The lake is fed by the water running through the Tammerkoski rapids in the center of the city of Tampere. Because of the rapids, the water in Pyh�j�rvi is warmer and richer in ozone than that in the northern lake N�sij�rvi. As an effect, the life in this lake is richer, but the water is also more polluted.
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The town of Pyh�j�rvi is located in the southernmost corner of the province of Oulu in an area we call Oulu South. Pyh�j�rvi bordering also on the provice of Eastern Finland and Western Finland. The town belongs to the subregion of Nivala-Haapaj�rvi
As the highway 4 (E75), the highway 27 and the Ylivieska-Iisalmi railway all run through the town, Pyh�j�rvi is well situated in an intersection of communication and transport services. The town has also an airfield, equipped for instrument flying.
The town of Pyh�j�rvi. Formerly the municipality of Pyh�j�rvi, was founded in 1866, and it was then named after lake Pyh�j�rvi, a lake of 125 square kilometers and rich in fish. Pyh�j�rvi became officially a town January 1993.
The town has about 7.000 inhabitants, of whom some 60 percent live in the two population centre Pyh�salmi and Ruotanen.