HomeMy WebLinkAbout042 - 03/16/1999 - AMENDING THE STORM DRAINAGE DESIGN CRITERIA AND CONSTRUCTION STANDARDS BY REVISING THE RAINFALL INTE ORDINANCE NO. 42, 1999
OF THE COUNCIL OF THE CITY OF FORT COLLINS
AMENDING THE "STORM DRAINAGE DESIGN CRITERIA
AND CONSTRUCTION STANDARDS" BY REVISING THE
RAINFALL INTENSITY DURATION CURVE GRAPH
WHEREAS, in 1984 the Council of the City of Fort Collins (the "Council') approved
Resolution 84-41 pursuant to which it adopted the"Storm Drainage Design Criteria and Construction
Standards"for the purpose of setting forth the technical criteria to be used in the analysis,design and
construction of storm drainage systems within the City and its urban growth area; and
WHEREAS, in 1991 the Council adopted Resolution 91-44 pursuant to which it amended
the Storm Drainage Design Criteria and Construction Standards by the addition of the"Construction
Erosion Control Criteria" (the "Erosion Control Criteria"),- and
WHEREAS, the Storm Drainage Design Criteria and Construction Standards, as amended
by the addition of the Erosion Control Criteria, constitute the Storm Drainage Design Criteria and
Construction Standards that all new developments in the City are currently required to comply with,
pursuant to City Code Section 26-544 and Section 3.3.3 of the City's Land Use Code; and
WHEREAS, in January of 1998, the City embarked on a study to reevaluate the amount of
rainfall associated with the 100-year frequency storm, as well as with other storm frequencies(i.e.,
2-year, 5-year, 10-year,25-year and 50-year),and in doing so established a Precipitation Study Task
Force(the"Task Force")made up of technical experts,representatives from regulatory agencies and
citizens; and
WHEREAS, a majority of the members on the fask Force has recommended an increase in
the 100-year design rainfall criterion from 2.89 inches to 3.67 inches over a two-hour period,as well
as a similar increase for other storm frequencies, to be applied uniformly over the entire City; and
WHEREAS, the Colorado Water Conservation Board, Larimer County and the Federal
Emergency Management Agency have all expressed support for this proposed change; and
WHEREAS,the Fort Collins Water Board has also recommended this proposed change; and
WHEREAS, a minority of the members on the"Cask Force has recommended an increase in
the 100-year design rainfall criterion from 2.89 inches to 4.37 inches over a two-hour period,as well
as similar increases for other storm frequencies, to be applied uniformly over the entire City; and
WHEREAS, the Council has determined that it is in the best interests of the citizens of the
City and necessary for the public's health, safety and welfare, that the Storm Drainage Design
Criteria and Construction Standards be amended as recommended by a majority of the members on
the Task Force; and
WHEREAS, in order to so amend the Storm Drainage Design Criteria and Construction
Standards it is necessary to replace in it the existing Figure 3-1 which constitutes the "Rainfall
Intensity Duration Curve" graph dated November, 1975, (the "Existing Figure 3-1") with a new
"Rainfall Intensity Duration Curve" graph dated February, 1999, a copy of which new Figure 3-1
is on file in the Office of the Fort Collins City Clerk(the "New Figure 3-1"); and
WHEREAS, the City has also determined that in order to provide better flood protection
within the City that a City-wide network of monitoring devices be established, maintained and
operated by the City to measure and record precipitation and stream flow data; and
WHEREAS,this datawould be used,without limitation,foremergency response,emergency
preparedness,planning and design of stormwater facilities in the City's master drainage plans, and
for the development of future storm drainage design criteria and construction standards; and
WHEREAS, Council also desires that this precipitation and stream flow data be used by the
Director under Code Section 26-543 as one of the factors the Director may use to make decisions
concerning enhancements to the City's master drainage plan so that such enhancements do not result
in any diminishment in flood protection to the public.
NOW, THEREFORE, BE IT ORDAINED BY THE COUNCIL OF THE CITY OF FORT
COLLINS as follows:
Section 1. That the Storm Drainage Design Criteria and Construction Standards be amended
by substituting and replacing the Existing Figure 3-1 with the New Figure 3-1.
Section 2. That the Storm Drainage Design Criteria and Construction Standards,as amended
by Resolution 91-44 and by this Ordinance, are hereby reaffirmed, readopted and reenacted by the
Council.
Section 3. That Section 26-543 (b) of the Code of the City of Fort Collins shall be
amended to read as follows:
(b) The above master drainage plans are on file in the office of the
City Clerk. The city may adopt additional master drainage plans by
reference and declare them to be a part of this Article and copies of
such master drainage plans shall be on file in the office of the City
Clerk. Any of these plans may be modified by the Director for the
sole purpose of enhancement, provided that such enhancement does
not diminish the general purpose and specific objectives of the plan,
does not diminish the ability of the plan to address the disposition of
stormwater runoff in the applicable basin, and does not result in a
diminishment of the flood protection provided to the public in the
plan; and if so modified, the modification shall be filed in the office
of the City Clerk. In considering and making any enhancement to a
master drainage plan, the Director shall use such reliable data and
information that is available to the Director, including, without
limitation,the precipitation and stream flow data collected by the city
through its monitoring program established in Section 26-548.
Section 4. That a new Section 26-548 be added to Chapter 26 of the Code of the City of
Fort Collins to read as follows:
Sec. 26-548. Precipitation and stream flow monitoring.
Subject to any needed appropriation, the city shall establish, maintain and
operate a city-wide network of monitoring devices that will measure and record
precipitation and stream flow data. The data obtained from such network shall be
used,without limitation,for emergency response,emergency preparedness,planning
and design of stormwater facilities in the city's master drainage plans, and for the
development of future stormwater design criteria and construction standards.
Section 5. That the amendments to the Storm Drainage Design Criteria and Construction
Standard, as set forth in Section 1 above, shall not apply to any land development for which an
application for preliminary or final subdivision plan approval, preliminary or final P.U.D. plan
approval, or project development plan or final plan approval has been filed with the City prior to
March 26, 1999, whether filed under the City's Land 1;se Code, or under prior law(now known as
the Transitional Land Use Regulations).
Introduced and considered favorably on first reading and ordered p lished this 2ndAay of
March, A.D. 1999, and to be presented for final passage on the 16th day of March, A.D. 1999.
X1ayot
ATTEST:
City Clerk
Passed and adopted on final reading this 16th day of March;A.D. 1999,
ATTEST:
City Clerk