Loading...
HomeMy WebLinkAboutPARK SOUTH PUD - PRELIMINARY - 46-88C - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTPRELIMINARY STORM DRAINAGE REPORT FOR PARK SOUTH P.U.D. — REPLAT Prepared for MARC MIDDEL Prepared by STEWART & ASSOCIATES, INC. 214 NORTH HOWES STREET FORT COLLINS, COLORADO 80521 AUGUST 5, 1991 r� PRELIMINARY STORM DRAINAGE REPORT PARK SOUTH P.U.D. — REPLAT LOCATION AND DESCRIPTION OF SITE Park South P.U.D. — Replat is located south of West Horsetooth Road and west of Manhattan Avenue. The site includes 2.97 acres of the Four Seasons development along the east side of Benthaven Street. The total site area, to the centerline of adjoining streets, is 37.30 acres. The site is presently covered with moderate vegetation and slopes from west to east on a one percent (1%) slope. The surrounding streets, West Horsetooth Road, Manhattan Avenue, and Benthaven Street, .are existing; and there is an existing storm drainage channel along the south boundary of the site. There is also an existing 30—inch storm drain pipe along the west side of Manhattan Avenue which runs from Horsetooth Road to the storm drainage channel. HISTORIC DRAINAGE Park South P.U.D. — Replat drains to the Park South and South Glen detention pond, which was constructed in the early 1980's, except for the 2.97 acres of the Four Seasons area, which drains to the pond in Four Seasons. At the time the Park South and South Glen detention pond was designed and constructed, it was the intention that it would detain for all of the Park South area, and that no additional onsite detention would be required. We plan to have ng onsite detention in the single family portion of the Park South P.U.D. — Replat, but there may be onsite detention required in the parking lot of the proposed shopping center, due to a lack of capacity in the existing 30—inch storm drain along the west side of Manhattan Avenue. The Four Seasons detention pond, located on Tract A, outflows through the existing swale along the south boundary of Park South P.U.D. There are no offsite flows across the Park South P.U.D. — Replat except for this detention pond outflow through the south Swale and except for runoff from Horsetooth Road which is through the 30—inch pipe along the east side of Manhattan Avenue. PROPOSED DRAINAGE DESIGN There are to be two drainage swales through the 2.97 acre Four Seasons area. The larger swale will pick up the runoff from the existing pipes under Benthaven Street just south of Bonita Avenue and will carry it south, through the existing pipes under Dennison Avenue, to the existing detention pond on Tract A. This swale will be sized to carry the flow from the pipes as well as the 100—year overflow. The second swale, which is much smaller, will pick up surface flow from Benthaven Street and carry it east to the large swale. The lots in this 2.97 acre area will drain to the streets from the front yards and to the swales from the rear yards. • • PRELIMINARY STORM DRAINAGE REPORT PARK SOUTH P.U.D. - REPLAT Page 2 The single family portion of Park South P.U.D. - Replat, which was originally within the Park South area, will drain south to the existing Swale along the south boundary, and east to the existing 30-inch pipe along the west side of Manhattan Avenue. The northerly 10 acres of the site, which is proposed to be a shopping center along with multi -family or offices, will drain to the existing 30-inch pipe along the west side of Manhattan Avenue. Some onsite detention may be required in the parking lots of this northerly 10 acre development. The attached map shows the Park South P. U.D. - Replat and shows the proposed storm drainage. The attached calculation sheets determine the 2-year and 100-year runoff quantities for subbasins of the development. EROSION CONTROL All erosion control procedures shall comply with the "Erosion Control Reference Manual for Construction Sites" of the City of Fort Collins, Colorado. Phillip I, Robinson, P.E. & L.S. 11 COMPUTATIONS Stewart & Associates, Inc. 214/ /N. Howes St. Ft. Collins, CO 80521 (303) 482-9331 BY: Date ! Client: Me►`c Ad & odP__ ( Sheet No. of Chkd By: Date Project: Pa r�c S0V Il D l s1 Subject 15(11b bczs / h ry r) o �T �.. I L _ �� I T, 7 ¢ �y z O IG A C- 0 S : 3 0� i l k ! /. 7 .3 (1 2. V-Q! e 7 0' 13A SIN (�'' .4 � �. � �� I C �, S __i_ = �j� �a,$)j('2.2) C ,. _ d0_ _ I TG�� DA:91AJS0 of- -i Gr ►. s C o. S C 5. [- J s -*V! 6) . � z = cis � d.• sl Cz.:� ��.. - _� i ��s -C�roo�! �f'C1�1 ,i �r s ( � z.rr I� 7 71 cTS i � z- cif/' - I �•; ��C �-J /f�.� lei I �- Q �VV I ���•►�I! T i" I. Zj)' � .0. 1 , s 1 1 ' CII I =(U.� 2i )(l.ix4 GCS! i � , T i i I ' ! COMPUTATIONS Stewart & Associates, Inc. 214 N. Howes St. Ft. Collins, CO 80521 (303) 482-9331 By: PI TZ Date Client: /Yto(rc 11AI dd Sheet No. of Chkd By: Date FITS I Project: � r� °vA �rr• U Subject p1_o17USed PO )_� vcr4- o-P JZr-o i eC't" S�)O��i �� Cer,7er elG 7 I 1 I � I I .F.. of I.0PFD � 1 I .I- - II _ _ -7 I ! 2 • ? cS i S , . I I .� - - I - I 1