سؤال 25 — Academic Reading 25 — Vocabulary

Wetlands include marshes, swamps, peatlands, and other environments in which water strongly influences soil and biological communities. They perform several ecological functions. During heavy rainfall, some wetlands temporarily store water and can reduce downstream flooding. Wetland plants and soils may also trap sediments and transform certain nutrients, affecting water quality. In addition, wetlands provide habitat for fish, birds, amphibians, insects, and specialized plants. For much of modern history, many wetlands were drained because they were viewed as unproductive or as obstacles to agriculture and construction. Ecologists now recognize that losing wetlands can remove services that would otherwise be expensive to replace with engineered infrastructure. Nevertheless, wetland restoration is not simply a matter of adding water to a low-lying area. Successful projects must consider hydrology, soil chemistry, plant communities, surrounding land use, and the sources of water entering the site. Restored wetlands can recover important functions, but they may not become identical to the ecosystems that existed before disturbance. For this reason, scientists evaluate restoration using multiple indicators over long periods rather than relying on appearance alone.
In the passage, “hydrology” refers most closely to: