Industry and mining, urban waste-water and water related health hazards in the Andean region
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Transcript of Industry and mining, urban waste-water and water related health hazards in the Andean region
- 1. Industry and mining, urban waste-water and water related
health hazards in the Andean region
Mark Mulligan
Kings College London, Andes Basin Focal Project Leader.
Data on the locations and outputs from industry, mining and urban centres and their potential impacts on water quality and its effects downstream are very lacking in the Andes.Whilst the UNEP-GEMS database contains many stations for the Amazon, it has very few stations in the Andes.In order to better understand the potential quality of water and impacts upon it, we therefore look more broadly at the origins of water arriving at major dams and cities.We first examine the proportion of water arriving at dams and major cities that has originated from protected areas upstream.The impact of different land covers on watershed services is a highly debated topic.On the basis of the literature to date we can identify the following rules of thumb:
- Water quantity services:Protected ecosystems do not necessarily generate more rainfall than agricultural land uses and protected ecosystems may have higher evapotranspiration and thus lower water yields. Thus quantity benefits difficult to prove.
- 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 16Percentage of water derived from protected areas upstream
(extract for Colombia/Ecuador)