The Texas Department of Transportation (TxDOT) is paying for the boardwalk as compensation for taking several slices of parkland around Lady Bird Lake to make space for the expansion of I-35 through Central Austin. The payments are required under a federal law that compels transportation agencies to replace or improve public parkland when it's used for highway projects. Some of the parkland use is temporary, and TxDOT said it is paying the city based on the appraised value of the land.