Wetlands managed by beaver dams do this stuff but also recharge aquifers, promote formation of peat lands holding carbon under water and eventually in the soil, change local climate increasing rainfall and sustain forests and ecosystems that have further effects to enrich soil and keep areas livable for many centuries and millennia. This form of land management fights back desertification leaving lands better than they were and prevents land subsidence in coastal estuaries. Draining swamps with systems of canals, levees and dams for human habitation and exploitation, degrades soil, aquifers and biodiversity leading to deforestation, desertification, and places like the Louisiana estuary being slowly lost to the sea in the span of just generations.