The impact of roads and sediment basins on simulated river discharge and sediment flux in an experimental catchment designed to improve ecosystem services

Abstract

Payment of Environmental Services (PES) projects have grown our perception on the dependency of nature, yet the quantification and valuation of Environmental Services (ES) are key to evidence-base management. The modelling of the effect of deforestation in the water and sediment budgets of rural catchments usually prescribes baseline 5 scenarios with fully pristine vegetation. Such comparison however is hardly associated with the landscape conditions where observational data is collected to provide model calibration. For example, the existence of unpaved roads and small water retention basins (containments) are potential controls of runoff and erosion in small catchments. This work shows the impact of roads and barraginhas (small sediment retention basins 10 nearby the roads) on the water and sediment fluxes in a 12 km 2 catchment area in Extrema city, Brazil, which provides water for the Cantareira System's water reservoirs that supply about 50 % for the Sao Paulo megacity, and enrolled in the Water Producer Program (Water National Agency) as the first Brazilian PES project. Simulations with the InVEST model using high spatial resolution (5 m × 5 m) included the description of 15 unpaved roads and barraginhas. Calibration used river discharge and sediment flux estimated from water turbidity measurements. Sediment concentration was estimated both with the observation and simulations, and annual comparisons seemed reasonable for mean annual estimates. Unpaved roads produced sediment export 5 times higher compared to a scenario with no roads, and potentiated the effect of barrag-20 inhas on sediment reduction. This study showed the benefit from understanding effects of representation of the landscape particularities in modelling such as the roads, which apart from affecting calibration, are important issue for providing efficient modelling of the effect of the Best Management Practices in the landscape scale. We also demonstrated usefulness of our research methodology and its possible applications on 25 simulations of sediment concentration and streamflow in InVEST with few samples of observed data and thus quantify the impacts of land use change on hydrology in any other watershed.2 HESSD

Research on ecosystem services in Brazil: a systematic review

“…Land use, land-cover change scenarios, and hydrological models show problems related to water storage, food production and ES regulation, such as sediment control, water purification and retention (Koschke et al, 2014;Lima et al, 2014;Saad et al, 2016). The studies show the impacts of ecosystem degradation on water resources and propose forest restoration to protect them and increase aquifer recharge, groundwater flows and river discharge equilibrium (Watanabe and Ortega, 2011;Young and Bakker, 2014).…”

“…InVest, MIMES). The models are generally comprised of biophysical and environmental assessment components, which convert input data into ES and economic benefits (Andrade et al, 2015;Garcia and Romeiro, 2015;Saad et al, 2016;Song et al, 2014).…”

Estimasi Hasil Air Dari Daerah Tangkapan Air Danau Rawa Pening Dengan Menggunakan Model Invest

“…(Sharp et al, 2015;Zhang et al, 2012). Nilai hasil air yang diperoleh tersebut merupakan jumlah curah hujan yang tidak diuapkan ke atmosfer melalui proses evapotranspirasi (Bhagabati et al, 2012;Saad et al, 2016).…”