Water management is the principal environmental concern. A water shortage due to limited freshwater resources is exacerbated by limited rainfall and drought. The existing water supply is threatened by pollution from distilleries, food processing facilities, and other industrial operations. Deforestation resulting from the nation's energy demands, combined with agricultural development, contributes to soil erosion, as rainfall, which is concentrated in a short season, quickly runs off, compounding the water shortage problem on the islands. The nation's main city, St. John's, has developed a problem with waste disposal. Untreated sewage from resort hotels travels in open sewage lines across the land and empties into the sea. Construction of a desalination plant in 1970 relieved some of the water shortage. The government of Antigua and Barbuda created a Historical, Conservation, and Environmental Commission. There are four main protected areas, including the offshore islands of North Sound and Codrington Lagoon of Barbuda. Endangered species in the nation include the Antiguan ground lizard, the West Indian whistling duck, and the Antiguan racer.