Mississippi River Lock & Dam 15

In 2016, we traveled to Scotland. A highlight of our trip was the week-long barge journey from Inverness to Banavie. It followed the route of the Caledonian Canal allowing us to traverse Lochs Dochfour, Ness, Lochy, and Oich from the North Sea to the Atlantic side of Scotland. The canal was finished in 1822. A fascinating part of the canal is the system of 29 locks used to raise and lower boats. The highest elevation reached is 106 ft above sea level. Our post is here about the lock system. Pictured below is one of the sets of lock gates viewed with Google Maps. The water level in the upper right is higher than at the lower left.

Last week, my friend David and I traveled to the Mississippi River at the Quad Cities to do a boat tour of Lock & Dam 15 conducted by two engineers with the U.S. Army Corps of Engineers. They explained much of the history of the river and early attempts to navigate boats through this region. They also described the maintenance of the dam and locks to further their useful life. They also discussed some of the history of the Rock Island Arsenal as we passed by.

The multiple gates of the dam are on the left in the next image. They control the river flow from upper right to lower left. There are two locks for river traffic just right of center. Our tour boat passed through the smaller of the two locks. Large tugboats and their barges pass through the larger lock.

World Wide Shipping | Live Mapping

The image below is centered on the New York harbor area. The small colored markers are ships. The image is a capture from a website which tracks the movements of over 50,000 vessels worldwide. I live in Iowa. We have barge traffic on the Mississippi River. But, it is seasonal and stops in the winter or dry weather.

If you live near a major world port, this web site will allow you to see hundreds of vessels. Click on the image to go to the site. Zoom in anywhere. Hover your mouse over a colored marker. Click on it to see more details and often a picture of the vessel. This is an excellent use of Google Maps and how it is linked to other databases such as the AIS system.

AIS is initially intended to help ships avoid collisions, as well as assisting port authorities to better control sea traffic. AIS transponders on board vessels include a GPS (Global Positioning System) receiver, which collects position and movement details. It includes also a VHF transmitter, which transmits periodically this information on two VHF channels (…) and make this data available to the public domain.

Because I am a land-lubber, I can’t offer any expertise about ships, navigation, harbors, etc. The site was very interesting, though. It is a good diversion from the usual negative news of the day.

There is a good FAQ section explaining the site and the methods used to track ships.

There are links to Vessels, Ports, and Gallery of ship photos at the top. Find and click and be taken to that location on the map.

Click on the map and full steam ahead.

 

Devonian Fossil Gorge of Iowa

The Iowa River is one of several southeastern flowing rivers that drain the eastern half of Iowa to join the Mississippi River along the state’s eastern boundary. Record floods that swept the nation in the early 1930’s prompted Congress to establish the Flood Control Act of 1938. In an attempt to reduce flooding on the Mississippi River, the U.S. Army Corps of Engineers was authorized to construct several dams on tributary rivers, including the Iowa River. In addition to moderating flows on the Iowa River, Coralville Lake’s less evident, but equally important, role is part of the comprehensive flood control system for the Mississippi River. Construction of the dam started in 1949, but was delayed by the Korean Conflict.

The focus of this story is on the effects of two flooding episodes in 1993 and again in 2008. Both times water breeched the concrete spillway and revealed a layer of bedrock from the ancient Devonian seafloor which existed in this region 375 million years ago.

The area in the lower right corner of the previous image is labeled with the dam and spillway for the lake. Zooming into the Google Earth map to the dam gives the image below. Some key points are labeled A thru F where I have photographs or video for illustration. At point A, there is a tower to control the release gates to regulate the flow out of the lake. Three gates can be opened independently.

During drought, the minimum flow rate of 150 cubic feet per second provides a sufficient flow to meet downstream domestic and industrial water needs. During time of flood, the outflow can be increased to about 20,000 cfs via a 23 foot diameter flow pipe through the dam. Inflow to the lake can exceed 40,000 cfs during rainy flood episodes. The lake level rises and potentially goes over the spillway to the right of point B.