Page:Popular Science Monthly Volume 6.djvu/459

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WATER-SUPPLY OF ISLANDS.
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cactus and mesquite, showing that drought was not of rare occurrence there.

Our men encamped on Ship Island complained that the water in many of the wells which they dug soon became bad. Perhaps this was owing to the surface-water of the swamps getting into them, or perhaps the drainage of the camps. Those who know the habits of our men in camp can judge for themselves.

A glance at the map and profiles of Ship Island will show how admirably the island is adapted to collecting and holding rain-water. The broader parts of the island are completely surrounded by a raised beach, making large basins. The basin west of the lighthouse is comparatively new. All the islands in that chain grow at their western ends and wash away on the east. The only vegetation in this western basin was, at the time of my sojourn there, a few low, creeping herbs. The beach was so low that a heavy September gale blew the waves over it, and the whole basin became a salt lake, around-which I walked the next day on the beach. The sea having by that time fallen rather below its usual height, there was a difference of several feet between it and the surface of the lake. Observing that at one place the water was just level with the top of the beach, I scratched a shallow channel across it with a stick. In five minutes a strong brook was running out, and, in ten more, a roaring river. This part of the island being subject to such overflows, of course no wells are sunk in it. The fort depends on cisterns of rain-water; but it would be easy to run a pipe underground to a well above the lighthouse and get plenty of water.

The basin east of the lighthouse was a swamp in my time, thickly overgrown with grasses. Afterward, the commandant had it ploughed and made into a garden, said to have been very productive, especially in melons. The neck, of course, was barren, shifting sand, while the large basin beyond was not only swampy, but had a fresh pond in it. The drier parts were covered with a beautiful purple-topped grass, and had some showy flowers; while the wetter parts, and even the pond, were thickly set with woody shrubs of considerable size, and the wide, shallow mouth of the pond was so obstructed by them that the quiet waters of the Mississippi Sound never penetrated it. Beyond the pond were formerly some live-oaks and pines; but the oaks had all been cut down, and the pines were rapidly following them, being carried off for fuel by the prison-camp near the light-house. All around this end of the island, stumps and dead trees standing far out in the water showed that the sand was being gradually swept away by the waves.

Santa Rosa is Ship Island on a larger scale. It has several freshwater ponds, and many bushes and trees. On its barren western end I obtained an abundance of good waiter by sinking a well some four or five feet. The wooden curb was built larger at the bottom, and set in