In the construction of such waterway through the City of Joliet, the elevation of the water surface at normal stage shall not be higher at Granite Street than minus 40.5 Chicago city datum, and in the event that the shoal reach between the upper basin of the Illinois and Michigan Canal and the crossing of the Elgin, Joliet and Eastern Railway is deepened 2 feet or more, then the elevation of the water surface at normal stage shall not be higher at Granite Street than minus 41 Chicago city datum, and the channel through said city shall not be less than 270 feet in width between Spring Street on the north and Lafayette Street on the south. Any dams constructed in connection with and for the maintenance of this pool of water shall be of such design as to quickly dispose of all flood waters. Adequate intercepting sewers shall be constructed of sufficient size and at such depth as will provide outlets not only for the present sewers that may be interfered with by the construction of such waterway, but also of sufficient size and depth to take care of all the watershed tributary to the Des Plaines River that may be interfered with by changing the water levels through the City of Joliet. The Department of Natural Resources is authorized to utilize such riparian rights of the Sanitary District of Chicago in, through and near the City of Joliet and along the Des Plaines River in the County of Will as, in its judgment, may be found necessary for the construction, maintenance and operation of such waterway, or for the development of water power in connection therewith, and the Department of Natural Resources shall not be required to make compensation to such Sanitary District for the right so utilized, except that the Department of Natural Resources shall reimburse such Sanitary District for any expense to which it may be put as a result of such act of the Department of Natural Resources in the maintenance and operation of such Sanitary District channel. The Sanitary District of Chicago shall not be deprived of access to such waterway over any walls or embankments constructed, or of the enjoyment of dockage rights in connection with any property it has acquired or owns, subject only to the use of such property by the Department of Natural Resources for waterway and power purposes.