If the article's title does not lend itself to being used easily and naturally in the opening sentence, the wording should not be distorted in an effort to include it:
The 2011 Mississippi River floods were a series of floods affecting the Mississippi River in April and May 2011, which were among the largest and most damaging recorded along the U.S. waterway in the past century. (2011 Mississippi River floods)
Instead, simply describe the subject in normal English, avoiding unnecessary redundancy:
The 2011 Mississippi River floods were a series of floods affecting the Mississippi River in April and May 2011, which were among the largest and most damaging recorded along the U.S. waterway in the past century. (2011 Mississippi River floods)
The Mississippi River floods in April and May 2011 were among the largest and most damaging recorded along the U.S. waterway in the past century. (2011 Mississippi River floods)
