would be of great benefit to commerce; and its construction would be justified if a suitable location can be found where it can be formed at reasonable expense.

The act of Congress as to this harbor of refuge requires it to be one for deepdraft vessels. The great draft of such vessels of to-day, and the up and down motion, and swing of such vessels under heavy wave action, make ample depth and anchorage capacity essential features of the desired harbor of refuge in this bay. It should be near the main channel and easily accessible at all times and in all weather, and should shelter vessels from the prevailing storm winds, blowing from east to northwest round by the north, and protect them from floating ice descending from the northwest and north.

The information at present in the possession of the Commission points to the deepwater pocket on the west side of the main ship channel covered by the shoal, known as the Shears, as the best one for satisfying the required conditions. This position is now a favorite anchorage, is very conveniently located for communication with the shore, the existing harbor, and the channel, and is believed to have the approval of the maritime interests.

A definite decision upon this question should, in the opinion of the Commission, be postponed until after a detailed survey which shall show the present condition (both as to depth and area) of the above-mentioned deep-water pocket, and which shall also show the recent changes in the bottom of the bay in this neighborhood.

Under the authority of the Department, the Commission had a detailed survey made of the Shears and the adjacent deep-water spaces. Owing to the exposure of the locality, to very unfavorable weather, and to lack of sufficient funds to prosecute the work to the best advantage, the survey was made with great difficulty; and, although commenced as soon as practicable and prosecuted as diligently as allowed by cir cumstances, the fieldwork of the survey was not completed until late in the summer, during September, 1891. The survey covers an area of about 6 square miles, and contains about 7,000 soundings, about 3,500 of which were located by triangulation. The principal results are shown upon the map accompanying this report.* No borings were made, but all information so far collected indicates that the bottom consists of sand and mud, and furnishes a suitable foundation for breakwater construction, and a good holding ground for ships.

Comparisons of this survey with the engineer survey of 1881 and with the coast survey chart of 1843 show no changes in the bottom of the bay around the east fork of the Shears and nothing but unimpor tant changes at and around its west fork.

The Commission is of the opinion that the area occupied by the Shears and adjacent waters is "the best site near the mouth of Delaware Bay for a national harbor of refuge suitable for deep draft vessels." It is proposed to form the harbor by the construction of a breakwater located upon the line of least depth along the eastern branch of the Shears, as shown upon the accompanying map.

The heaviest winds and seas in this locality are from the east-northeast. The breakwater is extended as far towards the northwest as in the opinion of the Commission is necessary for sufficient protection against the heavy northeast winds and seas coming around the end of Cape May. From this point it extends in a southeast direction for a distance of 1 mile, and then, for a distance of half a mile, runs in a direction towards and tangent to Cape Henlopen; being extended as far towards the south as is thought best at present, considering the desira bility of allowing a free access to the proposed harbor. Against the heaviest storms, those from the east-northeast, the projected harbor has a protected anchorage area of 552 acres, with a minimum low-water depth of 30 feet; and an additional area of 237 acres, with a minimum low-water depth of 24 feet; this being sufficient to give free and good anchorage to more than a thousand vessels at once. As the proposed

Not reprinted. Printed in House Ex. Doc. No. 112, Fifty-second Congress, first

session.

breakwater lies in the direction of the ebb currents, its construction is not liable to cause any undesirable changes in the adjacent shoals.

The Commission is of the opinion that it will be unnecessary to construct a breakwater to cover the anchorage from northwesterly winds and seas, but protection from ice descending the bay during the ebb tide must be provided for. This can be accomplished by the construction of a row of ice piers across the upper end of the harbor, as shown on the accompanying map.

One of the important characteristics of a harbor of refuge is that it be capable of defense. While this Commission is not charged with the duty of arranging for the defense of the harbor of refuge now under consideration, it seems not inappropriate to say that the locality of the protecting ice piers could with unusual advatage be utilized for purposes of defense in connection with the objects of the harbor of refuge.

After full consideration of all the recent methods employed in breakwater construction, including the use of concrete in place, in bags, and in blocks of very large dimensions, the Commission is of the opinion that the method best adapted to this locality is the formation of a mound to the level of low water by the deposit of random stone and the construction of a superstructure thereon by the erection of outer and inner walls of very heavy stones, the interior space to be filled with rubble. This method of construction is in accord with the experience gained from past work on the old breakwaters in this vicinity. For the purposes of this project and estimate the Commission has assumed the dimensions adopted for the work now in progress for closing the gap between the breakwater and ice-breaker of the existing harbor. The cross section is shown on the accompanying map.

In determining the quantity of stone required it is assumed that each cubic yard of settled enrockment will contain 1.25 gross tons, this relation being the result of the latest experience at this particular work. The cost of the construction of the proposed harbor is estimated as follows, being based upon the assumption that funds will be supplied as fast as they can be economically expended:

APPENDIX H.

IMPROVEMENT OF RIVERS AND HARBORS IN DELAWARE, AND ON EASTERN SHORE OF CHESAPEAKE BAY, MARYLAND AND VIRGINIA, AND OF INLAND WATER WAY FROM CHINCOTEAGUE BAY, VIRGINIA, TO DELAWARE BAY, DELAWARE.

REPORT OF WILLIAM F. SMITH, UNITED STATES AGENT, MAJOR OF ENGINEERS, U. S. ARMY, RETIRED, IN CHARGE, FOR THE FISCAL YEAR ENDING JUNE 30, 1892, WITH OTHER DOCUMENTS RELATING TO THE WORKS.

UNITED STATES ENGINEER OFFICE,
Wilmington, Del., July 9, 1892.

GENERAL: I have the honor to transmit herewith the annual report for the works of river and harbor improvement in my charge for the fiscal year ending June 30, 1892.

I was ably assisted during the year by Mr. A. Stierle, assistant engineer, in the prosecution of these works.

Very respectfully, your obedient servant,

Brig. Gen. THOMAS L. CASEY,

Chief of Engineers, U. S. A.

WM. F. SMITH,
United States Agent.

ENG 92

-60

945

H 1.

IMPROVEMENT OF WILMINGTON HARBOR, DELAWARE.

At the beginning of the fiscal year the contract with the Atlas Dredging Company, of Wilmington, Del., was still in force, operations having been begun on February 11, 1891. The contract was completed on August 14, 1891. The amount of material removed during the fiscal year was 67,645 cubic yards, which increased the length of the channel previously dredged 1,000 feet. The total amount removed under the contract was 302,985 cubic yards, resulting in an improved channel, 15 feet deep at mean low water and 150 feet wide at the bottom, from the Shellpot railroad bridge to the Pusey & Jones shipyard, a distance of 6,200 feet. The dredged material was mud and sand, principally the former, and was deposited in a cove of the Delaware River below Edgemoor.

The approved project of improvement is for a 15-foot low-water channel, 150 feet wide from the mouth of the Christiana River to the Rolling Mill wharf (4,750 feet above the outer end of the jetty), 100 feet wide from this wharf to the Delaware and Western Railroad bridge, and 75 feet wide from this bridge to the pulp works; also for a channel, 12 feet deep and 50 feet wide from the pulp works to the Delaware Railroad bridge, and for the construction of a jetty 1,740 feet long on the north side of the mouth of the river. The Board of Engineers, which recommended these improvements in 1881 estimated the total cost at $175,551. The construction of the jetty and dredging operations were begun the following year. On page 662, Annual Report of the Chief of Engineers for 1883, a revised estimate is given for the completion of the above project. This estimate increased the channel width of the whole section from the Rolling Mill wharf to the pulp works to 150 feet, and did not include the 12-foot channel previously estimated for from the pulp works to the Delaware Railroad bridge, the total cost being given at $191,384, exclusive of the expense of building the jetty, which was then nearly completed. A modification of the plan of the jetty was made and approved in 1884, providing for an additional height of 4 feet and an extension of 322 feet in length. The former work was done the following year.

Up to the year 1871 the General Government had at various times expended $32,356 in the improvement of Christiana River or Wilmington Harbor. Between the years 1871 and 1881 improvements were continued under a project for a 12-foot low-water channel from 100 to 200 feet wide, and $83,500 had been expended when the project was completed in the latter year. Under the project adopted in 1881 $201,404.66 have been expended, making a grand total of $317,260.66 at the close of the fiscal year ending June 30, 1892.

The commission on the improvement of this harbor, appointed by the Secretary of War in accordance with a provision of the river and harbor act of September 19, 1890, have made their report and plan for a permanent improvement of Wilmington Harbor. The report is printed on pages 1138-1159, Annual Report of the Chief of Engineers for 1891.

Wilmington is a port of entry and in the collection district of Delaware. The amount of revenue collected during the fiscal year ending June 30, 1892, is $10,533.75.