1. Ice Swimmer says

    The pictures are from the westernmost shore of the bay Töölönlahti in Helsinki. The flowing water (half a cubic meter/second) is pumped from the sea, west of Helsinki Peninsula through a 1,7 km (a mile + 100 yd) long pipeline/tunnel, partly converted from old sewers/storm drains to improve the water quality and oxygen content of the shallow bay connected with a narrow passage to the rest of the sea. That way the phosphates in the mud on the bottom aren’t released into the water.

    There is often a gull or a tern in the place where the pumped waters flow into the bay. Black-headed gulls seem to be most common there.

  2. dakotagreasemonkey says

    Very interesting, pumping seawater into a bay. It makes sense, though, to keep the bay from getting stagnant. Phosphates retained in the mud reduces the algae, some of which is poisonous.

  3. Ice Swimmer says

    DGM @ 3

    Yes, that’s the point, the blue-green algae used to make Töölönlahti quite smelly in summer before they started the pumping.

    People used to swim in the bay back in the 19th century. Then came the sewage from the growing city and the sugar mill located on the southwestern shore. Now it’s fairly safe to swim, at least in the spring and early summer, though still not recommended.

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