the Mississippi, where the contributing area is enormous and the conservation of the waters would be impracticable even if the nature of the country would admit of the construction of reservoirs. In Switzerland, where the torrents occasioned by the rapidly melting snows are especially destructive, the flood waters are confined by a series of parallel dikes on each side of the river, which have the effect of dividing the flow into several parallel streams. As the main river channel fills and overflows the inner dikes, the overflow water collects into the first series of parallel channels, and when a height is reached at which the second dikes are overflowed the water collects into the third, and so on. This gives an enormous carrying capacity, the limit of which is approached slowly, and therefore abundant opportunity is afforded for preparation upon the part of the riparian owner.

The drainage basin of Passaic River is admirably adapted to the development of the conservation system. At its headwaters in the mountains of northern New Jersey are numerous sites for reservoirs. The comparatively limited area draining into Passaic River makes such a scheme relatively inexpensive. On the other hand there is abundant opportunity for effective work in removing obstructions and straightening and deepening the channel of the lower river. So that, all things considered, the prevention of flood damages in the Passaic Basin can be best accomplished by a combination of the two general methods above outlined.

LOWER VALLEY IMPROVEMENTS.

The channel of Passaic River below Great Falls, at Paterson, is of limited capacity. To anyone making an inspection, especially within the city of Paterson, it is readily apparent that the river bed has for years been considered a legitimate field for encroachment. Owners of lands fronting on the river have increased their holdings by filling in beyond the channel line. Buildings have been erected upon these tracts and the builders have not hesitated to extend retaining walls still farther into the river bed. Refuse from the city's streets, light and unstable in character, has been freely deposited upon the bank to be carried out into the river. Thus the channel has been constricted laterally, the bottom raised, and there is left for the flood waters no alternative than that of extending themselves in the upward direction. It would seem that this, at least, should have been unobstructed. Such, however, is not the case.

The bridges across the Passaic have apparently been erected without reference to channel capacity. The authorities have evidently considered it more important to retain established approach levels than to provide proper capacity for river water. As an example the following instance may be cited: During the flood of 1902 a steel truss bridge across the river in Paterson was carried away. The point of

crossing was one of the narrowest places in the stream and it should have been clear to everyone that the space beneath the bridge was not large enough to carry flood waters. It should have been apparent that a new bridge, if erected at that point, must be higher than the old one, to be thoroughly safe. Notwithstanding, the new bridge was erected at the level of the old one, and in addition to this, it was a concrete arch structure, and the great piers and low arch springs reduced the former channel capacity about 15 per cent. This new bridge, as might be expected, collapsed during the October flood.

Along the entire course of the stream in the lower valley we find a continuation of instances of unreasonable encroachment and illconsidered bridge engineering, and there is opportunity for relieving a large part of the purely local obstructions by straightening the channel at chosen points.

Although this matter has not been thoroughly investigated it is readily apparent to one traversing the river bank that considerable relief may be secured in this manner. Damage, however, can not be prevented by this means alone. It would, of course, be possible to erect high and resistant levees along the entire course of the river, but this would be extremely expensive and would destroy the water front for commercial purposes. In fact, such a plan is quite visionary. At the present time there are no obstructions in lower Passaic River the removal of which would give relief in the event of floods like those of 1902 and 1903. When one considers the amount of water which was carried into the lower valley, the heights which it reached, and the area which it inundated, the futility of any local improvement except levee construction is emphasized. The present channel of the river will not carry without damage the amount of water recently thrown into it, and while it is important to provide regulations which will in the future prevent encroachment, and which will correct the evils now present along the channel, these measures can not, operating of themselves, give relief from flood devastation. Immunity from flood destruction in the Passaic must come, if it ever comes, from the construction of flood-catchment reservoirs in the uplands.

It is not necessary to spend any great amount of time in determining the cause of floods upon the Passaic. A review of the flood history of this river shows that in every case floods arise from extraordinary precipitation. High waters occur through the melting of snows and during periods of abundant rain. The heavy floods which have been regarded as extraordinary are clearly the result of unusual conditions of precipitation. The river carries the usual flood waters, and no damage is done until the water poured into it is far beyond its carrying capacity. Therefore the provisions which are made for preventing damage by floods must, if they be effective, be designed to meet extraordinary conditions, and means which would prove effectual in