Monday, May 13, 2013

Understanding Military Terrain: The Battle of Credit Island Part IV

Once again, we return to Credit Island with our guide, Chris Espenshade, who is going to walk us through a KOCOA analysis of the 1814 battle. Parts I-III can be found by clicking the links below.

Part I
Part II
Part III


As noted in the earlier posts, the study of the Credit Island Battlefield was hindered by weaknesses in two areas, archaeological data and collector information. The nature of the battle actions, the natural forces of the Mississippi River and its flooding, and modern intrusions onto key battle locations together meant little evidence of the battle survived.  There were not any productive areas for avocational metal detectorists, and the archaeological survey likewise came up empty.  In the previous blog (Part III), we discussed how the various battle accounts were reconciled.  It is now time to look at the military terrain.

 Glossary of Terms Used in KOCOA Analysis (from McMasters 2009).

Key Terrain
Any local feature that dominates the immediate surrounding by relief or another quality that enhances attack of defense
Decisive (or Critical) Terrain
Ground that must be controlled in order to successfully accomplish the mission
The ability to see friendly and enemy forces and key aspects of the terrain to allow management of the conflict
Field of Fire
An area that weapons may effectively fire upon from a given position
Dead Space
An area within the maximum range of a weapon or an observer, but which cannot be seen or fired upon from a given position
Protection from enemy fire
Protection from enemy observation
Natural or man-made terrain features that prevent, impede, or divert military movement
Avenue of Approach
Relatively unobstructed ground route that leads to an objective or key terrain
Avenue of Withdrawal
Relatively unobstructed ground route that leads away from an objective or key terrain
Mobility Corridor
Area or location where movement is channeled due to terrain constrictions

One of the key issues in the KOCOA analysis was the position of the American boats.  Earlier studies assumed that the boats were on the western side of Pelican Island, because the British had a clear line of sight from the Iowa bank of the river.  However, as we examined the accounts, two items called this conclusion into question. Both items appear in the accounts of clearing the Native Americans from Pelican Island.

Zachary Taylor reported driving the troops across the island, emerging on the Iowa side, implying an east-to-west movement.  The Americans would not have been moving toward the own boats, and that would have created the risk of friendly fire incidents. Taylor further reported that the American left was close enough the Credit Island to fire on the Native Americans wading to Credit Island from Pelican Island.  For the American left to have been on the south, the Americans had to be moving east-to-west.

When the American boats are repositioned to the northeast shore of Pelican Island, a number of KOCOA outcomes are derived.  In the War of 1812, artillery depended on line of sight, and shots were not made through or over vegetated landforms. This fact, combined with the reported distance of approximately 600 yards from the artillery to the boats, and with the report that the British could see the boats broadside, led to a secure best guess of the British artillery. Once this position was determined, it was possible to address other issues such as where the dead space began as the Americans retreated downstream.
KOCOA Analysis figure showing field of fire (yellow) and dead space (red) from the likely British artillery position (produced in Google Earth 2013).
The archival data for this battle are strong, and the landscape allowed us to place great confidence in our KOCOA analysis. Although it would have been great to have collector information or archaeological data, by using multiple means of data collection and analysis, we have crafted a well-supported battle analysis.

But wait, there's still a missing piece to this puzzle! More on that in the fifth and final post!

This research – conducted by Commonwealth Cultural Resources Group -- was sponsored by the American Battlefield Preservation Program and the City of Davenport, Iowa.  This material is based upon work assisted by a grant from the Department of the Interior, National Park Service. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the Department of the Interior.

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