Challenges of Data Integration in the Study of a Complex System: A Case Study of Lake Atitln in Guat


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Challenges of Data Integration in the Study of a
Complex SystemA Case Study of Lake Atitlán in
Guatemala
Edwin J. Castellanosa Maricruz de Mejíaab
Beatriz Lópezb Nancy Giróna and Willy Knedela
a Universidad del Valle de Guatemala b
Medical Entomology Research and Training
Unit/Guatemala-CDC
SITE DESCRIPTION

• Lake Atitlán is a very deep lake (340 m) of
  volcanic origin located in the highlands of
  Guatemala at 1562 m above sea level.
  
• The lake has no surface outlets underground
  fissures and seep holes allow water to filter to
  two rivers draining to the Pacific.
  
• Lake sides are steep due to its geological
  origins. The lake lies in a heavy seismic zone.
  
• Hundreds of thousands of Mayan inhabitants
  belonging to two linguistic groups have lived
  there for centuries. More recently the crystal
  blue lake has attracted thousands of tourists
  from around the world.
• The lake and its watershed were declared a
  National Park in 1955. To date no conservation
  laws are enforced in the area.
  
• The region is considered one of the poorest in
  the country with high rates of illiteracy and
  public health problems.

Town of Sololá
Town of San Lucas
GENERAL RESEARCH QUESTION
How can we use physical and chemical water
quality parameters as integrative indicators of
the effects of human-induced changes on the
resources of a lake watershed
METHODS

• Landsat TM images from 1986 and 1996 were used to
  examine patterns of land use and land-cover
  change for the region.
  
• Special emphasis was placed on differentiating
  coffee plantations from natural forests given the
  importance of that crop on the land-use dynamics
  for the region. Band 6 (thermal) of the images
  proved to be crucial in achieving this goal.
• A complete GIS system was developed for the area
  that included physical and social features.
  
• Water quality parameters were measured in situ at
  28 sites around the lake during the dry (April)
  and rainy (September) seasons. Each site was
  located using a GPS. Samples were brought back
  to the lab for more sophisticated microbiology
  and chemical analyses.
• Relevant socio-economic indicators for the 11
  municipalities that surround the lake were
  compiled from various sources.

Pumping water to analyze for Giardia
SITE LOCATION
Onion plantations near San Pablo