HomeMy WebLinkAboutLibbey-Nicolet_Watersheds_Common_Council_Presentation_10-11-20111
City of Oshkosh
Stormwater Management Study
City Council Meeting; October 11, 2011
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Project Goals
Rain Event Management Goal
10yr 1 hour rain(167” .
100 yr – 1 hour rain (2.98”)Passableroad for emergency
vehicles
Reduce stormwater pollution
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Project Area Description
Study area includes 2 watersheds: Nicolet Ave. (240 ac)
Libbey Ave . (490 ac)
Packer Ave.
Packer Ave.
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Linwood Ave.
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Linwood Ave.
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Existing Conditions (10-yr Storm Event)
Significant Flooding Locations
Packer Ave
& HarrisonNorth HS
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Packer Ave.
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Jackson St.
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Alternative Evaluation
12 alternatives analyzed
¾Each alternative included multiple management components
¾Improvements to existing storm sewers
¾New storm sewers
¾Detention basins
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Alternative Evaluation
Potential Detention Basin Sites
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BasinName
Flood
Storage
Volume
(ac. ft.)
1. Libbey/ No. Main Wet Basin 34
2. Libbey/ No. Main Dry Channel 15
3. Tree Farm Wet Basin 49
4. Packers Ave (south) Wet Basin 17
5. Packers Ave (north) Wet Basin 16
6. North H. S. Wet Basin 15
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Alternative Evaluation
Alternativeswere evaluated basedon:Alternatives
¾Elimination of street flooding in 10-year storm event
¾¾eas y o cons ruc on we an s, u y con c s, e c.
¾Construction cost
¾Reduction of flooding for larger storm events (25-yr & 100-yr)
¾Pollution control
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Alternative Evaluation
Alternative10 OptionAlternative
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Alternative Evaluation
Alternative12 OptionAlternative
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Alternative Evaluation
25--
Jackson Street (greater than 1-ft)
Evaluated larger storm sewer (box culverts) on Jackson
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¾Replaced circular storm sewer with box culvert (5’ x 8’)
¾Other components remain the same
¾Improved flood control during larger storm events
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Alternative Evaluation – Pollution Control
Sediment RemovalSummary
Alternative
Sediment
Removed
tons year
Alternative 10 A 48.6
Alternative 12 A 48.1
Cost Summary *
(with box culvert in Jackson)
lternative Estimated Cos
Alternative 10 A $9.4 million
Alternative 12 A $8.7million
* Cost estimates based on 2010 -2011 City of Oshkosh projects
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Recommended Alternative
Alternative12AAlternative
¾Flood control benefits (Jackson street flooding eliminated
un er yr even
¾Water quality benefits
¾Cost
¾Fewer detention basin sites
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Phased Implementation
Im lementation Phase I North Hi h School Area
Constructed in 2010
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G. Discussion/Questions