WHY WE HAD ONLY A GALLON OF WATER.
The Brandreth Wells. — Failure of the Spring. — Mr. Cross's happy discovery. — A fickle spring. — How the water is collected. — Dampiers. — Mulberry Drip. — Duck-Pond Drip. — White Wall Drip. — Middleton Drip.
EVER since our arrival on the island, we had been much interested about the water supply, and now that we were at the source, we hoped to be able to learn the parentage and history of our one gallon per day.
We had already seen, peeping aboveground here and there, the pipe which we knew conveyed the water to Garrison, there to be stored for the use of man and beast; but we had seen no spring, and I was delighted at a proposal to visit the "Wells" under guidance of Captain Phillimore, who made himself so thoroughly acquainted with the all-important system of our water supply
Starting from Garden Cottage, we again passed through the tunnel I have already mentioned; this time with lanthorns, which showed it to be worked out of compact beds of cinders and ashes, and occasionally of clay and trachyte, to which clung green moss and lichens. Along one side, just aboveground, an iron pipe ran the length of the tunnel, and we did not lose sight of it until we found sun-light once more in Break-neck Valley. Here we found the two circular wells that contributed so largely to our daily gallon of water. These are known as the "Brandreth Wells," named after Lieutenant Brandreth, R.E., who came out here in 1830 to assist Captain Bates in his anxious search for water. With regard to the sinking of these wells, Lieutenant Brandreth writes:—
"During twelve or fourteen months the island had been afflicted with a severe drought, and I found bare forty tons (of water) in store. The search for it in the low lands had failed; the springs, or water-drips, instead of gushing out plentifully, were scantily trickling, and the skies were glorious, but unproductive in their unclouded splendour. Under these circumstances I pressed for further experiments in boring, and fixed on a spot high up in the mountain district, on the windward side of the island and at the bottom of a deep ravine, the sides of which were eighty feet in height, and where the- section showed the arrangement of the strata to consist of volcanic matter lying on beds of retentive clay. The clouds and mist and constant evaporation from the sea were evidently arrested by the high land and their moisture deposited here; and the experiment fully succeeded. At a depth of twenty-five feet from the surface we found a spring that for the last five years has yielded from four to seven tons daily, and has probably averaged about five tons a day throughout the year. The question of a supply of water was thus set at rest," concludes Lieutenant Brandreth. But the rest seems to have been temporary.
I do not know for how much longer than five years the Brandreth spring continued to flow, but it was not long, and only a tradition of it remained in 1877, when continued drought again urged the Ascensionites to renewed efforts to find water.
Then there was no sign on the slopes of Break-neck Valley to mark the position of the spring of 1830—the wells having long since been choked up,—but after some trouble Mr. Cross, the Lieutenant of Marines, hit upon it, and found, to the joy of all the inhabitants, that water was again flowing to the extent of three tons a day. Now the supply had again dwindled down to one ton, and the fickle spring was looked upon with doubt and suspicion. Indeed, when we saw it I should never have thought of calling it a spring at all. I should have described it rather as moisture oozing from the mountain side.
The wells penetrate for the most part a light, ashy soil, but fortunately at the depth of twenty-five feet they strike a layer of clay, barely two inches thick. Here is checked the downward course of the surface water that has percolated through the loose soil, till, arrested by the retentive clay, the precious drops ooze out, and, as they drip slowly from their clayey shelf, are caught in a cement-lined basin prepared for them below. The water collected in the upper well flows into the lower one through a narrow gutter, running along a tunnel cut between the two; and it was by means of this tunnel that we were able to get into the wells, and not merely to look down upon them from the surface of the ground above.
The lower well is simply a reproduction of the upper one. The drip comes from the same little stratum of clay, and is in its turn carried off by an underground pipe to a large octagon tank a few yards lower down the valley. By the side of this tank stands the windmill we had espied from the Peak. By means of it, the water is pumped up to a level sufficient to send it into the pipe which runs through the Garden Cottage tunnel to the barracks. Thus far on its journey, the Break-neck Valley water then flows into the main pipe, which has reserve tanks placed along its course to Garrison.
From the northern side of Green Mountain, and near its base, other pipes run out to join the main line; and on another day Jimmy Chivas carried me clown the Ramps to explore this source of supply. Here we found two large stone-built tanks called "Dampier's" and "Bates," capable of holding respectively 500 and 312 tons of water; but these are fed by no steady drip such as exists at the "Brandreth Wells," and are dependent for their supplies on such surface water as falls on the slope above. Both tanks are uncovered, and much moisture is thus lost by evaporation.
A natural gully forms a good, catch-water for "Dampier's," while a cement-paved channel, laid along the mountain side, carries the precarious rain-fall into the "Bates" tank; both, however, were dry when we saw them, and the tanks empty.
At different levels on the same slope as these tanks are three little water-drips, falling from a friendly seam of compact oxide of iron-which seems to extend over a considerable area. These are the springs supposed to have been found by the famous pirate and navigator Dampier, when his vessel Roebuck was stranded on the island in 1701; and tradition says that he was led to this happy discovery by following the footsteps of a wild goat when he was almost dying of thirst.
The spring next below the tanks is called the "Mulberry Drip," from the solitary mulberry tree growing close beside it—the best of its kind I had seen on the island; and, on the hot afternoon that we visited Dampier's, I heartily relished some of its juicy fruit. The "Duck Pond Drip," and "White Wall Drip," are a few yards lower down, and it was quite refreshing to watch the clear drops of water trickling from the damp hill-side into the troughs; from which the overflow is carefully sent off in branch lines to join the main pipe on its way to Garrison. There St. George's tank receives all contributions, and is open for more.
One more source of supply—"Middleton Drip"—exists near the centre of the island; but analysts have pronounced the water here to be unwholesome. It tastes slightly saltish, and leaves a bitter flavour on the tongue. Partly on this account, and partly because the drip is situated in an almost inaccessible spot, no pipe has been laid from it; but the water in the open trough placed there is very grateful to thirsty sheep and goats, as well as to the mules and donkeys at large on the clinker.
Excepting the insufficient condenser, more often useless than not, the catch-waters formed by the roofs of the mountain cottages, are, I think, the only other means of supplying water to the human and brute population on Ascension; and, after our visit to the Mountain, we no longer wondered why we had only a gallon of water per day—we wondered rather why we had so much.