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.
This is precisely what happens as the pH of water increases; that is the water becomes more alkaline. You may recall that alkalinity is caused by an increase in hydroxyl ions. An increase in hydroxyl ions (or alkalinity) pushes the equilibrium to the left and more unionized ammonia is formed.