Dr. Mark Lander

Dr. Mark Lander
Professor of Water Resources Engineering


Phone: 671-735-2690 (fax 734-8890) (GMT+10 hrs)
mlander(weri)uguam.uog.edu?subject=Faculty - WeriGuam.org

Ongoing Projects

Pacific ENSO Applications Center

The Pacific ENSO Application Center (PEAC) was formally established in 1994 and funded by the National Oceanic and Atmospheric Administration (NOAA). It was among the first areas of the world to develop such a center. This center has been a collaborative effort between NOAA's Office of Global Programs (OGP), NOAA National Weather Service (NWS) - Pacific Region, University of Guam (UOG), the University of Hawaii (UH), and the Pacific Basin Development Council (PBDC). The goals of PEAC are to tailor products of global ENSO prediction models to the Pacific region and to interpret and dissemination regional forecasts to public and private policy officials in the Pacific islands.

To achieve these goals, the activities of PEAC revolve around two components, research and outreach. The research components include:

  • A study of the regional climatology.
  • Development and publication of regional synoptic climatology.
  • Development of a statistical rainfall forecast model.
  • Development of sea level statistics and correlations.
  • Evaluation of and feedback on the performance of climate models from other agencies and institutions.
  • Evaluation of the forecasts in the PEAC Newsletter.

The outreach components include:

  • Providing tailored ENSO advisories and forecasts.
  • Publishing a quarterly bulletin which includes information on El Nino and climate predictions for the region.
  • Presenting on-island workshops to interpret the predictions for decision makers and to offer suggestions for local water resources management.

This project was initiated in response to relatively high levels of mercury being detected in fish from the Micro Beach area in the northern section of Garapan Lagoon, Saipan. Soil from drainage basins within the Garapan area and sediments from the coastal belt are currently being analyzed in an attempt to locate possible terrestrial source of contamination and identify drainage pathways into the lagoon. Biotic representatives from this popular fishing spot are also being considered. Potential sources of mercury contamination so far identified include the local hospital and a newspaper printing press. Soil from a drainage ditch in the grounds of the former site contained in excess of 1200 ng Hg/g dry weight of soil -- approximately 40 times higher than normal background levels. Expected completion date: Summer 2008. (Funding source: NOAA).

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Rainfall and Stream Flow Measurements on Pohnpei Island

The USGS sponsored a project to study the weather and climate of Pohnpei to include: general rainfall statistics, a summary of the annual distribution of rainfall, and an examination of the return periods of short-term high-intensity rainfall events; the effects of ENSO on the climate and weather of Pohnpei; a summary of tropical cyclones affecting the island; and, an examination of month-to-month, inter-annual, and inter-decadal variations in mean annual rainfall. The distribution of rainfall on Pohnpei is affected by the topography, and the mean annual rainfall totals among recording stations on Pohnpei differ by as much as 150 inches! The region in the vicinity of Pohnpei's international airport receives the lowest annual total of about 120 inches. The highest measured annual average of approximately 325 inches occurs atop Nahna Laud in the highland rainforest of Pohnpei's interior. Charts of Pohnpei's mean annual rainfall were produced from the first year of data collected from the WERI/CSP rain gage network. Earlier charts of Pohnpei's mean annual rainfall using PRISM were found to be quite accurate. Future refinements are expected. The Pohnpei rain record is too short to develop accurate return periods of extreme rainfall events (although attempts were been made for this project and by others that may be refined as more data is gathered). More rain records need to be collected in typhoons and throughout the ENSO cycle to produce reliable tables of return periods for short-term extreme rain events. In any case, intensity-duration-frequency tables were generated with the existing short Pohnpei rainfall data sets. The rainfall data is now complementing a network of stream flow gages. A thorough study of several of Pohnpei Island's major watersheds is now possible. Important questions to be addressed include the impact of human activities on the freshwater resources of the island. Local residents believe that the stream flows on the island have been altered by natural and human causes to include such things as: (1) Forest clearing for sakau growing; (2) Dug wells for municipal water; (3) Residential construction and expansion; and lastly, (4) Climate change.

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Ground Water Under the Direct Influence of Surface Water Determination for Guam.

The highly fractured nature of Guam's ‘karst’ limestone aquifer allows for rapid recharge of groundwater reserves during storm events. This characteristic can also facilitate the transport of sediments and other waterborne contaminants into the aquifer including pathogenic organisms associated with human and animal waste. Not surprisingly then, it has been suggested that Guam's aquifer should be classified as 'groundwater under the direct influence of surface water' (GWUDI) in accordance with recent USEPA guidelines. The implications of a GWUDI designation are clear. Wells within the northern Guam lens aquifer (NGLA) would require regulation under the Surface Water Treatment Rule (SWTR) as “Subpart H” surface water systems, would have to be appropriately monitored and disinfected, and would either have to install and operate filtration systems, or meet filtration avoidance criteria. In addition, long-term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR) requirements would mean Cryptosporidium, E. coli and turbidity monitoring for each well. This would be an expensive and problematic burden for Guam, and would not obviously provide commensurate additional public health protection. A recent cost estimate for complete GWDUI compliance by the Guam Waterworks Authority (GWA) was $145 million. In the absence of any data highlighting the necessity for implementing such measures, the USEPA agreed to a deference of the GWUDI declaration pending the completion of a sound, scientific investigation to determine seasonal water quality changes in the NGLA. Correlating measurable increases in aquifer turbidity with significant storm events is of fundamental importance to the success of such a program. Other indicators of aquifer vulnerability during wet season conditions include changes in temperature, conductivity, hardness, microscopic particle characteristics, coliform bacteria detections and coliphage detections. This project addresses the collection and analysis of the rainfall data necessary to provide a meaningful interpretation of all other parameters measured in the GWUDI program. It also addresses collection, analysis and correlation of coliphage data with the rain event data. (Funding source: US Environmental Protection Agency and Guam EPA).

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