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.

水文流域是有效区域规划的基本单位。然而，同一地区可能出现对退化过程的敏感性较高或较低的区域，需要采取不同的行动来保护土壤和水等自然资源。在此背景下，本研究旨在提出一个优先级模型，以指导水文流域的领土管理。该研究是在位于巴西圣保罗州西南部地区的塔鲁马河流域进行的。首先，根据小流域的划分和分组，将流域划分为规划单元。在每个单元中，计算了七个形态测量参数。通过主成分分析评估参数之间的关系，从中对参数进行加权。它产生了一个表示规划单位环境脆弱性的指数。在规划单位中，20% 为非常高优先级，仅 5% 为非常低优先级，75% 为低、中、高优先级。优先级较高的单元通常位于流域的源头，那里集中了线性渠道和较陡的斜坡。较低优先级的单元呈现不利于高强度侵蚀过程的低地势和水文条件。所提出的方法可以有效地根据形态参数识别高度易退化的区域，应优先考虑流域的领土管理。由于这些参数可以很容易地计算出来，