The commissioners were appointed to apportion the expenses of the metropolitan parks district in such manner as they deemed just and equitable, and for this purpose they were to determine and make award for the succeeding five years of the proportion in which each of the cities and towns should annually pay money into the treasury of the Commonwealth, for the amount estimated to meet the interest and sinking fund requirements of the appropriations and loans authorized for the metropolitan park system; and for the Nantasket beach reservation and the Charles River basin as well as the amount necessary to meet the expenses of the board of park commissioners, incurred in the care, maintenance and operation of the parks, reservations, boulevards and other works acquired, cared for, or controlled by the board, and to make up the deficiency if any in the estimates and payments for preceding years as found by the treasurer. St. 1893, c. 407. St. 1894, cc. 288, 483. St. 1899, cc. 419, 464. St. 1903, c. 465. St. 1906, c. 368, § 1; c. 402, § 2. St. 1909, c. 524, § 2. See also Sts. 1894, c. 483; 1909, c. 524; 1911, c. 587; 1913, c. 539.
*192It will be seen upon comparison of these statutes that while the original act of 1893, c. 407, which established the park commission to care, maintain and make available to the inhabitants of the district as defined in § 4 open spaces for exercise and recreation, and provided in § 10 that three commissioners were to be appointed by this court to apportion the expense of preservation to be paid by cities and towns comprising the district, for the term of five years “next following the year of the first issue of . . . scrip or certificates, to meet the interest and sinking fund requirements,” and upon the expiration of the first term, for appointments of commissioners every five years thereafter, the St. of 1894, cc. 288, 483, authorized the commission to build roadways and boulevards to connect any road, parkway or other public open space with any part of the cities or towns of the district by suitable roadways or boulevards, and also conferred jurisdiction over the Revere beach reservation and the Nantasket beach reservation.
The commissioners accordingly were required to ascertain and apportion the expenses during the next five years succeeding their appointment, for the construction and maintenance of the park system and of the roadways and boulevards constructed by the commission and the expenses required for the several reservations, of which only the Nantasket reservation is before us on the appeal. In the performance of these duties, “the commissioners are clothed with a wide discretion as to the considerations which should guide them in making the apportionment. It is to be made in such a manner as they may deem just and equitable. Their reasonable determination and not that of the court is to prevail.” In re Metropolitan Park Commissioners, petitioners, 209 Mass. 381, 384.
It is stated in the report that, by reason of the development of the park system with its extensive and numerous roads and boulevards, “As the investment grows the maintenance expense also grows, and the problem of a just apportionment becomes more serious because of the large amounts involved.” The advantage to the public of open and ornamental spaces for the enjoyment of light, air and prospect were provided for by the original statute, and the combination of roadways and of parks apparently has become during each quinquennial period more and more a place of recreation for the public, while the avenues and boulevards subsequently authorized have rendered the system more accessible to *193the inhabitants of the district, which as a whole constantly has grown in population and wealth. If the element of valuation must be a constant factor in making the apportionment, we find no reason for holding as matter of law, that the commisssioners acted unreasonably or inequitably or unconstitutionally when in ascertaining the apportionment for the maintenance of the parks, they based the percentage on the average valuation, in combination with the average population. It is plain that by reason of proximity, the parks would afford a more convenient and more frequently used pleasure resort for the inhabitants of certain municipalities than that which is afforded to the remote or “fringe” towns of the district. Kingman, petitioner, 153 Mass. 566, 579. Kingman, petitioner, 170 Mass. 111, 118. De Las Casas, petitioner, 180 Mass. 471.
The commissioners having decided that Nantasket beach had become a shore resort frequented much more largely by the general public than by the people living within the reservation, we are unable to say that in levying the assessment on valuation only, the burden was not justly equalized. In re Metropolitan Park Commissioners, petitioners, 209 Mass. 381, 386.
Nor are the tables showing the percentages resulting from levying the apportionment in the mode observed open to the objection that they “fail to indicate exactly the apportionment made by the commissioners.” It is not contended that the tabulations are founded upon inaccurate or insufficient data, and the commissioners were not required to set forth their arithmetical computations in detail. Adams, petitioner, 165 Mass. 497, 501. It is to be presumed that they followed the last decennial census and the last valuation as established by statute. Amendments to the Constitution, art. 21. St. 1905, c. 17. St. 1909, c. 490, Part I, §§ 57-62. And the grounds of their judgment are not so insufficiently set forth, that the constitutional rights of the appellants are shown to have been invaded. De Las Casas, petitioner, 178 Mass. 213, 220; S. C. 180 Mass. 471.
We now come to the rulings requested and refused. It is stated that the appeal rests substantially on that portion of the report concerning the Charles River basin where the commissioners say, “The Apportionment Commission of 1910 has already determined what portions of the construction costs were specifically to be *194assessed upon the cities of Boston and Cambridge under the provisions of section 9, chapter 465 of the Acts of 1903, as amended by section 2, chapter 402 of the Acts of 1906, and we regard that matter as settled. All the remainder of the construction and all the maintenance expense we apportion among the several municipalities according to valuation.”
By agreement of parties and with the approval of the single justice the previous reports of the park commission, and the reports of the apportionment commissioners for certain years, could be referred to at the argument. While it is to be assumed that the present commissioners were familiar with the reports of former commissions, the report of the last preceding commission from which liberal excerpts appear in the briefs of counsel seems to be the only report which it is necessary to consider in connection with the record. The language of the report is, that “The different works to be performed under the Charles River Dam and Basin Act have been completed ...” and the apportionment which followed is stated tobe for the office expenses of the park commission “the care and cost of maintenance and all other lawful charges with reference to the Charles River Dam and Basin, excepting therefrom sinking fund and interest requirements, for the term beginning Jan. 1, 1910, until the first day of' January of the year in which a new award is made as provided by law.” This report having been confirmed by In re Metropolitan Park Commissioners, 209 Mass. 381, the award was a final adjudication for the term for which it was made of all matters referred to the commissioners, and is binding on the parties, which included the appellants who appeared and were represented by counsel. St. 1899, c. 419, § 1. See St. 1909, c. 175.
The public work since denominated as the Charles River basin was authorized by St. 1903, c. 465, as amended by St. 1906, cc. 368, 402. By St. 1909, c. 524, upon completion of the “main parts,” or “in any event, on and after the first day of July in the year nineteen hundred and ten, ” the commission appointed under St. 1903, c. 465, as amended to build the dam, and construct the basin as therein specified and required was abolished, and all its powers, and duties were transferred to, and were thereafter to be exercised by, the metropolitan park commission. The “next appointed” apportionment commissioners, namely the commissioners of 1910, *195in apportioning the expenses of the metropolitan park system were by § 9 to include as part of the cost of maintenance the amount already incurred and disbursed under St. 1903, c. 465, and independentlyof the cost of Craigie bridge and the construction of a suitable bridge in its place, the entire expense of which was to be borne by the cities of Boston and Cambridge, they also were to determine “as they shall deem just and equitable” what portion of the total amount expended for construction under §§ 3, 4, 5, 6, 7, 11 and 12 as amended by St. 1906, c. 402, should be apportioned to Boston and Cambridge because of any special or peculiar benefits, treating the balance remaining as part of the cost of the park system. Their report appears in the record of In re Metropolitan Park Commissioners, petitioners, 209 Mass. 381, and upon examination of the papers, the commissioners are shown to have considered the work of construction as completed and after having determined the cost of construction made certain deductions for any special benefits conferred on Boston and Cambridge before levying the assessment required for the remainder. If any dredging has since become necessary to maintain the original depth of the several canals, or of the basin outside the navigable channels, or of other dredging and the relocating or removal of pipes or conduits before the dredging could be done effectually, or any repairs however extensive which are required to maintain the entire work as designed and completed, the moneys so expended are properly chargeable to the expense of maintenance, and constitute no part of the original construction. St. 1903, c. 405, §§ 4, 5. And the appropriations subsequent to 1910 appear to have been for care and maintenance only. St. 1911, c. 570. St. 1912, c. 301. St. 1913, c. 374. St. 1914, c. 222. Spec. St. 1915, c. 153. It is urged that as the reports of the park commissioners since the former apportionment show that the granite block pavement of the roadway of the dam settled and, the pavement having been relaid on a concrete foundation, Boston and Cambridge should pay so much of the expenditure as might be just and reasonable, leaving the remainder to be borne by the district. St. 1903, c. 465, §§ 3-9. The stability and permanence of the roadway having required the work, it was in the nature of necessary repairs or replacements which are chargeable to maintenance. We discover no error in the application by the commission of the report of their predecessors except in the *196refusal to give the appellants second and third requests for rulings of law.
The marginal conduits named in those requests having been completed formed part of the metropolitan park system. While the commission was not obliged to ascertain anew the cost of construction but could take the amount fixed by the commission of 1910, it was appointed to make an apportionment for the next succeeding five years, as provided by the statute, which required the commission to determine for itself what special or peculiar benefits, if any, Boston and Cambridge had derived from the construction of the respective conduits before any assessment could be levied on the appellants. If it so determined the commission could adopt, increase or diminish the percentage of apportionment in each instance shown by the former apportionment, or could find that no deduction should be made; but for the reasons stated it could not treat the question as having been finally or conclusively adjudicated by the former report and the decree thereon.
The objections to the confirmation of the report which are open on the appeal remain. Old Colony Railroad, petitioner, 163 Mass. 356, 359. No contention is made that the commissioners were not required to provide for maintenance, and as the whole apportionment shown by table “C” is on the. basis of valuation, we perceive no sound objection to combining with the assessment for the cost of maintenance, an assessment for the cost ofj construction, instead of separate assessments and separate tables as urged by the appellants. “All the remainder of construction” having been apportioned, the appellants who must pay their proportion maintain, that they are entitled to know what the “remainder” comprises, and that the grounds on which the commissioners based their conclusion should be sufficiently stated to enable the court to decide whether an error of law has been committed. De Las Casas, petitioner, 178 Mass. 213. If on the face of the report, the completion of any of those parts of the basin is not referred to, it is plain that “all the remainder of construction” is intended to cover and to provide for any work of construction in connection with the care and maintenance of the basin which the Legislature from time to time might deem necessary during the succeeding period. But if no further appropriation for construction should be authorized, yet even then the apportionment, in *197their judgment was just and equitable for care and maintenance only.
The decree confirming the report must be reversed and what further proceedings should be taken are to be settled before a single justice.
So ordered.