TY JOUR TI Analysis of energy efficiency of polder of pumping stations in a Slavsk district of the Kaliningrad region KW polder KW energy efficiency KW pumping equipment KW geodesic pressure KW weighted average pressure KW land improvement KW drainage KW hydraulic calculation JO Melioration and Water Management AU Spirin, Y.A. AU Puntusov, V.G. PY 2020 IS 2020 PB ANO Editorial Board Melioration and water management