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VANCOUVER ISLAND.--Limnoria and Xylotrya are present and very destructive in the harbors of Ladysmith, Nanaimo, Nanoose, and Port Alberni, and appear to be growing more active in the last few years. Untreated fir piling has been destroyed in less than a year and preserva
TABULATION SHOWING MEANS OF IDENTIFICATION OF FOUR MARINE BORERS
COMMON TO THE PACIFIC COAST
Quter 3".... Mud Line.. Short, double-Brackish
polluted. Perimeter.. Low Tide. Small size 3432" High SalinHigh Tide. wide x 4" long, ity. Pol
flat,oval shape. luted or Sliding back Unpolluted "scales." Light translucent
oval shape. Salinity, or
Note-Where fresh water flows into salt water possibility of presence of marine borers is indicated by gathering of barnacles or common forms of molluscs on pile surface.
Pile surlace indication of Teredo and Xylotrya is difficult with naked eye, but minute en trance holes may be detected with magnifying glass.
MARINE BORERS AND LIFE OF CREOSOTED FIR PILING AT Various Pacific
Marine Borers Reported
Life of Creosoted
Xylotrya Vancouver Island.
Xylotrya Puget Sound.. Xylotrya Tillamook Bay.
Xylotrya Yaquina Bay
Xylotrya Coos Bay..
Teredo Navalis San Francisco Bay.. Xylotrya Teredo Diegensis San Pedro Bay.
Xylotrya Teredo Diegensis San Diego Bay.
Xylotrya Teredo Diegensis
tive methods have been in use for many years. Victoria harbor does not suffer as severely as those mentioned above because of the volume of fresh water flowing into it. It is in this vicinity that Australian turpentine piles have been used. After 14 years of service they are reported to have completely resisted the Xylotrya, and to hav allowed only a slight Limnoria surface action.
Puget SOUND.---The extensive lumber business of the Sound, together with the innumerable timber marine wharves built of untreated or imperfectly treated piling, have permitted the Limnoria and Xylotrya to establish themselves firmly at many points around this body of water. Tide and currents coupled with the great depth of water serve to reduce the element of local pollution, and to maintain a high, clear salinity, thus providing the most favorable condition for the marine borers. The infestation seems to have grown worse in recent years, and at present untreated fir piling will be destroyed in less than a year.
TILLAMOOK AND YAQUINA Bays.--Limnoria and Xylotrya are reported at both of these bays, but no definite data is available as to the degree of infestation.
Coos Bay.-Limnoria and Xylotrya are present in limited numbers, and their attack seems to fluctuate with lapses of comparative inactivity. The Southern Pacific Company has a structure here which contains creosoted fir and untreated cedar piling, the latter having been placed in 1912. These cedar piles consisted of sound “dead timber” cut from land which had been burned over by a forest fire. The balance were of freshly cut green timber. Recent inspection disclosed the interesting fact that the “dead timber” had been attacked, but that the green timbers were practically unaffected.
San Francisco Bay.This harbor has probably suffered the greatest inroads of marine borer attack of all on the Pacific Coast, and the subject has already been given widespread publicity in engineering publications.
Shipping activity and the harbor's peculiar geographical configuration have allowed the borers to become well established. San Francisco Bay and the adjoining San Pablo Bay have a total length of about 80 miles, with an average width of about 10 miles. The only inlet from the sea to this great body of water is through the narrow gate, and the result is that a tremendous current is created at the ebb tide. This current rushes by the whole San Francisco waterfront, thus causing extreme borer action, except where sewers pollute the water.
The water of the San Joaquin and Sacramento Rivers was formerly of sufficient volume to hold back the salt water from San Pablo Bay, and to prevent it from entering Carquinez Straits, but extensive agricultural development of the Sacramento Valley, including rice culture, and the years of slight rainfall, have served to reduce the amount of fresh water reaching the Straits. As a result, the water from the juncture of San Pablo Bay and the Straits, through Suisun Bay to the point where the above-mentioned rivers meet, a distance of about 25 miles, has become brackish. A great number of industrial wharves had been built within these limits, using untreated piling, and the resulting destruction from Teredo navalis and Sphaeroma has already run in millions of dollars. The activity of both borers give practically no surface indications, and the imminent danger was not realized until wharves and warehouses collapsed.
The condition of borer infestation on the east side of San Francisco Bay has been disclosed by investigation which attended the removal of the Old Long Wharf of the Southern Pacific Company in 1919. This wharf,
originally completed about 1871, consisted of five docks, A, B, C, D, and E, radiating from the approach pier, somewhat as the fingers of a hand, and was first built of untreated 'fir piling. By 1889 the borer action had become so severe that it was decided to re-drive the docks with creosote piles. This was carried out between the years 1890 to 1901, there being driven an estimated total of about 14,000 creosoted piles, a few of which had been treated at the Southern Pacific Company's temporary plant at San Pedro, and the balance at their permanent plant at Oakland.
Changes in the Oakland City waterfront necessitated the removal of the above wharf in 1919, and when this was done, a majority of the creosote piles were found to be sound and unaffected by marine borers. Replacements in the intervening period had been too small in number to be appreciable. The following tabulation reflects the results of inspection of the piling : Creosoted Piles in Dock A, Driven in 1890 :
Removal of piling completed before inspection was inaugurated : Thirty-three creosoted piles showed following condition :
Per cent. Sound, fit to redrive.....
22 66.67 Slightly attacked between low and high water. 6 18.18 Severely attacked, between low and high water.... 3 9.09 Completely destroyed, between low and high water.. 2 6.06 Total number examined
33 100 Creosoted Piles in Dock B, driven in 1898:
Removal of piling completed before inspection was inaugurated. Creosoted Piles in Dock C, Driven in 1897 :
Per cent. In sound condition, fit to redrive...
333 63.67 Severely attacked, between low and high water. 74 14.15 Completely destroyed, between low and high water. 116 22.18 Total number inspected
523 100 Creosoted Piles in Dock D, Driven in 1899 :
100 Creosoted Piles in Dock E, Driven in 1901 :
2,485 100 SUMMARY-Docks C, D and E.
All the sound piles were redriven elsewhere. There is no reason for believing that the Summary of Docks C, D and E would have been greatly affected had it been possible to include piles from Docks A and B. Hence it is likely that 75 per cent of the original creosoted piles are still in service. Attention is also called to the fact that many of those slightly attacked were redriven inshore, with the result that about 80 per cent. of the original total are still serving.
Investigations of the Dumbarton Cut-Off trestle of the Southern Pacific Company, at the extreme south end of the Bay, have disclosed the presence of Xylotrya, Teredo navalis, Limnoria and Sphaeroma.
Teredo diegensis has been found at only one point in the Bay, at the Schaw-Batcher ship yards, near South San Francisco, on the West side.
The foregoing briefly outlines the manner in which San Francisco Bay has become infested with five forms of marine borers, with conditions such that they can thrive and work severe damage. The brackish water at the north in Carquinez Straits and Saisun Bay is infested with Teredo navalis and Sphaeroma, and the water of San Francisco Bay proper, with high salinity, is infested by both of the above, together with Xylotrya, Limnoria and Teredo diegensis.
SAN PEDRO AND San Diego Bays.--Both of these harbors have suffered attacks of Xylotrya and Limnoria, with Teredo diegensis present in a minor degree. Test piles were driven at both places, including untreated piles, old creosoted piles from Long Wharf, and freshly creosoted piles. Those untreated have already been severely attacked by Limnoria, and one of the Long Wharf piles at San Pedro shows slight evidence of borer action.
Tests.—The following list shows special service tests now being observed by the Sub-Committee:
1. Four sets of 7 piles each driven as follows: March, 1920, Northern Pacific Ry. Co....
Seattle September, 1919, Northwestern Pac. R. R. Co.
.Tiburon September, 1919, Southern Pacific Company.
San Pedro June, 1920, Santa Fe Railway Company..
San Diego Each set includes 1 untreated fir pile, 2 freshly creosoted for piles, and 4 creosoted fir piles taken from Old Long Wharf in 1919.
2. Twelve creosoted Douglas fir piles from Old Long Wharf, driven as brace piles in Southern Pacific Company Wharf No. 2–Oakland Pier, October, 1919.
3. Sixteen eucalyptus piles driven in dolphins of Alameda Ferry Slip of Southern Pacific Company, 1921.
4. Sixteen eucalyptus piles driven in dolphins of Oakland Auto Ferry Slip of Southern Pacific Company, 1921.
5. Eighteen dolphin piles in Georgia Street Wharf, South Vallejo, of Southern Pacific Company covered to above high water with “Moran" paint, 1921.
6. Eighteen dolphin piles in Georgia Street Wharf, South Vallejo, of Southern Pacific Company, covered to above high water with “Paraffine" paint, 1921.
Insufficient time has elapsed since the inauguration of the tests above enumerated to allow a conclusive report of definite results. All of the creosoted piles of Tests Nos. 1 and 2 reported on to date are in good condition. One of the old Long Wharf creosoted piles at San Pedro shows a slight Limnoria action. The untreated pile of the set at this location has been eaten by Limnoria to a depth of 2 inches, near lowtide level.
The San Francisco Bay Marine Piling Committee has established a laboratory and aquarium on the Oakland Pier Wharf of the Southern Pacific Company, where living marine borers can be observed working in specimens of wood submerged in glass tanks. This gives an excellent opportunity to see the syphon which the Teredo, or Xylotrya, extend out of the entrance to their burrows into the water, and through which they obtain their nourishment. This is about the only manner in which this delicate syphon can be seen because of the fact that the borer draws it back into the wood at the slightest disturbance, or when taken out of salt water. The ejection of wood “sawdust" can also be watched, and likewise the breeding process.
In addition to these tests, your Sub-Committee has under observation numerous structures of creosoted piling just completed by the Southern Pacific Company, viz.: Auto Ferry Slip, Oakland; new Ferry Slip, Port Costa; Ferry Slip, Benicia; etc.
In conclusion, the Sub-Committee makes the following recommendations :
1. That the co-operation of Pacific Coast bodies in position to contribute data on the condition of marine borers in the various harbors be further solicited.
2. That standard Service Records be prepared and that owners of marine wharves be requested to institute them, and place the results at the disposal of this Sub-Committee.
3. That publicity be given to the nature of the individual marine borers under investigation, so that correct identification may be possible.
4. That temperature and salinity tests be made at regular intervals in the main harbors.
5. That efforts be made to co-operate in the movement now under way to cause the removal of unused marine structures, which are the breeding places of marine borers.
6. That biological study of the marine borers be continued and given as wide publicity as possible.
7. That the analysis of all structural timber used for marine substructures be investigated to ascertain qualities of absorption and adsorption.