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Mr. Sandstrom stated that there are different kinds of liners but explained that <br />they City has been installing the more structurally sound liners that would <br />essentially hold up even if the entire original pipe deteriorated. <br />Member Misra asked if the liners are the standard practice today and what the life <br />expectancy is. Mr. Sandstrom replied that the pipe liners have been around for <br />about 35 years and stated that case study report he read indicated that the life <br />expectancy is about 75 years which is comparable with the standard PVC pipe. <br />Member Kruse questioned if there would be a pause in rehabilitating the system if <br />they continue with the 18 -year plan for the City because the life expectancies <br />would be longer and more consistent with each other. Mr. Freihammer replied <br />that some of the manholes might need to be lined in the future. He stated that <br />there are other things to look at that can be upgraded. <br />Member Kors inquired if they can measure success rates with the liners. Mr. <br />Sandstrom stated that it is difficult to measure because the heavy rains are not <br />always consistent, but he pointed out that since they City started lining pipes in <br />2006 they have not gone over the Metropolitan Council threshold. He stated that <br />there seems to be a positive impact. <br />Vice Chair Wozniak asked if they would use the same map to reschedule the <br />lining projects or if there were more projects that were not on that map. Mr. <br />Freihammer stated that map was used as an assistance tool but emphasized the <br />importance of timing the lining projects with the pavement projects. <br />Mr. Sandstrom stated that they are also monitoring the sump pumps and if they <br />see a reduction in I&I after the ordinance enforcement then they can attribute that <br />that to the non-compliant sump pumps. <br />Vice Chair Wozniak asked if the funds for the lining program were coming from <br />sewer charges. Mr. Freihammer replied yes and explained that 80-90 percent of <br />the funds dedicated to the Capital Improvement Program from the sanitary sewer <br />charges are used for lining projects because they do not do many dig and replace <br />proj ects. <br />Mr. Sandstrom stated that they also apply for grants as well. <br />Member Misra referenced the graph that showed the flow data and questioned if <br />there were other attributes besides rainfall that would contribute to the variations <br />in flow. Mr. Sandstrom stated that most of the variability was due to rain events <br />because flows are fairly consistent otherwise. <br />Mr. Freihammer stated a rainfall graph if overlaid on the flow graph would have a <br />direct correlation. <br />