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Koshi Basin

Supporting integrated water resources management in the Koshi Basin

Integrated water resource management requires agreement and understanding of the amount of water available, the demands that are made on this water, and how water resources can be best shared to ensure that the livelihoods of people and functioning of ecosystems are sustained.

Agriculture land use in Nepal. Source: Tanya Doody, CSIRO
Agriculture land use in Nepal. Source: Tanya Doody, CSIRO

In the Koshi Basin, CSIRO through the Sustainable Development Investment Portfolio (SDIP), is working with Nepali organisations with the aim to assist in building the evidence base necessary to guide strategic investments in water resources development. Preliminary research and development by CSIRO has focussed on understanding the biophysical, cultural and policy environments of the Koshi watershed of Nepal, and supporting capacity development activities within the Government of Nepal.

Measuring the water resource

CSIRO is improving understanding of the water balance of the Koshi Basin catchments [click to view a map of estimated water balance].

CSIRO has supported revisions to rainfall station locations, development of new gridded rainfall products and refinement of hydrological models, all of which lead to better understanding of the timing and availability of water in major streams, including projected climate change scenarios. In one catchment, the better spatial representation of rainfall led to the elimination of a false streamflow bias in the corresponding catchment runoff model.

The report From the Mountains to the Plains: Impact of Climate Change on Water Resources in the Koshi River Basin, published by International Water Management Institute staff and their collaborators, quantifies and assesses the past and projected future spatial and temporal water balances in the Koshi Basin (fact sheet). Results show that precipitation and net water yield are lowest in the transmountain region and the Tibetan plateau.

Modelling hydrological processes

Working with local modelling experts, we improved models of the Koshi basin hydrology. The preliminary analysis of hydroclimate and streamflow modelling can be used as a tool to explore how different climate change and development scenarios might impact streamflow.

Improving rainfall and temperature data

Daily precipitation, minimum and maximum temperatures gridded datasets have been generated for the Koshi Basin. These are more accurate than existing products due to the improvements in locations of rainfall stations (providing better validation against observed data) and the use of sophisticated statistical methods.

Describing river flow characteristics

Expert ecologists identified a lack of knowledge about current flow regimes, and how ecologically significant aspects may change under altered flow regimes. Using a suite of hydrological metrics (e.g. mean daily flow) to classify and cluster flow regimes, we can map these to look at their spatial distribution.

Connecting flow and ecology

The fact sheet and report Connecting flow and ecology in Nepal: current state of knowledge for the Koshi Basin focuses on the relationship between river flow and ecology to increase our understanding of how future hydrological changes in the Koshi Basin (and beyond the Basin) might impact different ecological components of the ecosystem. This is valuable information to assist in Nepal’s water reform journey and fills a knowledge gap about freshwater ecosystems.

Livelihoods rely on water availability, Nepal. Source: Tanya Doody, CSIRO
Livelihoods rely on water availability, Nepal. Source: Tanya Doody, CSIRO


A comprehensive multi-variate livelihood analysis was implemented across the region with the goal of quantifying patterns of activities that generate means of survival as livelihood strategies. A review of frameworks to integrate ecosystem services and livelihoods was also conducted. With the aim of making expert knowledge applicable an Argument-Representation-Implementation (ARI) framework was implemented. This allows broad abstract recommendations in the literature to be linked to specific policy advice that will lead to desired and informed outcomes.


Key collaborators for this work include the Government of Nepal through the Nepal-Australia Joint Advisory Committee on Water Resource Management, and SDIP partners, especially International Centre of Excellence in Water Resources Management (ICE-WaRM), International Centre for Integrated Mountain Development (ICIMOD), and International Finance Corporation (IFC).

Project leader: Dave Penton

About SDIP

This SDIP work is part of a portfolio of investments supported by the Australian Government addressing the regional challenges of water, food and energy security in South Asia.

The SDIP2 aims to improve the integrated management of water, energy and food in the Himalayan river basins, addressing climate risk and the interests of women and girls. It seeks to:

  • strengthen practices for regional cooperation
  • generate and use critical new knowledge to enhance regional cooperation
  • improve regional enabling environment for private sector engagement.

Find out more about SDIP work in Nepal

Access SDIP publications

Find more information about international water research at CSIRO