3. Groundwater elevations less than 6 feet; or, <br />4. Ground surface slopes greater than 10%. <br />Geotechnical work has not yet been completed; however; based oil the City of Eugene soil maps <br />and NRCS Soil soil survey (see Storm Drainage Report provided as Attachment the <br />development site is expected to have Hydrologic Soil Group A soils. These are well drained <br />soils, which are anticipated to have infiltration rates exceeding 2 inches per hour. Ground water <br />will be approximately at the elevation of the Willamette River, which is 13 feet below the lowest <br />point oil the site. Bedrock is not anticipated in the upper five feet of the soil profile. These <br />conditions will be verified with the geotechnical report to be submitted with the building permit <br />application. Existing contour elevations are shown on the existing conditions map, (Attachment <br />B). <br />(b) For land use applications proposing the construction of a public street, stormwater <br />quality facilities to treat the stormwater runoff from the proposed public street shall be <br />selected from the Stormwater Management Manual and shall be based on the following <br />priority order: infiltration, filtration, mechanical treatment. <br />1. If selecting an infiltration or filtration facility to treat the stormwater runoff from the <br />public street, the facility can be sized to also treat the stormwater runoff from the <br />one and two family dwelling lots or parcels adjoining the public street based on full <br />buildout of those lots or parcels. <br />2. If using a mechanical facility to treat the stormwater runoff from the public street <br />or if the infiltration or filtration facility is not sized to also treat the stormwater <br />runoff from the adjoining lots or parcels at full buildout, all lots or parcels created <br />by the land division application shall comply with EC 9.6792(3)(d)-(g) at the time of <br />development permit application. <br />No public street improvements proposed through the subject application. <br />(c) For land use applications proposing construction of a private street or shared <br />driveway, stormwater quality facilities to treat the runoff from the proposed private <br />street or shared driveway shall be selected from the Stormwater Management Manual <br />and shall be based on the following priority order: infiltration, filtration. <br />1. An infiltration or filtration treatment facility to treat the stormwater runoff from the <br />shared driveway or private street can be sized to treat the stormwater runoff from <br />the proposed one and two family dwelling lots or parcels that adjoin the shared <br />driveway or private street based on full buildout of those lots or parcels. <br />2. If the infiltration or filtration facility is not sized to treat the stormwater runoff from <br />the adjoining lots or parcels at full build out, all lots or parcels created by the land <br />division application must comply with EC 9.6792(3)(d)-(g) at the time of <br />development permit application. <br />No new private street or shared driveway improvements are proposed. The shared driveway is <br />served by all existing drainage system, which is not being modified or impacted by the proposed <br />development. <br />(d) For development permit applications, stormwater quality facilities shall be selected <br />from the Stormwater Management Manual and shall be based on the following priority <br />order: infiltration, filtration, off-site stormwater quality management. <br />Eugene Towneplace Suites Page 31 April 4, 2016 <br />