Stories tagged flooding

NOAA/USGS and US Army Corps of Engineers (COE) forecast charts are showing a new predicted crest for the Mississippi River here in downtown St. Paul at a whopping 19.8' late on 3/25.

That's 2 feet higher than predicted yesterday, and would make the 2010 flood #7 on the top-ten list of recorded floods at this site.

Check out our full feature on the 2010 Mississippi River flooding.

Mar
18
2010

If you're visiting the Science Museum of Minnesota, look out the windows from the Mississippi River Gallery on level 5. If you're in downtown St. Paul, stop by the museum and look at the river from the overlook on Kellogg Plaza. (City officials are asking folks not to flock to areas where barriers are going up - especially Harriet Island - but the view from in or around the museum is spectacular and safe.)

Kate's photos, 3/18 (3): Looks peaceful, doesn't it? Still, the city is warning people to stay off of the river, out of the low-lying parks, and away from Harriet Island and Water Street.
Kate's photos, 3/18 (3): Looks peaceful, doesn't it? Still, the city is warning people to stay off of the river, out of the low-lying parks, and away from Harriet Island and Water Street.Courtesy Kate Hintz

The Mississippi is going up FAST today, and forecasters expect that the river will officially reach "flood stage" by early this afternoon. (It's 10:45am, and the river's at 11.67'. It's risen a foot and a half in the last 24 hours, should reach 12' ("action stage") pretty soon, and 14' ("flood stage") by late today.

Kate's photos, 3/18 (2): Look across the river to the floodwall: that's the high-water mark for the 1965 flood, the highest in recorded history. That year, the river crested here in downtown St. Paul at 26.01' and marked the end for the communities then down on the river flats.
Kate's photos, 3/18 (2): Look across the river to the floodwall: that's the high-water mark for the 1965 flood, the highest in recorded history. That year, the river crested here in downtown St. Paul at 26.01' and marked the end for the communities then down on the river flats.Courtesy Kate Hintz

Kate's photos, 3/18 (1): Shepard/Warner roads will close from Chestnut Street to US 61 starting Saturday morning, and could remain closed for weeks. Take your river sightseeing drive/bike ride/walk before then!
Kate's photos, 3/18 (1): Shepard/Warner roads will close from Chestnut Street to US 61 starting Saturday morning, and could remain closed for weeks. Take your river sightseeing drive/bike ride/walk before then!Courtesy Kate Hintz

So what's going on around the river?

  • The city has closed all city boat launches and temporarily banned all recreational boating within the city limits.
  • Water Street will be entirely closed, starting this afternoon.
  • Hidden Falls and Lilydale regional parks are closed.
  • Flood barriers are going up at the St. Paul downtown airport and at Harriet Island.
  • Harriet Island will close once the river reaches 17'.
  • Warner/Shepard Roads will be closed from Chestnut Street to US 61 starting Saturday morning in preparation for the construction of a temporary levee that could withstand river levels to 26'. These roads could be closed for weeks, depending on the extent of the flooding.

Here's the latest hydrology graph:
3/18 hydrology graph, 10:15am
3/18 hydrology graph, 10:15amCourtesy USGS

Check out our full feature on the 2010 Mississippi River flooding.

Mar
17
2010

Look out the window or walk down the street to nearly any river or stream in Minnesota right now and you are likely to observe two things about the river:

  1. it is getting deeper (or “rising” in relation to the banks); and
  2. it appears to be moving faster.

You can, of course, confirm these observations by investigating reports from gauging stations along these rivers, maintained by the U.S. Geological Survey. (See data for the gauging station serving downtown St. Paul.) But what is really happening?

It may be high and fast...: ...but (as of today) the Mississippi at St. Paul is still in a bankfull state.
It may be high and fast...: ...but (as of today) the Mississippi at St. Paul is still in a bankfull state.Courtesy Liza Pryor

Until a river flows over its banks, it is considered to be in a “bankfull” state. In this state, the water flowing through the river is confined to a relatively fixed channel area. Simply put, floods occur because more water is being introduced into this channel from upstream, due to snowmelt, heavy rains, or a dam breach. As this added volume of water moves through a fixed area, it both increases in velocity and in depth until it overflows the banks, at which point some, but not necessarily a lot, of the volume and velocity moving through the channel are reduced.

Scientists call the rate of flow through a channel “discharge." Discharge is defined as the volume of water passing through a given cross-section of the river channel within a specified period of time.A simple equation for determining discharge is

Q = D x W x V

where Q = discharge, D = channel depth, W = channel width and V = velocity.

Looking at this equation, it is easy to see that if discharge becomes greater and channel width is fixed, then an increase in both volume and depth (or height relative to the banks) is likely to be the cause. Discharge can be measured in cubic feet per second or cubic meters per second, for example.

But is the river flowing at the same rate at the surface as it does along its banks and beds? Understanding this requires investigating some more detailed equations, as the banks and bed introduce friction, which affects the rate of flow.

To learn more about rivers and how they flow, you may want to check out the works of Luna Leopold, and M. Gordon Wolman. In particular:

  • Leopold, Luna B. (2006, reprint). A View of the River. Harvard University Press; and
  • Leopold, Luna B.; Wolman, M. Gordon; and Miller, John P. (1995). Fluvial Processes in Geomorphology. Dover Publications, both classics for understanding how rivers work.

Also, check out our full feature on the 2010 Mississippi River flooding.

Mar
17
2010

As of 11:19am, the US Geological Survey is forecasting that the Mississippi River will crest here in downtown St. Paul at 18 feet.

New flood crest prediction, 3/17
New flood crest prediction, 3/17Courtesy USGS

That would put Water Street and the lower section of Lilydale Regional Park underwater (at 14'), require secondary flood walls at the St. Paul Downtown Airport (17'), submerge much of Harriet Island (17.5'), and make Warner Road impassable due to high water.

An 18-foot crest would also make this year's flood #9, historically speaking, bumping the flood of 1986 (16.10') off the top-10 list.

Also, check out our full feature on the 2010 Mississippi River flooding.

Mar
16
2010

All day, up in the Mississippi River Gallery, people have been stopping to look out the window and watch the river.

Here's how the US Geological Survey sees it:
Mississippi River, actual vs. forecast, 3/16/10, 1pm
Mississippi River, actual vs. forecast, 3/16/10, 1pmCourtesy USGS

The river's rising, but not as fast as yesterday. And yesterday's rise outpaced predictions by almost a foot, but today the rise matches the predicted curve almost exactly.

So what are folks seeing out the window? Take a look.

Also check out our full feature on the 2010 Mississippi River flooding.

Watch the steps: They're a good benchmark.
Watch the steps: They're a good benchmark.Courtesy Liza Pryor

Raspberry Island: Still high and dry
Raspberry Island: Still high and dryCourtesy Liza Pryor

Looking upstream: You're still looking at Harriet Island. But low-lying areas of Lilydale (upstream, south side of the river) get inundated when the river reaches 14 feet or so. Right now, that's predicted to happen sometime after 7pm on Sunday, 3/21.
Looking upstream: You're still looking at Harriet Island. But low-lying areas of Lilydale (upstream, south side of the river) get inundated when the river reaches 14 feet or so. Right now, that's predicted to happen sometime after 7pm on Sunday, 3/21.Courtesy Liza Pryor

It's been a very snowy winter so it should come as no surprise that the flood risks in Minnesota are going to be high as well. There's a 60-percent chance that the Mississippi River will be creeping up close to our backdoor here at the museum in the latest forecast announced today. Start packing the sandbags right now in Moorhead and Fargo. There's a 98-percent chance that the Red River will flood this spring.

Check out the Science Buzz 2010 flood feature now.

If your answer is "Nothing, yet," then you might consider stopping by the museum.

Minnesota's Water Resources: Impacts of Climate Change
Dr. Lucinda Johnson, National Resources Research Institute, University of Minnesota-Duluth
Thursday, April 9, 2009
7 - 8:30 pm in the Auditorium

Over the past 150 years, Minnesota's climate has become increasingly warmer, wetter, and variable, resulting in undeniable ecological impacts. For example, more recent changes in precipitation patterns combined with urban expansion and wetland losses have resulted in an increase in the frequency and intensity of flooding in parts of Minnesota. Learn about exciting new research which will develop a prediction model for future climate changes specific to Minnesota, and discover its potential economic and civic impact.

Check it out.

Red River flooding: NASA image created by Jesse Allen, using EO-1 ALI data provided courtesy of the NASA EO-1 Team. Caption by Holli Riebeek.
Red River flooding: NASA image created by Jesse Allen, using EO-1 ALI data provided courtesy of the NASA EO-1 Team. Caption by Holli Riebeek.Courtesy NASA

This was the Earth Observatory Image of the Day today. It was captured by the Advanced Land Imager on the EO-1 satellite on March 28, 2009. The main channel of the river is slightly darker than the flooded land in these areas, an indication of how extensive the flooding is.

According to the National Weather Service, "flood stage" is the point at which a "rise in water surface level begins to create a hazard to lives, property, or commerce." In Fargo, that's at 18 feet. Today, the water level at Fargo climbed past 40.5 feet, passing all other recorded levels. If you're familiar with the city, here's an interesting list of flood stages as they correspond to geographic locations in the Fargo/Moorhead area.