The dolerite, positioned above the clay shale, is fractured enough to let water through down to the porous, soft, and much fractured clay shale. Wellsprings in the clay shale often have good groundwater as it is rarely affected by human activity, because the clay shale’s extent is more or less limited to that of the mountains’ dolerite plateaus.
Ruskela Stream runs westwards from Ruskela Spring, down the slope. Along the stream is a rich moss flora and plenty of dead wood. The hiking trail Faledreven runs across the reserve. There are benches and a fireplace by the wellspring. The spring is situated in the nature reserve Ruskela källa.
Ruskela källa is a nature reserve.