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Monitoring of Water Quality and Land Use Changes in the Lake Titicaca Basin

Lake Titicaca's watershed experience is very complex. It is the largest lake of South America, the highest navigable lake in the world located on the highest plateau in Andes at 3,657 to 4,000 meters. The high levels of solar radiation and the high rate of evaporation make the system very vulnerable, particularly to pollution problems.

The lake’s basin is located on the border between Peru and Bolivia and comprises of the hydrological system of approximately 140,000 square kilometers including three other water basins: Desaguadero River basin, Lake Poopó basin and Coipasa Salt Lake basin. Of the five major rivers flowing into the lake, four run through the Peruvian territory.  The trans-boundary character of the lake is one of the biggest challenges related to its sustainable management along with sharp population increase, fast-pacing urbanization and the fact that most of the agricultural activities are located in the areas surrounding the lake. In fact, the main environmental concerns are organic and bacteriological contamination caused by improper agriculture practices (fertilizers and pesticides runoff), urban wastes (solid waste, sewage discharge and lack of secondary waste water treatment which generates a process of eutrophication) as well as mining (dumping of wastewater from mines is deemed a principal cause of heavy metal contamination and alarming concentrations of cadmium, arsenic, and lead in various parts of the lake.) UNEP estimates that by 2025, the volume of wastewater in the basin will double, which in turn may lead to the disappearance of fish and aquatic life, among other adverse environmental impacts.

Local communities depend on the lake resources for their economic livelihoods and well-being therefore the protection of the long-term water quality and ecological integrity is one of the long term priorities. The central concern is to reduce the flow of nutrients and pollutants, and reverse some of the adverse environmental developments of the past.

The creation of a Bolivia-Peru Binational Autonomous Authority of Lake Titicaca (ALT, Autoridad Binacional del Lago Titicaca Bolivia-Perú) in 1996 addressed some of the transboundary issues related to water resources management, including the need for appropriate institutional and regulatory frameworks. The main challenges, however, are related the persistent lack of reliable data on the water parameters, incomplete inventories of pollution hot-spots and outdated water resources management plans. ALT, working along with UNEP, is currently engaged in addressing some of the problems with defunct water-quality monitoring stations and laboratories, improving data collection and data dissemination, providing platforms for sharing and consolidating available information, and promoting standardization of information generated by different institutions.

Collaboration with the European Space Agency

National-level authorities in both Bolivia and Peru as well as international organizations such as ALT, UNEP and the World Bank are increasingly involved in creation of a shared vision of Lake Titicaca sustainable management. The World Bank has partnered with the European Space Agency to enhance the mechanisms for the protection of the lake's long-term water quality and ecological vitality with the use of innovative satellite-based Earth Observation applications.

To address the problem with the lack of area-wide reliable data on the water parameters ESA set up a pilot monitoring system for a systematic observation of temporal and spatial dynamics of the Lake. The observation system was specifically designed to look at ecological and environmental rather than administrative borders of the Lake Titicaca basin facilitating regional integration. As a result it  provided first-of-its-kind harmonized water quality information concerning the flow of nutrients and pesticides to the lake. Moreover, the combination of the water quality information with detailed analysis of land use trends gave a clear evidence of how changing land use affects the status of water bodies.

Taken as a whole the project represents validated options for the future systematic, consistent and cross-boundary data collection method.  Such information can be used for a multiple applications in environmental monitoring answering some key questions:

  • Where are hot spot areas suffering from water pollution?
  • Where does the pollution come from?
  • Which are the best counter measures to keep or improve water quality?

Monitoring of land use (2003-2010)

 Lake Titicaca Land Use Change Puno Bay (c) GAF

Figure1: Land use change map (2003-2010). Credit: GAF 

The observations covered 47,000 square kilometers of the basin territory creating the most comprehensive and detailed land cover inventory produced  for this area to date. The land use maps give detail overview of the fourteen land use classes (forest, major agricultural surface types, settlements, primary roads, bare soil, water bodies, rivers, and wetlands) including conservation areas (treated as a separate class). The land use change analysis focuses on the basin’s wetlands, known for their biodiversity value, as well as agricultural land to address three major environmental concerns: soil erosion, land degradation and succession of water bodies by other types of land cover.

Further advantage of the land use mapping is the possibility to analyse their content with a specific thematic focus. For instance the World Water Development Report (WWDR, 2003) has indicated that while most of the crop production area in Bolivia is located in the areas surrounding Lake Titicaca, only 17 percent of the total basin area is truly suitable for crop production. The EO-based analysis revealed that expansion of agricultural activities affects other vegetation and ecosystem types such as water bodies, rivers, wetlands an forests. Collected land use data also provided the first evidence of the alarming rate of receding water levels of the Lake Titicaca and revealed a succession of water bodies by wetlands, reeds and agricultural land. The estimated loss of the shoreline amounts to as much as 100km while the retreat of water area is an equivalent of the 7 percent of the lake extent.

Lake Titicaca land use statistics (c) GAF

Figure2: Change Statistics for the LUCM2010/2003. Credit: Eoworld project, GAF for European Space Agency/World Bank

The study has also revealed that the Reserva Nacional del Lago Titicaca at the Puno Bay — which is an area protected as a RAMSAR Convention and an important wetland/breeding ground for endemic species— is facing unprecedented changes in land use: a fast emergence of shrubs/grassland, agriculture surface types and bare soil.

Pollution hotspots

This is the first time such EO-based information has been generated for the Lake Titicaca basin addressing the following key questions:

  • Where are hot spot areas suffering from water pollution?
  • Where does the pollution come from?
  • Which are the best counter measures to keep or improve water quality?

The EO-based water quality monitoring is a very powerful scientific tool used to improve the understanding of the impact of sediment-bound nutrient and contaminants on the various aquatic ecosystems. This information is extremely helpful in managing pollution hot spots caused by organic and other types of contamination, including eutrophication sources and mechanisms, nutrient concentrations, pollution, turbidity, sediment and phosphorus flows into the water bodies.

In the Lake Titicaca basin poor waste disposal from all the important urban centres as well as coastal villages surrounding the lake is the central cause of organic pollution. The most polluted areas located on the Peruvian side are within the Puno's interior bay, the Torococha River and the lower course of the Coata River. On the Bolivian side the hot spot areas are within the Cohana Bay, northwest of La Paz.

The satellite-based analysis confirmed the alarming trends of eutrophic process in the Puno Bay (likely resulting from the untreated sewage and agricultural run-off carrying fertilizers). In the South Eastern part of the Lake (Lake Huiñaymarca, which includes Cohana Bay and its tributaries: Rio Seco, Pallina and Katari) some regression in water quality was also observed. Moreover, increased nutrient concentrations are frequent near Golfo de Achacachi and the Ramis River Delta.

Lake Titicaca pollution hotspots (c) EOMAP

Lake Titicaca Total Suspended Matter (TSM) derived from ENVISAT images (c) EOMAP

  Figure3: (Up) Examples of satellite RapidEye retrieved total suspended matter in 50m (left) and 5m (right) resolution for the northern and central part of Lake Titicaca. (Left) Examples of satellite MERIS retrieved products for total suspended matter (TSM) concentration. Credit: Eoworld project, EOMAP for European Space Agency/World Bank

There are many environmental and health concerns with regard to toxic waste and mineral residues inflow to the lake, a phenomenon usually correlated with sediments being flushed out from the mines up the river streams or with dumping of the industrial wastewater. Satellite TSM analysis measuring sediments and other depositions originating from the rivers is a good source of information to support the analysis of origins of such pollutants. For example, according to UNEP the Ramis River and River Suches are particularly affected by physical (suspended solids) and chemical (heavy metals) contamination. Indeed, satellite analysis shows spatial peculiarities in both Ramis and Suches rivermouths having transboundary effect on the entire lake. 

 

Satellite retrieved water quality information:

The project demonstrated the flexibility towards integration of different satellite sensors (such as ENVISAT MERIS, MODIS Aqua/Terra and RapidEye) to measure increased chlorophyll and suspended matter distributions. The results are provided in 5m, 50m and 300m scale resolution. These datasets were used:

  • to provide an ecological evaluation of Lake Titicaca with respect to the relevant water quality parameters for phytoplankton and chlorophyll concentration, total suspended matter and turbidity,
  • to identify the location, the spatial and temporal impact of hot spots areas such as river inflows, 
  • to increase the spatial and temporal resolution of the measurements, and optimize the survey planning by integration of EO data with standard ground truth sampling methods, and 
  • to provide an independent, area-wide long-term monitoring instrument with standardized and comparable water quality products, that are generated independently on ground truth data.

The JAGUAR PLAN: Future Options of Lake Titicaca Monitoring

In 2008, the European Space Agency commissioned a feasibility study for development of the Lake Titicaca Territorial Observatory to demonstrate the potential of EO products for various lake monitoring and development tasks. Plan Jaguar was implemented in 2009 and defined steps for the creation of the Lake Titicaca Territorial Observatory.

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Last updated: 2012-08-15




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