Part 8

Near the headwaters of Wanaque River is Greenwood Lake, a large body of water described in Water-Supply Paper No. 88. Its value as a flood catchment basin is somewhat uncertain, as it is used as a storage feeder for Morris Canal. The surface level of this lake is controlled by gates, which naturally are operated by the canal authorities for the benefit of the canal. Therefore it is the object to store as great a volume of water as possible, and the water falls below the dam crest at the outlet of the lake only when the dam opens in dry seasons and makes it necessary. Under such conditions there is no certainty that storage capacity will be available during the time of a great storm, and in fact Greenwood Lake has been overflowing at the commencement of the storms which caused both of the recent floods.

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.

Rockaway River offers a greater number of available reservoir sites than either of the other highland tributaries of the Passaic. Some of the reservoirs which could be constructed could be used solely as catchment areas to hold back flood waters, while the capacity of others would be so much greater than any single flood run-off that they might serve also as compensating reservoirs. A large dam is now in process of erection at Old Boonton, conserving a considerable amount for the water for the municipal supply of Jersey City. This reservoir can not be depended upon as a flood-catchment area, as it will be the aim of those in authority to maintain the water in it as high as possible.

Powerville reservoir.--A short distance above Boonton the erection of a comparatively small dam would flood a large, irregular, flat basin having an area of a little more than 4-1/2 square miles and extending up the Rockaway Valley to Rockaway Village, up Beaver Brook to Beech Glen, and north and south for considerable distances. The probable capacity of this reservoir has been estimated, and it is fairly certain that it is considerably more than would be sufficient for flood catchment. Its construction would, moreover, improve the entire valley and be of advantage to many interests.

The northern New Jersey flood commission has selected for investigation a reservoir site on Rockaway River at Powerville. By the erection of a dam across the stream at this point, 28 feet in height and 470 feet long, a reservoir 4.6 square miles in area, with a capacity of 1,565,000,000 cubic feet, would be afforded. The drainage area above this point is 114 square miles. The cost of such a reservoir is estimated at $600,000.

North from Powerville, near the confines of the proposed Powerville reservoir, there is an available reservoir site along Stony Brook. By the erection of a dam 1,100 feet long and 120 feet high a lake would be formed 645 acres in extent, which would serve as a flood-catchment basin and a compensating reservoir. This reservoir would hold approximately 850,000,000 cubic feet. The construction of a reservoir at this place offers no engineering difficulties, and the project may be regarded as extremely favorable.

Dixons Pond, west of Rockaway Valley and northwest of Powerville, is a small sheet of water which lies in a valley which might be flooded to a greater height. By the erection of a dam 450 feet long and 30 feet high a lake of 136 acres would be created, which would form a part of the flood catchment and compensating service.

Longwood Valley reservoir.--A large storage basin is afforded in Longwood Valley which, if developed to its full extent, would extend from a point about a mile below Lower Longwood 7 miles up the headwaters and reach to about 1-1/2 miles above Petersburg. An alternative proposition is afforded which involves the submerging of less than half this area.

A dam 800 feet long and 55 feet high might be erected across a gorge about 1 mile south of Petersburg. There would be formed a lake of about 1.247 square miles, or 800 acres in extent. The hamlet of Petersburg would be submerged, but the damages from the destruction of improved property would not be very great, as the improvements and the land are not especially valuable. This reservoir would have a capacity of about 964,000,000 cubic feet and the surface would be at a height of 800 feet above sea level.

The alternative plan, that of using a longer stretch of the valley for reservoir purposes, would involve the construction about 1 mile below Lower Longwood of a dam 1,300 feet long and 110 feet high. The reservoir thus formed would be 1,900 acres in extent and contain approximately 3,447,000,000 cubic feet. The drainage area above this dam is limited, and if the reservoir were drawn down to an amount equivalent to 15 inches upon the drainage area there would still remain an enormous amount of water which could be used in a compensatory way to tide over dry seasons.

Splitrock Pond.--By erecting a dam 550 feet long and 30 feet high across a gorge at the outlet of Splitrock Pond, a lake could be formed having an area of 625 acres and adding to the present storage capacity of the lake an amount approximately equal to 475,000,000 cubic feet, equivalent to 38.75 inches on the drainage area.

Thus it is seen that if this reservoir were drawn down an amount equivalent to 15 inches on the drainage area, which would without doubt give sufficient protection from all floods, there would still remain a storage capacity of 23.75 inches for compensating purposes in addition to the amount now available in Splitrock Pond. This project is one of the most attractive in the Rockaway Basin, as the damages which would be caused by flooding would be, comparatively speaking, nil. The property is, however, now owned by the East Jersey Water Company, and is prized highly as a reservoir site by that corporation.

UPPER PASSAIC BASIN.

Millington reservoir.--There is an area of swamp land, comprising a part of the drainage area of upper Passaic River above Millington, which is known as Great Passaic Swamp. It is bounded on the south by a long, narrow trap ridge known as Long Hill, the summit of which ranges from 400 to 500 feet in elevation, or roughly 200 feet above the border of this swamp. To the northwest the land rises gradually toward Trowbridge Mountains, while to the northeast is the terminal moraine. The outlet of Passaic River at Millington is by a narrow gorge, which offers natural facilities for the erection of a dam.

The whole situation is exceptionally good, and the surface of a reservoir might be fixed at any elevation between 240 and 300 feet above sea level. With the surface of the reservoir at 300 feet a dam 1,600 feet long and 90 feet high would be required. This lake would have an area of 28.46 square miles. The drainage area above Millington has, however, an area of only 53.6 square miles, and the proposed reservoir would therefore cover more than half of this. Therefore the conservation of so large a quantity of water would not be necessary nor advisable, unless the beautifying of the surrounding country were an object to be taken into consideration, which might be profitable.

A better project, however, would be to construct a dam at Millington 900 feet long and 50 feet high, the crest being about 260 feet above sea level. There would be formed a lake with an area of 19.41 square miles, and a capacity of 1,477,600,000 cubic feet, equal to 9.864 feet on the drainage area. This project is too great for the necessities here presented, and would not be wisely considered unless it were found advantageous to improve the country generally as a place of suburban residence. The land which would be flooded with the reservoir crest at 260 feet is of a wet, swampy character, and its value for agricultural purposes is somewhat doubtful. Such construction would involve the flooding of 13 miles of road, which, however, would not involve a great loss of invested capital, as the roads generally are of a poor character.

A second alternative would involve the construction of a dam across the Millington gorge, 550 feet long and 30 feet high, raising the water to 240 feet above sea level and creating a lake of 14.40 square miles. This would conserve 4,026,000,000 cubic feet, equal to 2.69 feet on the drainage area. This would be ample for flood purposes and would still afford a large impounded area, as the drawing off of an amount equal to 10 or even 15 inches on the watershed would not reduce the size of the lake to any great extent.

The whole project here presented involves few difficulties, and as the drainage area above is of small extent, the mere question of conserving the flood waters could be met without great difficulty. The natural advantages, however, are so great and the land included within Great Passaic Swamp is of so little value that the surrounding country would be improved and beautified by the construction of such a reservoir. The opportunity for varying the character of the reservoir to meet the ideas of those interested seems unexampled, and as a whole it presents an extremely interesting field which may be profitably exploited.

SADDLE RIVER.