Climate change (CC) is impacting the hydrology in the basins of the Himalayan region. Thus, this could have significant implications for people who rely on basin water for their lives and livelihoods. However, there are very few studies on the Himalayan river basins. This study aims to fill this gap by presenting a water balance for the Brahmaputra River Basin using the Soil and Water Assessment Tool (SWAT). Results show that snowmelt contributed about 6% of the total annual flow of the whole Brahmaputra, 21% of the upper Brahmaputra, and 5% of the middle Brahmaputra. The basin-wide average annual water yield (AWY) is projected to increase by 8%, with the maximum percentage increase in the pre-monsoon season. The annual snowmelt is projected to decrease by 17%, with a marked decrease during the monsoon but an increase in other seasons and the greatest percentage reduction in the upper Brahmaputra (22%). The contribution of snowmelt to AWY is projected to decrease while rain runoff will increase across the entire Brahmaputra and also in the upper and middle Brahmaputra. The impact assessment suggests that the upper Brahmaputra will be most affected by CC, followed by the middle Brahmaputra. The results can be used to support future water management planning in the basin taking into account the potential impact of CC.

Nepal is highly vulnerable to flood-related disasters which cause considerable loss of lives and property. The vulnerability of communities to flood-related hazards can be reduced by proper planning, preparedness, and responses using various structural and nonstructural measures. The community-based flood early warning system is one such tool that enables local communities to enhance their resilience to flooding risks. This paper highlights the efficacy of the community assessment of flood risks and early warning systems. Using qualitative and quantitative methods, this paper evaluates the progress of a community-based flood early warning system implemented in the Ratu River—a small tributary of the Koshi River. The establishment of a community network in 2015 was instrumental in the dissemination of flood early warning information and in building local capacities to understand the risks and take timely action. The flood early warning resulted in awareness-raising, strengthened upstream–downstream linkages, and resulted in a greater willingness among communities to help each other prepare for flood disasters in the Ratu watershed.

A foundational tenet of the ecosystem services concept is that they arise from biophysical processes. Riverine landscapes are process-response systems where river flow and geomorphology generate a heterogeneous physical template that influences ecological processes, suggesting that the supply of ecosystem services in riverine landscapes should be congruent with the character and heterogeneity of the physical template. In this study, we examine the congruency between the physical template (river functional process zones; FPZs) and the supply of river flow dependent ecosystem services from riverine landscapes of the Koshi River Basin, Nepal. The supply of ecosystem services was congruent with FPZs. Social factors were shown to mediate the use and value of ecosystem services between FPZs. Heterogeneity of the physical template interacts with place, social activity, and demography to influence the use and potential value of ecosystem services across the riverine landscape. These spatial patterns of greater use of some types of riverine ecosystem services in certain areas of the riverine landscape are indicative of a highly coupled agricultural or “green loop” social-ecological system (SES) and show that maintaining riverine template heterogeneity is an important element of this green loop SES that supports 40 million people in the Koshi River Basin.