People at Work : : Vacuuming the Lake

I read an article in the newspaper last year about how the SanFrancisco Bay Conservation group was trying to figure out how to get rid of the sedge that was planted around the bay by the Army Corps of Engineers for erosion control. Unfortunately, they planted the wrong kind of sedge. They planted sedge which gets to be ten feet tall, instead of one of the  smaller varieties which doesn't block the spectacular views of the bay.

I doubt if the Army Corps of Engineers planted giant sedge around Spring Lake, but somehow it has migrated there and within just a few years has formed an almost impenetrable barrier around the lake. Another unintended consequence is that its seed heads float on top of the water forming an unattractive brown mat.

Another interloper at Spring Lake is the water hyacinth which is so aggressive it can actually kill the lake. It forms a thick layer that floats on top of the water and chokes off inlets before it spreads to the larger body of water.  When I was in Thailand I went to see the famous Floating Market, and the water hyacinth was so thick that the boats full of vegetables and fruit were surrounded by it. It is definitely planta non grata in many places where it jams rivers and lakes with tons of floating plant matter.

I was amazed to see this large contraption with its jaunty yellow umbrella tooling around the middle of Spring Lake this morning, too far away initially to take a picture, or even make out what it looked like. I could hear it getting closer to us as we made our way around, but I couldn't see it at all because of the giant sedge. As we rounded a little inlet, which has become choked with vegetation, a window in the sedge, opened up and this floating vacuum came into view. It had two paddlewheels in the back which turned and caused water to spray into the air as the, er, vehicle got up to speed.  I think they must have been cutting blades of some sort. (A healthy stand of sedge with its seedheads on top can be seen behind it.) The front was a giant maw which sucked up everything that was floating on top of the water, drew it up a sort of conveyer belt and spit it out into big baskets between the paddlewheels.

The driver was absorbed with backing out of the inlet and turning around, but when he saw me watching, fascinated, he gave me a wave and a big smile...There seems to be a giant machine for almost every big job....