ABSTRACT This study aims to understand the response of the trophic state index (TSI) of a reservoir under different watershed land-use scenarios. A novel methodology was applied to the Verde River Basin in the south of Brazil, which is exploited by agricultural activity and has a reservoir for water supply. An ecohydrological model was used to calculate daily nutrient concentrations in the water system, which allowed the determination of the reservoir’s TSI. The authors propose a new TSI known as TSImod, considering phosphorus, nitrogen, and chlorophyll in its determination. The results indicate that TSImod may be more appropriate for classifying highly impacted environments when compared to the index currently used in Brazil. The Verde River Reservoir was classified as mesotrophic under the current land-use scenario and eutrophic under the proposed scenarios. The framework developed in this study can be replicated in other watersheds to evaluate the impacts of land-use change on water quality.

中文翻译：

---

严重受影响流域的营养状态指数：模拟水体中扩散污染的影响

摘要 本研究旨在了解不同流域土地利用情景下水库营养状态指数 (TSI) 的响应。一种新颖的方法被应用于巴西南部的 Verde 河流域，该流域被农业活动利用并有一个供水水库。生态水文模型用于计算水系统中的每日营养浓度，从而可以确定水库的 TSI。作者提出了一种称为 TSImod 的新 TSI，在其测定中考虑了磷、氮和叶绿素。结果表明，与巴西目前使用的指数相比，TSImod 可能更适合对受严重影响的环境进行分类。Verde 河水库在当前土地利用情景下被归类为中营养型，在拟议情景下被归类为富营养型。本研究中开发的框架可以在其他流域中复制，以评估土地利用变化对水质的影响。