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HomeMy WebLinkAboutOVERLAND HILLS 2ND FILING PRELIMINARY - 38 90A - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTOVERLAND HILLS SECOND FILING log atit) film SI IMCalislagOlial JULY 1990 PREPARED BY STEWART & ASSOCIATES. INC. SITE LOCATION: The site is located in the Northwest '—, of Section 33, Township 7 North, Range 69 West of the Sixth P.M., Fort Collins, Larimer County, Colorado. The area is 8.0681 acres more or less. It is located in the Springcreek Drainage Basin. EXISTING CONDITIONS: The site is bounded on the East by Tract A, Springfield Sixth Filing, which is a detention pond. It is bounded on the South by an existing single family residence and a portion of the Overland Hill First proposed subdivision. There is no development on the West or North side. The site drains South to North and then West to the Springcreek Drainageway. The average slope is about 1.6%. There is no offsite drainage" from the North, East or West sides of this proposed site. There will be some runoff from the single family residential property to our site. Discharge from that site is Q2 = 0.3 c.f.s.. Q 0 = 0.5 c.f.s and Q1 = 1.1 c.f.s. Our runoff to Springcreek is Q2 = 2. c.f.s, Q10 = 4.1 c.?.0 s. and Q100 = 8.6 c.f.s. DEVELOPED CONDITIONS: The proposed site will be divided into 4 lots served by a cul—de—sac from Horsetooth Road. The average size.lot will be about 2 acres gross. Because of the proximity to Springcreek Drainageway there will be no detention for these 4 lots. The runoff will still be directed from the South to the North to Horsetooth Road and to the existing Springcreek Drainageway. The developed Q = 2.85 c.f.s., Q1n developed = 5.18 c.f.s. and Q100 = 11.02 c.f.s. The Total drainage including the offsite runoff. to Springcreek will be Q2 = 3.15 c.f.s., Q10 = 5.68 c.f.s. and Q1DD = 12.12 c.f.s. The 100 year flood plain line shown on the Preliminary Drainage Plan across lots 1 and 3 of the proposed development were calculated from the Springcreek Master Drainageway Plan completed in March 1988 by Engineering Professionals, Inc. There_plan_begi.ns_at_Hor_setooth_Road and has the 10 —year flood plain Q = 1580 c.f.s. We used this Q to develope the 100 year flood plain going upstream which should be a little bit conservative for use on our site. Franklin D. Blake, P.E. & L.S. JIM ;ompvrAT*IO S James H. Stewart & Associates, Inc. 214/N..Howees St. Ft. Collins, CO 80521 (303) 482-9331 By: Date Client: -Sheet_� No. of—�— Chl<d fay: Date Project:- Job No. Subject �/"�ii�<�,. -. �',; �� •/s, ,�� — ��,% — I I i I I _ - - -- - --_ - '_-Op � i I 0 ! i i I i iv I I I OMPUTA10 IONS James H. Stewart & Associates, h1c. 214 N..Howes St. Ft. Collins, CO 80521 (303) 482-9331 Date Client: Sheet No. 4' of 7— Chl(d By: Date- Project: Job No. Subject iT� .... ... - 75 10 I AC-5 100 'Z' 4 fill -,.ompvrAIriorvS James H. Stewart & Associates, Inc. 214 N..Howes St. /Ft. Collins, CO 80521 (303) 482.9331 13y: �2G,� Date Client: ��/CSheet No. of_� Chkd By: Date Project:_ Z,<''�' �'��� �� Job No. Subject,.' _ .:.: !- ./.-.•� !,�� '� /^'� �i i�' I 145 i I _ I i- i i I I , ` 1 I I 7 —S/o Sri o - 1 77 L10 ,. `... _- �i Z Z a ro -1 4 xz ; All ,OMpu'rA'I*IONG James H. Stewart & Associates, Inc. 214 N..Howes St. Ft. Collins, CO 80521 (303) 482-9331 By: Date 7 90 Client: i7 Sheet No. 4 of 7 Chl<d By: Date Project: Q�/�i�= ����� 2 ef/ Job No. Subject f ;omr�u�rATry �ioS James H. Stewart & Associates, Inc. 214 N..Howes St. Ft. Collies, CO 80521 (303) 482-9331 Date % 90 Client: cJ �i%i 1 Sheet No. .S ei-7 _-- Chkd By: Data Pioject:Z-A-/'-i� :�� ? Job No. Subject OompvrATIONS James H. Stewart & Associates, Inc. 214 N. Howes St. Ft. Collins, CO 80521 (303) 482-9331 Date 90 Client:— 9!t5�;12 (=!52ZO'� '/—Slreet No. G of 7 Chl(d By: Date Project: —Job. Subject ... -nrl /At/Jr %.;OMPUTATIONS James H. Stewart & Associates, Inc. 214 N.,Howes St.. Ft. Collins, CO 80521 (303) 482-9331 By: - Date Client: Sheet No. of 7 Chkd By: - Date- Project: Job No. Subject