Global climate change has substantial impacts on local and regional hydrological regime. However, the general understanding of how hydrological regime is affected by climate change at catchment scale is limited. In this study, the potential impacts of climate change on water resources in Ngerengere River catchment in Tanzania were assessed. The HBV model was used to undertake water resources assessment for the Ngerengere catchment and subsequently impacts of climate change on the same. Future climate for 2050s (2040–2069) and 2080s (2070–2099) were downscaled using a statistical weather generator (LARS-WG) from outputs of the Global Circulation Model (HadCM3) under SRES A2 scenario.

The HBV model was calibrated and validated using observed streamflow data at Mgude gauge station for the baseline period (1971–2000). The Nash-Sutcliffe efficiency (NSE) of 0.7 and 0.6 was attained during calibration and validation respectively. Downscaling results revealed that LARS-WG performed well in generating future rainfall and temperature data series. The results indicated an increase in minimum and maximum temperature of around 0.2–2.6 °C in the 2050s and around 2.7–4.4 °C in the 2080s. Future rainfall is predicted to decrease by 12–37% in April, May, June and July, while rainfall in the remaining months are predicted to increase by 3–58%. The impact assessment on streamflow of the Ngererengere catchment revealed a decline in the mean annual streamflow by 2.1% in 2050s, whereas an increase of up to 58% in mean annual streamflow is predicted in the 2080s.

全球气候变化对地方和区域水文制度有重大影响。但是，关于流域尺度的气候变化如何影响水文状况的一般理解是有限的。在这项研究中，评估了气候变化对坦桑尼亚Ngerengere流域水资源的潜在影响。HBV模型用于对Ngerengere流域进行水资源评估，并随后评估气候变化对其的影响。在SRES A2情景下，使用全球天气模型（HadCM3）的统计天气生成器（LARS-WG）缩小了2050年代（2040-2069）和2080年代（2070-2099）的未来气候。

使用基线期（1971–2000年）在Mgude液位站观察到的流量数据，对HBV模型进行了校准和验证。在校准和验证过程中，纳什-舒克利夫效率（NSE）分别为0.7和0.6。缩减结果表明，LARS-WG在生成未来的降雨和温度数据序列方面表现良好。结果表明，最低和最高温度在2050年代增加了约0.2–2.6°C，在2080年代增加了大约2.7–4.4°C。预计4月，5月，6月和7月的未来降雨量将减少12–37％，而其余月份的降雨量预计将增加3–58％。对Ngererengere流域流量的影响评估显示，2050年代年均流量减少了2.1％，