Streamflow, the key component of catchment-scale hydrology is acknowledged as being induced by climate change and land-use alterations. The potential quantification of these hydrological drivers on streamflow variations is quite challenging. This study quantitatively assesses the isolated influences of climate change and land-use alterations on the streamflow variations in the Brahmani (36,800 km²) and Baitarani (12,094 km²) River catchments of eastern India by applying three complementary techniques involving: (i) m-DMC approach (traditional trend analysis); (ii) m-SCARQ approach (slope change ratio approach); and (iii) SWAT-based hydrological modeling approach. The hydro-meteorological (precipitation, temperature, and streamflow) data variation and its significance are studied at a decadal time-spell followed by the Mann-Kendall test and the linear regression technique. The relative contributions of changing climate (${\theta }_{\mathit{ji}}^C$) and land-use alterations (${\theta }_{\mathit{ji}}^L$) are quantified at a decadal time-spell considering the initial time-spells as baseline periods (1979–1988, 1989–1998, and 1999–2008) and the subsequent time-spells as impacted periods (1989–1998, 1999–2008, and 2009–2018). Outcomes of our comparative assessment of the study area indicate that the empirical approaches (m-DMC and m-SCARQ) result in land-use alterations as a dominant contributing factor in streamflow variations. However, the performance of the SWAT-based hydrological approach specifies identical contributions from both the climate and land-use changes. The diversity in results from these three approaches is associated with different sources of errors and uncertainty. Thus, it is necessary to interpret the results of different separation approaches cautiously while addressing the adaptive management of a catchment for sustainable water resources planning in the future.

流域是流域规模水文学的关键组成部分，被认为是由气候变化和土地利用变化引起的。这些水文驱动因素对流量变化的潜在量化非常具有挑战性。这项研究定量评估了气候变化和土地利用变化对Brahmani（36,800 km ²）和Baitarani（12,094 km ²）通过应用以下三种互补技术来实现印度东部的河流集水：（i）m-DMC方法（传统趋势分析）；（ii）m-SCARQ方法（坡度变化率方法）；（iii）基于特警队的水文模拟方法。在十年的时间周期内，通过Mann-Kendall检验和线性回归技术研究了水文气象（降水，温度和流量）数据的变化及其意义。气候变化的相对贡献（${\theta }_{\mathit{ji}}^C$）和土地用途变更（${\theta }_{\mathit{ji}}^{\mathrm{大号}}$）以十年时间段进行量化，将初始时间段作为基准时间段（1979-1988年，1989-1998年和1999-2008年），并将随后的时间段作为受影响时间段（1989-1998年，1999-2008年，和2009–2018）。我们对研究区域的比较评估结果表明，经验方法（m-DMC和m-SCARQ）导致土地利用变化，这是导致流量变化的主要因素。但是，基于SWAT的水文方法的性能说明了气候和土地利用变化的相同贡献。这三种方法的结果差异与错误和不确定性的不同来源有关。因此，