English - ambiotek.com
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English - ambiotek.com
A detailed scientific analysis of the impact g on water resource of land use change provision to Bogotá D.C. and implications for the development of PES schemes Chingaza Park Bogotá City Chingaza Park Guavio catchment Golillas Guavio Sumapaz Park Leonardo Sáenz and Mark Mulligan Environmental Monitoring, Modelling and Management Group Description 1. KCL objectives 2. USE of FIESTA model and main datasets 3. Implementation of other FIESTA model components 4 4. M i h Main hydrological d l i l findings fi di 5. Main policy implications 6. Main Conclusions KCL objectives 1. Produce a baseline scenario of water resources p provision to dams from forests and paramos surrounding Bogotá D.C. 2 2. Estimate E i potential i l hydrological h d l i l benefits b fi off forest and paramo conservation through PES schemes h for f different diff t scenarios i off land cover change to the year 2050. 2. Estimate potential economic effects of PES conservation on water provision and hydroelectric power generation. FIESTA Delivery Model FIESTA is the most sophisticated model of mountain hydrology to help understand the magnitude of fog contributions to the water balance at national and regional scales (Mulligan and Burke 2005). FIESTA models: * fog interception p * evaporation * water balance * Accumulated water b l balance (runoff). ( ff) With appropriate soils data it also models: * soil hydrology y gy * estimates sedimentation yields. FIESTA is applicable elsewhere with appropriate data processing an uses globally available datasets and free software. FIESTA implementation - datasets - Humidity (%) - Temperature (°C) - Wind speed (m s-1) s 1) - Wind direction. - Precipitation (mm) - Air Ai pressure (mb) ( b) and d - Cloud frequency (%). - Potential solar radiation (W m-2). - Elevation (m). - Land cover: % of tree cover (MODIS VCF) - Roads and river streams. N Baseline1977 Land Cover Classes Paramo Forest Crops Bare soil Baseline2000 Land Cover Classes Paramo Forest Crops Bare soil Creation of Land Cover Change scenarios. Forest and paramo resources to the years 1977 and 2000 surrounding Bogotá D.C. Derived from Landsat and MODIS datasets FIESTA scenarios – year 2050 N PES scenario: Forest and paramo loss avoided within the Chingaza park NO PES scenario: Forest and paramo loss Allowed within the Chingaza park at Current rates 79,000 39,500 0 79,000 Kilometers11,000 5,500 0 11,000 Kilometers PES and NOPES scenarios, detail of natural cover loss in the Chingaza National Park. FIESTA Components: Paramo a M d lli off paramo water Modelling t storage, t retention t ti and d contribution to runoff FIESTA Components: dam filling Guavio dam Water storage and discharge discharge, hydraulic head head, and hydroelectric generation potential. FIESTA and Dams database Main dams surrounding Bogotá D.C. Dams database - KCL effort to enhance the knowledge of hydrological impacts from land cover and climate change upon highly engineered human infrastructure Main hydrological findings Cloud forest hydrology and implications to dams Tota Tota N Copa Copa Neusa Neusa Sisga Sisga Tomine Tomine Chivor Guavio Guavio Golillas Golillas Chingaza lagoon Prado Chivor Regadera Regadera Chingaza lagoon Prado Overall: Fog inputs are of major importance in dry areas to the north of the Bogotá region and in the western fringes towards the Magdalena basin, where Tota lake and Copa, Sisga, Tomine, Chivor and Prado dams receive important seasonal fog inputs. Main hydrological findings fi di Deforestation impacts on fog inputs and implications to dams a. Overall: Fog inputs are already minor in most of the flat areas of the high Bogotá sabana since most of the cloud forest resources have already been converted to other land uses uses, but not so in the steep slopes surrounding Chingaza and Sumapaz parks. b. Deforestation b D f t ti has h already l d potentially t ti ll increased i d flows fl for f mostt of the dams in the region. c. However, further deforestation threatens the seasonal regulation of base flows to dams especially in the driest areas, for Copa, p , Tomine,, Sisga g and Chivor dams,, where fog g inputs p are an important proportion of seasonal water balances. Main hydrological findings fi di Paramo loss and implications to dams a. Overall: Climatic and topographical conditions and high water balances with regard to the high Bogotá sabana make paramo areas essential to sustained water supplies to Bogotá City. b. The importance of paramo conservation is with respect to maintaining water quality and regulation. Much research is needed to better understand the g generation of the runoff phenomenon in undisturbed and intervened paramo catchments. M i policy Main li implications i li ti Implications to PES a. In dry areas to the north and south west Bogotá D.C surrounding Tota lake and Sisga, g , Copa, p , Chivor and Prado dams,, deforestation and thus the reduction in fog interception affects river flows seasonally. b In paramo catchments surrounding areas of Chingaza lake, b. lake Golillas Guavio and regadera dams, where flows are not enhanced by deforestation and could even reduce with increased evapotranspiration when paramo is converted to pasture or crops, conservation measurements are essential to maintain regular flow regimes and water quality downstream. M i policy Main li implications i li ti Implications to PES a. In highly engineered systems any change in flows exciding design specifications is bad. Therefore, PES schemes could potentially maintain the safety y of operation of hydraulic y infrastructure in Golillas and Guavio dams. b E b. Economic i impact i t off infrastructure i f t t f il failure d to due t increased i d peak k flows fl has yet to be estimated in the surrounding areas of Bogotá D.C. M i policy Main li implications i li ti Implications to PES - Economic Estimates a Implementation of PES schemes preventing the loss of paramo in the a. Chingaza park could potentially maintain up to 0.9% of hydropower generation of the Guavio dam to the year 2050 (up to about 3.2 USD million year-11). ) b. PES implementation in the Chingaza park could potentially conserve up to 3.8% 3 8% of water inputs to Golillas dam from paramo conservation to the year 2050 (up to about 6.2 USD million year-1). c. Further enhancements of the paramo protected area in Chingaza would help maintain seasonal water resources that would otherwise be lost if paramo loss takes place at the same rates of today. Conclusions a. Results from paramo conservation are encouraging since conservation efforts through g PES schemes could p potentially y represent p positive economic impacts b. Study outcomes must now be validated and compared with information from respective relevant drinking water, hydroelectric and environmental organizations and understood within the economic context of the provision of these services in the region to support and potential t ti l PES schemes h i l implementation t ti surrounding di B Bogotá tá D.C. DC c. Conservation of cloud forest and p paramo resources should be tackled not only considering potential benefits of water quantity but of water quality and flood mitigation specially in the eastern Andes, which are essential to the efficient, economic and safe operation p of dams in the region.