 10%Elimination of Bypasses 5%Manhole Rehabilitation 5%Miscellaneous Repairs and Rehabilitation 0% to 5%TOTAL 40% to 70%


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5.2 - Economic AnalysisThe following table presents itemized cost estimates for each plan component included in

Options 1 and 2. When compared to the other alternatives considered for Whitefish Bay, bothoptions of the proposed Facility Plan offer a cost effective approach to reducing basementbackups and sanitary sewer overflows. The main feature of the proposed Option 1 is that itaddresses the core problem rather than its symptoms and it establishes a process by which thedeterioration of the Villages sanitary sewer infrastructure can be reversed.

Facility Plan Option 1

Facility Plan Option 1Repair and rehabilitation of private sanitary laterals

Estimated Cost

Repair, Replacement, or Rehabilitation of approximately 1,550 PrivateSanitary Laterals (680 laterals during sewer replacement, 870 laterals tobe lined against stormwater leakage)

$3,532,800

Sanitary Sewer Replacement $2,367,400

Sanitary Sewer Lining $556,850

Storm Sewer Replacement $1,470,000

Elimination of Bypasses $65,000

Manhole Rehabilitation $800,000

Miscellaneous Repairs and Rehabilitation $62,000

SUBTOTAL CONSTRUCTION COST $ 8.85 M

Contingency Allowance 20% of Construction Cost $ 1.77 M

SUBTOTAL TOTAL CAPITAL IMPROVMENTS $ 10.62 M

Surveying, Design Engineering and Construction Management 25% of Sanitary Sewer Replacement (0.25 x $2.3 M = $575,000)25% of Storm Sewer Replacement (0.25 x $1.47 M = $367,000)12% of Sanitary Sewer Lining (0.12 x $0.5 M = $50,000)10% of Private Sanitary Sewer Lining (0.10 x $2.3 M = $230,000)

$ 1.21 M

TOTAL $ 11.83 M

Option 2 offers a slightly scaled back approach that takes advantage of recent findingsregarding the benefits of storm sewer lining to prevent clear water leakage into the privatesanitary sewer laterals. However, we do note that the Village already has a storm sewer anddrainage improvement plan in place, and the lining of storm sewers in Option 2 may interferewith recommended storm sewer improvement projects. The economic analysis of Option 2 ispresented below.


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Facility Plan Option 2

Facility Plan Option 2Repair and rehabilitation of private sanitary laterals

Estimated Cost

Repair, Replacement, or Rehabilitation of approximately 680 privatesanitary sewer laterals during sewer replacement. $1,352,800

Sanitary Sewer Replacement $2,367,400

Sanitary Sewer Lining $556,850

Storm Sewer Lining $753,500

Elimination of Bypasses $65,000

Manhole Rehabilitation $800,000Miscellaneous Repairs and Rehabilitation $62,000

SUBTOTAL CONSTRUCTION COST $ 5.96 M

Contingency Allowance 20% of Construction Cost $ 1.19 M

SUBTOTAL TOTAL CAPITAL IMPROVMENTS $ 7.15 M

Surveying, Design Engineering and Construction Management 25% of Sanitary Sewer Replacement (0.25 x $2.3 M = $575,000)12% of Sanitary Sewer Lining (0.12 x $0.5 M = $50,000)12% of Storm Sewer Lining (0.12 x $0.75 M = $90,000)

$ 0.71 M

TOTAL $ 7.86 M

The following matrix compares the selected alternatives against the rejected alternatives, andclearly shows the cost effectiveness of the measures included in the Facility Plan. The matrixindicates that the approach proposed in this Facility Plan meets the expectations of the Village,MMSD and the Department of Natural Resources: the removal of known inflow sources reducesbasement backup risks, seeks to eliminate the need for sewer overflow, and does not increaseflows discharged to the MMSD MIS.

In addition, the proposed approach brings the Village sewer infrastructure towards a state ofreasonably good repair so that future maintenance needs are predictable and economical.

Among all other options, the proposed approach is the only one that accomplishes all goalswithout drawbacks, and for the lowest total cost.


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Comparison of Solution AlternativesAlternative Cost Benefits Drawbacks

Storage $ 17.7 M Reduces basement backups andsewer overflows.

Does not address I/I sources.Does not address structural defects insystem.Does not address surface drainageproblems.

Upsizing $ 30 M

Reduces basement backups andsewer overflows.Corrects I/I sources and structuraldefects.

Equivalent to re-building entiresanitary sewer system.Cannot discharge higher flows intoMIS.May require overflow to MilwaukeeRiver.Does not address surface drainageproblems.

Relief Sewers $ 10 M Reduces basement backups andsewer overflows.

Does not address I/I sources.Does not address structural defects in

system.Requires new overflow to MilwaukeeRiver.Does not address surface drainageproblems.

FoundationDrainDisconnection

$12.3 M May reduce some of wet weatherinflow.

Does not address other I/I sources.Does not address structural defects insystem.Unproven removal rates.Does not address surface drainageproblems.May worsen surface drainage.

Proposed Plan Option 1 $ 11.83 M

Reduces basement backups andsewer overflows.Corrects known I/I sources andstructural defects.Includes known private propertysources.Does not require new overflowconstruction.Reduces total discharge into MIS.

Requires partial ownership of sanitarylateral by the Village.

Proposed Plan Option 2 $ 7.9 M

Reduces basement backups andsewer overflows.Corrects known I/I sources andstructural defects.Does not require new overflowconstruction.Reduces total discharge into MIS.

Requires partial ownership of sanitarylateral by the Village.Only partially addresses private lateraldefects.Storm sewer lining does not integratewell with recommended storm sewerimprovements in the StormwaterManagement Plan.

Does not address surface drainageproblems.


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5.3 Facility Plan SelectionThe selected alternative for implementation is Option 1 Facility Plan consisting of the following

components: Repair, Replacement, or Rehabilitation Private Sanitary LateralsSanitary Sewer ReplacementStorm Sewer ReplacementSanitary Sewer LiningElimination of BypassesManhole RehabilitationMiscellaneous Repairs and Rehabilitation

The estimated cost of implementation is $11.83 million, and it is expected that a 45 to 70percent reduction in wet weather inflow and infiltration will be achieved. The following table

summarizes the estimated construction cost for the Facility Plan implementation.Facility Plan Estimated Costs

Basin Sanitary SewerReplacementStorm SewerReplacement

Sanitary SewerLining

Private Lateralrepair

ManholeRehabilitation

and otherrepairs

Contingencies,Engineering,

Survey,Inspection

Cost per Basin

WB1 $103,600 $ 55,000 $76,650 $59,200 $ 115,875 $ 372,500 $782,825.00WB2 $186,200 $ 285,000 $19,950 $146,400 $ 115,875 $ 372,500 $1,125,925.00WB3 $188,300 $ 570,000 $38,850 $162,600 $ 115,875 $ 372,500 $1,448,125.00WB4 $141,400 $ 80,000 $194,250 $130,800 $ 115,875 $ 372,500 $1,034,825.00WB5 $198,800 $ 250,000 $18,550 $113,600 $ 115,875 $ 372,500 $1,069,325.00WB6 $529,900 $ 50,000 $75,250 $317,800 $ 115,875 $ 372,500 $1,461,325.00

WB7 $576,100 $ 150,000 $114,800 $349,200 $ 115,875 $ 372,500 $1,678,475.00WB8 $443,100 $ 30,000 $18,550 $2,253,200 $ 115,875 $ 372,500 $3,233,225.00

Total $2,367,400.00 $1,470,000.00 $556,850.00 $3,532,800.00 $927,000.00 $2,980,000.00 $11,834,050.00

5.4 - Facility Plan Implementation ScheduleIn order to manage the implementation of the Facility Plan, and to address the most pressingproblem areas first, the Village proposes to base the implementation schedule on the maximumday to base flow ratios previously developed by MMSD.

The following table includes the ranking of the eight basins as a function of wet weather I/I. Inaddition to the problem severity ranking, the improvements proposed in each basin were alsodetermined, so that an index of problem per implementation cost can be developed.The cost index for each basin is computed as follows: the total cost of implementation in eachbasin is normalized by peak flow ratios. The number thus obtained indicates the cost permultiple of daily base flow, which represents the cost of removing each multiple of the base flowfrom the daily wet weather flow peak. The lower the number, the more cost effective it is toremove each multiple of the daily base flow from the system.


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The following table summarizes the ranking of basin implementation costs by total constructioncost, by maximum flow ratio, and cost per multiple of daily base flow. We see that the most cost

effective ranking is very similar to the maximum flow ratio ranking. We therefore recommendthat the Facility Plan be implemented in the order presented in the following table.

Facility Plan Implementation Schedule

SewerBasin Cost

Max Day toBase Flow Ratio

Rank bymax flow

ratio

Cost to reduceeach multiple of

base flow

Rank by costeffectiveness

ImplementationSchedule andannual cost

WB1 $782,825.00 13.6 2 $57,500 1Year 1

$ 2.94 MWB4 $1,034,825.00 17.7 1 $ 58,500 2

WB2 $1,125,925.00 12.6 3 $ 89,400 3

WB3 $1,448,125.00 8.5 5 $ 170,400 4 Year 2$ 2.52 MWB5 $1,069,325.00 5.8 7 $ 184,400 5

WB8 $3,233,225.00 8.9 4 $ 363,300 7 Year 3$ 3.23 M

WB6 $1,461,325.00 7.1 6 $ 205,800 6 Year 4$ 1.46M

WB7 $1,678,475.00 4.6 8 $ 364,900 8 Year 5$ 1.68 M

The last column of the table presents the timeline for implementation following the five-year planpreferred by the Village. This timeline is chosen because it is compatible with otherinfrastructure maintenance activities in Whitefish Bay.

bonestroo, rosene, anderlik, & associates - sanitary sewer facility plan - 2002

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