Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Landslides: How rainfall dried up Panama's drinking water

18.05.2011
To understand the long-term effects of a prolonged tropical storm in the Panama Canal watershed, Robert Stallard, staff scientist at the Smithsonian Tropical Research Institute and research hydrologist at the U.S. Geological Survey, and Armando Ubeda, the LightHawk Mesoamerica program manager, organized four flights over the watershed to create a digital map of landslide scars.

Two feet of heavy rain inundated the Panama Canal watershed between Dec. 7 and 10, 2010. Landslides tore down steep slopes, choking rivers with sediment and overwhelming Panama City's water-treatment plant. Flooding closed the Panama Canal for the first time since 1935. Despite the deluge, the influx of sediments in the water forced authorities to shut down the plant, leaving a million residents of central Panama without clean drinking water for nearly a month.

LightHawk, a conservation organization based in the U.S., donates flights for research and conservation efforts. Retired United Airlines captain David Cole flew the Cessna 206 aircraft, and the four flights yielded images of 191 square miles (495 square kilometers) of watershed. Stallard observed numerous new landslide scars left behind by the December storm, supporting his prediction that landslides supplied much of the suspended sediment that disrupted Panama's water supply.

The new watershed erosion map will allow Stallard and collaborators from the Panama Canal Authority to calculate the landslide risk of future storms and direct strategies to minimize the effect on Panama's water supply.

Tropical hydrologists agree that river-borne sediment originates from surface erosion or from deep erosion from landslides. In 1985, Stallard predicted that "deep erosion, not shallow surface erosion, is the primary process controlling the chemistry and sediment levels in many tropical rivers that pass through mountainous areas." Few studies have been conducted to test this prediction.

Deforestation of steep slopes is the primary factor determining the number of landslides. Six decades of aerial photographs analyzed by USGS researchers in similar landscapes in Puerto Rico showed that landslide frequency doubles outside protected nature preserves, and that roads and infrastructure make landslides eight times more likely. Although landslides happen in natural forests, the objective is to limit their impact through appropriate land-use practices.

"With development, landslide intensity increases dramatically," said Stallard. "In its history, the Panama Canal watershed has experienced huge floods. It's still hard to say whether future floods will be accompanied by disastrous landslides like those produced by Hurricane Mitch in Central America." In 1998, Hurricane Mitch swept across Honduras, Guatemala, Nicaragua and El Salvador causing more than 10,000 deaths and incalculable economic damage. Panama's proximity to the equator puts the country outside the usual hurricane zone, but prolonged tropical storms may occur.

Erosion control is possible. Partnering with the Panama Canal Authority and Panama's Environmental Authority, the Smithsonian is conducting a 700 hectare experiment in the canal watershed funded by the HSBC Climate Partnership to compare the effects of land-use choices, such as cattle ranching or reforestation with native tree species on water supply, carbon storage and biodiversity. Stallard hopes that this research will provide new information about which land uses provide a steady supply of clean water for the Canal.

With the first rains in May, the eight-month wet season begins anew in central Panama. Drinking water flows freely, the rivers are clear and the Panama Canal is open for business. But bare slopes of past landslides continue to create secondary erosion, which will dislodge sediments from the steep, rainy and rugged Panama Canal watershed in 2011. The long-term effects of the 2010 storm may continue as renewed interruptions in the water supply in 2011.

The Smithsonian Tropical Research Institute, headquartered in Panama City, Panama, is a unit of the Smithsonian Institution. The Institute furthers the understanding of tropical nature and its importance to human welfare, trains students to conduct research in the tropics and promotes conservation by increasing public awareness of the beauty and importance of tropical ecosystems. Website: www.stri.org

Beth King | EurekAlert!
Further information:
http://www.si.edu

More articles from Earth Sciences:

nachricht In times of climate change: What a lake’s colour can tell about its condition
21.09.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)

nachricht Did marine sponges trigger the ‘Cambrian explosion’ through ‘ecosystem engineering’?
21.09.2017 | Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum GFZ

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>