Managing sub surface space – opportunities and experience

Andrew Ross PhDSenior Groundwater Specialist

UNESCO, Paris

1

Benefits of managing sub surface space

• Cost-effective water storage, reduced evaporative losses• Maintains aquifer levels, offsets depletion• Water quality can be improved, subject to good management • Helps communities adjust to climate variability, maintain food

production• Can help synchronise environmental water with requirements

2

Elements of managing sub-surface space: aquifer storage and recharge

• Physical aspect– Water to store in an aquifer – Aquifer where water can be held until users want it– Means to transfer water to the recharge site and the use site

• Institutional aspect– People store water underground – a water bank– They need to have guarantee that they can withdraw water less

proportion to cover leakage and management costs• Water may be stored underground in two ways

– Infrastructure based: managed aquifer recharge– Non-infrastructure based: natural recharge: reduction in groundwater

use, land and water management practices

3

4

Examples of managed aquifer recharge

Managed aquifer recharge in the US and Australia

5

US - over 150 operations, many are commercial. Examples:

Orange Co – stores 300 GL/yr enough for 2.3 m people.

Semitropic water bank holds 860 GL, irrigation water for 140000 acres, dry year reserve for 4.4 m households.

Between 2007-2010 water banks in Kern Co and Southern California Supplied 600 GL of dry year supplies.

Australia – over 30 operations, mostly experimental &/or small scale

Largest operation, Burdekin delta in Queensland, average storage and recovery 45 GL/year

Source: Dillon et al 2009

Questions for discussion

• What are the opportunities for managing sub surface space and its water resources to achieve better collective outcomes?

• What are the barriers against taking advantage of these opportunities?

• How can collective action achieve better management of subsurface resources?

6

AR 4.3.2014

Thanks for your attention

a.ross@unesco.org