Eugene Planning Commission <br />July 9, 2019 <br />Page 6 <br /> <br />that such considerations are already factored into the Santa Barbara Unit Hydrograph modeling <br />system. As the Technical Memorandum explains, GeoScience, Inc. does not follow professional <br />engineering standardsin its effort to evaluate stormwater flow, which leads to incorrect <br />conclusions. This is perhaps because Mr. Schleider, despite being a CEG, is not a Professional <br />Engineer trained in stormwater modeling and design. GeoScience is commenting on matters <br />outside its area of expertise. <br />The final paragraphs of the Technical Memorandum drive home just how far off <br />GeoScience’s allegations are. The Technical Memorandum explains: <br />“The storm report establishes that the proposed development is meeting pre- <br />developed discharge rates down the hill for the two (2) 38’ wide level spreaders. <br />By releasing runoff at an equivalent rate, the design meets the City’s intent to <br />have little to no affect to pipe or ditch capacity downstream. Therefore, one <br />cannot claim that a design that matches pre-developed discharge rates will affect <br />the peak depthof any downstream creek. <br />“Something the storm report does not elaborate on as much as it could is that <br />under the proposed development, the runoff release rate to the east will actually <br />be less than under the existing conditions. * * *. This is not a requirement for the <br />project, but just a statement to show how the current design is more conservative <br />than required, and in contradiction to Mr. Schleider’s claims.” (emphasis added). <br />Strangely enough, Branch Engineering’s solution to stormwater management provides <br />whatGeoSciences recommendedto the Planning Commissionshould be done–i.e., <br />“demonstrate how the development could be designed to mitigate the issues at least to some <br />degree.” GeoSciences, p. 14. <br />The stormwater management and tree retention strategy targets two of the three key <br />geotechnical concerns Branch Engineering has stated throughout the proceedings. It does not <br />remove the resisting force at the toe of potential slide areas by removing soils and cover <br />vegetation, and it does notadd water into the slide area. Instead the proposalreducesthe water <br />to the steeply sloped areas by conveying itto a more suitable point of disposal to be metered out <br />at the same rate it currentlyflows. The proposal does notincrease the risk of a slide;it decreases <br />slide risk. <br />The Planning Commission should conclude that the evidence in the record demonstrates <br />that there will be no adverse on-site or off-site impacts due to storm water from the proposed <br />development and that the development will not be a threat to public health or safety. <br />Floral Hill Drive Properties <br />Neighbors and GeoScience express concerns about the conditions that residents of Floral <br />Hill Drive are currently experiencing, to include claims of cracked foundations, leaking <br />foundations and periodic flooding. Notethatthese are current conditions prior to the <br />6 <br />