06/12/1978 Meeting - Laserfiche WebLink

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~ - Those speaking against the appeal were as follows: Peter Thompson, 2440 Oak Grove Drive, spoke on behalf of the applicant as the Design -- Team Coordinator. He noted this was a preliminary approval, and his applicant was in agreement with the Hearings Officia1's recommen- dations regarding the problems and how they should be addressed. He said his team had worked with City staff to ensure this would be a safe development. The water problems on the site had been reviewed. It was felt this project could be built and the design team had the expertise to do so. Jack Tompkins, 4630 Larkwood Street, was the engineering geologist for the design team of the PUD. Regarding soil movement and Mr. Knapp.s comments of the six conditions from the South Hills Study, he noted that study does identify a number of general conditions, any one of which could increase the potential for large soil movement. He said there was soil depth to 40 inches, with a general 20-percent slope which may cause the soil movement. However, he felt a number of the existing and natural man-made slopes would be stable. He felt if any of the hillside were going to have given way, it would have done so by now. Regarding the bedrock classification, the discrep- ancy was a nomenclature. He and Mr. Williamson both agreed the bearing strength would equate to 10,000 pounds per square foot, which was considerably higher than 1,000 required by the architect. This was felt to be more than adequate for development. Regarding Mr. Knapp's demonstration of the crumbling of shale, he said that would occur when the material was taken out of its natural state. However, he noted that had nothing to do with the inherent strength of the material in place on the site in its natural surrounding. In the -- testing he had done, he said there were no indications of instability, and no indications of deleterious material beneath the existing fill. Regarding the dewatering, the plan is to take out only the excess water. Regarding runoff, an underground storm system will be designed to carry off the excess drainage. In preparing the footing, he said it was planned to excavate through the clay and fill with crushed rock, which would allow greater strength. He noted in Eugene, the moisture content in depths of three to four feet were pretty constant throughout the year. He concluded by saying this is a buildable site and the expertise was available to make it safe. Tom Poage, 4325 Catalina, Project Engineer, said storm sewers would be located immediately downstream from the site. He felt the drainage issue could be answered by the teChnOlogical equations and knowledge of the hill. The effect of Treehouse PUD is small in terms of studying the entire basin that affects the Amazon Channel. The present design of storm sewers for runoff is 47.6 cfs; with Treehouse added, it would be increased to 53.2 cfs. He said adequate drainage would have to be provided for only one-half inch of higher water. Storm sewers have been designed for the entire development and can be provided to each and every house. He said if the PUD were developed, there would be about 1/40th of the foot change in elevation of the Amazon Drainage System. e 6/12/78--3 '12., -