I seem to recall seeing a map of the defenses of St. Louis in Hans Christian Adamson's "Rebellion in Missouri, 1861; Nathaniel Lyon and his Army of the West. The rise of Brigadier General Nathaniel Lyon, USA, who saved Missouri from secession in the Civil War" (Philadelphia, PA: Chilton Co., 1961). If I recall right, it was on the the inside cover. The maps weren't all that detailed, but they showed the basic fortications.

You might want to post an inquiry with the webmaster of the following site: http://www.civilwarstlouis.com/index.html#History

It's a website on the War in Saint Louis. You might also contact the Civil War Round Table of St. Louis.

Hope this helps.