| Title: | Modeling freshwater quality scenarios with ecosystem-based adaptation in the headwaters of the Cantareira system, Brazil |
| Authors: | Taffarello, D., R. Srinivasan, G.S. Mohor, J.L.B. Guimarães, M. do Carmo Calijuri and E.M. Mendiondo |
| Year: | 2018 |
| Journal: | Hydrology and Earth System Sciences |
| Volume (Issue): | 22(9) |
| Pages: | 4699-4723 |
| Article ID: | |
| DOI: | 10.5194/hess-22-4699-2018 |
| URL (non-DOI journals): | |
| Model: | SWAT |
| Broad Application Category: | hydrologic and pollutant |
| Primary Application Category: | land use change assessment |
| Secondary Application Category: | ecosystem and/or biodiversity services |
| Watershed Description: | 7,390 km^2 upper Tietê River and 14,178 km^2 Piracicaba–Capivari–Jundiaí River, located in the state of São Paulo in southern Brazil. |
| Calibration Summary: | |
| Validation Summary: | |
| General Comments: | |
| Abstract: | Although hydrologic models provide hypothesis
testing of complex dynamics occurring at catchments, freshwater
quality modeling is still incipient at many subtropical
headwaters. In Brazil, a few modeling studies assess
freshwater nutrients, limiting policies on hydrologic ecosystem
services. This paper aims to compare freshwater quality
scenarios under different land-use and land-cover (LULC)
change, one of them related to ecosystem-based adaptation
(EbA), in Brazilian headwaters. Using the spatially semidistributed
Soil and Water Assessment Tool (SWAT) model,
nitrate, total phosphorous (TP) and sediment were modeled
in catchments ranging from 7.2 to 1037 km2. These headwaters
were eligible areas of the Brazilian payment for ecosystem
services (PES) projects in the Cantareira water supply
system, which had supplied water to 9 million people in
the São Paulo metropolitan region (SPMR). We considered
SWAT modeling of three LULC scenarios: (i) recent past
scenario (S1), with historical LULC in 1990; (ii) current
land-use scenario (S2), with LULC for the period 2010–2015
with field validation; and (iii) future land-use scenario with
PES (S2CEbA). This latter scenario proposed forest cover
restoration through EbA following the river basin plan by
2035. These three LULC scenarios were tested with a selected
record of rainfall and evapotranspiration observed in
2006–2014, with the occurrence of extreme droughts. To assess
hydrologic services, we proposed the hydrologic service
index (HSI), as a new composite metric comparing water
pollution levels (WPL) for reference catchments, related to
the grey water footprint (greyWF) and water yield. On the
one hand, water quality simulations allowed for the regionalization
of greyWF at spatial scales under LULC scenarios.
According to the critical threshold, HSI identified areas as
less or more sustainable catchments. On the other hand, conservation
practices simulated through the S2CEbA scenario
envisaged not only additional and viable best management
practices (BMP), but also preventive decision-making at the
headwaters of water supply systems. |
| Language: | English |
| Keywords: | non |