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Home My WebLink Aboutordinance.council.016-11 ORDINANCE NO. 16 (Series of 2011) AN ORDINANCE OF THE CITY COUNCIL OF THE CITY OF ASPEN, COLORADO, AMENDING THE URBAN RUNOFF MANAGEMENT PLAN WHEREAS the City's Surface Drainage Master Plan identifies deficiencies in the condition and capacity of its existing drainage system, and WHEREAS it is in the City's interest to protect its infrastructure, the environment, and the ecology of the Roaring Fork River from the effects of stormwater runoff, and WHEREAS the city of Aspen has adopted the Urban Runoff Management Plan (Manual) under Chapter 28.02 Title 28 of the Aspen Municipal Code which states, in part, that the aforementioned Manual may be amended from time to time by the City Engineer and/or City Council, and WHEREAS amendment of the Manual to change and enhance the stormwater detention standards will increase the requirements upon certain properties for the detention of rainfall runoff, and WHEREAS a combination of enhanced stormwater detention standards and implementation of a voluntary fee -in -lieu of the improved detention requirement will both reduce flooding and generate funds for improving the City's existing drainage system related to development and redevelopment of property within the boundaries of the City of Aspen. WHEREAS the amendments to the Manual are delineated as follows: • Text being removed is delineated with strikethrough. Text being removed look:, likc this. • Text being added is bold and underline. Text being added looks like this. • Text which is not mentioned in this Ordinance is not affected; and NOW THEREFORE BE IT ORDAINED BY THE CITY COUNCIL OF THE CITY OF ASPEN, COLORADO; Section 1. That Chapter 1 of Urban Runoff Management Plan of the City of Aspen is hereby amended as follows: Table 1.1 General Requirements for Minor and Major Projects ibr . .baJ - ia J. d ` W ousa , P ed a ku hSxGeneralRequlremer rrrS`' �+.Nax. t7i 551flWti0A ,j. <�r �` k,rjF 1 < 200 square feet No requirements 200 - 1000 square feet "" Water quality improvements for the 2 Drains to Green Minor (green) disturbed /added area Infrastructure Detention not required Does not require a Professional Engineer 200 —1000 square feet WQCV for the disturbed or added area 3 Drains To Hard Infrastructure Minor (urban) Detention above WQCV not required Does not require a Professional Engineer WQCV for the disturbed or added area > 1000 square feet and Detention to the pre -developed historic 4 e C0% of site Major undeveloped rate or FIL for the entice—site < 25% of the site disturbed or added area Requires Professional Engineer > 1000 square feet, and WQCV for the entire site 50% of site Detention to the we-development 5 > 25% of the site or Major historic undeveloped rate or FIL for the > 50% of existing structure or entire site. more Requires Professional Engineer Section 2. That Chapter 5 of Urban Runoff Management Plan of the City of Aspen is hereby amended as follows: The City of Aspen's stormwater management goal is to mimic Aspen's natural hydrology to the maximum extent practicable. By requiring treatment of the water quality capture volume, discussed in Chapter 8— Water Quality, it, in effect, provides infiltration or detention for many very small events (on the order of a 6 -month to 1 -yr event), approximately 80% of the storms in Aspen. For the remaining 20% of storms, the larger events, a small portion of the runoff will be detained in the water quality treatment areas. The remaining runoff must be conveyed to the river safely and in a manner that doesn't increase the flooding potential of downstream properties. • - .. - - - - - - - - - eenditienc. Given these observations, the City's detention policy is as follows, by area: 1. Commercial Core /Downtown and Sub -urban Areas Draining to the Sewer System These drainage areas are highly impervious and are served by the City of Aspen stormwater infrastructure. In general, the minor, 10 -year, event in this area is handled by storm sewers and the major, 100 -year, event is accommodated by a combination of storm sewers and street flow. Currently, there are portions of the commercial core where storm sewer capacity is less than the 10 -year event and areas where the storm sewer plus streets do not have adequate capacity for the 100-year event; - -- - _ -': - - - •- - to 10 year capacity. Detention(above the WQCV)) to the historic peak flow rates for the 10- and 100 -year events is net-required for development or redevelopment activities that de-Ret year events is required. disturb or add more than 1,000 square feet of impervious area. If the disturbed or added impervious area is less than 25% of the total site then only the new area must be so treated. If the disturbed or added impervious area is more than 25% of the total site then the site shall be treated as a new development and the total site shall meet detention requirements to the historic peak flow rates. A proiect has the option to pav a fee - in -lieu of providing the required detention (see Section 2.12.140 of the Municipal Code). 2. 3. Sub -urban Areas not Served by Public Storm Sewer - - - - - • • :.: - •• - - • • -, Detention fabove the WQCV) to the historic peak flow rates for the 5- and 100 -year events is required for new development and redevelopment. : - - - - - - - - - • - - - ."' • activities that disturb or add more than 1.000 square feet of impervious area. If the disturbed or added impervious area is less than 25% of the total site then only the new area must be so treated. If the disturbed or added impervious area is more than 25% of the total site then the site shall be treated as a new development and the total site shall meet detention requirements to the historic peak flow rates. A project has the option to pav a fee -in -lieu of providing the required detention (see Section 2.12.140 of the Municipal Code). Section 3 That if any section, subsection, sentence, clause, phrase or portion of this ordinance is for any reason held invalid or unconstitutional in a court of competent jurisdiction, such portion shall be deemed a separate, distinct and independent provision and shall not affect the validity of the remaining portions thereof. Section 4 That this ordinance shall not have any effect on existing litigation and shall not operate as an abatement of any action or proceeding now pending under or by virtue of the ordinances amended as herein provided, and the same shall be construed and concluded under such prior ordinances. A public hearing on the ordinance shall be held on the 9 day May, 2011, in the City Council Chambers, Aspen City Hall, Aspen, Colorado. INTRODUCED, READ AND ORDERED PUBLISHED as provided by law, by the City Council of the City of Aspen on the 25 day of April 2011. Michael C. Ireland, ayor ATT ST: .i ■ / Kathryn Ko City Clerk FINALLY, adopted, passed and approved this f day of A //I 011. .� lI eland, o Michael C. Ireland, ayor ATT ST: APPROVED AS TO FORM: Kathryn KocjCity erk John orcester, City Attorney Tue, Apr 26, 2011 19:02:22 6457832 e i- I �, 0 1 , Ad Ticket #5 5 I Acct: 1013028 Name: Aspen (LEGALS) City of Phone: (970)920 -5064 Address: 130 S Galena St E ANGELA SCOREY Client: Caller: Kathryn Koch C i t y: Aspen _ Receipt State: CO Zip: 81611 Ad Name: 6457832A Original Id: 6457824 Editions: 8ATII8ATW/ Class: 0990 Start: 05/01/11 Stop: 05/01/11 Color: Issue 1 Copyline: 6457832 atw ORDI #16 R AT Legals Lines: 18 LEGAL NOTICE ORDINANCE #16, 2011, PUBLIC HEARING Depth: 1.51 Ordinance #16, Series of 2011, was adopted on first reading at the City Council meeting April 25, Columns: 1 2011. This ordinance. if adopted, modifies the Discount: 0.00 Urban Runoff Management Plan. The public hearing on this ordinance is scheduled for May 9. Commission: 0.00 2011 at 5 PM. City hall, 130 South Galena. Net: 0.00 To see the entire text, go to the city's legal notice 0.00 website Tax: t :/ lwww. aspenpitkin .com/DepartmentstClerk/ Legal - Notices/ Total 9.11 If you would like a copy FAXed or e- mailed to you, call the city clerk's office, 429 -2686. Payment 0.00 Published in he Aspen Times Weekly on May 1, 2011. [6457832] Ad shown is not actual print size ON a a La Cr � u °' r o f hi g w n jp' n rr CD n 7 re a G rt a S. F % a N M r-. S , N ` rt rt N N O .-- G 4, n CL cc N G C n G n a .-.• cn r rro a x Z z 5' t o ro n c M H � o' O R' .ni S a o n ro n a P I--' in ^ n a n n n z ,.o., r D ., p a. a E �' o r o ' C rD . w w CD G n n rt O� 0 : b ?? Q 6. n O ¢. a n n n ti n r O O O a o ��° H aet� � n , ° 3 ro N a n a °= 2 °' 0 rr rt rt S x- a x O n n d b fro V O a 0 G ro 116, _ rt b �' n ¢, ^ a c G. 'Z7 ��' n .O N p ^ G' ''S IH r+ a ' G' n A so to `C n A• rt a - n .v a rt ' e Q. Z n 14 E C Y CD � cr ti ° CD rt ^ro 0 . ,t; nP G z O O G In 1 N \ " G ,C rt rn. . 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