Item 1: PH on Ordinance Amending Metro Plan (Delta Sand and Gravel)

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Mr. Hughes said there were other e~perts for the applicant that had more knowledge of the issue but said his understanding of the reasoning behind the low permeability barrier was to prevent the ground water levels for adjoining properties to be drawn down. Ralph Christensen, EGR and Associates, 2535 Prarie Road, submitted written material into the record. He said the low permeability barrier could better be described as a 'coffer dam' in a river. He said a coffer dam did not substantially change the water level of a river since the water would simply go around the dam and flow away. He said the barrier would reduce the amount of water seeping into the pit but would also hold the level of ground water stable in the areas around the quarry. Regarding the concern that the barrier would cause flooding in the area, Mr. Christensen said in a flood situation the ground water would be measured and might hold as much as 1-3 cubic feet of water in a square foot of ground ten feet deep. He said a flood over the top of that would be measured in cubic feet per second so a cubic foot of ground ten feet deep, in extreme situations, could possibly hold three seconds of water before it was saturated. He, stressed that it did not matter how much saturation of the ground there was during a flood event. Regarding the concern that the low permeability barrier was unproven technology, Mr. Christensen said there were many references in the written report that the bairier was not new technology and had been made use of in many other locations. . MR. Christensen also commented on the replacability of gravel with basalt rack, and added that LCDC and OPOT had written areport on crushed aggregate and sand & gravel which stated that they were not the same thing. He said sand'& gravel was preferentially used in concrete and it was not appropriate to switch that with quarried rock. Regarding sampling, Mr. Chris~ensen said there had been reference made by the opposition regarding the ASTM standards on how" sampling was done. He stressed that it was particularly important to note that when open face mining was taking place, the prescribed method was a composite sample of rock" from top to bottom. He said the same ASTM standard stated that the actual rock that should be samples was the pr~cessed rock that was ready to be sold. He stressed that the'samples used for the quality analysis in the application were not the processed rock but composite samples that still met the requirements for being listed as a significant resource. He added that if the processed rock had been used.as a sample then the resource quality rating would have been even higher. In response to a questioI) from Eugene Planning Commissioner Ms. Colbath regarding where ground water would go when it met the low permeability barri~, Mr. Christensen said the'water would flow out into the Willamette River where all the ground water in the River Road/Santa Clara area was moving. He said during the winter when water levels were high .enough the water would flow out through small channels that passed through that area. In response to a question from Mr. .Zdzienicki regarding the effect of the low permeability barrier on the east Santa Clarawat~rway which needed to be protected ,under Environmental, Social, Economic, and Energy, (ESEE) standards, Mr. Christensen said there was less water flowing in the waterway now than when the barrier was constructed. He noted that the water table would be raised to the bottom of the water way when the barrier was constructed. He remarked that the waterway was dry for a significant portion of the y~ar. In response to a question from Mr. Z~ienicki regarding the size of th~ setback from the waterway to protect its natural vegetation, Mr. Christensen said the setback had already been proposed by the applicant. He said setbacks were not part of his area of expertise but remarked a setback would be adequate as long as the vegetation was not ~INUTES-Lane County Planning Commission Eugene Planning Commission .,' January 17,,2006 4