The board of park trustees, on the first Monday of January each year, shall make a written report to the legislative authority of the municipal corporation of its proceedings, with a detailed statement of its receipts and expenditures during the year. The board shall at the proper time submit to the legislative authority a detailed estimate of the amount of money necessary to maintain and improve parks for the ensuing year, and to dredge, straighten, clean, deepen, and otherwise improve watercourses and purchase and acquire water rights, easements, and privileges.