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HomeMy WebLinkAboutcoa.lu.sm.City Footbridges.27A.1985 • - CASELOAD SUMMARY SHEET - City of Aspen DATE RECENED:#.1-1-C \$S tt - ^� A . DATE RECEIVED COMPLETE: 5 \9S CASE N0. O STAFF: < e PROJECT NAME: S Vv‘ - 1‘•"- �i•ew.. Q.a1 C °A I% g APPLICANT: (-- "•k 0C- A-, -. Applicant Address /Phone: REPRES ENTATIVE: 0-AA-GA( ti-o Representative Address /Phone: Type of Application: I. GMP/SUBDIV IS ION/PUD (4 step) Conceptual Submission ($2,730.00) Preliminary Plat ($1,640.00) Final Plat ($- 820.00) I�. SUBDIVISION /PUD (4 step) Conceptual Submission ($1,900.00) Preliminary Plat ($1,220.00) Final Plat ($ 820.00) III. EXCEPTION /EXEMPTION /REZONING (2 step) ($1,490.00) W. SPECIAL REVIEW (1 step) ($ 680.00) Special Review Use Determination �. Conditional Use Other: 5 c\ aA - P &Z CC MEETING DATE: Srk 3 PUBLIC HEARING: 5 e.) DATE REFERRED: INITIALS: A /Q.,j' REFERRALS: City Atty Aspen Consol. S.D. _ School District City Engineer _ Mtn. Bell _ Rocky Mtn. Nat. Gas Housing Dir. Parks Dept. State Hwy Dept (Glenwd) Aspen Water Holy Cross Electric _ StateH City Electric _ Fire Marshall wy De I) Envir. Hlth. Fire Chief — Ot Zoning/Inspect Other: FINAL ROUTING : DATE ROUTED: y OUTED: 9� � ti INTTIAL: - City Atty City Engineer t Building Dept. Other: n� _ Other: / FILE STATUS AND LOCATION: l ('d af2-e< ! / / �� ,SE DISPOSITION: -3 �s Reviewed by: aspen P City Council "M d Z ap frovad -k C F Pi�2 WL t Mt is key; sa, yett iv Ikkaellt Gnat.tr Q . l , rr,tn A1, - d- k 411 eit 10 h4,p d n 4 xi, 0‘141., te�// d na a 1. Ga� , h <f , / 1,y„ri.«.. • . • n Y /� / 2 p ru 44,n,' .,441 c 41 , , , l - 9 !�M li t. .L7 anti titaip rah FJ ntn. �'�", • 1 A �'�M✓IM}h k • Reviewed By: Aspen P &Z City Council 1 MEMORANDUM TO Aspen Planning and Zoning Commission FROM: Steve Burstein, Planning Office RE City Footbridges Stream Margin Review DATE: September 3, 1985 == REQUEST: The City of Aspen requests approval of a stream margin review to raise three (3) footbridges to a minimum of two (2) feet above the 100 -year floodplain, based on the most recent 100 -year floodplain study. Findings of the Locations of Bridge Distances to be Raised: 1. Smuggler Area Footbridge (on bike path 1.6 ft. leading north of Herron Park) 2. Hopkins Street Footbridge (between East 1.8 ft. Hopkins Street and Dale Avenue) 3. Upper Aspen Club Footbridge (between housing 3.0 ft. project and Club) APPLICABLE CODE SECTION: Section 24 -6.3 (C) of the Municipal Code states the review criteria for stream margin reviews. See Chuck Roth's letter attached for a detailed discussion of the review criteria. PLANNING OFFICE REVIEW: As stated in the July 29, 1985 letter from Chuck Roth of the City Engineer Department "current design standards call for bridges to be a minimum of two (2) feet above the 100 -yaer floodplain height in order for debris to pass underneath the bridges durin a flood." The above criteri mentioned bridges on and problems with the passage of debris n is haveoccurred as l a result. The stated objective of raising the footbridges is directly in support of Stream Margin Review criteria Section 24- 6.3(c)(1). The timber falsework to be placed temporarily underneath the bridges would cause some disturbance to the stream bed that should be monitored. Efforts should be made to minimize these disturbances. The pouring of concrete on the existing abutments may cause a disturbance of bank vegetation; and revegetation should be accomplished in accordance with the Roaring Fork Greenway Plan. Similarly, modifying the paved trails in order to match the grade of the raised bridges may cause some disturbance of bank vegetation, and revegetation should follow. RECOMMENDATION: The Planning Office recommends approval of this Stream Margin Review subject to the following conditions: 1. The Engineering Department shall monitor the construction and make all efforts to keep disturbances to the stream channel and bank at a minimum. 2. Revegetation shall be accomplished in accordance with the Roaring Fork Greenway Plan. SB.32 4. CITY ,;+ 4, PEN oi 130 _ - ' reet ' asp -. --, 611 s 31 1 July 29, 1985 Planning & Zoning Commission City of Aspen 130 South Galena Street Aspen, Colorado 81611 RE: Stream Margin Review - Raise Footbridges Ladies and Gentlemen: Greetings. This letter is a request for a Stream Margin Review pursuant to Section 24 -6.3 of the Aspen Municipal Code, for the City of Aspen work to raise three footbridges. Current design standards call for bridges to be at a minimum elevati^- of two feet above the 100 -year flood height in -'rder for deb..- to pass underneath tite bridges during a floc.... The past three snowmelt seasons have been a problem with debris getting caught on footbridges. A new 100 -year floodplain study has recently been performed of the rivers within the City of Aspen. Our most problematic bridge was missed by that study. This has been called to the attention of the engineers, and hopefully we will have that bridge, the upper Aspen Club footbridge, amended into the study. The high water of this past June was up to only a few inches below that bridge, so this bridge is undoubtedly within the 100 -year flood - plain. The upper Aspen Club footbridge is important because the next bridge down the river has a city water main on it which could be damaged if the upper bridge washed out. The heights above 100 -year floodplain of the other footbridges are as follows: Art Museum footbridge 1.2 feet Smuggler area footbridge 0.4 feet Hopkins Street footbridge 0.2 feet Lower Aspen Club footbridge 0.8 feet In terms of the debris which accumulates on the bridges, the next most critical bridge after the upper Aspen Club footbridge is the Hopkins Street footbridge, as can be seen from the above informa- tion. It is the Engineering Department's intention to raise the upper Page Two Stream Margin Review - Raise Footbridges July 29, 1985 Aspen Club footbridge three feet during this construction season,the summer of 1985, and the Hopkins Street and Smuggler area footbridges during the construction season of 1986. The following are the responses to the review criteria: "(1) No building shall be located so as to be within a flood hazard area designated by the U.S. Corps of Engineers Floodplain Report for the Roaring Fork Valley River." The footbridges are existing structures which are in the 100 -year floodplain, and it is our intention to raise them to a height two feet above the 100 -year flood level to provide for debris clear- ance. In order to accomplish this, the Engineering Department will raise the abutments and piers to provide two foot debris clearance and modify the asphalt paved trail approaches to match the raised bridges. This will require us to construct timber falsework in the riverbed on which to jack up the bridges in order to be able to do the formwork and concrete pours underneath them. "(2) In the event that there is a trail designated by an approved trail plan within the development site, such trail shall be dedicated for public use." All of the above referenced footbridges are within the City trail system. "(3) All attempts should be made to implement the recommendations of the Roaring Fork Greenway Plan prepared by the Roaring Fork Greenway Committee." It is not anticipated that any existing vegetation will be disturbed. Any revegetation necessary will be performed in accordance with the Roaring Fork Greenway Plan. "(4) Vegetation shall not be removed nor any slope grade changes made that may produce erosion of the stream bank." We do not anticipate removing any existing vegetation, nor will there be any slope grade changes made which will produce erosion of the stream bank. "(5) There shall be permitted no changes to the stream channel or its capacity, and no activity shall be allowed which will increase stream sedimentation and suspension loads." There will be no excavation within the river channel. Although we do not plan to have to enter the river with any construction Page 3 Stream Margin Review - Raise Footbridges July 29, 1985 equipment, we need to retain the flexibility should the need to do so arise. All activities within the river will be kept to a minimum, and every effort will be made to maintain existing water quality for the duration of the project. "(6) All efforts must be made to reduce stream pollution and interference with the natural changes of the stream, and to enhance the value of the stream as an important natural feature." The reason for raising the footbridges is to permit the 100 -year flood and debris to pass underneath and not dam up, presenting a potential threats to property. The Engineering Department requests that you approve this stream margin review application so that we may provide bridge heights meeting current design standards. Thank you for your consideration. Sincerely, C4 b Chuck Roth Assistant City Engineer CR/cr /footbridge.strm.marg I vie MEMORNDOM TO: City Attorney City Engineer FROM: Steve Burstein, Planning Office RE: City Footbridges - Stream Margin Review DATE: August 9, 1985 Attached for your review and comments is an application submiteed by Chuck Roth requesting stream margin review pursuant to Section 24 -6.3 of the City C••- • aise three footbridges. Please review this material .•• return you referral comments to the Planning Office no later th.n , f .„ 0 in order for this office to have adequate time to • -,__are for its .' - sentation before City P &Z on September 3, 1985. Thank you. ( `. " e i i ) ("4 (J el: Q � Al i Se- / C • i fi g f e �'�;:� I' St eG k M Ar n Rtuie lc; cheu -ForttOr 1.2 0,$ 2 m u J �aV f rl'�',tru ^ ,_ aAftdiA 0 - i y 00 p t kW 1,, p p < U ✓rexfi+�t iy in 4 �� Cwl�ht (GJ . i1 i ! o),al/Vh p ip ItiLet prkitiv (U�Y .r/ 1n i'Mi Molt So i 1 , oks^h�a f wyJi f a t gLOo J J Si (ch p ntU55eum f n Jtbr�i�e �'I