Cant Find Any Data

I live on the Mississippi River just north of Little Falls and have been looking for data/maps detailing contour depths for the Mississippi River form Little Falls to Brainerd. The MN DNR has detailed maps available on their website from the Iowa Border right up to Zebulon Pike reservoir just south of Little Falls but from the dam in Little Falls to Brainerd or even Camp Ripley I have found nothing! I inquired with a buddy that works for the MN Board of Water and Soil Resources and he suggested contacting the St Cloud MNDOT office since they had built the HWY 10 Bridge across the river near LF in the 70’s and may have done soundings, again, nothing. Any insight that can be passed along is appreciated.