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The necessary preliminary steps to a utilization of the creek would be the rebuilding of the bridges as draw-bridges, and the diking of both banks of the stream where necessary to confine its waters.

Until these works shall have been at least begun, no other measure for the improvement of the navigation would seem to be required, for which reason no estimates are submitted. Very respectfully, your obedient servant,

WILLIAM LUDLOW,
Captain of Engineers,

But. Lieut Col., U. S. A. The CHIEF OF ENGINEERS, C. S. A.

F 26.

EXAMINATION OF MANTUA CREEK, GLOUCESTER COUNTY, NEW JERSEY,

FROM DELAWARE RIVER TO HEAD OF NAVIGATION.

UNITED STATES ENGINEER OFFICE,

Philadelphia, Pa., February 20, 1882. SIR: The following report and accompanying papers on the examination of Mantua Creek, Gloucester County, New Jersey, are submitted in compliance with the requirements of the river and harbor act of March 3, 1881.

The general outlines and topographical features of the stream were obtained from the best available printed maps, but the hydrographic conditions were personally ascertained by Mr. Gieseler, assistant engineer, whose report is appended.

Mantua Creek discharges into the Delaware River about 3 miles below League Island. The upper limit of navigation is at Mautua, about 11 miles from the mouth, and the intermediate towns of Paulsborough and Berkley mark both the natural limits of sections of equal length and the points of successive diminutions in the navigable depths.

In the lowest section the 9-foot low-water curve is nearly continuous; in the middle section the 6-foot curve predominates; this depth decreasing in the upper section to 4 feet, and finally, at Mantua, to 2 feet.

The velocity of the tidal wave in the successive sections is represented by the same figures in miles per hour, and the rise of 6 feet at the mouth, due to the Delaware tides, is likewise reduced to 2 feet at Mantua.

The stream is characteristic in its tendency to follow the line of the fast land, and to excessive curvature when relieved from that control and flowing between marsh banks.

For the improvement of the navigation, a channel should be dredged with a low-water depth and width of 10 by 80 feet at the mouth, diminishing to 4 by 40 feet at Mantua.

The material to be removed is sand and mud, and in amount about 90,000 cubic yards.

With suitable appliances the cost of the work should not exceed $25,000, but the estimate must be increased to $35,000 to conform to the present prices of dredging under contract.

The existence of permanent bridges across the stream near Berkley makes that point the head of navigation for masted vessels, and may interfere with dredging operations above. In this case the estimate for the construction of the channel from Berkley to the Delaware will be the removal of 70,000 cubic yards, at a cost of about $27,000.

If, on account of the predominating traffic from Paulsborough down, as shown in the commercial statistics, the improvement should stop there, the cost would be $17,000 to $18,000. Respectfully submitted.

WILLIAM LUDLOW,
Captain of Engineers,

But. Lieut. Col., U. S. A. The CHIEF OF ENGINEERS, U. S. A.

REPORT OF MR. E. A. GIESELER, ASSISTANT ENGINEER.

UNITED STATES ENGINEER OFFICE,

Philadelphia, Pa., February 17, 1882. COLONEL: I have the honor to report as follows upon the examination of Mantua Creek, New Jersey.

The examination extended over that part of the creek lying between the mouth and the head of navigation at Mantua, a distance of about li miles, as measured on the water.

A small amount only of money being available, it was decided to direct the field work towards the collection of hydrographic data only, and to rely on the chart of the creek contained in J. M. Hopkins's "Atlas of Philadelphia and Environs" for the necessary topographical elements. The field-work was executed between the 10th and 18th of August, 1881.

Partly from the fact that the mouth of the creek was not fully shown in the abovedamed atlas, partly from the fact that the main obstruction at this place was a bar lying out in the Delaware, the contours of which could only be determined by the aid of instrumental observations, it became necessary to make a survey of the mouth and its vicinity, the results of which are shown in detail No. 1 of sheet No. 2 of the chart.

The rest of the creek was examined by sounding cross-lines at suitable distances, which were located on the map by ineans of the general topographical formation. Wherever a line was sounded across the creek, the width between high-water marks was also taken. The existing shoals were exammed carefully, a sufficient number of soundings being taken on each to develop their contours.

Four țide gauges were established in the creek, one near the mouth, one at Paulsborough, one at Berkley, and one at Mantua; and mean rise and fall at these places was computed at 5.8 feet for the mouth, at 5.1 feet for Paulsborough, at 4 feet for Berkley, and at 2 feet for Mantua.

The duration of rise is about four and a half hours, and the duration of fall is about eight hours at the mouth, and from these figures there does not appear to be any material deviation at any point of the creek.

Both the high-water and the low-water traverse the distance from the mouth to Mantua in about three hours, and the motion in both cases is a retarded one, the first 3 miles being traversed in about twenty minutes, the next 3 miles in about forty-five minutes, and the last 5 miles in a little less than two hours.

The means available for the examination admitted of only a limited number of tidal observations being taken. From these—not sufficient in themselves to furnish independent results of value—the tidal data were computed by comparing them with simultaneous observations taken on the standard gauge at Fort Mifflin, on the opposite shore of the Delaware. In the upper parts of the creek, which are farther removed from the Delaware, the tidal conditions naturally are to a greater extent influenced by local causes and to a lesser extent dependent on the fluctuations of the tidal wave in the Delaware. The latter, however, forming the basis on which the abovegiven data have been computed, it follows that those for Berkley and Mantua are not as reliable as those for the mouth and for Paulsborough.

The general direction of the creek is a north-northwest one. The banks for the greater part consist of low-lying meadows, which are all embanked. In many places, however, the banks are formed of high ground, low hills, and bluffs.

Besides numerous farmis, there are three populous settlements on the banks of the creek, viz, Paulsborough, with about 1,500 inhabitants; Berkley, with about 800; and Mantua, with about 1,000. Both Paulsborough and Berkley are reached by railroads. From and to these places there is a considerable trade in lumber, coal, manure, bricks, lime, and farm products.

Near the mouth are situated the phosphate works of Coe & Richmond, an extensive establishment with important transatlantic and Southern trade.

About twenty vessels, aggregating 1,500 to 2,000 tons, and two steam-tugs, are owned on the creek.

In a subjoined table will be found in a condensed form carefully collected figures and data concerning these matters.

The creek is crossed by five bridges, namely, two at Paulsborough, two at Berkley, and one at Mantua. Two of these, one at Paulsborough and one at Berkley, are rail. road bridges; the other three are turnpike bridges. The two bridges at Paulsborough are draw-bridges, with openings of 35 and 40 feet. The three upper bridges are permanent, the last one, at Mantua, being at the head of navigation.

The obstructions to navigation commence at the month, a bar with 8 feet maximum low-water depth closing the channel, wbich in the creek shows 10 and 12 feet of water. A little below Richmond's dock the depth is again diminished to 8 feet, and so at present the large schooners that carry the trade of the phosphate works cannot as a rule

enter the creek, but have partially to load and unload outside the bar. From Richmond's up to Paulsborough there is at present a 6-foot low-water channel which, if it were clear and unobstructed, would answer almost all purposes, nothing drawing more than 9 feet going up to Paulsborough. But this channel is narrow and tortuous in many places, and notably so at three points given on the detail-sheet, viz, in Long Reach, in Susie's Reach, and in Gravel Reach.

From Paulsborough to Berkley the trade is carried by craft under 64 feet draught, and these vessels find their way easily up to Mulford's Reach, a little below Hoffman's dock. There a gradual and general shoaling up of the creek commences, and on reaching Mantua we find little more than 2 feet of water at low-water. At the same time it must be remembered that the two permanent bridges at Berkley (which are 12 feet high in the clear at low-water) do not allow the passage of anything that cannot strike its mast, and consequently the upper trade is carried by canal-boats and small sloops drawing only, say, up to 5 feet of water.

A channel 80 feet wide at the bottom and 10 feet deep, with side slopes of 1 on 4, as far up as Richmond's, would necessitate the removal of 26,000 cubic yards of sand and mud; a channel 75 'feet wide and 7 feet deep from Richmond's to Paulsborough would necessitate the removal of 20,000 cubic yards sand and mud; a channel 50 feet wide and 6 feet deep from Paulsborongh to Berkley would necessitate the removal of 23,000 cubic yards of sand and mud, and a channel 40 feet wide and 4 feet deep from Berkley to Mantua would necessitate the removal of 20,000 cubic yards of sand and mud.

Putting the prices for dredging at, respectively, 35 cents per cubic yards for the mouth and 40 cents aboveThe cost for the improvement from the mouth to Richmond's would be

$9, 100 Richmond's to Paulsborongh. Paulsborough to Berkley Berkley to Mantua .

Representing a total of ..

8,000 9, 200 8,000

....

34,300

BRIDGES SPANNING THE CREEK. Paulsborough:

1. Delaware Shore Railroad Bridge, draw with 35-foot opening.

2. Crown Point Road Bridge, draw with 40-foot opening. Berkley :

3. Swedesborough Turnpike Bridge, permanent, 26-foot span, 12-foot clear height.

4. Swedesborough Railroad Bridge, permanent, 25-foot span, 12-foot clear height. Mantua :

5. Mullican Hill Turnpike Bridge, permanent.

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SURVEY OF MAURICE RIVER FROM DELAWARE BAY TO MILLVILLE, CUM

BERLAND COUNTY, NEW JERSEY.
UNITED STATES ENGINEER OFFICE,

Philadelphia, Pa., February 3, 1882. SIR: I have the honor to make the following report on the survey of Maurice River, New Jersey, called for in the act of March 3, 1881.

The report by Mr. Gieseler, assistant engineer, who had charge of the field-work, and his chart, in three sheets, drawn to a scale of 500 feet to the inch, are submitted herewith.

Maurice River is one of the largest streams in Southern New Jersey. It drains an area of about 400 square miles, covering the greater part of Cumberland County, with portions of the bordering counties of Salem, Gloucester, and Atlantic, and discharges southward into Delaware Bay, through Maurice River Cove, which occupies the upper part of the notable widening of the bay just inside of the capes.

Several thriving towns are built upon the banks of the river, anıl Millville, at the head of navigation, distant from the mouth 13 or 14 miles in a straight line and 24 miles by water, is a prosperous manufacturing center, with a population of 8,000.

Between Millville and Mauricetown, which is half way to the bay, the stream has a tolerably direct course southward and eastward, with upland, sometimes bold, shores and moderate expanses of meadow.

For about 4 miles below Millville the navigation is much obstructed, the low-water channel depth varying from 2 to 10 feet, the low-water widths from 200 to 400 feet, and the high-water widths from 300 to 800 feet.

Near “Ferguson's" the 6-foot low-water channel becomes a permanent feature, with a gradually increasing width, and soon after, the 10-foot low-water curve also becomes continuous thence to the mouth.

Below Mauricetown the margins of the fast land recede, both banks are level and liable to overflow unless protected by dikes, and the tor. tuous channel, with general direction to the south ward and westward, traverses broad expanses of salt meadow.

Port Norris, on the limit of the fast land, is about 3 miles from the bay.

The river in its lower section varies from 500 to 1,000 feet in width, with channel depths in excess of 10 feet, and long stretches of 20 feet and over. Soon after emerging into Maurice River Cove the 10-foot curve closes, and then the 6-foot, leaving an available depth of entrance of about 5 feet at low-water.

The rise of tide at the entrance is 6.1 feet, reduced at Millville to 5.2 feet, and the tidal wave traverses the 24 miles in two and one-half hour.i, with an average velocity of 9.6 miles per hour.

The obstructions to navigation are confined to the approach from Delaware Bay through the cove and to the upper 4 miles below Mill. ville. The shoaling in this latter section, shown in sheet 1 of the chart, is probably due mainly to the washings from streets and other drainage, combined with imperfect attempts at channel improvement by the city.

Mr. Gieseler's estimate to make a 6-foot low-water navigation, with channel width to Millville of 100 feet, and for a short distance along the city front above the bridge a 4-foot navigation, putting the cost of dredg. ing at 35 cents per cubic yard, is $112,000.

The dredgings can be disposed of to advantage by depositing them above the low-water mark in those enlargements

of the river where the width is excessive.

The broken lines on the chart indicate, in part, what should be the position of the high-water banks, in order to better the hydraulic conditions and give comparative permanence to the improvement. The cutting off of the peninsula near Silver Run appears to be quite pecessary for a good navigation, and this involves a readjustment of adjacent shore-lines.

The Riparian Commissioners of the State of New Jersey have drawn lines of solid filling for the entire length of the navigable part of Maurice River, and since the attainment and future maintenance of a satisfactory navigation depend, in great measure, upou a proper regulation of the stream by means of a judicious adjustment of the shore and wharf lines, modifications in the location of the commissioners' lines, which at present follow rather closely the lines of low-water, will be necessary at several points.

According to Mr. Gieseler's data the tidal volume of Maurice River is to the fresh-water volume as 500 to 20, or as 25 to 1. The navigable section should, therefore, be regarded and treated as almost purely tidal. Such being the case, the areas between high and low water limits are the tidal reservoirs for all parts of the river below, and excessive encroachments upon them by the undue projection of the lines of solid filling will involve certain loss of tidal volume, with a corresponding loss of capacity for maintenance. To advance the high-water banks so far into the stream as the low-water marks would not only perpetuate existing unfavorable conditions, but would permanently reduce the tidal volume of the stream, which is the main source of power, by from 25 to 30 per cent., and a corresponding loss of depth would inevitably result. This loss of depth, by obstructing the tidal flow, would again react upon the tidal volume, with additional diminution of both elements. It is evident, in fact, that were the high-water banks to be continually advanced to the low-water mark for the whole length of the stream, the river from loss of width and depth would gradually become non-tidal, the head of navigation would constantly approach the mouth, and ultimately the cross-section would shrink to little more than that due to the fresh-water flow.

The proper regulatiou of the high-water banks is therefore an extremely important element, and should be based upon broad engineering and not upon inerely local considerations. Correcting both excessive enlargements and contractions, they should be held apart, with a gradnal approach upstream, and be so drawn as to secure a uniform flow, avoiding angles and sharp turns.

The tendency with riparian owners wishing to secure a landing is to build out to such depth as may be required, without reference to any other consideration. There would be no objection to such an extension

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