This chapter discusses the management of open bodies of water and wetlands on seasonally or permanently waterlogged soil. It concentrates on freshwater habitats, but briefly discusses management of brackish habitats, such as coastal grazing marshes, where they form a continuum with freshwater ones. Topics covered include principles of manipulating water levels, water quality, methods of improving the value of deep water bodies (>1 m) and large, shallow (less than about 1 m) for wildlife; temporary pools, permanent ponds and water-filled ditches, rivers, swamps and fens, bogs, wet scrub, wet woodland, wet grasslands.