Flooding trends In Iowa and across the Midwest Larry Weber Executive - - PowerPoint PPT Presentation

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flooding trends in iowa and across the midwest

Flooding trends In Iowa and across the Midwest Larry Weber Executive - - PowerPoint PPT Presentation

Aug 21, 2023 387 likes •668 views

A vision for a m ore resilient Iow a A vision for a m ore resilient Iow a T he Iow a Wat ershed Approach T he Iow a Wat ershed Approach Flooding trends In Iowa and across the Midwest Larry Weber Executive Associate Dean College of Engineering

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A vision for a m ore resilient Iow a

T he Iow a Wat ershed Approach

A vision for a m ore resilient Iow a

T he Iow a Wat ershed Approach

Flooding trends In Iowa and across the Midwest

Larry Weber

Executive Associate Dean College of Engineering The University of Iowa

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A vision for a m ore resilient Iow a

T he Iow a Wat ershed Approach

A vision for a m ore resilient Iow a

T he Iow a Wat ershed Approach

Trends in floods and heavy rainfall events

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A vision for a m ore resilient Iow a

T he Iow a Wat ershed Approach

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T he Iow a Wat ershed Approach

Trends show more floods in recent decades

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A vision for a m ore resilient Iow a

T he Iow a Wat ershed Approach

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T he Iow a Wat ershed Approach

Trends show more frequent floods and heavy rainfall

Increased flooding Increased heavy rainfall

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A vision for a m ore resilient Iow a

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A vision for a m ore resilient Iow a

T he Iow a Wat ershed Approach (a)

(b) (c)

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Q100 = 26,350 cfs

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Q500 = 35,800 cfs

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A vision for a m ore resilient Iow a

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A vision for a m ore resilient Iow a

T he Iow a Wat ershed Approach Historic Crests At Decorah, IA (1) 17.90 ft, 34100 cfs, on 06/ 09/ 2008 (2) 15.20 ft, 25640 cfs, on 05/ 29/ 1941 (3) 14.35 ft, 20500 cfs, on 08/ 17/ 1993 (4) 13.68 ft, 19800 cfs, on 08/ 24/ 2016 (5) 13.08 ft, 20200 cfs, on 03/ 27/ 1961 (6) 12.31 ft, 15300 cfs, on 06/ 01/ 2000 (7) 12.20 ft, 14754 cfs, on 03/ 17/ 1945 Historic Crests at Dorchester, IA (1) 24.30 ft, 38000 cfs, on 08/ 25/ 2016 (2) 22.46 ft, 31200 cfs, on 06/ 09/ 2008 (3) 22.20 ft, on 02/ 28/ 1948 (ice) (4) 21.80 ft, 30400 cfs, on 05/ 30/ 1941 (5) 20.89 ft, on 03/ 05/ 1937 (ice) (6) 20.02 ft, 25500 cfs, on 06/ 23/ 2013 (7) 20.00 ft, 22000 cfs, on 08/ 17/ 1993

More flash flooding occurred in Decorah and Freeport in 2016.

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A vision for a m ore resilient Iow a

T he Iow a Wat ershed Approach

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A vision for a m ore resilient Iow a

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T he Iow a Wat ershed Approach

drone video by Jewellable Productions

2016 Flood (19800 cfs)

Wal‐Mart Freeport Menards Site

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A vision for a m ore resilient Iow a

T he Iow a Wat ershed Approach

A vision for a m ore resilient Iow a

T he Iow a Wat ershed Approach

2016 Flood (19800 cfs)

Freeport

drone video by Jewellable Productions

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A vision for a m ore resilient Iow a

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A vision for a m ore resilient Iow a

T he Iow a Wat ershed Approach

1D Model of Upper Iowa River created by USGS in 2010 used to develop Preliminary FEMA Study

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What is a Floodway?

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A vision for a m ore resilient Iow a

T he Iow a Wat ershed Approach LiDAR Terrain Data

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A vision for a m ore resilient Iow a

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1D Model created by USGS in 2010 Used to create the Preliminary FEMA Study

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A vision for a m ore resilient Iow a

T he Iow a Wat ershed Approach 2008 Flood (33800 cfs) High Water Marks Compared to Simulation

Obs = 849.5 Sim = 849.5 Obs = 850.1 Sim = 849.2 Obs = 845.9 Sim = 846.5 Obs = 843.1 Sim = 842.5 Obs = 841.6 Sim = 841.6 Obs = 840.7 Sim = 841.2 Obs = 844.4 Sim = 844.0

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A vision for a m ore resilient Iow a

T he Iow a Wat ershed Approach Addition of Proposed Menards

Menards Pond Depth = 10ft Assuming the Menards detention pond is at permanent pool, the fill added to floodplain is approximately 1.7 million cubic feet. At the peak of the 2008 Flood, this volume would have filled in 1 minute.

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Removal of Wal‐Mart Site

Removal of Existing Wal‐Mart site

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Iowa Flood Center The University of Iowa 100 C. Maxwell Stanley Hydraulics Laboratory Iowa City, IA 52242 319-384-1729 www.iowafloodcenter.org

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