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Project
Impacts of Climate Change on Catchment Runoff for the Paute River Basin in the Southern Ecuadorian Andes
K.U.Leuven SBA Phd scolarship
1. Preamble
The National Park Cajas is only 35 km from the city of Cuenca. The altitude of the Park ranges from 3,000 to 3,500 m. The Park measures nearly 30,000 ha (300 km2), contains mountains and 232 glacial lagoons, interconnected by small rivers and streams. Two of the main rivers surrounding Cuenca, the Tomebamba and the Yanuncay, begin in the National Park. The most common vegetation includes paramo grasses, polylepis, romerillo, chachacoma, genciana, romerillo and the sarar. The annual rainfall ranges from 800 to 2000 mm, the evapotranspiration due to the low average temperatures varies between 350 and 1200 mm, resulting in an rainfall excess which thanks to the specific characteristics of the plant-soil system is gradually and fairly uniformly released throughout the year, securing the water supply to the City of Cuenca and its surroundings, being the 3rd largest city of Ecuador. The population density of Cuenca city and the strongly urbanized surrounding communities is estimated at 600,000 inhabitants. The lagoon system of Cajas is the major water source for domestic, industrial and agricultural use. Among the industrial uses, the major players are the hydro-electrical plants, of which the Paute plant is the largest of Ecuador, producing 50% of the nations electricity. Plans of new hydro-electrical plants are on the drawing table as to meet the increasing demand for electricity.
The conservation of the water resource system of Cajas National Park, being a fragile ecosystem, is becoming crucial important, and this for the following two reasons:
(1) The rapidly expanding population of the country, and in particular of the Provinces of Azuay and Cañar in which the National Park is situated, leads to a further occupation of the land by the indigenous people which convert the paramo landscape to grassland for cattle grazing and crop farming.
(2) Climate change will induce warmer temperatures year-round, which will be more pronounced in the mountain range than at sea level. It is expected that the increase in temperature might be detrimental for the paramo vegetation which stretches over the Andean mountain range, and eventually could result in a change to other vegetation types which are less effective in water storage and the replenishment of the glacial lagoons. It is reckoned that disappearance of the paramo-ecosystem might have large, and possibly catastrophic, implications for the countrys economy and for human life.
The effect of both phenomena on the hydrological cycle will result in an increase in peak flows with increased flooding hazard in the downstream regions, and a reduction of the storage capacity of the paramo-ecosystem with the consequence that during drier periods insufficient runoff water will be available to sustain the operation of the hydro-electrical centrals, irrigation schemes, the supply of potable water and water for industrial activities.
2. Objectives
The objective of the research is to gain a better understanding of both mechanisms and consequences related to the disappearance of the paramo-ecosystem by human interference and climate change. Increased knowledge on how fast the paramo-ecosystem degenerates and how much this will affect future runoff and water availability from the Andes should form the basis for the formulation and testing of future mitigation and adaptation strategies. More in particular, the research aims at better understanding the interaction between the paramo-ecosystem and the glacial lagoon system of Cajas National Park.
3. Methodology
The research will be conducted at two different scales, i.e. the impact of human interference on the degradation of the paramo-ecosystem will be studied on microbasins in the paramo of Cajas National Park, and the effect of climate variability and change will be examined on regional scale.
3.1. Assessment of the human induced degradation of the paramo-ecosystem on the runoff and water storage
Research activities will consist in conducting a detailed survey of microbasin-lagoon systems with varying degree of human interference. Use will be made of the pioneering work conducted in this field and reported in the doctoral dissertation of Dr. Wouter Buytaert. Dataseries on climate and runoff will be continued and used for the hydrological analysis of those systems, and for quantifying the impact of human interference on the water storage and runoff. This requires the derivation of a databased hydrological model, the determination of model parameters, model calibration and validation, and the formulation of scenarios mimicking human impact in a format useable by the selected modelling tool.
3.2. Assessment of the degradation of the paramo-ecosystem should climate change proceed
Two main research activities can be distinguished, i.e. the reconstruction of the climate variability and change in the Andes under both present-day conditions and different IPCC-SRES emission scenarios with regional climate models, and relating vegetation changes to climate change. In the doctoral thesis of Dr. Rolando Celleri already a good basis of the present-day climate system of Cajas National Park and the surrounding region is available. For the construction of the future climate use will be made of the downscaling of regional climate models, for which assistance will be searched for by INAMHI (Instituto Nacional de Meteorología en Hidrología, Quito-Guayaquil, Ecuador). For the assessment of the potential evolution of the paramo-ecosystem as a function of climate change cooperation will be searched for by CONDESAN (Consorcio para el Desarrollo Sostenible de la Ecorregión Andina, Dr. Bert De Bièvre).
3.3. Assessment of the regional hydrological impact of a change in the paramo-ecosystem
The aim is to make a hydrological analysis of a sub-region of the Cajas National Park, containing various glacial lagoons and interconnecting streams, using a hydrological model capable of simulating the reservoir system composed by the glacial lagoons. The work will involve the monitoring of data in addition to the data already existing, analysis of the existing data, selection of an appropriate hydrological-reservoir model, the model calibration and validation. The calibrated/validated model will thereafter be used for making a prognosis of the effect on the hydrology induced by a change in climate and/or a change in the water release characteristics of the paramo-ecosystem.
It is evident that as the proposed research goes on changes/reductions in the methodology and workplan might be required as a function of data availability and other constraints. The work will be done in cooperation with PROMAS of the University of Cuenca and the authorities of Cajas National Park.
4. Result
It is believed that the proposed research addresses a key issue related to future climate change and human interference in the tropical Andes, which is of scientific interest but also of primary socio-economic relevance for the region. The potential for a future water crisis is evident and this water shortage is related to a projected future change in runoff, due to the observed degradation of the paramo-ecosystem.
1. Preamble
The National Park Cajas is only 35 km from the city of Cuenca. The altitude of the Park ranges from 3,000 to 3,500 m. The Park measures nearly 30,000 ha (300 km2), contains mountains and 232 glacial lagoons, interconnected by small rivers and streams. Two of the main rivers surrounding Cuenca, the Tomebamba and the Yanuncay, begin in the National Park. The most common vegetation includes paramo grasses, polylepis, romerillo, chachacoma, genciana, romerillo and the sarar. The annual rainfall ranges from 800 to 2000 mm, the evapotranspiration due to the low average temperatures varies between 350 and 1200 mm, resulting in an rainfall excess which thanks to the specific characteristics of the plant-soil system is gradually and fairly uniformly released throughout the year, securing the water supply to the City of Cuenca and its surroundings, being the 3rd largest city of Ecuador. The population density of Cuenca city and the strongly urbanized surrounding communities is estimated at 600,000 inhabitants. The lagoon system of Cajas is the major water source for domestic, industrial and agricultural use. Among the industrial uses, the major players are the hydro-electrical plants, of which the Paute plant is the largest of Ecuador, producing 50% of the nations electricity. Plans of new hydro-electrical plants are on the drawing table as to meet the increasing demand for electricity.
The conservation of the water resource system of Cajas National Park, being a fragile ecosystem, is becoming crucial important, and this for the following two reasons:
(1) The rapidly expanding population of the country, and in particular of the Provinces of Azuay and Cañar in which the National Park is situated, leads to a further occupation of the land by the indigenous people which convert the paramo landscape to grassland for cattle grazing and crop farming.
(2) Climate change will induce warmer temperatures year-round, which will be more pronounced in the mountain range than at sea level. It is expected that the increase in temperature might be detrimental for the paramo vegetation which stretches over the Andean mountain range, and eventually could result in a change to other vegetation types which are less effective in water storage and the replenishment of the glacial lagoons. It is reckoned that disappearance of the paramo-ecosystem might have large, and possibly catastrophic, implications for the countrys economy and for human life.
The effect of both phenomena on the hydrological cycle will result in an increase in peak flows with increased flooding hazard in the downstream regions, and a reduction of the storage capacity of the paramo-ecosystem with the consequence that during drier periods insufficient runoff water will be available to sustain the operation of the hydro-electrical centrals, irrigation schemes, the supply of potable water and water for industrial activities.
2. Objectives
The objective of the research is to gain a better understanding of both mechanisms and consequences related to the disappearance of the paramo-ecosystem by human interference and climate change. Increased knowledge on how fast the paramo-ecosystem degenerates and how much this will affect future runoff and water availability from the Andes should form the basis for the formulation and testing of future mitigation and adaptation strategies. More in particular, the research aims at better understanding the interaction between the paramo-ecosystem and the glacial lagoon system of Cajas National Park.
3. Methodology
The research will be conducted at two different scales, i.e. the impact of human interference on the degradation of the paramo-ecosystem will be studied on microbasins in the paramo of Cajas National Park, and the effect of climate variability and change will be examined on regional scale.
3.1. Assessment of the human induced degradation of the paramo-ecosystem on the runoff and water storage
Research activities will consist in conducting a detailed survey of microbasin-lagoon systems with varying degree of human interference. Use will be made of the pioneering work conducted in this field and reported in the doctoral dissertation of Dr. Wouter Buytaert. Dataseries on climate and runoff will be continued and used for the hydrological analysis of those systems, and for quantifying the impact of human interference on the water storage and runoff. This requires the derivation of a databased hydrological model, the determination of model parameters, model calibration and validation, and the formulation of scenarios mimicking human impact in a format useable by the selected modelling tool.
3.2. Assessment of the degradation of the paramo-ecosystem should climate change proceed
Two main research activities can be distinguished, i.e. the reconstruction of the climate variability and change in the Andes under both present-day conditions and different IPCC-SRES emission scenarios with regional climate models, and relating vegetation changes to climate change. In the doctoral thesis of Dr. Rolando Celleri already a good basis of the present-day climate system of Cajas National Park and the surrounding region is available. For the construction of the future climate use will be made of the downscaling of regional climate models, for which assistance will be searched for by INAMHI (Instituto Nacional de Meteorología en Hidrología, Quito-Guayaquil, Ecuador). For the assessment of the potential evolution of the paramo-ecosystem as a function of climate change cooperation will be searched for by CONDESAN (Consorcio para el Desarrollo Sostenible de la Ecorregión Andina, Dr. Bert De Bièvre).
3.3. Assessment of the regional hydrological impact of a change in the paramo-ecosystem
The aim is to make a hydrological analysis of a sub-region of the Cajas National Park, containing various glacial lagoons and interconnecting streams, using a hydrological model capable of simulating the reservoir system composed by the glacial lagoons. The work will involve the monitoring of data in addition to the data already existing, analysis of the existing data, selection of an appropriate hydrological-reservoir model, the model calibration and validation. The calibrated/validated model will thereafter be used for making a prognosis of the effect on the hydrology induced by a change in climate and/or a change in the water release characteristics of the paramo-ecosystem.
It is evident that as the proposed research goes on changes/reductions in the methodology and workplan might be required as a function of data availability and other constraints. The work will be done in cooperation with PROMAS of the University of Cuenca and the authorities of Cajas National Park.
4. Result
It is believed that the proposed research addresses a key issue related to future climate change and human interference in the tropical Andes, which is of scientific interest but also of primary socio-economic relevance for the region. The potential for a future water crisis is evident and this water shortage is related to a projected future change in runoff, due to the observed degradation of the paramo-ecosystem.
Date:25 Sep 2008 → 23 Oct 2013
Keywords:Climate change impact, Hydrology, Paramo, Ecuador
Disciplines:Construction engineering, Earthquake engineering, Geotechnical and environmental engineering, Water engineering, Wind engineering, Physical geography and environmental geoscience
Project type:PhD project