Environmental flow plays a crucial role in the sustainability of rivers and aquatic ecosystems. Reduction in the flow of rivers degrades its ecosystem functions and health, resulting in severe impacts on aquatic ecosystems. Additionally, meteorological drought, which occurs due to a substantial reduction in normal rainfall, subsequently affects the river flow. To understand such consequences, long-term observed flow data are required, which is not readily available for geographically different catchments. The present study is an effort to explore the relationship between the drought characteristics based on percent rainfall departure (%RD) and average annual flow (%AAF) based environmental flow conditions. Drought characteristics and the environmental flow conditions have been assessed for 17 Indian catchments from 5 different river basins of India, namely Godavari, Mahanadi, Tapi, Brahmani-Baitarini and Mahi. Relationship analysis showed a coefficient of determination (R²) value of more than 0.55 for 11 out of 17 catchments, showing satisfactory results. Furthermore, the analysis represents that %AAF and %RD are positively correlated. The explored relationships can be useful for assessing environmental flow conditions in Indian catchments without discharge data. Also, the study approach is extendable to understanding drought linkage to environmental flow conditions for the ungauged catchments with rainfall departure records only.

环境流量对河流和水生生态系统的可持续性发挥着至关重要的作用。河流流量的减少会降低其生态系统的功能和健康，从而对水生生态系统造成严重影响。此外，由于正常降雨量大幅减少而发生的气象干旱也会影响河流流量。为了了解这种后果，需要长期观测的流量数据，而这些数据对于地理位置不同的流域来说并不容易获得。本研究致力于探索基于降雨偏离百分比 (%RD) 的干旱特征和基于环境流量条件的年平均流量 (%AAF) 之间的关系。对印度 5 个不同河流流域（即戈达瓦里河、马哈纳迪河、塔皮河、婆罗门-拜塔里尼河和马希河）的 17 个流域的干旱特征和环境流量条件进行了评估。关系分析显示，17个流域中有11个流域的决定系数（R ²）值大于0.55，结果令人满意。此外，分析表明%AAF 和%RD 呈正相关。探索的关系可用于在没有排放数据的情况下评估印度流域的环境流量条件。此外，该研究方法还可以扩展到了解干旱与仅具有降雨离开记录的未计量集水区的环境流量条件的联系。