In view of the condition expressed above it will be necessary in providing for flood catchment in the Wanaque drainage area to omit entirely from consideration the possibility of assistance from Greenwood Lake. Below this point in the basin are several sites at which could be raised dams, which would effectually retain a large proportion at least of storm run-off. They may be described as follows:
Midvale reservoir.—By building a dam 60 feet high and 1,200 feet long across Wanaque River near Midvale, a reservoir would be formed which would have a water surface of 2.1 square miles and a capacity of 1,491,000,000 cubic feet. The drainage area above this site is 83 square miles, and the storage capacity would therefore be equal to about 7.7 inches on the drainage area. The construction of this project would involve the relocation of about 4-1/2 miles of the New York and Greenwood Lake Railroad; the damages apart from this would be nominal, the cost of the entire reservoir construction being about $1,000,000.
Ringwood reservoir.—Ringwood Creek runs through a gorge about 1 mile above its confluence with the Wanaque. Above this is a well-defined basin. A dam about 70 feet high and 585 feet long would create a lake having an area of 520 acres, the surface of which would be 380 feet above sea level. The drainage area tributary to this point has an area of about 20 square miles, and as the proposed reservoir would have a capacity of 915,800,000 cubic feet, there could be conserved a run-off of 20 inches. Allowing for a flood run-off of 12 inches there would still be available for compensating purposes 8 inches on the basin, equal to 373,550,000 cubic feet. The construction of this reservoir would involve the relocation of about 2 miles of the Ringwood branch of the New York and Greenwood Lake Railroad, and the condemnation of comparatively valuable improvements in the proposed basin.
West Brook reservoir.—The drainage from 5.7 square miles might be conserved by the erection of a dam on West Brook, a tributary of Wanaque River, which enters it from the west. There is an available site at which a dam 280 feet high might be erected. At this elevation the length along the top would be about 1,150 feet and about 2,330,000,000 cubic feet of water would be impounded. Little benefit would be derived from such a reservoir, as the limited drainage area affords a comparatively small proportion of flood run-off that might be well cared for at a lower point. For compensating purposes, however, a reservoir might be constructed here, the capacity of which could be adjusted to the actual demands. If the dam were raised to a height of about 280 feet from the base the storage afforded would be equal to 176 inches on the watershed, or about four average years of precipitation, which is far beyond all probable storage necessities. The maximum available storage capacity is given in this case merely to show possibilities.
PEQUANAC SYSTEM.
There are few available reservoir sites of large size along the lower reaches of Pequanac River. In the upper basin, however, there is a sufficient available storage capacity to afford almost complete control of destructive floods from that part of the drainage area. Large tracts are already reserved by the city of Newark for collection of municipal supply, and the storage capacity developed is sufficient to serve the city throughout the driest seasons. The total capacity of Clinton, Oakridge, and Canistear reservoirs is about 1,155,000,000 cubic feet. These basins are not available for flood catchment, as the water is used for city purposes and an endeavor is made to have in storage at all times the largest possible amount. The condition is exactly similar to that described in the case of Greenwood Lake. In considering the means for the construction of flood-catchment reservoirs in Pequanac Basin there must be taken into account the conservation and delivery of the Newark supply. The adjustments with reference to the amount of water available at Macopin intake would have to be met, and if the system were interfered with compensation therefore would be taken into consideration.
Newfoundland reservoir.—Pequanac River passes through a deep gorge between Copperas and Kanouse mountains, just below the village of Newfoundland. This point has been considered an excellent site for the construction of a dam, and in the installation of the present water-supply system of Newark it is proposed that the entire valley in which Newfoundland is situated be overflowed. The site is one of the most advantageous known for the creation of a flood-catchment basin. If a dam 50 feet high were erected across this gorge, a lake would be formed which would have a surface area of 3.15 square miles and a capacity of 3,267,200,000 cubic feet, equal to a storage of about 30.5 inches on the 46.12 square miles of contributing drainage area. This would afford complete protection in case of a sudden run-off of 12 inches, would provide for the supply of the city of Newark without greatly disturbing the present storage system of that city, and would still yield a large amount of water for compensating purposes in dry seasons.
The construction of Newfoundland reservoir would be very expensive, as it would involve the flooding of Newfoundland Village, in which there is considerable improved property. About 3 miles of the track of the New York, Susquehanna and Western Railroad would be submerged, as well as a considerable mileage of macadamized highways. On the whole, however, the Newfoundland reservoir project is the most favorable which can be found on the Pequanac Basin. There are above this point numerous reservoir sites, but their combined capacity would not be equal to that of the proposed Newfoundland reservoir, and the construction would be probably quite as expensive.
Stickle Pond reservoir.—Below Newfoundland there are few available places at which water could be stored. Stickle Pond is probably the best adapted of any of those available. If a dam 1,050 feet long and 80 feet high were erected across the river about 1 mile below the present outlet of Stickle Pond, a lake would be formed having a surface area of 422 acres and a storage capacity of about 800,000,000 cubic feet. The drainage area above this dam would be approximately 4 square miles. This is a comparatively small amount of storage, yet it would provide for all flood catchment in that comparatively limited area and would be of assistance at times in compensating the dry flow of the Pequanac.
ROCKAWAY SYSTEM.