Department of Ecology, Institute of Biosciences, University of São Paulo, Matão st., Travessa 14, 321, Cidade Universitária, São Paulo, São Paulo, Brazil.
Environ Manage. 2021 Apr;67(4):623-631. doi: 10.1007/s00267-021-01434-5. Epub 2021 Feb 8.
Hydrographic basins are the fundamental unit for the effective territorial planning. However, areas of higher and lesser susceptibility to degrading processes can occur in the same region, where different actions are required to preserve natural resources, as soil and water. In this context, this study aimed to propose a prioritization model to guide the territorial management in hydrographic basins. The study was conducted in the Tarumã River basin, embedded in the southwest region of the São Paulo State, Brazil. First, the basin was compartmentalized into planning units, based on the delimitation and grouping of small watersheds. In each unit, seven morphometric parameters were calculated. The relationships among the parameters were evaluated by principal component analysis, from which the parameters were weighted. It resulted in an index expressing the environmental fragility of the planning units. Among the planning units, 20% present very-high priority, only 5% very-low priority, and 75% low, moderate, and high priority. Units of higher priority are commonly at the basins' headwaters, where linear channels and steeper slopes are concentrated. Lower priority units present low relief and hydrography conditions that do not favor high-intensity erosive processes. The proposed method is effective in identifying regions of high susceptibility to degradation according to morphometric parameters, which should be prioritized on the basins' territorial management. Since these parameters can be easily calculated, it can be presumed that the results could assist the environmental planning and the optimization of natural resources management within different hydrographic basins.
流域是进行有效领土规划的基本单元。然而，在同一区域内可能存在易受退化过程影响的区域和不易受退化过程影响的区域，需要采取不同的行动来保护自然资源，如土壤和水。在这种情况下，本研究旨在提出一个优先排序模型，以指导流域的领土管理。该研究在巴西圣保罗州西南部的塔罗马河（Tarumã River）流域进行。首先，根据小流域的划定和分组，将流域划分为规划单元。在每个单元中，计算了七个形态参数。通过主成分分析评估参数之间的关系，然后对参数进行加权。由此得出一个表达规划单元环境脆弱性的指数。在规划单元中，20%具有非常高的优先级，只有 5%具有非常低的优先级，75%具有低、中、高优先级。优先级较高的单元通常位于流域的源头，那里集中了线性河道和较陡的坡度。优先级较低的单元地势较低，水文条件不利于高强度侵蚀过程。该方法能够根据形态参数有效识别易受退化影响的区域，并应优先考虑流域的领土管理。由于这些参数易于计算，因此可以假设该结果可以协助环境规划和不同流域的自然资源管理优化。
