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on the axis of the bridge at high water is 3,972 square feet, at low water 2,514 square feet; 2,514 is 31 per cent. of 8,020. The obstruction rises twenty feet above the level of the bottom up stream.

Our quotations and the general facts in regard to the history of the bridges, where not otherwise accredited, are from a report of Col. J. Albert Monroe.

Three separate influences, therefore, urge a radical change in regard to the bridges which span the Pawtucket navigation at the mouth of the river. First, The injurious effect of the present structures, considered as obstructions, on the tidal flow, and the resulting evils, which we have endeavored to make manifest in our discussion of the tides. Second, The highly objectionable location of the draws, and Third, The fact that in the event of no change in the matter, the river is likely to be dropped from the consideration of the general government. The $52,000 appropriated by the United States during the past twelve years to its improvement and conservancy, do not measure the whole loss which the abandonment would entail; since the care of the government means the attention of the United States engineers and all that that implies.

Our examinations in regard to the tides and the bridges at the Seekonk river, have made it clear to us that the interests of navigation require a radical change in the present conditions, which change would involve the removal of the dilapidated Washington bridge with its piers and foundations, and the dredging of deeper water-ways between the piers of the railroad bridge and of Red bridge. It would be hopeless to attempt much improvement at Washington bridge without the removal of that structure, which is as nearly worthless as a bridge used for public travel can well be. There would be great advantage in building, in a new location, a double-deck bridge, suited to the railroad traffic and the highway travel, on the same foundations; but, if this should prove impracticable, it is our present impression that the channel under the railroad bridge can be so improved as to give substantial relief from the present disadvantages without disturbing the structure as it stands. We have a similar opinion in regard to the

water-ways at Red bridge, and we understand that the engineer in charge of the recent reconstruction agrees with this.

The number of vessels passing through the draw of Red bridge, on the way to and from Pawtucket, is about sixteen hundred or more per year. When business was more active the number was greater. We have made no detailed estimates of the cost of the above mentioned improvements, but we are satisfied that the expense would be far less than the resulting value.

SURVEYS.

During the past year such surveys as were necessary to enable the commissioners to decide on the extent of encroachments into the harbor, and to design and locate the harbor lines proposed by them, have been made. As stated above these lines have been referred to the United States coast survey stations. To make the significance and value of this more evident, it may be well to explain that in carrying the triangulation system along the shores of the bay, the coast survey have established stations in a manner as nearly permanent as may be, the locations of which stations, in their system, forms part of the archives at Washington. It seemed to the board, therefore, that reference to these stations, provided more thoroughly for the contingency of lost land-marks than any other plan as inexpensive in its methods.

Beside this surveying of lines, quite extensive leveling operations have been carried on, with the object of establishing a common plane of reference, which it is hoped each of the three parties interested in the harbor, viz: the United States engineer department, the coast survey and the city of Providence, may agree to adopt for a plane of reference for future work. Hitherto each party has been working with a special base, and it is desirable, for the proper comparison of tidal observations or soundings, for example, made by each, that agreement in respect to a plane of reference should be brought about.

PAWCATUCK RIVER NEAR WESTERLY.

The attention of the board has been called to the need of some action on the part of the State, in regard to the construction of

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wharves in the Pawcatuck river near Westerly, and a definition of their limits, if a fair degree of convenience in the navigation of the channel is to be preserved. This locality is not within the limits of the jurisdiction of this board, but the importance of the matter to the locality named seems to demand this refence to it on our part.

WORK OF THE UNITED STATES ENGINEER.

By the courtesy of Gen. G. K. Warren, the board has received a printed copy of his report upon the government works under his charge in Rhode Island, for the year ending June 30, 1878. The following is a brief summary from the report of the Chief of Engineers in regard to the work upon which Gen. Warren's report in full will be found in the appendix:

Pawtucket or Seekonk River, Rhode Island.

No work has been done during the fiscal year, and none will be done this season, unless the shoals become troublesome or the channel is accidentally obstructed.

Providence River and Narragansett Bay, Rhode Island.

The project for this improvement consists in making a wide channel, with a ceutral depth of 23 feet at mean low water, from Providence to the sea, at an estimated cost of about $500,000.

The present ruling depth is about fourteen feet, the mean rise of the tide being about 4.7 feet.

It is proposed to expend the appropriation of $50,000 made by the act of June 18, 1878, in dredging a channel 23 feet deep at mean lowwater, to such width as the means at hand will allow-not exceeding, however, 200 feet.

The appropriation of $5,000 contained in the same act for the removal of Bulkhead rock in this river, is insufficient for its removal to the required depth (23 feet), and it is proposed to reserve it until a further appropriation is made for continuing the improvement of the river, when its removal may be undertaken.

The amount required for continuing the improvement during the next fiscal year is $100,000.

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