Modeling freshwater quality scenarios with ecosystem-based adaptation in the headwaters of the Cantareira system, Brazil

Author(s)

Taffarello, Denise ^[1] ; Srinivasan, Raghavan ^[2] ; Mohor, Guilherme Samprogna ^{[1, 3]} ; Bittencourt Guimaraes, Joao Luis ^[4] ; Calijuri, Maria do Carmo ^[1] ; Mendiondo, Eduardo Mario ^[1]

Affiliation

^[1] Univ Sao Paulo, Sao Carlos Sch Engn, BR-13566590 Sao Carlos, SP - Brazil

^[2] Texas A&M Univ, Ecosyst Sci & Management Dept, Spatial Sci Lab, College Stn, TX 77801 - USA

^[3] Univ Potsdam, Inst Earth & Environm Sci, Karl Liebknecht Str 24-25, D-14476 Potsdam - Germany

^[4] Aquaflora Meio Ambiente, BR-82100310 Curitiba, PR - Brazil

• Document type: Journal article
• Source: HYDROLOGY AND EARTH SYSTEM SCIENCES; v. 22, n. 9, p. 4699-4723, SEP 7 2018.
• Web of Science Citations: 5

Abstract

Although hydrologic models provide hypothesis testing of complex dynamics occurring at catchments, fresh-water 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 semi-distributed Soil and Water Assessment Tool (SWAT) model, nitrate, total phosphorous (TP) and sediment were modeled in catchments ranging from 7.2 to 1037 km(2). These head-waters 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 Sao 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 (S2 + EbA). 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 S2 + EbA scenario envisaged not only additional and viable best management practices (BMP), but also preventive decision-making at the headwaters of water supply systems. (AU)

• FAPESP's process: 12/22013-4 - Water footprint as a tool for ecosystem services valuation at watersheds under climate change
• Grantee: Denise Taffarello
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 14/50848-9 - INCT 2014: INCT for Climate Change
• Grantee: Jose Antonio Marengo Orsini
• Support Opportunities: Research Program on Global Climate Change - Thematic Grants
• FAPESP's process: 08/58161-1 - Assessment of impacts and vulnerability to climate change in Brazil and strategies for adaptation option
• Grantee: Jose Antonio Marengo Orsini
• Support Opportunities: Research Program on Global Climate Change - Thematic Grants
• FAPESP's process: 14/15080-2 - Water insurance as climate and land use change adaptation tool for optimization of water permits under water transfer conditions
• Grantee: Guilherme Samprogna Mohor
• Support Opportunities: Scholarships in Brazil - Master