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 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 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
(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.
Forest and landscape restoration (FLR) is a powerful strategy for large-scale tropical forest recovery, and payment for ecosystem services (PES) is used to support FLR programs and projects on privately-owned land. In this article, we discuss the lessons learned from the Water Producer Project, a pioneer, multiple-stakeholder, and PES-supported FLR project in the Atlantic Forest, south-eastern Brazil. The project was implemented in four landscapes located in two municipalities. Altogether, 41 PES contracts with landowners were signed, resulting in various FLR practices being implemented in a total of 342.4 ha (64.2 ha for riparian forest restoration, 90.8 ha for soil conservation, and 187.4 for forest conservation) of land, which represents 39% of the project goal. As of the end of the project, only 50% (USD 49,250) of the available PES funds had been spent. However, funds spent on project planning, implementation, communication, and monitoring were 12 times greater than those spent on PES. Several challenges restricted the progress and monitoring of the project. The main issue was landowner participation and/or engagement. In terms of lessons learned, we highlight that PES schemes are more complex than initially thought, and that sufficient funding does not guarantee the success of FLR projects. It is essential to promote landowner participation and engagement by considering them key players in FLR projects. Finally, acceptance from landowners was higher and implementation was easier for forest conservation practices that required no land-use changes. Thus, we suggest that similar future projects should focus on targeting private properties in marginal agricultural lands with a high probability of natural regeneration. Alternatively, future projects could focus on lands with remnant forest cover of high conservation value.
Integrated analyses of the qualitative and quantitative aspects of aquatic ecosystems play an important role in decision making, which is linked to water resources management and promotion of ecosystem services. However, the possible advantages of such integration are still hampered by basic aspects, such as high uncertainties due to the partial and non-synchronized monitoring of discharges and observed concentrations of water quality variables. The lack of data has been limiting the adequate representation of a more accurate hydrological regime, which is in turn possibly affected by the potential effects of land use and size of drainage areas. The aim of this research was to discuss the advantages of the integrated analysis of qualitative and quantitative data from water bodies. Under different specific discharge regimes (L.s -1.km-2), we assessed the total phosphorus (TP, t.day-1 .km-2) and thermotolerant coliforms’ (TC, CFU.day-1.km -2) specific loads in rivers with different drainage areas (27-26,500 km 2) and land uses. We compared such loads with the admissible specific loads for these variables, which were estimated based on long-term average discharges and water quality guidelines (i.e., Brazilian environmental standards). Based on data from 2001-2013, we sought to contribute to the qualitative and quantitative analysis of surface waters, focusing on the discussion of the results on critical thresholds of duration and critical loads and discharges. The results showed the existence of significant time intervals with conflicts between the specific admissible and observed loads. This non-compliance varied between 10 and 100% of the duration of the regime for TP, and between 25 and 100% for TC, with a more critical situation observed in rivers with smaller drainage areas. The critical loads ranged from 1 10-4 to 8 10-3 t.day-1.km-2 (TP) and 1 10-2 to 1 10-1 CFU.day-1.km-2 (TC). Although a relatively limited dataset was considered (total N=1,402), the significant variations in discharges and critical loads highlighted the need for considering how these dynamics would affect the traditional methodology for estimating ecological flows, whose current approach is almost exclusively quantitative.
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