Draining the Swamp

The grassy area just north of the picnic area on the west side, ringed by trees, was a swamp for many months following this past rainy winter.  The soil got so soggy that the mowing machine left deep tracks, bottomed out, and could not penetrate the area.  The vegetation in this half acre turned marshy and formed a distinct micro-environment.  When I tried to walk in it, my boots sank in the muck up to my ankles.  The water ran day and night into an iron drain next to the paved path, and sometimes overflowed the path on its way to the Bay.  

Recently, Parks staff installed an additional drain more toward the middle of the marsh, and surrounded that with a few feet of gravel to keep it in place.  A plywood sheet and a plastic barrier top off the work.  In the past couple of days, the area was dry enough to let the mower ride in and level off all the marshy vegetation.  With that, our local west side park swamp appears to have been drained.

Unsettled still is the cause of the accumulation of water in this area.  The heavy rains of last winter certainly played a part.  However, the rains also caused pooling in other areas of the park, including the kite lawn just south of this area; and those other pools drained, dried up and hardened within a few days of the downpours, while the water in the picnic area kept running vigorously.  A similar condition at this spot was observed in 2010 and was blamed on a fault in the irrigation system; when irrigation was shut off, the area dried up.   The sogginess recurred in 2012-2013, and the fault was again thought to lie in a leaky irrigation pipe, which was scheduled for repair.  

The park contains three separate water supply systems:  fire hydrants, irrigation, and drinking fountains.  Each has buried pipes, valves, and branches.  Drawings that show where the pipes are buried may be lost or inaccurate.  Engineers have occasionally found buried pipes that show on no maps, or lost pipes that show on maps but aren’t where they’re supposed to be.  Given this history, it remains to be seen whether the west side marsh is truly drained for good.  

The west side marsh dried and mowed Oct. 20 2017


Marsh vegetation July 2, 2017


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