The commissioner may also, when he shall determine that certain slope, drainage or easement rights or any or all of them, or parts thereof, are no longer required or necessary for the use of the state highway with which they are connected, convey, grant, bargain, sell and release to the owners of the fee, any slope, drainage or easement rights, or any or all of them, or parts thereof, including without limitation those easement rights or parts thereof which give the state the right to enter upon lands adjoining any state highway for the purpose of cleaning, straightening, widening, deepening and maintaining existing ditches and streams and the right to discharge water and maintain a flow of water over such lands adjoining the right of way of a state highway.