Lake levels are alarmingly low in many parts of the country

Without sustained heavy rainfall soon, the spring could bring serious groundwater problems

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By Martti Heikkinen
     
      Unless the next few weeks - before the first hard frosts set in - bring heavy and near-continuous rainfall, Finland's groundwater reserves look destined to be markedly below their normal level when next spring comes.
      At the same time, levels in the country's large lakes are still extremely low.
      To take just one example, in Kuopio the 1,100 GRT passenger vessel Kristina Brahe , which is just starting a series of short inland waterway cruises on Kallavesi, was obliged to tie up at the deep-water jetty rather than in the city's passenger harbour.
      Small pleasure vessels moored in the passenger harbour have all but vanished below the jetty wall, as the water level in Kallavesi is so low.
     
According to data collected by Finland's environmental administration SYKE, in large aquifers, such as Salpausselkä, the water level is if anything declining, despite the recent rains.
      On the other hand, in smaller groundwater areas there have been signs that the corner has been turned and an improvement is taking place.
      SYKE and the regional environmental centres are also following the water-level situation in lakes on a daily basis.
     
After the dry, warm summer, lake levels are at practically record lows, but the latest measurements indicate that the decline is slowing down.
      "Lake water levels are as low as this round about once in 20 years, but apart from the main Lake Saimaa drainage basin, things have actually picked up somewhat in recent weeks", says senior hydrologist Bertel Vehviläinen from SYKE.
      "If you take the case of areas north of Kallavesi and in the south and west of the country, the recent rain has made the soil wet and water is beginning to show up again in the lakes", says Vehviläinen. The accompanying map bears this out.
      The water level on Lake Saimaa is slightly more than 60 centimetres below the mean level for the time of year. The discharge run-off from Saimaa [through the Vuoksi River] was reduced still further from the beginning of October, and the lowering of the water level in Saimaa has now slowed down.
     
"On large open areas you can still sail safely enough, but some of our members have smacked the hulls of their boats on surprising rocks that have popped up near the shorelines", reports Robert Sandström, Commodore at the Lappeenranta Yacht Club.
      "At our summer cottage the jetty is practically high and dry, and you have to climb up a ladder to get on to it from the boat."
     
The exceptional shortage of water in this land of 180,000 lakes also shows up in the rivers draining out of the larger lake systems, for instance the Kymijoki and Vuoksi rivers in the south-east and Kokemäenjoki, which drains into the Gulf of Bothnia at Pori.
      The Kymijoki River, for instance, currently has only about 40 per cent of the mass of water that would normally be flowing at this time of year. The river has a volumetric discharge or flow of around 100 cubic metres of water a second, which compares unfavourably with the normal October figure of around 300m³/s.
      "The bigger rivers are the last to fill up again, since for instance the Kymijoki watercourse first has to experience a rise in the levels in drainage-basin lakes such as Päijänne, Puulavesi, and all the way up to Rautalampi, close to Kuopio", notes Vehviläinen.
     
The shortage of water is not merely an inconvenience for sailing enthusiasts or people with lakeside saunas: the current state of affairs can render the smaller and shallower lakes susceptible to hypoxia or oxygen depletion.
      Those in the greatest danger are lakes that are already in poor shape, suffering from eutrophication from excessive nutrient load.
     
Helsingin Sanomat / First published in print 7.10.2006

More on this subject:
 FACTFILE: Lakes and watercourses at a remarkably low level

Previously in HS International Edition:
  Lakes more than half metre lower than normal in unusually dry summer (2.8.2006)

Links:
  Lakes in Finland (Wikipedia)
  Finnish Environment Institute: Water Resources Management

MARTTI HEIKKINEN / Helsingin Sanomat
martti.heikkinen@hs.fi