Bank, usually of earth, constructed to control or confine water. Dikes were purely defensive at first but later became a means to acquire polders (tracts of land reclaimed from a body of water through the construction of offshore dikes roughly parallel to the shoreline). After a dike is built, the polder is drained by pumping out the water. Where the land surface is above low-tide level, tide gates discharge water into the sea at low tide and automatically close to prevent reentry of seawater at high tide. To reclaim lands that are below low-tide level, the water must be pumped over the dikes. The most notable example of polder construction is the system adjacent to Holland's IJsselmeer (Zuider Zee) barrier dam. If The Netherlands were to lose the protection of its dikes, its most densely populated portion would be inundated by the sea and rivers.
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According to the United States Census Bureau, the city has a total area of 1.3 square miles (3.4 km²), all of it land.
There were 379 households out of which 33.0% had children under the age of 18 living with them, 63.6% were married couples living together, 6.3% had a female householder with no husband present, and 27.2% were non-families. 24.5% of all households were made up of individuals and 10.6% had someone living alone who was 65 years of age or older. The average household size was 2.49 and the average family size was 2.97.
In the city the population was spread out with 25.7% under the age of 18, 8.2% from 18 to 24, 26.9% from 25 to 44, 24.9% from 45 to 64, and 14.3% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 99.2 males. For every 100 females age 18 and over, there were 95.8 males.
The median income for a household in the city was $65,750, and the median income for a family was $55,518. Males had a median income of $45,000 versus $28,321 for females. The per capita income for the city was $20,532. About 2.2% of families and 4.7% of the population were below the poverty line, including 6.1% of those under age 18 and 3.3% of those age 65 or over.