The term “improvement,” when used in this Charter shall include the improvement of any street, avenue, alley, highway, public place or square, or portion thereof, in the city by filling, grading, raising, paving, repairing or otherwise improving the same in a permanent manner, or the construction or reconstruction of sidewalks, curbs and gutters, and other necessary appurtenances, including drains and culverts, and also the laying out, opening, narrowing, straightening or otherwise establishing, defining or locating streets, alleys, avenues, public places, squares or sidewalks. Said term shall also include any other permanent street improvement for a public benefit.