求翻译：底层厚0.2m,粒径40~60mm,为粗砾石层；中层厚0。3m,粒径20~40mm，为中砾石层；上层厚0.15m,粒径10~30mm,为细碎石层。进水区与集水区的布置应尽量保证补水和集水均匀，避免在池内形成死水区和短流（2）。是什么意思？

Bottom thickness 0.2m, diameter 40 ~ 60mm, for the coarse gravel layer; in thickness 0. 3m, diameter 20 ~ 40mm, medium gravel; the thickness 0.15m, diameter 10 ~ 30mm, for the crushing rock. Water catchment area and the layout should ensure even water and water harvesting, to avoid the formation of

Particle size at 0.2 m thick bottom, 40 to 60 mm, and the rough gravel; middle thick layer 0. Particle size at 3 m, 20 to 40 mm for the gravel layer; the upper level, 0.15 m thick, particle size 10 ~ 30 mm, and the fine gravel layer. water catchment area and the layout should endeavor to ensure that

First floor thick 0.2m, particle size 40~60mm, is the coarse gravel level; Intermediate deck thick 0.3m, particle size 20~40mm, is the gravel bed; Upper formation thick 0.15m, particle size 10~30mm, is the riddlings in broken bits.Enters the water district and the catchment area arrangement should g

Bottom thick 0.2m, size 40~60mm, rough gravel; Middle thickness 0. 3M, size 20~40mm, gravel; upper deck thick 0.15m, size 10~30mm, fine gravel layer. Layout of water intake and catchment area should ensure uniform water and water collecting as much as possible, avoid formation of stagnant water in t

Bottom thick 0.2m, size 40~60mm, rough gravel; Middle thickness 0. 3M, size 20~40mm, gravel; upper deck thick 0.15m, size 10~30mm, fine gravel layer. Inlet area and arrangement of catchment areas should try to recharge and water uniform, backwater avoid pool formation and short streams (2 per).