The board of aldermen may establish, alter and change the channel of watercourses, and wall them and cover them over, and prevent obstructions thereon, and may establish, make and regulate public wells, cisterns and reservoirs of water, and provide for filling the same. The board of aldermen may purchase grounds and erect and establish market houses and marketplaces, and regulate and govern the same, and also contract with any person or persons, association or corporation, for the erection, maintenance and regulation of market houses, and marketplaces, on such terms and conditions and in such manner as the board of aldermen may prescribe. They may also provide for the erection, purchase or renting of the city hall, workhouse, houses of correction, prisons, engine houses, and any and all other necessary buildings for the city, and may sell, lease, abolish or otherwise dispose of the same, and may enclose, improve, regulate, purchase or sell all public parks or other public grounds belonging to the city, and may purchase and hold grounds for public parks within the city, or within three miles thereof.