Modeling of soil loss by water erosion in the Tietê River Hydrographic Basin, São Paulo, Brazil

Abstract

Since the mid-16th century, the Tietê River has been an important route for the territorial occupation and exploitation of natural resources in the interior of São Paulo and Brazil. Currently, the Tietê River is well known for environmental problems related to water pollution and contamination. However, little attention has been focused on water erosion, which is a serious issue that affects the soils and waters of the hydrographic basin. Thus, this work aimed to estimate soil loss caused by water erosion in this basin, which has an area of approximately 72,000 km², using the Revised Universal Soil Loss Equation (RUSLE). The RUSLE parameter survey and soil loss calculation were performed using geoprocessing techniques. The RUSLE estimated an average soil loss of 8.9 Mg ha-1 yr-1 and revealed that 18% of the basin's territory presents high erosion rates. These are priority zones for conservation practices to reduce water erosion and ensure long-term soil sustainability. The estimated sediment transport was 1.3 Mg ha-1 yr-1, whereas the observed sedimentation, which was calculated based on data from the fluviometric station, was 0.8 Mg ha-1 yr-1. Thus, the results were equivalent considering the large size of the study area and can be used to assist in managing the basin. Estimating soil losses can help in the planning of sustainable management of the Tietê River Hydrographic Basin and highlights the importance of minimizing water erosion, thus helping to prevent additional pollution and contamination with sediments, agrochemicals, and fertilizers.

Strategies and Public Policies for Soil and Water Conservation and Food Production in Brazil

“…In areas containing annual crops, high concentrations of nutrients and predominantly silt and clay were verified in the soil runoff, which has a strong relation with particle size due to cation exchange capacity [59]. This sediment runoff to the rivers may contaminate the water resources and the aquatic biota [66][67][68][69], which could be consumed by people [70,71], or the water contaminated with pesticides may be used for crop irrigation [72] or distributed to residences for human consumption, as observed by Panis et al [73] studying 127 grainproducing municipalities in Parana State, Brazil, which revealed contamination of drinking water and that contamination may increase the risk of cancer. In the Brazilian Amazon, pesticides were detected in aquatic ecosystems and sediments near a large zone of soybean production in the Santarém region [74], in the surface and ground waters, in drainage sediments in the indigenous lands surrounded by oil palm monoculture [75], and in aquatic and terrestrial ecosystems in the Brazilian Pampa [76].…”

Estimation of Soil Losses and Reservoir Sedimentation: A Case Study in Tillouguite Sub-Basin (High Atlas - Morocco)

“…Soil is a three-phase system that consists of solid particles, liquid, and gas, but also species that create a dynamic and complex ecosystem and is among the most precious resources to humans. On the other hand, soil erosion by water is acknowledged as a primary concern in the degradation of soil quality and functionality (Billi, & Spalevic, 2022;Saggau et al, 2022;Stefanidis et al, 2022;Lense et al, 2022;Chalise et al, 2019;Spalevic et al, 2017;Borrelli et al, 2016;Lal, 2014). The ever-growing availability of earth observation (EO) data and the well-established use of geographic information systems (GIS) during the last decades leads to the development of automated geospatial workflows for the estimation and mapping soil losses (Dominici et al, 2021;.…”

Research on Soil Management and Conservation

“…The soil is the base of a sustainable agricultural system; it is the key for food and energy production, a reservoir of water and nutrients [1][2][3], and a filter for water and contaminants [4]. However, inadequate soil management may significantly negatively impact the environment [5][6][7], crop development and yield [8][9][10][11][12], natural resources such as air and water [13][14][15], and human and animal health [16,17]. Soil management practices that favor soil and water conservation and the improvement of soil functions and structure are preferable.…”