[The Seventeenth, Eighteenth, and Nineteenth Annual Reports of the Board of Public Works to the General Assembly of Virginia… 7 (Richmond, 1835): 414-431:]
…the probable trade of the South Anna river…. from the best information which could be procured[:]
200,000 bushels of wheat, or its equivalent in manufactured flour, from between the Green springs and Rocky mills [about a mile west of the future site of the U.S. Route 33 bridge over the South Anna River--the intersection in 1835 of the South Anna River with a proposed railroad], 5178 tons.
1,000 hogsheads of tobacco, from Louisa and Orange counties, 625 [tons]
Staves, heading, hoop poles, boards, plank and miscellaneous freight, 597 [tons]
Return [ascending/upriver-bound] freight, amounting to one-third of the descending, 2133 [tons]
Total annual tonnage, 8533
This, for a season of 200 days, would be, per diem, 32 tons descending and 10 ascending.
[proposal for construction:] To provide for this trade, the river being narrow, the fall small, and the banks generally bold, a slack water navigation is proposed, the dams to be of variable height according to circumstances not yet correctly ascertained, such as the damage, if any, to low grounds, which would require a system of low dams—the comparative advantages, (for the purpose of obtaining sufficient depth in the refluent water at the head of each pond,) of excavating from the tail of the locks in the river bottom, or giving additional height to the dam next below—another consideration would be, the more advantageous application of water power from the adoption of high in preference to low dams.
This investigation is postponed for the present, as not necessary to shew, as will be done from data in actual possession, that the work is advisable in itself as a scheme of undoubted profit, as well as indispensable to any connection by rail-road with the James river.
The locks for which estimates have been made are on a cheap plan of construction, as most suitable to the present condition of the trade.
A floor of plank, supported on hewn logs, should extend under the entire chamber and side walls, projecting outside of the latter one foot—each side wall to be formed by two parallel walls of hewn timber one foot thick, connected with cross ties and braces, filled at the bottom with rubble and grout, but above the permanent water line with puddle, which will both be cheaper than a rubble stone filling, and will answer the further purpose of saving a lining of plank to the lock chamber. The locks should be constructed, like those invented by Canvas White of New York, with an inclined plane from the bottom of the upper reach to the foot of the grooves for the stop planks, dispensing with the breast wall, and having the upper and lower gates of equal height: this plan gives opportunity more speedily to fill the locks, without disturbance to a boat within or damage to the freight, and saves an expensive and inconvenient part of the structure.
Such locks, with chambers 80 feet long and 8 wide, having a lift of 8 feet and permanent depth of 4, with single gates similar to those delineated in Strickland's reports, and in use on the Birmingham and Liverpool canal, can be made for $1000, or $125 the foot lift.
Dams, it is proposed to build either of stone where convenient, or of hewn logs, united with ties, filled with rubble, and sheeted over with plank. $300 per dam, averaging low and high, will be an ample estimate.
The damage to manufacturing interests, from the use of the river water for the navigation, would be inconsiderable, even were the trade to attain such activity as to keep the locks in constant use, while the leases of water power would form a handsome addition to the revenue of the work. That resource has not, however, been calculated upon in the estimate. A lock chamber of the before described dimensions will contain a fall of 5120 cubic feet of water. A wicket of 3 feet wide and 1 foot depth, 1 foot from the bottom of the gate, would discharge per minute, into free space, 3430 feet—but from the reacting pressure as the lock fills, but half the quantity in the same time. From which it is apparent that the lock could be filled in rather more than 3 minutes, and that the passage of a boat could be effected in 5 minutes.
[evaluation of navigation system’s eastern terminus and connection with a potential, southward railroad at Bowles’s Factory or with a potential, southward railroad at Rocky Mills:] The South Anna was guaged, when nearly at its lowest, at the Rocky mills [about a mile west of the future site of the U.S. Route 33 bridge over the South Anna River] and Bowles's factory [near the future site of the Louisa Route 635/Factory Mills Road bridge over the South Anna River, and 12 miles west of Rocky Mills by river], and taking but 3-5 of the surface velocity, (instead of 4-5 as usual,) to make allowance for eddies, the mean of the guagings was 52.8 feet per second, or 3168 feet per minute: deducting 1715 feet per minute, (during the filling of a lock,) there would remain 1453 feet per minute, or more than 24 feet per second, running over the dam. At each dam there would be sufficient water to turn between 3 and 4 pairs of 5 feet burrs, and manufacture per day more than 100 barrels of flour.
The use, which has been politely accorded, of the field notes of a levelling and survey of the South Anna river from Mumford's bridge [future site of the Poindexter Road/Louisa Route 613 bridge over the South Anna River in the Green Springs National Historic Landmark District] to Bowles's factory, made at private expense [possibly for the Richmond Rail-Road and South Anna Navigation Company], furnishes the means of determining the cost of improving the navigation. The fall between those two points, which are distant from each other by the river 51 miles, is 125 feet, 69 of which are now occupied by dams, leaving 56 feet to be yet overcome.
An estimate for the improvement will be as follows, viz:
The whole lockage, 116 feet, at $125 the foot lift, will cost 15,625
7 dams, at $300 each, will cost 2,100
Short canals for 8 out of 16 dams, at $5 per linear yard, for 100 yards each, will cost 4,000
Whole cost, $21,725
N. B. The last item will include excavation of lock pits.
No examination was made between Bowles's factory and the Rocky mills, a distance of about 12 miles; but the fall, as determined by references to the canal and to tide water, is 22 1/4 feet; which, at $125, would cost $2,781 for locks—and adding $ 900 for 3 dams, the river, it would seem, can be improved between the two points for $3,681—and the whole improvement could then be made for $25,406—and adding for contingencies 10 per cent., the cost would be $27,946, on which the annual interest at 5 per cent. will be $1,397 30.
A trade such as was first hoped for would have authorized the subduing of obstacles, which, for the trade of the South Anna alone, could be but partially attempted. Under existing circumstances, the only eligible way for a rail-road, and the one which will without doubt afford the cheapest accommodation to the trade, is that now to be described.
Bowles's factory is about 12 miles above the Rocky mills: the fall being only 22 feet, which can easily be overcome with 3 locks, no doubt can be entertained that the very small quantity of produce from below the factory will ascend a part if not the whole of the distance.
Any rail-road…to become profitable, must be connected in one financial scheme with the South Anna navigation, as even this, by far the most eligible route, could scarcely, at the low estimate assumed for the South Anna trade, sustain itself without balancing its own deficiencies with the undoubted profits of the river improvement. It is confidently believed that the South Anna improvement will, at no distant day, be at least as valuable as that of the Upper Appomattox in the most favorable seasons, upon which the tolls have varied between $1,500 and $5,000 per annum, to speak in round numbers.
An important advantage possessed by [a] Bowles's factory[-connecting railroad] route over all the other routes examined is, its remarkable suitability for the use of gravity as a propelling power [on the railroad].
[competition from or alternative connections to railroads other than those potentially connecting to the navigation system at Bowles’s Factory or Rocky Mills:] The last subject for consideration is the probability of competition by rival improvements for the trade of the South Anna.
This resolves itself into a general proposition at once. In a transportation of a mixed character, as regards the mode of conveyance, (such as would be the case equally were the improvement of the river extended down[river from Rocky Mills] to the Fredericksburg rail-road [the Richmond, Fredericksburg and Potomac Railroad, then under construction north from Richmond toward Fredericksburg],) that will ever be the cheapest conveyance where the larger proportion is of water transportation, and always to be preferred for articles like wheat and tobacco, not subject to very rapid fluctuations in value. For the article of flour, a rail-road might sometimes command a preference over other modes; but that would be but occasionally, and as the bulk of the trade will consist of unmanufactured articles of stable value, the transportation could not be forced to take the way of a rail-road, were there one constructed on the ridge between the North and South Anna rivers, as has been spoken of [likely a proposal for what became the Louisa Railroad, which would be chartered and under construction in 1836], without a most unnecessary and injurious tax upon the industry of producers. That such a rail-road may become necessary for the accommodation of the travelling interest, is possible, but it is by no means to be apprehended that its competition will have any effect upon the trade of the river.
The question, whether the trade of the South Anna might not be better accommodated by an extension of the improvement to the Richmond and Fredericksburg rail-road, may, upon the principle just enunciated, be briefly answered thus: From Bowles's factory to Rocky mills, the fall is 22 ¼ feet, and thence to tide 163 feet, making 185 ¼ feet altogether. The water of the South Anna, at the crossing of the Richmond and Fredericksburg rail-road [north of the future site of Ashland], is believed to be (though the statement is made only from memory of a conversation with the assistant engineer on that work,) 50 feet above tide, leaving for the entire fall of the South Anna, between Bowles's factory and that rail-road, 135 feet in a distance of about 24 miles.
The improvement of the river by locks and dams would then cost…. exclusive of contingencies, $25,975.
Exceeding by more than $4,000 the cost of the 51 miles above the factory.
The cost of the lower improvement [of the South Anna from Bowles’s Factory to the crossing of the Richmond, Fredericksburg and Potomac Railroad] would necessarily double the tolls on the river without a single remunerating benefit.
In concluding this report, the improvement of the South Anna and the Bowles's factory[-connecting] rail-road, are recommended in preference to all the other ways enumerated….
CHAS. B. SHAW,
Principal Engineer [, Virginia Board of Public Works].
Richmond, 16th March, 1835.
[Abstract selection and notation by Noel G. Harrison, NPS]