Connell visits and inspects the beleaguered Ross Bay sea-wall in the wake of a winter storm. He considers the geography of the coastline in this location, the structure and suspected weaknesses of the wall, and proposes a natural (of course!) solution.
From the Victoria Daily Times, December 31st, 1932-
It will be some years before all the marks of the Christmas-week gale are erased from our coastline. We may restore the battered sea-wall parapet, but Nature alone can mend the cliffs, and Nature is usually many degrees slower as a repairer than as a destroyer.
In a few seconds she can wreck the greatest city or blast beyond recognition a whole countryside. In fact so spectacular and imposing is the destruction wrought by Nature as compared with the shortness of the time involved that it is indeed difficult to believe that her constructive work far outweighs the destructive. Yet it is so. Twenty years ago a Royal Commission on Coast Erosion in the British Isles reported after careful investigation that although the annual loss of land is great it is more than compensated by the building-up process of rivers, especially when they are supplemented by human effort. During the last hundred years about 75,000 acres of British land was sliced off by the sea, or, if the same rate has been maintained in the further past, nearly a million and a half since Caesar’s landing. But against this we have to set the large acreage of fen country reclaimed, and the undoubted fact that many old English seaports are now inland towns: Chester, for example, was once an important shipping point, but the River Dee has silted up the old harbor, and Liverpool has taken Chester’s place.
Natural reclamation is thus at first a mixed blessing though in process of time, hastened by artificial means, large areas of rich agricultural land are added to the resources of the country. In British Columbia the farming lands of the Fraser delta have such an origin, and on Vancouver Island we have rich soil behind Ross and Foul Bays of comparatively recent salvage from the sea, and to these we may add the lowlands from Shoal and Oak Bays inland to Mount Douglas. Of an earlier date are the farm-lands of the Saanich Valley from Cordova Bay to Saanichton and the hinterland of Sidney.
But while the natural reclamations have mostly been made long before the beginning of agricultural settlement, and others progress so slowly as to be quite unnoticed from year to year, the attacks of the sea upon the coast-line are comparatively infrequent and occasionally strikingly spectacular. Under ordinary conditions the sea works chiefly on the hard rocks and on the loose sands and gravels of the shore. Only under exceptional circumstances and especially when a powerful gale combines with an exceptionally high tide is the coast seriously eaten into. Cliffs of sand and clay thus suffer specially at such times; and even when they have already succeeded in obtaining through long periods of rest a plant cover more or less complete they may be stripped by the violence of the wind-driven billows. A great deal of our coast erosion, however, as along the south end of Cordova Bay is due to slipping from the land.
On Christmas Eve I visited Finlayson Point, where I found my foreboding as to the effect of the “beautifying” paths fully justified. The sea has taken advantage of the gash made in the steep grassy slope and has taken a good preliminary mouthful from the headland. To a botanist as well as to anyone interested in the question of conservation of the coast-line it is exceedingly interesting to see from this stripping the part played in the protective work of Nature by the long tough root or caudex of the grindelia or “gum weed”. It suggests that by planting this seashore inhabitant and encouraging those still present the ravages might be repaired, just as the shifting sands of many coasts are artificially protected by the planting and encouragement of the wild lymegrass and sea-matgrass with their perennial creeping roots.
To the east the cliffs, never wholly covered, have been scarred and worried by the sea, and fresh falls of clay are frequent. But it is beyond Clover Point where Ross Bay begins that the devastation is chiefly seen.
The low cliff between the sea-wall and the roadway as it slopes down to the cemetery has been laid open to such an extent that the geological anatomy can be now clearly perceived as it could not before. The stratification of the clays veiled, as they have been also along the Dallas Road cliffs, by a scree of material fallen from the face, is here beautifully displayed as a section of the widespread Maywood deposits laid down in the sea during the long interglacial period. But the most remarkable thing is that the clearing away of the old scree by the storm waves has laid bare a section of a raised beach built up against the older cliff of the Maywood clays. This beach is composed here of dark, coarse gravels well stratified. It is the outer fringe of the raised beach deposits that stretch inland across the cemetery and up to the base of Government House hill. In its lower parts this raised beach contains quite thick deposits of fresh water shells and peat lying above the marine shell deposits formed when it still lay beneath the sea. The raised beaches to which the late Dr. Newcombe called attention years ago in the Ottawa Naturalist were formed after the final stage of glaciation had passed away and have been elevated at a still later period.
Beyond the raised beach exposure there is a good example of the intense crumpling to which the Maywood clays and the smaller bodies of clay in the overlying Cordova sand and gravel deposits were occasionally subjected. The clay bands are twisted and contorted as one would expect plastic material to be after undergoing great lateral pressure. The precise nature of the pressure or its cause is not easily defined. As the contorted clay at Ross Bay, like another example at the foot of Gonzales Hill by the road between Foul Bay Road and Highland Drive, lies near the base of the clays the cause may well have been ice, either by direct pressure or by the yielding of the clay as it subsided under overlaying weight.
The disastrous collapse of the sea-wall parapet is of course the most obvious thing at Ross Bay. It is not, however, something wholly unexpected. For years the parapet has been showing signs of weakness, ominous cracks having opened at a large number of places as I have before pointed out. An examination of the broken fragments of cement will show at least one of the contributing causes. I have heard the quality of the cement questioned, but as far as I have been able to see the destruction was not directly due to lack of cohesion. The cement held well together, and that in spite of the severe pounding it received. The balusters of the parapet have of course undergone a good deal of fretting by the sea during the years they have been in place, just as has the sea-wall surface below, and the wearing away of the finer outer coating has enabled the salt water to enter the substance of the concrete easily. This brings us to the heart of the matter quite literally.
The concrete has a skeleton or spine of steel in the form of slender bars about half an inch square. This reinforcement of the concrete is a common feature of all modern structural work, and experience has shown that it enables buildings and erections of all kinds to resist shocks that would shatter to pieces simple concrete work, however strong. Thus, for example, in the great San Francisco earthquake the Call Building, many stories in height, withstood successfully the violence of the tremors.
But as you look at the masses of concrete that strew the foot-pavement you will see that the protruding and twisted rods are by no means as they were when they were fist incorporated in the gravelly paste. They are so seriously rusted that the rusted metal comes away in flakes. The original thickness is gone, some of the iron adhering to the concrete as a mere stain of red. I have before me as I write a piece no thicker than an old-fashioned slate pencil or an equally old-fashioned cut nail, at one end tapering to a sharp point: this is all that remains of the original half-inch rod. Numbers of such attenuated remains may be seen as well as larger flaking pieces. In spite of this serious reduction in size the rods are still remarkably tenacious. One concrete block some four or five feet long looks as if a giant had tried to snap it across his knee. It has three vertical cracks in it, the result of the strain which has bent without breaking the rod within.
The rusting away of the steel rods is due to moisture penetrating the cement, and the moisture of salt-water at that. Concrete as ordinarily used is unfortunately not waterproof, and the porous condition of the rougher kind where coarse pebbly gravel is used is such that water easily enters. I think there can be no doubt that here lies the weakness of the Ross Bay sea-wall parapet and the responsibility of its somewhat dramatic collapse last week. There is at one place at least a very noticeable break in the sea-wall itself which demands immediate attention before the trouble spreads further, and towards the east end of the wall there are two serious fractures in the foot-pavement. In these the pavement slopes from the fractures (which are rough arcs of circles) towards the sea and suggests undermining of the sea-wall. This is further suggested by the actual warping of the line of the parapet.