Inter-basin transfers

Objective
Sectors

Description

Inter-basin transfer is the moving of water from a watershed with a surplus (donor basin) to a watershed suffering from a shortage (recipient basin). The water is transferred primarily to alleviate water scarcity in the recipient basin and travels long distances via complex pipeline and canal systems.  Other reasons include recipient basin hydropower generation and the navigation route expansion. Inter-basin transfers are often considered a controversial practice, as the environmental and socio-economic consequences for the donor basin can be high, and difficult to predict. Therefore, it is strictly regulated in many areas, s and completely prohibited in others.  

Implementation

Inter-basin transfers are usually regulated by law and can only be implemented if certain conditions are met (e.g. only a limited amount of water is transferred, water conservation plans are included as part of the project, downstream flow protection plans are established, etc.) and the relevant water rights are obtained. Critical considerations include ensuring that the transfer does not disrupt any water-dependent activities or access in the donor basin and that it meets relevant environmental protection laws and regulations. 

Implementation involves the building of pipes or canals to divert water from the donor to the recipient watershed. This requires technical expertise and includes, for example, dredging and installation of pipes, as well as other diversion and storage structures. Diversion structure maintenance, in addition to environmental and socioeconomic impact monitoring, ensures optimal operation. Pipes and other equipment should be regularly checked, and repaired when necessary, to minimize potential transfer water loss and ensure maximum efficiency of resource use.  

Environmental Benefits

- Supports groundwater recharge in the receiving watershed and alleviates negative ecosystem impacts associated with critical water shortage.

Socioeconomic Benefits

- Increases water supply in the recipient basin to help meet a wide range of water demands, for example for agriculture, domestic use, recreation, industry, power generation, etc. On a national level it may improve the economic efficiency of resource use.

Opportunities and Barriers

Opportunities:

-    Provision of freshwater in recipient basin, providing numerous socio-economic benefits 

-    If well managed (and the negative environmental impacts can be limited) it can provide climate change adaptation benefits in water scarce regions 

Barriers:

-    Usually costly and time-consuming

-    Potential negative socio-economic consequences for communities downstream from the donor basin

-    Watershed removal changes river dynamics and can negatively affect ecosystem balance, including water quality and  flora and fauna

-    Potential negative environmental impacts in areas hosting transfer structures 

Implementation considerations*

Technological maturity:         4-5

Initial investment:         4-5

Operational costs:         2-4

Implementation timeframe:     3-4

* This adaptation technology brief includes a general assessment of four dimensions relating to implementation of the technology. It represents an indicative assessment scale of 1-5 as follows:

Technological maturity: 1 - in early stages of research and development, to 5 – fully mature and widely used

Initial investment: 1 – very low cost, to 5 – very high cost investment needed to implement technology

Operational costs: 1 – very low/no cost, to 5 – very high costs of operation and maintenance

Implementation timeframe: 1 – very quick to implement and reach desired capacity, to 5 – significant time investments needed to establish and/or reach full capacity

This assessment is to be used as an indication only and is to be seen as relative to the other technologies included in this guide. More specific costs and timelines are to be identified as relevant for the specific technology and geography.

Sources and further information