BROOKLYN’S WATER PROBLEM.
A PLAN proposed for solving Brooklyn’s water problem is to bring its supply from the Ramapo, fifty miles north of the city, in Rockland county, where, on the top of two parallel ranges of hills, 1,200 feet above the level of the Hudson river are two sets of lakes, whose area extends from 100 to 400 acres, their depth being fifty feet or more and their surfaces from 700 to 1,000 feet above the level of the sea. The outlets of these lakes unite and form the Ramapo’s headwaters at about 400 or 500 feet above the tide. The idea is that the new water supply of Brooklyn should consist at first of eight of these natural lakes and eight artificial ones, which would give a storage of 10,000,000,000 gallons of water that could be increased” at pleasure by one half more, affording a uniform daily supply of from 75,000,000 to 100,000,000 gallons of water, which,owing to the physical conditions of the district which the Ramapo drains, can never be anything else than perfectly pure.
A system of incorrosive metal pipes, starting at various levels from 600 to 800 feet above tide level, would unite in one main pipe in the valley of the Ramapo, follow it to near the New Jersey state line, and thence nearly parallel to such line, but a mile or more within the state of New York, to the Hudson river, and across the same to Hastings on the east shore, and thence southwest to, and along the Hudson and Harlem rivers. The hydraulic grade (that is, the level to which the water would rise to any place in a perpendicular pipe) of the main pipe, where it leaves the valley of the Ramapo (when discharging 80,000,000 daily), will be 430 feet above tide level; at the Hudson river crossing, 840 feet. The conduit pipes, except at the river crossings, will be of steel, coated inside and outside with asphalt, and on the outside also with a further coating of hydraulic cement, two inches thick. The pipes will be laid in a deep trench below the action of the frost and to some extent following the undulations, of the ground. They will be made of steel plates, riveted and caulked water tight. In one place the pipe will be be carried through a rock tunnel 2,700 feet long, and in another an open cut of one and onehalf miles in length will be used as an equalizing reservoir and one of the aerating places. The river crosssings will be either in tunnels under the bed of the river, through which the steel pipes will be carried, or in continuous steel or cast iron pipes, also laid under the bed of the river.
The watershed of these mountains is either leased, owned, or controlled by the Ramapo Water Company, and embraces about one hundred and fifty square miles. Over this, the rainfall, owing to the altitude and climatic conditions, is about twenty-two per cent, greater than over the Croton shed, from which New York is now receiving its supply. For the latter the claim of 1,000,000 gallons to the square mile is made, and from that may be gathered an idea of the fall over the Ramapo shed. In addition, owing to the shallow soil, underlying, which there is a solid rock foundation, the retention of the rainfall is vastly greater than in the Croton district.
In the matter of pressure, a factor of much weight, the Ramapo shed is exceptional. From its source, the water could be brought directly to the city mains without intermediate pumping or storage in reservoirs, and it is claimed that under the full natural pressure there is not a building in Brooklyn which could not be reached to the very top by a stream from the fire hydrants.
Should by any chance the Ramapo shed be insufficient., there are additional watersheds of almost limitless flow. Of these additional tracts, the Fort Montgomery shed comprises about sixty square miles and the Esopus about four hundred. Roughly estimated, the supply could be run up to 1,600,000,000 gallons a day and with no sign of a famine at that.