Our oceans, rivers, and lakes are always moving and changing.
Along the coast, tides rise and fall.
In the Great Lakes, water levels change with the seasons.
Strong winds push water around causing a dramatic rise or fall in water height.
Sea-level creeps higher every year,
causing more frequent and more severe coastal flooding.
We need accurate water level information
to know how changes in water height affect life on the coast.
Decision-makers use the data to protect lives, cities, and the environment,
and to boost the economy by ensuring safe maritime commerce.
NOAA Center for Operational Oceanographic Products and Services
operates the National Water Level Observation Network, or NWLON,
a system of water level sensors that form the backbone
of our nation's coastal observation infrastructure.
There are more than 200 stations around the United States, and its territories.
They monitor water level heights and other conditions,
such as wind speed and water temperature in near real-time.
The station's continuously take the pulse of the coastal ocean and Great Lakes;
recording data every six minutes and sending it to NOAA via satellite,
where it is published online.
NOAA uses the observations, along with ocean models,
to predict tides and forecast water levels, just like a weather forecast.
Some stations have been in place since the 1850s.
These long records give us an understanding
of how water levels have changed over time.
NOAA uses NWLON
to establish the nation's official vertical reference system
for water heights - what we call tidal datums,
and the International Great Lakes Datum.
A title datum is an elevation, defined from water level observations,
during a specific phase of the tide.
For example, the average of all low tides
forms the Mean Low Water Datum.
These datums provide a basis or zero level
for measuring local water heights and depths.
If you need to determine marine boundaries and property lines,
or decide how high above sea level to build,
or where to start a shoreline survey, you need to know the local tidal datums.
Many communities use and benefit from NWLON's reliable and accurate data.
The data is available online and decision-makers turn to it every day.
Most major seaports have a water level station.
Mariners use the data to navigate safely.
it helps them prevent accidents, while optimizing commerce
flowing through our waterways.
Just one additional inch of usable draft
can translate into millions of dollars of additional cargo per vessel transit.
Weather forecasters use water levels in coastal flood and storm surge forecasts,
and in warnings for hurricanes, nor'easters, and tsunamis.
Coastal managers and city planners use NWLON long records to protect roads,
buildings, and sewers, for more frequent and severe flooding, caused by sea level rise.
Ecosystem managers need water level information to restore marshes,
and rebuild coastlines.
and in the Great Lakes coastal managers use it
for water resource management and power generation.
NWLON is considered one of the most high impact,
high benefit Earth observing systems in the nation.
And while the network covers much of the coast,
it is not complete, especially in remote places like the Arctic.
We are slowly filling in the information gaps
through partnerships with communities,
so that they have the high quality information they need
to support their livelihoods and quality of life on the coast.