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Home My WebLink About03/21/1995, 4 - PILOT PROGRAM FOR INVESTIGATION OF PRIVATE SERVICE LATERALS. �I MEETING DATE: city Of San LJIS OBISPO March 21, 1995 i COUNCIL AGENDA REPORT 1TEM NUMBER: FROM: John Moss /11 PREPARED By: Dan Boyd, Wastewater Collection Supervisor Utilities Wector David Hix, Wastewater Division Manager SUBJECT: Pilot Program for Investigation of Private Service Laterals. CAO RECOMMENDATION By motion, approve Pilot Program for Wastewater Service Lateral evaluation and direct staff to prepare appropriate documents for consideration in the 1995-97 budget. DISCUSSION The City's wastewater collection system and Water Reclamation Facility (WRF) have long been experiencing problems with excessive wet weather Infiltration and Inflow (I/1). I/I interferes with the WRF's treatment ability by hydraulically overwhelming its processes causing effluent violations and the release of partially treated wastewater to San Luis Obispo Creek. The City's collection system experiences surcharging and runs the risk of periodic sewage overflows. In August 1994, staff presented to Council findings of a comprehensive investigation performed on drainage basin "B". Staff determined that privately owned service laterals were the largest contributor of infiltration in that area. At that time Council directed staff to return with a program that will begin evaluation of methods to correct and/or manage the private service laterals. The proposed program will look at roughly 10% of the service laterals in drainage area B and evaluate their condition. This pilot program will allow staff to effectively evaluate the problems in the private service laterals. Using this information staff will be able to better identify the methods for effective correction and/or management practices of the private service laterals in all of area B. A program for correction for the entire basin will then be proposed to Council for approval and funding. • The Pilot Program Service laterals in the City are entirely privately owned. The property owners are responsible for maintenance and repair of the lateral from the structure to the City main line. As noted in staff's August 1994 report, a significant portion of the I/I in area B is coming from the service laterals. Based on an average length of 50 feet per service lateral and 601 service connections, this equates to approximately 5.7 miles of private service laterals in area B. Inspection of 60 service laterals should give the City a good understanding of the types of problems in the service laterals. Staff will randomly select the sixty laterals in order to obtain a representative sample of the entire area. The program will have five components; developing agreements with the ��i�i��lllllh��a ug111�11 city of san ' s owpo COUNCIL AGENDA REPORT Pilot Program Page 2 sixty property owners, physically locating each lateral, installation of cleanouts for inspection of the lateral, cleaning and video inspection, and evaluation. The sixty property owners will be given all pertinent background information regarding UI in the City, in their neighborhood and pilot program information. If a property owner is unwilling participate in the program then another property will be selected. Lateral locating, cleanout installation and cleaning services will all be performed by a licensed plumbing contractor provided by the City. The contractor will locate the lateral, install a cleanout next to the structure to provide video inspection access, and clean the lateral to provide a clean interior for optimal video inspection. Staff recommends use of a private contractor to perform this work because it resolves public vs. private liability and competition issues concerning work on private facilities and plumbing contractors posses the tools and expertise to perform the work. After a lateral has been located, had the cleanout installed and is adequately cleaned, City staff will perform the video inspection. Existing Wastewater Collection staff have had extensive training and are experienced in operating sewer video equipment. Currently the City does not posses a video camera small enough to inspect four inch.-sewer laterals. Implementation of this portion of the program will require the City to purchase a service lateral video inspection system. Use of a video contractor for this portion would not be economical and would limit staffs flexibility for scheduling cleaning and video inspection. Purchase of the video inspection system is a one time cost and can be used on future UI projects and programs and can also be used with the City's existing video equipment to complement our mainline inspection capabilities. Laterals will be evaluated for defects that contribute to UI such as cracks, offset joints, breaks and holes. Other criteria that suggest I/I such as root intrusion and types of material(s) will also be utilized. Staff will identify the best method of correction dependent upon the findings for each lateral. Correction methods may include "point repairs" or small repairs at one or two specific locations on the lateral, replacement of a portion or replacement of the entire lateral. Staff will prepare an estimate for cost of correction per each lateral considering the most effective and economical method. After all evaluations have been made, staff will present the results of the pilot program and propose alternatives for correction and/or management of the private service laterals in drainage basin "B". The report containing this information should be ready sometime in the Spring of 1996. This program will begin to address the I/I problems identified in the City's Wastewater Management Plan and the recent investigation summarized in staff's August 1994 Council report. Staff feels that this program will effectively evaluate the service laterals using a cost effective small scale method that utilizes the skills of private contractors and City staff. Additionally the information from this pilot study will be used to develop a service lateral rehabilitation program which will then be recommended for application to the entire City. r� �u�iai��►►�IIIIIII�P� ��II city of San ' IS OBISPO COUNCIL AGENDA REPORT Pilot Program Page 3 FISCAL EMPACT The estimated cost for this program is detailed below: Eauin Lateral Video Inspection System $259000 Contract Services: Breakdown of per item cost for lateral: Locate lateral: $100 Install cleanout on lateral: $300 Clean lateral: $1100 Total to locate, install cleanout and clean per lateral: $500 Total Cost to Prepare Sixty Laterals for Inspection $30,000 15% Contingency $8.250 Total Cost $639250 The estimated cost for the program is $63,250 and will be identified in the 1995-97 capitol improvement plan for Wastewater Collection. Staff time for inspections and evaluations will be worked into the wastewater collection's I/I crew schedule. Some cost savings may be experienced because not every lateral will need to be located or requires a cleanout. ALTERNATIVES 1. Take no action. This alternative is not recommended. Private service laterals have been identified as the most significant of source of I/I in.area B. The laterals need to be evaluated so staff can determine the best method(s) for correction and/or management. Because the majority of the laterals are believed to be at least 35 years old and constructed of inferior materials, taking no action will result in further lateral degradation and increased 1/I. -40 COUNCILAGENDA Pilot Program Page 4 2. . Tuve contractors or staff perform all the work and inspections outlined in this'report. This action is not.recommended. Staff believes the proposed program offers the most effective and economical combination of private contractors.and City staff. Attachment _ h.\PILOTREH.rsr ATTACP T MEETING DATE: IIIII�I�I��Q�IIIII�I�� ,� CIt/ Of Sall LUIS OBISPO july 19 2 994 REM NUMBER: 1 COUNCIL AGENDA REPORT From: John Moss Prepared by: Dan Boyd Utilities Nektor Wastewater Collection Supervisor SUBJECT: Wastewater Drainage Basin B Infiltration and Inflow Investigation CAO RECOMMENDATION By motion, receive report concerning Wastewater Drainage Basin B Infiltration and Inflow investigation results and direct staff to develop and return to Council with a service lateral investigation and rehabilitation program. DISCUSSION The City's wastewater collection system and water reclamation facility has long been experiencing problems with excessive wet weather Infiltration and Inflow (I/1). The I/I has caused problems with the water reclamation and treatment processes, surcharging, overflows, effluent violations and the release of partially treated wastewater to the creek due to hydraulic overloading. In July 1989, Council directed staff to work towards elimination of UI rather than designing and constructing the phase II relief sewer project. The collection system is divided into fourteen I/I drainage basins (A-N). An I/I study, performed by Brown and Caldwell Engineers in 1987, indicated that the more significant contribution of UI was coming from drainage basins B,D,E,F and H. Subsequently, drainage basin "B" was selected as the first target basin to be investigated. The investigation consisted of smoke testing, video inspection, dry and wet weather flow monitoring, physical inspection and dye testing. LI INVESTIGATION COMPONENTS AND RESULTS • Smoke Testing Smoke testing shows pipe leaks that are located under permeable surface materials such as open fields and lawn areas, inflow sources such as storm drains, roof drains etc. connected directly to the sewer system, and waste and vent systems that are not working properly. The majority of the privately owned upper service lateral system (building to property line) is located under permeable surface material. The majority of the lower service lateral system (property line to City sewer main) and public sewer system is located under impermeable surface material (asphalt and/or concrete). Subsequently the smoke test works well for identifying leaks in the upper service laterals and those few public sewers located under permeable material (mostly easement areas), but does not work well for the lower service laterals and the majority of the public sewer that is located under impermeable surfaces. �-5 r' N0 city 4 san .-.,is osispo COUNCIL AGENDA REPORT I Investigation Components and Results page 2 • Smoke Testing Result The smoke testing performed in drainage basin B tested 601 service laterals and 32,731' feet of public sewer. The smoke testing is accomplished by isolating a section of pipe (manhole to manhole) and pressurizing the pipe with air and srhoke. The smoke is forced through the sewer mains, service laterals, service lateral vent pipes and any cracks, offset joints etc. located in the collection system. The result of smoke testing the service laterals indicated that 10.1% of the service laterals leaked and 15.1% displayed no smoke through the vent system. No smoke through the vent pipes indicates other problems, such as, improperly vented waste pipes, a p-trap in the primary service lateral, and/or. the primary service lateral not being installed at the proper grade. The smoke testing results thus indicate 25.2% of the service laterals tested had some problems. . The public sewer system not covered by impermeable material also showed some deficiencies. A less significant number of leaks were identified in the public sewer system. A majority of the manholes tested leaked because of age and design but appear to be a less significant source of III because of their location in the drainage area. Only a few inflow sources, a roof drain, floor drain and storm drain, were identified. These inflow sources have been corrected. • Video Inspection Video inspection identifies pipe defects such as offset joints, root intrusion, cracks, broken pipe, etc. The video inspection also identifies tap.locations (point of service lateral connection to the City mainline), infiltration of water from defects, pipe material, pipe length, and many other'important factors related to the inspection Video inspection was only performed on sewer main lines. Additional specialized equipment will be required to perform video inspection on private service laterals. • Video Inspection Results The video inspection consisted of inspecting 36,442' feet of public sewer. Root intrusion was the most significant problem identified but does not appear to create a significant source of III in the public sewer system. Numerous structural defect were identified but also do not appear to create a significant source of I/I in the public sewer system. It is assumed this is the case because the majority of the public sewer system is located under impermeable surfaces. Infiltration of ground water.(as opposed to rainfall dependent Un does not appear to be a problem in basin B. The video inspection did reveal 708 tap locations (not capped) as active services. 601 service laterals were confirmed as the 11'iNV111 city of son LUIS oBispo COUNCIL AGENDA REPORT 1/1 Investigation Components and Results Page 3 actual number of services in drainage basin B. Subsequently, there are 107 service laterals that may have been improperly abandoned and may be a significant source of 1JI. The video inspection also revealed that 11% of the tap locations identified showed roots entering the public sewer main from the service lateral. During wet-weather video inspections numerous service laterals were observed infiltrating lain water at the tap location. • Flow Monitoring Flow monitoring records average flow and peak flows. The flow monitoring was performed during dry and wet weather. During wet weather the flow monitor showed a significant increase to the average and peak flows. The increase shows the amount of UI entering the system for that specific rain episode. • Flow Monitoring Results Flow monitoring performed in drainage basin B evaluated the basin in three sub-areas, upper, middle and lower. - Several different locations through-out the basin were flow monitored. The data recorded from one monitoring location at the intersection of Ramona and South Tassajara (upper basin B) will be used as an example. This location monitored a specific reach of sewer mainline(8,842 feet of public sewer that serves 201 residences). Dry weather flows at this location recorded an average of 7 gpm (gallons per minute) in July 1991, at 2:00 am. An average of 446 gpm was.recorded during wet weather flows in February 1992, at 2:00 a.m. in the same location. The data recorded shows the difference between dry and wet weather flows during a specific rain episode. The overall results of the flow monitoring in drainage basin B indicate the III problem is wide spread through-out the basin. • ' Physical Inspection Physical inspection of manholes identifies and,records defects, infiltration of water from defects, inflow sources, material used and physical location of the manhole (if the manhole is located in street or drainage channel etc.). Physical inspections are also performed on all sewer mainlines and the surface area above sewer mainlines to identify surface material, surface material defects, location, type of pipe etc., to assist in the evaluation process. • Physical Inspection Result There are 173 manholes in drainage basin B. All of the manholes were inspected and the results were recorded. Numerous manhole problems were identified and will be repaired as priorities dictate. Manholes that are found to be in drainage channels which 4 city of san L..AIs OB1sp0 ffli;% COUNCIL AGENDA REPORT 1/1 Investigation Components and Results Page 4 may contribute significant UI are scheduled for immediate repair_ The manhole problems appear to be a less significant source of III as related to the overall collection system. • Dye Testing Dye testing is performed to verify inflow and infiltration sources. The dye test will also verify service lateral locations in mainlines. Extensive dye testing was not performed in basin B, however, the dye test was used to verify the source of water observed entering the main at a tap location as being infiltration. • Dye Testing Results A test was performed, on one of the service laterals that appeared to be infiltrating rain water during a video inspection and also revealed smoke during the smoke testing. Ten gallons of water mixed with tracing dye was poured onto the ground above the lateral, the camera was positioned in the City main at the tap location of the service connection, the tracing dye appeared at the tap Iocation in 3 minutes. Three inflow sources were also verified through dye testing, a roof drain, floor drain and storm drain. These inflow sources were identified through smoke testing and verified through dye testing as sources of inflow to the wastewater collection system. These inflow sources have been corrected. „OVERALL I/I EVALUATION • Public Sewers A less significant number of sources were identified infiltrating rain water in the public sewer system. A majority of the public sewer system is located under impermeable surface material such.as, asphalt and concrete. No significant ground Aster infiltration problem Ass found in drainage basin B and identified inflow sources have been corrected. • Service Laterals The video inspections performed in drainage basin B during the wet weather in January through March of 1992, revealed- numerous service laterals that appeared to be infiltrating rain water. The laterals were observed at the tap location in the City main. The tap locations that appeared to be infiltrating water, displayed a continuous flow at a high velocity that appeared to be abnormally clear. The water did not display the usual signs of wastewater, such as, debris, human waste or steam that is generated from a shower or dishwasher. To substantiate the source of the water the UI crew contacted several of the residences in question. They found that some of the residences were not occupied, and others were not using any facilities at the time of the inspection. 12211I!)"1I`1 city of san lues osispo COUNCIL AGENDA REPORT I/I Investigation Components and Results Page 5 The investigation indicates that a significant portion of the I/I in basin B is coming from the service laterals. A video inspection of all service laterals should be performed to identify the condition of the service lateral system and insure the most cost effective repair. SIGNIFICANT AEXT STEP If the recommended action is approved by Council, staff will present the results of the I/I investigation of basin B and seek input from public interest/neighborhood groups to help define and incorporate public concerns in the development of a comprehensive lateral rehabilitation program. Staff will return to Council with a program that will be designed to correct i/I.and manage the private and public sewer system. SUND&ARY . The recent comprehensive investigation of drainage basin B was completed for publicly owned sewer mains and manholes but could only partially address the private service laterals through smoke testing. The privately owned service laterals need to be investigated, rehabilitated and maintained in conjunction with the City maintained collection system. This will enable the City to achieve the highest impact on reducing 1/I. A service lateral inspection and rehabilitation program will enable the City to manage this portion of the system and insure its safelsani.tary operation. FISCAL BOACT There is no fiscal impact as with the recommended action. However, a service lateral rehabilitation program could have a significant fiscal impact. If the recommended action is approved by Council, staff will provide a detailed cost analysis with the lateral rehabilitation procr once developed. ALTEMATIVES Take no action. This alternative is not recommended. The wastewater collection system and service laterals are aging and in need of rehabilitation to correct UI. The on-going rehabilitation of the entire wastewater collection system through long and short range programs will correct the problems, enhance customer service and provide improved management. . 1 rviLL-ONG AGENDA DATE -f-Jl-9S'ITEM # MEMORANDUM FROM THE OFFICE OF THE CITY ATTORNEY March 17, 1995 TO: City Council FROM: Jeff Jorgensen SUBJECT: Pilot Program f Investigation of Private Sewer Laterals Because my residence is located in drainage basin "B, " and to avoid even the appearance of a conflict of interest, I will refrain from advising the Council or otherwise participate in this matter. Should questions arise at the Council meeting, they may be directed to Assistant City Attorney Cindy Clemens for follow-up. I have explained the potential for conflict to her and requested that she provide independent advice to the Council if necessary. JGJ/sw cc: John Moss Dan Boyd David Hix Cindy Clemens COUNCIL ❑ CDD DIR W1CAO ❑ FIN DIA QO'ACAO ❑ FIRE CHIEF eTTORNEY ❑ PW DIR ❑ CLFJiKIOAIO ❑ POLICE CHF TEAM E E ) ❑ OR, DIR D FILE � UT 13 C DIR MAR 1 7 1995 1 s' ❑ PERS DIR CITY CLERK SAN LUIS OBISPO,CA lhlegram4hbune 3825 South Higuera•Post Office Box 112•San Luis Obispo, California 93406-0112 • (805) 781-7800 i'TuululQN'H'''V city of 11111111011M san tuts oatspo; CITY COUNCIL I PUBLIC HEARINGS. 1: On Tuesday, March 21, In The Superior Court of The State of California '1995, the San Luis Obispo ,City Council will hold publiE In and for the County of San Luis Obispo -hearings beginning at 7:oo 'P.m.In the Council Chambers AFFIDAVIT OF PUBLICATION of City Hall,990 Palm Street, on the Items listed below. The reports will be available dV 71705-0-7 for review in the City Clerk's City Of SLO Department on the Wednes- day before the meeting. For more information,please call 781-7103. The Council may also dis. STATE OF CALIFORNIA, cuss other hearings or busi. ness items before or after S5. those listed. N you challenge County Of San Luis Obispo any one of the proposed actions described below in court,you may be limited to I am a citizen of the United States and a resident of raising only those issues you the Countyaforesaid; 1 am over the age of eighteen or someone else raised et the g g public hearing described In and not interested in the above entitled matter, I am this notice, or in written publication correspondence delivered to now, and at all times embraced in the p the City Council at,or prior to, herein mentioned was, the principal clerk of the the public hearing. MOBILE HOME PARK printers and publishers of the SAN LUIS OBISPO RENT STABILIZATION - to COUNTY TELEGRAM-TRIBUNE, a newspaper of consider amending section 5.44.060 (E) of the Mobile general circulation, printed and published daily, Home Park Rent Stabilization y pt at the City of San Luis Obispo in ordinance concerning auto- Sundays excepted, uratic adjustments to rent to the above named county and state; that notice at make such adjustments appli. cable to both increases or which the annexed clippings is a true printed copy, decreases in expenses, to was published in the above-named newspaper and clarify that expenses do not not in an supplement thereof - on the following Include ongoing maintenance y pp g or ongoing maintenance dates,to-wit: March 11 costs, and to extend the notice period for such in. that said newspaper was duly and regularly creases or decreases to 90, ascertained and established a newspaper of general days, consistent with Civil circulation by Decree entered in the Superior Court Code section 798.30. (15 min). Of San Luis Obispo County, Sate of California, ARKING GARAGE USERia, On FEES-to consider authorizing June 9, 1952, Case #19139 under the provisions of parking garage user fees until Chapter 1, Division i Title of the Government Code 9:30 p.m. on Thursday, Frl- day, and Saturday evenings. of the State of Cafifomia. (30min.). FRENCH ANNEXATION/ PRE-ZONING - to consider I certify (or declare) under the penalty of perjury that giving final passage to an the foregoing is true and correct. ordinance concurring with eg g the negative declaration of environmental Impact and amending the zoning map from Low-density-Residential (County zoning)to Low-Dens- ity-Residential, with specific overlay(R-1-SP)for a 14-acre (Signature of Principal Clerk) parcel adjacent to the City limits at 4380 Broad Street (ANNX/R 110.93).(30 min.). . Date: March 11, 1995 , N y, ANNX R 110-93 CITY OF SAN LUIS OBISPO Diane R.Gladwel, City Clerk. Mar.11.1995 ...,.,_-