The document discusses analyzing water quality in the Andean region by examining the proportion of water arriving at dams and cities that originates from protected areas upstream. It notes that data on industry, mining, and urban water impacts is lacking for the Andes. Protected areas are likely to have higher water quality since they encourage infiltration, reducing erosion and pollution from activities like agriculture, pesticides, and mining. The document calculates the percentage of upstream flow originating from protected areas using rainfall and land cover datasets to identify potential areas of higher or lower water quality arriving at different points.

2. Water regulation services: Protected ecosystems do not protect against the most destructive floods. For ‘normal’ events they do encourage more subsurface flow and thus more seasonally regular flow regimes. Therefore benefits are likely especially in highly seasonal environments.

3. Water quality services (where quality is quantity for a purpose). Protected ecosystems encourage infiltration leading to lower soil erosion and sedimentation. Unprotected land will tend to have higher inputs of pesticides, herbicides, fertilizers etc. There are thus clear quality benefits of protected areas: generation of higher quality water than non-protected areas.Assuming that protected areas have a positive impact of water (especially water quality) the proportion of streamflow at a point that is derived from protected areas upstream is thus an indicator of the potential quality of water received and lack of impacts from industry and mining as well as urban waste-water. This was calculated by combining 1km resolution gridded datasets for rainfall (Hijmens et al., 2004), protected areas (WDPA, 2007) flow direction (HydroSHEDS, Lehner et al., 2008), urban areas (CIESIN et al., 2008) and population (Landscan, LandScanTM Global Population Database, 2007). Annual total rainfall (long term mean) was multiplied by a binary value representing the protected area status in each pixel and summed along the flow network from source to mouth to give RfC. The rainfall falling on all areas was also calculated and summed along the flow network to give RfA. (RfC/RfA) * 100 is then the percentage of flow in a given pixel that fell as rain on an upstream protected area. This is shown for part of Colombia/Ecuador in Figure 16. Clearly the influence of protected areas declines significantly downstream of their areas. Figure 16 Percentage of water derived from protected areas upstream (extract for Colombia/Ecuador)