Mario Freitas Feb 13, 2016:

English lessons When a term is used as an adjective, it is not used in the plural form: 10-year plan, not 10-years plan; ten-thousand-year flood, not ten-thousand-years flood.
When it is used as a noun with a number greater than 1 before, it must be in the plural form: Once in ten millenia, once every ten years.
But I'm not a "native speaker" so I'm probably wrong, huh?

Lara Barnett Feb 13, 2016:

e também a nota ...the plural of year is "years"...

Mario Freitas Feb 13, 2016:

Só para constar, O plural de "millennium", em inglês, é "millennia". Trata-se de termo em latim.
https://en.wiktionary.org/wiki/millennia

Mario Freitas Feb 12, 2016:

I would say Is this an unquestionable reference, now?
U.S. Department of the Interior | U.S. Geological Survey

Matheus Chaud Feb 12, 2016:

Additional references https://www.google.com.br/search?sourceid=chrome-psyapi2&ion...

Matheus Chaud Feb 12, 2016:

Absolutely normal I agree with Mario and that's the way it is used by specialists.
In fact this kind of structure seems to be normal. It is pretty obvious that a ten-thousand-year flood is not a flood that lasts 10,000 years. Only a very uncooperative reader would understand it that way.

The same applies to "a thousand-year flood", "a hundred-year flood", and so on. Even Wikipedia users know that:

https://en.wikipedia.org/wiki/100-year_flood

"100-year flood

A one-hundred-year flood is a flood event that has a 1% probability of occurring in any given year. The 100-year flood is generally expressed as a flowrate. Based on the expected 100-year flood flow rate in a given creek, river or surface water system, the flood water level can be..."

Technically, that is the way we refer to the probability of a flood.

More references:

U.S. Department of the Interior | U.S. Geological Survey
http://water.usgs.gov/floods/events/2015/Joaquin/HolmesQA.ht...
"Is this flooding in South Carolina truly a 1000-year flood?"

Title of a book:
http://www.amazon.com/The-Thousand-Year-Flood-Ohio-Mississip...
The Thousand-Year Flood: The Ohio-Mississippi Disaster of 1937

Mario Freitas Feb 12, 2016:

Actually, In the documents we are translating, they sometimes use 10000 YF in some places where the space is even shorter.

Mario Freitas Feb 12, 2016:

Engineering Jargon This may sound like a flood that lasts 10,000 years for the ears that are not used to the engineering jargon. However, while translating an engineering document, we must use the standard term used by the engineers, no matter how bad it sounds to our ears. The Vale/Samarco official glossary uses the term 10,000-year flood, as a reference value, a variable or constant that has a reduced name as it is used in tables, formulas, etc. So, it does sound weird, but the engineers konw well what it is.
Richard's suggestion is perfect; however, the reduced and universal form is meant to be used in reduced spaces, and that's why it is a bit strange.
Now, if your client uses another term, found in dictionaries and not in engineering sites, I would advise you ask them what they prefer.

Richard Purdom Feb 12, 2016:

Maria, the most accurate description is 'flood with a 10,000-year return period', see https://www.ferc.gov/industries/hydropower/safety/initiative...

Mario Freitas Feb 10, 2016:

@ Maria, Se você porventura estiver trabalhando para a GeoText, Vale ou Samarco, pode ir na sugestão do Matheus de olhos fechados. Recebemos um glossário da Vale/Samarco traduzindo "cheia decamilenar" como ten-thousand-year flood ou 10,000-year flood. O glossário está disponível no FTP da GeoText.