Friday, February 23, 2024
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Groundwater: an untapped solution to climate variability

Ethiopia is naturally exposed to climate variations as witnessed by the ongoing drought in Borena and Kabribeyah zones and consecutive years of failed rainy seasons in the lowland parts of the Afar, Oromia, and Somali regions. Rainfall shortages in successive years has caused a significant water scarcity, crop failures and livestock deaths, drastically threatening the lives and livelihoods of nearly seven million people this year alone.

Unfortunately, climate change is expected to intensify climate variability in Ethiopia and exacerbate related challenges by affecting the amount, seasonality and intensity of rainfall. Like many countries in the Horn and Sub-Saharan Africa, Ethiopia has been exploring potential solutions to combat climate variability and adapt to the realities of climate change.

Because groundwater is naturally shielded from drought and climate variability, it is deemed a primary solution to develop climate resilience. The favorable distribution of groundwater lends itself as a sustainable, decentralized and cost-effective solution to improve water supply, boost climate resilience, and enhance adaptation to climate change.

The exponential population growth in urban areas and the agriculture-led industrial development have also forced the country, especially cities, to look to groundwater as an accessible and cost-effective water supply source. While rural areas mostly rely on hand dug wells that are ~30 m deep and renewable groundwater sources, cities are heavily dependent on ~200 m to 600 m deep and finite aquifers for their water supply.

The dependency is particularly true in big cities across Ethiopia where groundwater provides a lion’s share of the water supply. For instance, groundwater accounts for over 40 percent of the water supply for Addis Ababa and Bahir Dar, and nearly all the domestic water supply for Mekelle and Dire Dawa.

Detailed groundwater information in Ethiopia is limited and there is a huge need for proper groundwater assessment, mapping and monitoring. However, the total groundwater volume is currently estimated at 40 billion cubic meters and the annual sustainable groundwater withdrawal rate is estimated at less than three billion cubic meters. This represents approximately two percent of the average renewable surface water of 122 billion cubic meters flowing in Ethiopian river systems annually.

Given that the safe groundwater yield represents a small fraction of the annual renewable surface water supply, water utilization strategies in Ethiopia should emphasize efficient surface water use as much as possible. In essence, deep groundwater sources should be regarded as savings bank accounts whereas renewable surface water sources represent a checking account for everyday transactions.

Groundwater in Ethiopia is also exposed to several challenges that affect water access and its potential to function as a buffer to drought and an adaptation mechanism to climate change. Due to its finite nature and the ever-increasing demand for water access, overexploitation is causing extreme groundwater depletion, weakening water service delivery and extending rationing in cities across the country.

For example, groundwater decline has forced Dire Dawa to extend the depth of its well fields to more than 500 meters in areas where groundwater was accessible at 200 meters. Dry wells that are unlikely to recover are often decommissioned and water demand will need to be met from new sources, which can take years to develop.

Beyond water availability, increasing well depths significantly spike resources required for drilling, borehole installation and energy cost for groundwater pumping and distribution. Deeper wells in some aquifers are also exposed to natural contamination such as arsenic and fluoride in the Rift Valley cities, salinity in Mekelle and hard water related to calcium bicarbonate in Dire Dawa. The immense health risks, water treatment cost and water infrastructure damage associated with poor groundwater quality are well documented.

Expansion of built-up areas in major Ethiopian cities and inappropriate land use and land tenure policies have contributed to groundwater quality and quantity decline. Urban expansion of impervious surfaces, especially in high recharge zones such as the foothills of Addis Ababa and surrounding cities, has severe implications on groundwater availability.

Bacterial contamination of groundwater wells related to pit latrines from informal settlements such as in the vicinity of the Sabian Well field in Dire Dawa poses tremendous risk to public health. Nitrate and industrial heavy metal contamination and farm fertilizer leach upstream of well fields are also major causes for concern.

In the strategic groundwater management and development framework, the Government of Ethiopia has identified the importance of integrating groundwater and development policy to ensure water supply as the most pressing priority. However, effective strategy for proper implementation of land use policy and integrated watershed management to protect water sources still lag behind the vision.

Overexploitation and inefficient groundwater use, unregulated discharge and degradation of high potential groundwater recharge zones remain persistent challenges that require significant capacity and investment to address.

To this end, the World Resources Institute, in partnership with government and non-government institutions, has prioritized nature-based solutions and integrated water resources management to ensure urban and rural water resilience in the face of increasing water demand and water risks related to climate change.

The Urban Water Resilience Initiative, for instance, is working with six cities in Africa, including Addis Ababa and Dire Dawa, to identify specific place-based actions for building water resilience. Deep research, spatial analysis and broad stakeholder engagement underpins this work to advance integrated urban development and water management plans and policies.

Sufficient access to clean water is essential for our health and development, of which groundwater plays a critical role. Promoting effective, integrated groundwater management and ensuring water access and availability in Ethiopia will require a coordinated effort by government, development partners, the private sector, and communities across Ethiopia.

As we celebrate the World Water Day on March 22, we have confidence that committing to safeguard groundwater resources will reduce the risks posed by climate related water shocks and stresses on public health, development and well-being of all Ethiopians.

(Zablon Adane and Tinebeb Yohannes are experts specialized in water systems working for World Resources Institute)

Contributed by Zablon Adane and Tinebeb Yohannes

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