Water
Where can I find flood maps?
What is the difference between a confined and unconfined aquifer?
Does the use of pesticides affect our Nation's water quality?
How much natural water is there?
The USGS monitors and studies a wide range of water resources and water conditions, including streamflow, groundwater, water quality, and water use and availability.
How does acid precipitation affect marble and limestone buildings? How does acid precipitation affect marble and limestone buildings?
When sulfurous, sulfuric, and nitric acids in polluted air and rain react with the calcite in marble and limestone, the calcite dissolves. In exposed areas of buildings and statues, we see roughened surfaces, removal of material, and loss of carved details. Stone surface material may be lost all over or only in spots that are more reactive. You might expect that sheltered areas of stone buildings...
What is methane and why is it a safety concern? What is methane and why is it a safety concern?
Methane (a gas composed of carbon and hydrogen) is produced two ways: Through biologic decomposition of organic matter at shallow depths. Swamps, landfills, and even shallow bedrock are some settings where this occurs. Methane can also be derived over millions of years by high pressure and high temperature processes that produce fossil fuels deep underground. Examples include coal deposits and oil...