national monument. noun. Definition of national monument for English Language Learners. : a place (such as an old building or an area of land) that is owned and protected by a national government because of its natural beauty or its importance to history or science. Britannica.com: Encyclopedia article about national monument.
Brown or discolored water is caused by minerals, sediment, or rust that may accumulate in the water mains over time. When the water from your tap is brown this indicates a disturbance in the water main that stirs up these deposits.
Copper, iron or manganese pool problems. Pool water problems - copper, iron or manganese. Copper, iron or manganese in swimming pool water all cause the water to discolor without affecting the water's clarity much. If the water changes color after chlorine (or any other oxidizer) is added, the swimming pool water probably contains a metal.