WEEKLY WATER NEWS

DataStreme WES Week Nine: 31 October--4 November 2005

Water in the News:

(Thurs.) Katrina and Rita tore up the marshes -- Hurricane damage to coastal marshlands turned 100 square miles into open water. This was normally 50 years of work by gradual natural processes. [USA Today]
(Thurs.) Tropical clouds to be studied in detail -- Scientists from the University of Manchester were setting off to study tropical clouds and associated aerosols in Australia in an effort to determine the role of clouds on climate change. They will focus on some of the tall clouds that reach the tropical tropopause to see how the clouds and aerosols affect the depletion of the stratospheric ozone layer. [EurekAlert!]
(Thurs.) NOAA studies water vapor plumes (atmospheric rivers) -- NOAA scientists are looking into the formation and behavior of streams of water vapor from the tropics to midlatitudes that are involved with heavy rain episodes and potentially deadly flash flooding. [NOAA News]
(Thurs.) Use of arms money for water urged -- The widow of former French President Francois Mitterrand recently began a campaign to make drinking water available to residents of the some of the world's driest regions. She argued that one percent of the money used annually for armament should be used in this endeavor. [ENN]
(Thurs.) Virginia Tech scientists work with EPA to develop biological indicators of water quality -- Researchers are studying how fish populations, aquatic insects and vegetation can all be used to aid water chemistry studies for stream health. [EurekAlert!]
(Thurs.) California delta is failing -- Fish populations in the network of rivers and streams in central California is plummeting. Apparently there is not sufficient water getting to San Francisco Bay due to heavy use and diversions that threaten the ecosystems allowing alien species to invade as well. [CNN]
(Thurs.) Ancient hurricanes leave their remains -- UNC Charlotte micropaleontologist has found fossil evidence in South Carolina back-barrier marshes of past intense hurricane activity. Forams from open sea areas have formed layers well inland, suggesting surges due to prehistoric hurricanes. [EurekAlert!]
(Tues.) Mangroves serve as an important defense -- The director of the Global Environment Centre in Malaysia reported that those coastal areas that had mangrove or other forests appeared to have suffered less damage from last year's major tsunami in the Indian Ocean than areas without forested vegetation. [EurekAlert!]
(Tues.) Climate change in Arctic has wide implications -- Researchers from a variety of disciplines at the University of Alaska-Fairbanks have reported on the effects that recent climatic change across the Arctic has had on the region's land, vegetation, animals, weather and human systems. [University of Alaska-Fairbanks]
(Tues.) Suburban streams have high pesticide concentrations -- A professor at the University of California, Berkeley and colleagues have detected high levels of a popular pesticide in the streams in suburban Sacramento streambeds, raising concerns of the effects upon aquatic life. [EurekAlert!]
(Tues.) Desertification tracked by satellites -- Representatives from the European Space Agency recently briefed delegates to a conference held by the United Nations Convention to Combat Desertification as to the role that satellites are used to track desertification across Europe. [ESA]
Role of water in an African oasis seen from space -- Images taken of southern Egypt's Safsaf Oasis by various instruments onboard NASA's orbiting satellites reveal the impact that water during wet times has had on the terrain around the oasis. [NASA]
Nicaragua belted by Beta -- Hurricane Beta, the 26th named tropical cyclone and the 13th hurricane of the extremely active 2005 North Atlantic hurricane season, made landfall along the Caribbean coast of Nicaragua on Sunday morning as a category 2 hurricane on the Saffir-Simpson Scale. Heavy rains and winds exceeding 100 mph battered Nicaragua and neighboring Honduras. [CNN]
Tropical cyclone forces evacuations in India -- A tropical cyclone (the Indian Ocean's equivalent to a hurricane) approaching the southeastern coast of India from the Bay of Bengal last Friday prompted Indian authorities to begin evacuating thousands of people [BBC News]
More on Wilma:
- Death toll from Wilma rises -- Florida officials reported that as of Saturday, the death toll from Hurricane Wilma had reached 21 people in the Sunshine State. The total death toll from this system as it left a path of destruction across Haiti, Jamaica, Mexico's Yucatan Peninsula and Florida was 38. [USA Today]
- Aerial survey taken of Wilma's damage -- NOAA's Remote Sensing Division conducted aerial survey missions of southern Florida last week, taking more than 1500 aerial images of the damage to the region produced by Hurricane Wilma. These images have been posted on a website. [NOAA News]
- Slow recovery for Mexican resorts after Wilma -- Some of the islands off Mexico's Yucatan Peninsula that are tourist areas sustained significant damage due to Hurricane Wilma, a category 4 hurricane that hit the region over one week ago, with only slow recovery expected. [ENN]
- Wilma's winds monitored from space -- The radar scatterometer instrument onboard the European Space Agency's ERS-2 satellite was able to acquire and rapidly transmit wind data to weather forecasters from Hurricane Wilma just before this powerful hurricane made landfall along Florida's southwest coast one week ago. [ESA]
Mississippi shrimp showing no elevated contaminants -- NOAA Fisheries Service officials recently announced that tests of the white shrimp caught off the coast of Mississippi in mid September showed no elevated levels of contaminants, even though some of these waters had received runoff and oil spills from Hurricane Katrina at the end of August. [NOAA News]
Recreation is now fine in Delta waters -- Federal and state officials in Louisiana recently announced that following testing after Hurricane Katrina, the waters of the Mississippi River's Delta are safe for recreational activities. [ENN]
Satellites help improve insurance risk modeling -- Satellite data obtained from the European Space Agency's satellites have been used to help model the impact of flooding in order to improve insurance risk modeling as part of the ESA Earth Observation Market Development project. The record flooding of the Elbe River in August 2002 was used as a case study in this investigation. [ESA]
Compromise sought for exporting Great Lakes water -- The National Wildlife Federation and the Council of Great Lakes Industries have been urging inclusion of a provision for the export of bottled water from the Great Lakes basin in a pending regional water use agreement between the state and provincial governments surrounding the lakes. [US Water News Online]
Pollution-free deicing system tested -- Officials with the Oslo, Norway airport and SAS airlines have announced the testing of an infrared system that would be employed to de-ice aircraft during this winter season rather than the more traditional glycol deicing agents, which can runoff and pollute the environment. [ENN]
Global and US Hazards/Climate Extremes -- A review and analysis of the global impacts of various weather-related events, including drought, floods and storms during the current month. [NCDC]
Global Water News Watch -- Other water news sources can be obtained through the SAHRA Project at the University of Arizona [SAHRA Project]
Earthweek -- Diary of the Planet [earthweek.com] Requires Adobe Acrobat Reader.

Concept of the Week: Seiche

You probably remember as a child agitating the bath water so that it sloshed back and forth in the tub. (If you never did this as a child, there's still time.) You produced a seiche, a phenomenon first studied in Lake Geneva, Switzerland in the 1700s. A seiche (pronounced "say-sh") is a rhythmic oscillation of water in an enclosed basin (e.g., bathtub, lake, or reservoir) or a partially enclosed coastal inlet (e.g., bay, harbor, or estuary). With this oscillation, the water level rises at one end of a basin while simultaneously dropping at the other end. A seiche episode may last from a few minutes to a few days.

A seiche is a standing wave. Whereas wind-driven waves (pages 181-182 in your DataStreme WES textbook) are progressive in that they propagate through a body of water, standing waves are stationary. With progressive waves, crests and troughs travel along the water surface but with standing waves, crests alternate vertically with troughs at fixed locations. For both progressive and standing waves, the restoring force is gravity.

With a typical seiche in an enclosed basin, the water level near the center does not change at all although that is where the water exhibits its greatest horizontal movement; this is the location of a node. At either end of an enclosed basin, vertical motion of the water surface is greatest (with minimal horizontal movement of water); these are locations of antinodes. The motion of the water surface during a seiche is somewhat like that of a seesaw: The balance point of the seesaw does not move up or down (analogous to a node) while people seated at either end of the seesaw move up and down (analogous to an antinode).

Go to the University of Delaware's Seiche Calculator at http://www.coastal.udel.edu/faculty/rad/seiche.html. Set the "Modal Number" to 1 and then press "Calculate" for a graphical simulation of a seiche in an enclosed basin.

Partially enclosed basins usually have a node located at the mouth (rather than near the center) and an antinode at the landward end. Go to the Seiche Calculator, set the "Modal Number" to 0.5 and then press "Calculate" for a simulation of a seiche in a basin open to the right. Furthermore, some basins are complex and have multiple nodes and antinodes; these can be simulated on the Seiche Calculator by selecting different values of "Modal Number" greater than one.

A seiche can be induced by wind, regional differences in air pressure, earthquakes, or tidal forces. For example, wind blowing persistently in the same direction down the long axis of a bay causes water to pile up at the downwind end of the bay. When the wind slackens, the water oscillates (as a seiche) back-and-forth from one end of the bay to the other until eventually the water calms to a horizontal surface. A line of thunderstorms moving eastward from Wisconsin in late May 1998 produced a seiche in Lake Michigan that killed several people by drowning at the southern end of the lake. Previous seiches have produced 8 to 10 ft waves on Lake Michigan. A tsunami generated a seiche in the harbor of Hilo, HI following a major earthquake in the Aleutian Islands on 1 April 1946.

The natural period of a seiche depends on the length and depth of the basin and generally ranges from minutes to hours: The period is directly proportional to basin length. For example, the natural period of a seiche in a small pond is considerably shorter than its period in a large coastal inlet. In addition, for the same basin, the natural period is inversely proportional to water depth; that is, the period shortens as water deepens. Using the Seiche Calculator, you may wish to experiment with different values of basin length and depth. Conversely, one can estimate the average depth of a lake by determining the period of the seiche and the length of the lake.

Usually a seiche in a lake or harbor is of little concern because the changes in water level are minor--often only a few centimeters. Under certain circumstances, however, a seiche may grow to great heights with serious consequences including flooding and damage to moored vessels. A seiche grows as a consequence of resonance, that is, when the period of the disturbance (e.g., wind, earthquake) matches the natural oscillation period of a specific basin. Recall again your youthful bathtub experience. By timing your rhythmic disturbance of the water to match the natural period of the tub (about one second), you were able to cause the seiche to build until the water splashed out of the tub and onto the floor. Through resonance, vibrations from the 1994 Northridge, CA earthquake caused swimming pools to overflow throughout Southern California. In bays open to the ocean, if the period of tidal forcing matches the natural period of the bay, resonance can greatly increase the tidal range.

Concept of the Week: Questions

Seiches are [(standing) (progressive)] waves.
The natural period of a seiche [(depends on) (is independent of)] the size of an enclosed basin.

Historical Events:

31 October 1876...A 10 to 50 ft storm surge ahead of the Backergunge cyclone flooded the eastern Ganges Delta in India (now Bangladesh). Over 100,000 people drowned. (The Weather Doctor)
31 October 1846...Eighty-seven pioneers were trapped by early snows in the Sierra Nevada Mountains that piled five feet deep, with 30 to 40 ft drifts. Just 47 persons survived the "Donner Pass Tragedy." (The Weather Channel)
31 October 1874...A waterspout (a tornado-like vortex that travels over water) formed over Lake Erie and reached the lakeshore approximately 0.5 mi west of Buffalo, MY. Upon reaching the shore, it dissipated, scattering sand in all directions. (Accord Weather Calendar)
31 October 1965...Fort Lauderdale, FL was deluged with 13.81 inches of rain inches over a two-day period (30^th-31^st), the second heavy rains in two weeks. This brought their rainfall total for the month of October to an all-time record of 42.43 inches. More road and street damage occurred and some homes were flooded for the second time. (David Ludlum) (The Weather Channel) (Intellicast)
31 October 1984...An exceptional thunderstorm at Al Wajh on the Red Sea coast of northern Saudi Arabia produced 4.81 inches of rain, which was more than the total rainfall there in the previous ten years. At Tabuk 150 miles to the north, 0.49 inches of rain fell to set a daily October rainfall record at that location. (Accord Weather Calendar)
1-6 November 1570...The All Saints Day Floods killed an estimated 400,000 people in Western Europe. (The Weather Doctor)
1 November 1861...A hurricane near Cape Hatteras, NC battered a Union fleet of ships attacking Carolina ports, and produced high tides and high winds in New York State and New England. (David Ludlum)
2 November 1946...A heavy wet snow began to cover the Southern Rockies. Up to three feet of snow blanketed the mountains of New Mexico, and a three-day snowstorm began at Denver, CO. By the time it ended, this storm had dropped 31 inches, making it the second greatest snowfall ever in city history and causing roofs to collapse. (David Ludlum)
2-4 November 1927...The "Great Vermont Flood" occurred as a two-day rain event totaling up to 15 inches at the higher elevations. The deluge put rivers in western New England over their banks and caused the worst flooding in the history of Vermont. Somerset, VT received 8.77 inches of rain to establish a 24-hour record for the state. (3^rd-4^th) The Winooski Valley was devastated. Eighty-four died in the Vermont town of Vernon. Flooding left up to eight to ten feet of water in downtown Montpelier. Across New England the flooding claimed 200 lives, caused $40 million in damage and halted traffic for days. (The Weather Channel) (Intellicast) (David Ludlum)
4-5 November 1966...The River Arno surged above flood stage and caused irreparable damage to much of the architectural and art treasure of Florence, Italy. Millions of historical library volumes were either damaged or destroyed. More than 15,000 vehicles were also destroyed. Roughly two-thirds of Florence was flooded, 113 people died and 30,000 were made homeless by the flooding on both the Arno and Po rivers. (Accord Weather Calendar) (Wikipedia)
5 November 1977...A slow moving storm produced five to nine inch rains across northern Georgia causing the Toccoa Dam to burst. As the earthen dam collapsed, the waters rushed through the Toccoa Falls Bible College killing three persons in the dorms. Thirty-eight persons perished at a trailer park along the stream. Eighteen bridges were washed out in Madison County. (David Ludlum)
5 November 1987...Heavy rains in California's Death Valley National Park washed out many park roads. As much as 1.20 in. of rain fell at Scotty's Castle, compared with the annual rainfall average of 2.28 in. Up to 8000 people attending a recreational encampment were stranded. (Accord Weather Calendar)
6 November 1994...Downtown San Francisco, CA was drenched with 6.19 in. of rain in 24 hrs to set an all-time record for the city.
6-13 November 1969...Severe ice storm between Quebec City and Manicouagan River power dams in Quebec caused over $1.5 million damage to transmission lines and towers. Over 30 transmission towers under construction were brought down. (The Weather Doctor)