Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Schematic diagram of key processes governing water and salt balances in a polder. The blue arrows depict the movement of water without salt—rainfall and evapotranspiration. The brown arrows for the movement of water and salt between the rivers, groundwater, surface canals and ponds, and the soil. GW denotes groundwater.
