There is only one type of flood that can last over a year and that is the floods that occur in swamps floodplains and deltas. Some famous floodplains are the Okavango Delta of South Africa, the Sudd along the Nile, the Mekong Delta in Cambodia, and the lower Euphrates floodplain. Some years, the rain is minimal, and the flooding might last only a couple of months. In other years, the rain is so extensive, that the flooding can remain until the next rainy season. If the second year is minimal, the flood could end after one year and three months. Some river like the nile are reliable. The floods come every year and do not usually vary much. Other rivers, like the Euphrates vary radically. Some years, the river can dry up completely. This is a very flat region and the flood plain extends up to Baghdad at an elevation of 41 M. (~120 feet.) At almost 600 miles from the gulf, that means the land rise a measly 1/5 foot per mile. Thus, in a very wet year, and with plenty of snow in the Turkish mountains, the plains would remain flooded all year. Then, if the next year, the land receives almost no rain, the rainy season which ends in march, would soon thereafter see complete dry land. Remember, Baghdad receives an average of 2" rain per year. Anything under 8" per year is considered desert, so without the rivers, no one could live here. Thus, only flood plains fit the description that the flood lasted one year and three months. Among the flood plains, the ones with reliable floods, such as the Nile river, don't really match the description. Only floodplains along variable rivers like the Euphrates/Tigris complex do we have a solid fit.
The location of the flood is problematic if we assume a worldwide flood. We do have some clues as to the location of Noah. The first clue is that the Garden of Eden is near the Tigris and Euphrates rivers. Then we have the incident with sons of God marrying the daughters of men. The Nephilim were on the earth in those days. The only location we have for Nephilim is in Canaan. After the flood, there were several more clues. Men moved east and found the plain of Shinar, (apparently empty) and settled there. They made buildings with baked bricks and tar mortar. They decided to make a tower that reaches to the heavens. An empty Shinar would correlate to Sumer after the flood where baked bricks were used with tar mortar to build buildings and ziggurats, towers that were imitation mountains and reached into the first heaven, the sky. In Egypt, stone was used for the pyramids and brick buildings used mud mortar and later gypsum for mortar, and in Harrapa, though bricks were used, mud mortar or less commonly, gypsum was used. Tar was used rarely as a waterproof covering, but not as a mortar. Even the greeks used a lime mortar. Again, we see Sumer as the location of Noah and the Ark. A further connection to the area is Noah's descendants. The people mentioned in Gen 10 are not all the descendants but the ones that started Tribes, cities, or Nations. All the groups mentioned are located near Turkey, Syria, Iraq, and Palestine. The story of Nimrod might even be Sargon, for they conquered the same cities in the same order. Clearly, Noah is associated with the Tigris Euphrates valleys and most likely Sumer. Whether the flood was regional or world-wide, the setting is clear.
There are many statements that indicate a world wide flood. "an end to all people." "destroy all life under the heavens." "all the high mountains under the entire heavens were covered." similar statements were made but using terms like "all the earth" and "on dry land" instead of "the heavens." These are rather compelling statements that make the interpretation of that the flood covered the whole world rather compelling. To establish that it was a regional flood we have to see if another interpretation is reasonable. We can use three lines of reasoning. The words can be interpreted to mean region rather than world, the people spoke from a frame of reference rather than our modern understanding of the terms, and that the Bible frequently uses hyperbole for emphasis.