A flood is an overflow of water that submerges land, dry. In the sense of "flowing water", the word may be applied to the inflow of the tide. Floods are an area of study of the discipline hydrology and are of significant concern in agriculture, civil engineering and public health. Flooding may occur as an overflow of water from water bodies, such as a river, lake, or ocean, in which the water overtops or breaks levees, resulting in some of that water escaping its usual boundaries, or it may occur due to an accumulation of rainwater on saturated ground in an areal flood. While the size of a lake or other body of water will vary with seasonal changes in precipitation and snow melt, these changes in size are unlikely to be considered significant unless they flood property or drown domestic animals. Floods can occur in rivers when the flow rate exceeds the capacity of the river channel at bends or meanders in the waterway. Floods cause damage to homes and businesses if they are in the natural flood plains of rivers.

While riverine flood damage can be eliminated by moving away from rivers and other bodies of water, people have traditionally lived and worked by rivers because the land is flat and fertile and because rivers provide easy travel and access to commerce and industry. Some floods develop while others can develop in just a few minutes and without visible signs of rain. Additionally, floods can be local, impacting a neighborhood or community, or large, affecting entire river basins; the word "flood" comes from a word common to Germanic languages. Floods can happen on flat or low-lying areas when water is supplied by rainfall or snowmelt more than it can either infiltrate or run off; the excess accumulates in place, sometimes to hazardous depths. Surface soil can become saturated, which stops infiltration, where the water table is shallow, such as a floodplain, or from intense rain from one or a series of storms. Infiltration is slow to negligible through frozen ground, concrete, paving, or roofs. Areal flooding begins in flat areas like floodplains and in local depressions not connected to a stream channel, because the velocity of overland flow depends on the surface slope.

Endorheic basins may experience areal flooding during periods when precipitation exceeds evaporation. Floods occur in all types of river and stream channels, from the smallest ephemeral streams in humid zones to normally-dry channels in arid climates to the world's largest rivers; when overland flow occurs on tilled fields, it can result in a muddy flood where sediments are picked up by run off and carried as suspended matter or bed load. Localized flooding may be caused or exacerbated by drainage obstructions such as landslides, debris, or beaver dams. Slow-rising floods most occur in large rivers with large catchment areas; the increase in flow may be the result of sustained rainfall, rapid snow melt, monsoons, or tropical cyclones. However, large rivers may have rapid flooding events in areas with dry climate, since they may have large basins but small river channels and rainfall can be intense in smaller areas of those basins. Rapid flooding events, including flash floods, more occur on smaller rivers, rivers with steep valleys, rivers that flow for much of their length over impermeable terrain, or normally-dry channels.

The cause may be localized convective precipitation or sudden release from an upstream impoundment created behind a dam, landslide, or glacier. In one instance, a flash flood killed eight people enjoying the water on a Sunday afternoon at a popular waterfall in a narrow canyon. Without any observed rainfall, the flow rate increased from about 50 to 1,500 cubic feet per second in just one minute. Two larger floods occurred at the same site within a week, but no one was at the waterfall on those days; the deadly flood resulted from a thunderstorm over part of the drainage basin, where steep, bare rock slopes are common and the thin soil was saturated. Flash floods are the most common flood type in normally-dry channels in arid zones, known as arroyos in the southwest United States and many other names elsewhere. In that setting, the first flood water to arrive is depleted; the leading edge of the flood thus advances more than and higher flows. As a result, the rising limb of the hydrograph becomes quicker as the flood moves downstream, until the flow rate is so great that the depletion by wetting soil becomes insignificant.

Flooding in estuaries is caused by a combination of storm surges caused by winds and low barometric pressure and large waves meeting high upstream river flows. Coastal areas may be flooded by storm surges combining with high tides and large wave events at sea, resulting in waves over-topping flood defences or in severe cases by tsunami or tropical cyclones. A storm surge, from either a tropical cyclone or an extratropical cyclone, falls within this category. Research from the NHC explains: "Storm surge is an additional rise of water generated by a storm and above the predicted astronomical tides. Storm surge should not be confused with storm tide, defined as the water level rise due to the combination of storm surge and the astronomical tide; this rise in water level can cause extreme flooding in coastal areas when storm surge coincides with spring tide, resulting in storm tides reaching up to 20 feet or more in some cases." Urban flooding is the inundation of land or property in a built environment in more densely populated areas, caused by

Lawrence Poitras

Lawrence A. Poitras is a retired judge in the Canadian province of Quebec, he is best known for serving on an inquiry into the wrongful conviction of Donald Marshall and overseeing a high-profile public inquiry into the Sûreté du Québec. Poitras has a Bachelor of Arts degree from McGill University and a law degree from the Université de Montréal, he worked as a journalist with the Montreal Star before training as a barrister. He started a private law practice in 1957 and was named as a Queen's Counsel in 1973. Poitras was appointed as a justice of the Quebec Superior Court in 1975, became associate chief justice in 1983, was promoted to chief justice in 1992, he left the bench in 1996 and joined Borden Ladner Gervais LLP, from which he retired in 2007. In 1986, Poitras was appointed to serve on a three-person commission of inquiry examining the wrongful conviction of Donald Marshall, a member of Nova Scotia's Micmac community who served eleven years in prison for a murder he did not commit; the commission's seven volume report, released in 1990, described Nova Scotia's justice system as plagued by racism, unprofessionalism, unfairness.

The commissioners concluded that Marshall was "convicted and sent to prison, in part at least, because he was a native person," recommended an independent review process to investigate alleged cases of wrongful conviction, called for more members of visible minority communities to be appointed to the bench and hired for correctional services. In late 1995, Poitras appointed a single judge to oversee all aspects of former Canadian prime minister Brian Mulroney's libel suit against the Canadian Department of Justice and Royal Canadian Mounted Police regarding statements made by RCMP officials about Mulroney's dealings with businessman Karlheinz Schreiber. Poitras's decision was regarded as a procedural victory for Mulroney. Poitras was given discretion as to the inquiry's parameters and indicated that it would not be limited by a time frame; the 2,700-page report, issued in 1999, accused the force of abusing its powers of arrest, being more concerned with protecting its image than investigating misconduct, having an "unhealthy air of solidarity, expressed through the law of silence and retaliations" against dissident officers.

Poitras prepared a report on municipal de-mergers in the buildup to the 2003 Quebec municipal elections. He concluded. In 2005, he served as an election monitor in the Mohawk community of the Kanesatake

First Church of Christ, Scientist (Marshalltown, Iowa)

First Church of Christ, Scientist was a Prairie School church building located at 412 West Main Street, in Marshalltown, United States. Designed by architect, Hugh M. G. Garden, it was once on the National Register of Historic Places, but was bulldozed in August, 1985, was removed from the National Register. First Church of Christ, Scientist ** 412 W. Main St. Marshalltown Historic Significance: Architecture/Engineering Architect, builder, or engineer: Garden, Hugh M. G. Architectural Style: Prairie School Area of Significance: Architecture Period of Significance: 1900-1924 Owner: Private Historic Function: Religion Historic Sub-function: Religious Structure Current Function: Religion Current Sub-function: Religious Structure List of Registered Historic Places in Iowa List of former Christian Science churches and buildings First Church of Christ, Scientist National Register listings for Marshall County, Iowa National Register Weekly List, 5/22/98 Prairie School Traveler Book on Christian Science Churches Hugh Garden Library of Congress search: put in the name of this article to pull up holdings with 2 images