Planting Waterscapes

This blog post introduces a technical journal article written by Castelli et al. (2017) examining how the Pirai river basin in Bolivia is managed. This catchment contains forests, woodlands, grasslands and wetlands; it is the water source for three million people, supplying the urban centre of Santa Cruz de la Sierra. One particularly useful feature of this study is its demonstration of the feedbacks between changing landscape cover in recent decades and shifting hydrological patterns. Its modelling of future hydrological scenarios for the basin, which privilege an ecosystemic approach to water management, are specifically focussed on involving local stakeholders in watershed management decisions that are designed to increase the resilience of urban and rural populations. A Soil Water Assessment Tool (SWAT) is used in a predictive model that forecasts hydrological changes in this region. Twenty years’ worth of climate data have been inputted into this modelling tool, to identify how the hydrological regime is evolving with changing land use. Significantly, the study notes that high increases in runoff are associated with zones within the catchment where forests have been cut down, as land is converted for agricultural use. To counter this trend, the study recommends that agroforestry and reforestation be included in the 'green infrastructure’ that has the potential to buffer the effects of peak river charge, which is a hazard for the city of Santa Cruz.