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Home My WebLink AboutGrading Plans - 08/10/2016FORBES ENGINEERING Full Service Civil & Structural Engineering July 28, 2016 DanMogen City of Fort Collins Stonnwater Engineering 700 Wood Street Fort Collins, CO 80521 lslCco\ 497 L.o\ 20, ~\to.._ v~s.tc .. O..<-c.«*~ ~ r.s~~ ~.uf,M.~'\ "¥lo/~ -o,, c.~k-svbb::v;.~ 414 \,...-. ~ '"='~:~cµ,,;l).v-~ ~~J~o..,-=-:. o{-'9;~ RE: Grading & drainage memo .for site improvements Parcel #97014-05-020 729 Martinez Street Fort Collins, CO 80521 Mr. Mogen, This letter and attached exhibit are to serve as a drainage memo for the above referenced single family residential property. The property is located along the west side of Martinez Street and has an approximate lot area of 6288 square feet. The property is vacant & covered with native vegetation but for a small patch of concrete and asphalt (approximately 300 square feet). The surrounding neighborhood to the north, south and east are single family residential lots and the land to the west is an undeveloped field. The existing spot elevations for the proposed grading & drainage plan are based on survey data provided by Centerline Surveying LLC, dated September 11, 2015. The proposed improvements include a 1680 square foot pre-manufactured home and a small amount of concrete flatwork (see attached grading plan). The existing asphalt & concrete flatwork will be removed and it is the intent of the builder to maintain the natural lot grade which flows towards the east. Approximately 2331 square feet of impervious area will be added to the property. The existing percent impervious has been calculated at 13.4% and the proposed percent impervious has been calculated at 35.4%. The property is located within the Poudre River 500-year floodplain and the historic stonn water runoff presently is directed towards the east and into the street gutter system of Martinez Street. The finish floor elevation has been established at approximately 20" above existing grade. Historic drainage patterns will be maintained (see grading & drainage plan) with a small change on the west portion of the property which will contain the spoil pile from the crawlspace excavation (any additional soil not used for the berm will be transported off the property). A swale on the south side of the home will be constructed to divert storm water run off towards the west and towards the east with a high-point located approximately 20' east of the west gable end of the home. Any necessary erosion control measures will be provided at the time of construction including, but not limited to, perimeter silt fencing and a vehicle tracking control mat if necessary. ? 729 MARTINEZ ST FT COLLINS, CO COUNTY LAND & HOMES LLC PERCENT IMPERVIOUS VALUES BASED ON THE FOLLOWING Character of Surface Streets Paved Gravel Walks Roofs Lawns EXISTING CONDITIONS AdLawns) Sq Ft 6263 Ac(Conc) Sq Ft 169 Percent Impervious PROPOSED CONDITIONS AL(Lawns) Sq Ft 4014 Ac(Conc) Sq Ft 210 Percent Impervious Percent Impervious 100 40 90 90 0 AR(Roofs) Sq Ft 0 13.4% AR(Roofs) Sq Ft 1680 35.4% FORBES ENGINEERING Project #: 2605 By : KEF Date: 6-28-16 NOTE; THE TOTAL AREA & PERCENT IMPERVIOUS CALCULATIONS INCLUDE LANDSCAPING AND ASPHALT WITHIN ~ OF THE ROAD ROW AG(Gravel) Sq Ft 0 AG(Gravel) Sq Ft 800 AG(Pavement) Sq Ft 816 AG(Pavement) Sq Ft 544 Ai (Total) Sq Ft 7248 Ai (Total) Sq Ft 7248 Page 1 . . .. $ i ~--X a-?> ,. ---"-9.«~. I (J\ 0 " / \ --0.s ---X \ / \ --, ~<o-tf),,,,,..~~1---t----+/--\-\--------:1~-""'r~~s----- ~ , ~ ' I -~ • i\ ll) I X SPOIL PILE, SIZE DETERMINED FROM CRAWLSPACE EXCAVATION, (TOP OF BERM ELEVATION NOT TO EXCEED 57 .5) ----~ SOUTH SIDE SWALE SLOPED C 1.5% TOWARDS THE FRONT & BACK, HIGH POINT LOCATED APPROXIMATELY 20' EAST OF WEST END OF HOME LOT 19 725 MARTINEZ STREET EOA SITE BENCHMARK LOCATION: SE PROP CORNER TOP OF #4 REBAR u, \ a, I ~ X ' ... I I I I t>,", I o I ' / 1$'· .,/ i )( \ ,,, ~~ -....J co co N (J1 (J1 co Ill -....J -....J ~~ 0 0) ~ (J1 )> ~~ ;-I :::0 to 0 oJ -l • 0, z • z rr1 rri oJ oJ N Or z (/) -l MAINTAIN MIN. SWALE SLOPE AT 1.33% LOT 21 733 MARTINEZ STREET 20' WIDE RECYCLED ASPHALT DRIVEWAY, SLOPE AS NEEDED ROAD CL LINE OF STREET GRADING & DRAINAGE PLAN SCALE 1 • = 20' ----~c:==-- LEGEND EXISTING GRADE ,.... (69.6U. PROPOSED GRADE ,..... 69 ·6 DOWNSPOUT os 181 SLOPE DIRECTION --,. PROPERTY INFORMATION OWNER: ALEJANDRO & MAR~ GOMEZ 4412 E. MULBERRY ST FORT COWNS, CO 80524 ADDRESS: 729 MARTINEZ ST. FORT COWNS, CO 80524 LEGAL: LOT 20, ALTA VISTA PARCEL #: 97014-05-020 FORBES ENGINEERING CUENT: COUNTY LAND & HOMES LLC PREPARED BY KEVIN FORBES 2908 CHERLY STREET, Ft. Collins, Colorado 80524 Tele : (970) 295-4874 FULL SE1MCE £NGtNEERtNG, DRAFT1NG AND O£SIGN CIVfL/STRUCTURA FOUNDATIONS, LAND It IIUNICIPAL Pt.ANNING PROJECT: 729 MARTINEZ ST FT COLLINS, CO SHEET TTTLE: GRADING & DRAINAGE PLAN DRAWN: KEF PROJECT I 16-2605 DATE 6-28-16 DWG I 2605-EX