One of the losses to Hurricane Agnes in 1972 was the bridge that connected Olmsted Island to Maryland at Great Falls. With the bridge out, few people have been able to cross over to the island or to its neighbor, Falls Island. Either the river was too rapid to canoe across, or there was simply too much river flowing between the rocks to allow an easy hop across.

About a month ago, the river began to run low from lack of rain. Someone contrived a bridge from a gray, weathered plank and set it across some rusty metal prongs that stuck out of the water. The plank linked a series of rocks to the exposed ledge of an old fish ladder, and Olmsted Island was connected to Maryland again.

It was not long before the idea about the plank was copied, and other plank bridges appeared up and down the channel between Maryland and Olmsted Island. The bridges shared one thing with the bridge that was knocked out in 1972: they were destined by their simple form to be short-lived. The planks, after all, could be topled by a stiff breeze. This did not deter people from walking across them, and sometimes there were even short lines of people waiting to cross over.

The attraction of exploring new or different places is, I think, natural to humans, and this in part was why the islands became to popular so quickly. Remember, the islands had been deserted for eight years; there was a lot of catching up to do. Old trails had to be blazed again, the rusted railings at the Great Falls overlook needed sweaty palms to polish them up, and the half-dozen trash cans around the island, still chained to boulders, had to be uprighted. In this way, the islands offered something that was out of the ordinary on a Sunday afternoon walk along the C&O Canal. Call it serendipity.

During warm weekends this fall; there seemed to be as much litter on the islands as people. Even in remote areas, people found nooks and crannies in which to stash empty six-pack bottles and broken shells from steamed crabs. And I frequently came across ravines where the river in its floods had piled high its debris of tree trunks and limbs, twisted hulks of aluminum rowboats and plastic bleach containers. It was hard to tell who was the devil with debris -- man or the river. At times there seemed to be direct competition. Where the river had crushed an oil drum and left it high on a ledge, someone (not to be outdone) had left a crushed aluminum beer can.

Among the debris on Olmsted Island stood a picnic table, intact and upright. Four picnickers -- a man and three women (all in business by their talk) -- sat down with a bottle of wine and set up lunch. The picnic table wabbled so they decided to move it up onto a large, flat-top rock. They struggled, but the table was too heavy, so finally they gave up. One of the women suggested placing a rock under the table's legs. The simple suggestion was approved overwhelmingly and was enacted immediately. The meeting then adjourned for lunch.

Later, when I walked along a less trampled side trail on Falls Island, I came across a plank leaning against a tree. As I got closer, I realized it was the tree that was doing the leaning, bent over backward with the weight of something tied up in it limbs. As I look up, I recognized the wreckage of a picnic table that had been hefted into the tree by the river.

One Sunday I came across a ledge where three kids tossed boulders the size of their heads into the river. They'd run up to the ledge's edge with the boulders at their waists and hurl them into the air. The boulders would hit the river and send up shafts of water with deep harrumphs and splashes.

The river could do as well at tossing stones. I approached a rock with a sign bolted to it that greeted me with a question, "Where from?" and took up conversation with me. "Not all of the rocks you see around you were formed here," it read. "Some were carried from far upstream by the river. This small boulder is quartzite, which is not found as bedrock any closer than Point of Rocks, about 35 miles up river. The same powerful force that moved it here has often been harnessed by man to turn the waterwheels of industry."

Everywhere I went I felt I had to act fast. It was only a matter of time before the Potomac rose and swept the islands out of reach again.

One week later I returned, but I found the bridge washed out. The planks were swept away, the rocks were submerged again. Everything became the way it was before the river ran low. True, rivers have often been harnessed to turn the waterwheeels of industry. Man has harnessed a lot of things in his time to the wheels of industry, including himself. One thing, however, is for certain: he hasn't yet harnessed this river.