%0 Journal Article %T Improving the efficiency of drainage systems by arranging drains in two tiers %A Ponomarev, A.B. %A Shtykov, V.I. %A Yanko, Y.G. %K cavity-free drainage, drainage, poorly permeable soils, drainage cost, closed collectors %J Melioration and Water Management %D 2026 %N 2025 %P 0 %I ANO Editorial Board Melioration and water management