TowaRds the future Projection and management of the Impact of Climate Change on Bolivian water Supply (TROPICCS)

In Bolivia, a large proportion of the water supply of the capital city, La Paz, is provided by meltwater from glaciers. During the year glaciers tend to melt when conditions are dry and warm, and so they provide water when it is needed most. However, these glaciers are shrinking rapidly due to climate change, and their reduction and possible total disappearance will reduce the water available for La Paz for drinking water, agriculture and hydropower. It is therefore important to understand exactly how important glaciers are for water supplies and how glacier runoff interacts with vegetation and peatlands, especially during very dry conditions when other sources of water are lacking. It is also necessary to build modelling tools that will allow us to predict how the glaciers and water resources from the catchments will change in the future, since this information can be used to better manage and adapt to the future change in water supply.

Our new project will combine scientists that work with state-of-the-art glacier and hydrological models from Northumbria University, UK, with Bolivian glaciologists and hydrologists from Universidad Mayor de San Andrés, Bolivia and experts on operational melt models from CIMA Research Foundation in Italy. We will first collect high resolution satellite data for the catchment, create a map of landcover by classifying satellite imagery and install a new weather station on one of the glaciers in the catchment. These data will be used, together with existing datasets and satellite derived products, to run a detailed model that can represent in a physical manner all of the processes that affect the amount of water available for use in the catchment, including from glacier melt, groundwater, evapotranspiration and all the main hydrological processes occurring in high mountain catchments. We will also run a simpler, but faster model over the glacier areas and compare the results of the models. We will then construct a model that can represent the melt of Bolivian glaciers well while remaining efficient enough for use by water managers and for modelling into the future.

Through this work, the project will meet the following objectives:
1. Provide a new baseline of glaciological and hydrological data for the La Paz/El Alto water supply catchments;
2. Determine the drivers of glacier melt water contribution to water supply and its interannual fluctuations, including during droughts;
3. Determine the importance of feedback mechanisms between glaciers, snow, hydrology and vegetation in the magnitude and seasonality of catchment runoff and;
4. Establish the model complexity required to adequately represent glacier runoff in operational water resource modelling.

The results of our work will be published in peer-reviewed journals, but we will also write a briefing document in Spanish for local stakeholders (water managers and government officials) which will be presented at a dissemination workshop in Bolivia. The project will lead to: a new partnership between the organisations involved; new knowledge of Bolivian glaciers and their importance to water supplies; and the development of operational modelling tools that work well in the region. This will allow us to apply for future funding with the long-term aim of predicting glacier change over the entire Cordillera Real and its effect on water supplies into the future - thereby providing the information needed to better manage Bolivian water resources. This will allow planning for additional catchment water storage, implementation of water use efficiency measures, or the implementation of improved drought prediction systems to enhance decision making about water resources.