Permit - 1267316 - Laserfiche WebLink

Home Browse Search

Boatwright Engineering Inc. 2613 12th S'/SE, SALEM, OREGON 97302 civil engineers * land surveyors 363-9225 October 20,1989 Marion County Community Development 220 High Street N.E. Room 230 Salem, Oregon ATTENTION: Sterling Anderson, Senior Planner REFERENCE: FLOODPLAIN DEVELOPMENT/FARM DWELLING Case No. 89-14 Condition 5,6 and 7. Dear Sterling, I have inspected the building plans, location of the house on the property and ground surface elevation at the 4 corners of the house and FIRM Community No. 410154, Panel 275 Suffix C dated August 19, 1989 and have reached the following conclusion: 1. The residence is located in the floodway portion of the floodway of Mill Creek. 2. The elevation of the FIRM water surface for a l~ occurrence storm is 340. 3. The ground elevation at the 4 corners of the residence are 339.4 at the N.E. corner, 338.5 at the N.W. Corner, 338.7 at the S.W. Corner and 339.6 at the $.E. corner as surveyed by Barker Surveying of salem, Oregon. 4. The water depth from the natural ground at the occurrence of a 100 year storm (1~ occurrence) will have a maximum depth of 0.6 feet on the upstream side of the house and 1.5 feet on the downstream side of the house. 5. The footing stem wall height to produce the finish floor elevation one foot above the 100 year storm water surface will result in only concrete contract with water, with the full weight of the structure and part o~ the footing stem walls above the water surface resulting in no significant buoyancy effect or water pressure on the upstream face of the residence. The footings should have 2 - #4 bars continuous and ~4 @ 3'on center horizontal a #5 bar should be placed Continuous at the top of the stem wall at 3" clear and #4 at 3' o.c. vertical on all stem walls.