aring the fiscal year ending June 30, 1888, the excavation and paving of the resoir has been completed, except in the gate-house recess, and no work can there be dertaken until lining in the heading from the east shaft of the tunnel has been pleted and the cages employed in hoisting material have been removed. he work of lining the tunnel was continued with a small force until September when operations were suspended on account of a lack of funds. As the worst k encountered had been lined, the tunnel was allowed to fill with water, not only m motives of economy, but also to test the strength of the lining already conucted. In the general deficiency bill approved March 30, 1833, Congress approated $355,000 to complete the lining of the tunnel, etc., with the proviso that the rk should be finished November 1, 1888. The water was then pumped out and work as resumed, but it was not until the end of May that the building of the masonry h could be actively commenced. During the year 3,959 5 linear feet of the tunnel were lined with brick and rubble sonry, of which nearly one-third (1,186 feet) were constructed during the month of ne. The total length of the tunnel lined is 10,069.5 feet. There remains to be ed 10,626.8 feet. The following table shows the location of the various lined sections of the tunnel, e numbers under the heading "Class of lining" referring to the cross-sections subitted herewith: Note.-Brick-work of 4 rings was used in west heading Champlain avenue shaft between stations 815-846, 867-1050, 1390-1440. A 3-ring invert was built from 815-846. About 2,100 feet have been enlarged for lining and 379 feet of side-walls constructed. As will be seen from the above method of lining the tunnel has been materially modified from time to time. The reasons for the change from dry-stone packing to a filling of rubble masonry have been fully explained in preceding reports. In the sections in which the invert is omitted there is no danger of the rock decomposit to an extent sufficient to endanger the stability of the side-walls, and the duty of th lining is merely to hold the rock in place. Section 4 is employed in rock consider solid enough to resist the pressure of water, and is introduced as a precautionar measure to prevent any possibility of the roof caving in. If the tunnel could readily be emptied from time to time, it might have been a visable to have left these sections unlined, but the time necessary to pump out t water and make any repairs will be so long, and the discomfort to the citizens of Was ington during that interval so great, that a reasonable expenditure should bems. to reduce the chances of accident to a minimum. In this connection the recori the pumping out of the tunnel when work was resumed is submitted. The paz: employed were four Knowles's mining pumps, cylinders 10 inches and 6 inches, lengof stroke, 12 inches, and one Cameron pump of corresponding size. Pumping commenced at Rock Creek shaft with two pumps, March 26. At the east shaft with one pump, March 28. At Foundry Branch shaft with one pump, March 29. At Champlain avenue shaft with one pump, April 6. Foundry Branch shaft was cleared of water April 13; Rock Creek shaft, April 2 Champlain avenue, May 3; east shaft, May 16. The extra pump at Rock Creek was transferred to the east shaft when the wate in the former shaft had been reduced to a depth of 6 feet. The tunnel filled will water until it flowed out at Rock Creek in about one and one-half months. The work will be vigorously prosecuted during the next fiscal year, but as it w not be completed on the 1st of November, as directed by act of Congress, it seem proper to explain fully the reasons therefor. In previous years the course had been adopted of lining those sections of the to... nel in which the rock was bad, with the intention of leaving a large portion unlite. and the lining was therefore very irregularly distributed in the different heading Thus in the west headings, from Champlain avenue and the east shafts, the wh was nearly completed, while in the east heading from Foundry Branch no masour had been laid. In the bill approved March 30, 1888, the lining of the entire tunnel is authoriz The time necessary to complete the work now becomes a function of the rate of proce ress in the longest unlined heading. The operations of breaking down the rock to large the tunnel for lining, and of laying the brick and rubble masonry, can be car ried on simultaneously at many points, so that the rate of progress is limited only the removal of the blasted rock and the introduction of brick and cement. By t substitution of rubble side-walls for brick, the work of hauling the material is expe dited, as less stone is removed from the tunnel and less brick brought into it. Onl small force, however, can be used in loading the rock in cars, due to the small wid. of the tunnel, and it is found that, working continuously, the muck can be removed a rate of but 20 feet per day when near the shaft. After the tunnel is lined the bot tom must be cleaned and the tracks removed; the timbering in the working shaf must then be taken out and the shafts filled up. To complete the work in the tir specified is therefore an impossibility. The attention of Congress should be called: this subject, as the proviso would appear to make the expenditure of the funds appro priated unlawful if the work is not completed at the time specified. Very respectfully, your obedient servant, C. McD. TOWNSEND. Y Y 3. ERECTION OF FISH-WAYS AT GREAT FALLS OF THE POTOMAC. No work has been in progress on the fish-ways during the past fiscal year, the balance of appropriation ($5,634.82) being insufficient for any useful work. Congress has, however, at its recent session appropriated $25,000 for their completion, and the United States Commissioner of Fisheries, after having caused certain preliminary surveys to be made during the months of May and June, is now engaged in the preparation of plans for carrying on the work. It remains to be determimed whether this office is to have any further part or responsibility in the execution of the proposed work, this question being now pending in the War Department on my recommendation that the entire charge and responsibility are more properly vested in the office of the United States Commissioner of Fish and Fisheries. In the mean time I have been directed to pay the expenses of the recent surveys, and bills to the amount of $435.50 have been rendered on account of work done to June 30, 1888. The original appropriation for the work was $50,000, of which there had been expended prior to June 30, 1888, the sum of $44,365.18, leav $5,634.82 as the balance then available. The money statement for the year ending June 30, 1888, is as follows: July 1, 1888, amount available $5,634.82 Amount appropriated by act of February 1, 1888.. 25,000.00 30, 634.82 July 1, 1888, amount expended during the fiscal year.. $000.00 435.50 July 1, 1888, balance available No estimate for further appropriation submitted. 435.50 30, 199.32 |