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Perspectives
Basic engineering could save Somalilandâs water, expert urges
29 March 2017 | By David Rogers | 1 Comment
A water expert in Los Angeles is warning his former country, the Republic of Somaliland, to perform some basic civil engineering to save its underground water reserves â or face permanent unviability as a place for human habitation.
Simple techniques such as recharge dams and âspreading groundsâ, which catch rain when it comes and channel it into depleting aquifers, are needed urgently as the impoverished and drought-ravaged nation intensifies water drilling to cope with urbanisation.
The self-declared republic, home to 3.5 million people, must spend more of its limited budget on engineering works now common in Los Angeles, said Adan Iman, a management consultant at the Los Angeles City public works department and writer on Somaliland.
The bottom line is that the government must do something about it. I want to say to them, you are using the water that is supposed to be used by your great grand kidsâ Adan Iman, Los Angeles City public works department
Along with Yemen, South Sudan and areas of northern Kenya and Nigeria, Somaliland is experiencing famine brought by a prolonged drought. Its government declared a state of drought in August 2015 after experiencing two failed rainy seasons.
The failures, which were associated with an El Niño event in the Pacific Ocean, are particularly serious for Somaliland because it has no permanent rivers or lakes and has an economy that relies largely on the herding of sheep, camels and cattle for export to the Gulf states.
âDrill, drill, drillâ
Adan Iman, who grew up there, said the more serious long-term effects of the drought would be to deplete the countryâs store of underground water. He urged the government to invest in civil engineering schemes to replenish its aquifers.
He told GCR: âThe government has an annual budget of $250m and they have to allocate some of it to water. When Somaliland was under British rule they carried out surveys, and they know where the water is. They should now build spreading grounds and recharge dams where the aquifers are.â
He said that instead, the governmentâs response was to âdrill, drill, drillâ, but that increasingly the water table was becoming depleted.
âPeople are coming into urban centres, and they are building more homes with septic tanks so the per capita consumption of water has increased. But this water is going to end. When I was growing up in the 1960s you could reach water right away; now itâs going deeper and deeper.â
Government could lead
The position of the government is complicated by chronic instability of its surroundings, which means that it spends half of its revenue on security.
There is also a problem with its legal status. The Republic of Somaliland has declared itself to be an independent state, but it is internationally recognised to be an autonomous province of Somalia. That means that all aid from international donors is given to the government of Somalia. In practice, Somaliland receives minimal international support.
Iman argues that if the Somaliland government were to take action the international community would find a way to help it. He said: âThere is a business community that has money and the government could increase the budget for the department of water to third after defence and education. If the international community sees they are helping themselves, then they will get assistance to build dams and spreading grounds.â
Spreading grounds are a technique used to replenish underground water stores in low-rainfall areas that experience occasional storms. They are relatively inexpensive in civil engineering terms, and consist of a basin with a porous or permeable subsoil connected to a target aquifer that can be filled by storm drains. The City of Los Angeles has 27 of them.
The dams are similar in effect, in that they prevent the run-off from storms from flowing past the ârecharge zoneâ of an aquifer.
Iman said: âThe bottom line is that the government must do something about it. I want to say to them, you are using the water that is supposed to be used by your great grand kids.â
As surface water diminishes in the Western US, people are drilling deeper wellsâand tapping into older groundwater that can take thousands of years to replenish naturally.
Communities that rely on the Colorado River are facing a water crisis. Lake Mead, the riverâs largest reservoir, has fallen to levels not seen since it was created by the construction of the Hoover Dam roughly a century ago. Arizona and Nevada are facing their first-ever mandated water cuts, while water is being released from other reservoirs to keep the Colorado Riverâs hydropower plants running.
If even the mighty Colorado and its reservoirs are not immune to the heat and drought worsened by climate change, where will the West get its water?
Thereâs one hidden answer: underground.
As rising temperatures and drought dry up rivers and melt mountain glaciers, people are increasingly dependent on the water under their feet. Groundwater resources currently supply drinking water to nearly half the worldâs population and roughly 40% of water used for irrigation globally.
What many people donât realize is how old â and how vulnerable â much of that water is.
Most water stored underground has been there for decades, and much of it has sat for hundreds, thousands or even millions of years. Older groundwater tends to reside deep underground, where it is less easily affected by surface conditions such as drought and pollution.
As shallower wells dry out under the pressure of urban development, population growth and climate change, old groundwater is becoming increasingly important.
Drinking Ancient Groundwater
If you bit into a piece of bread that was 1,000 years old, youâd probably notice.
Water that has been underground for a thousand years can taste different, too. It leaches natural chemicals from the surrounding rock, changing its mineral content. Some natural contaminants linked to groundwater age â like mood-boosting lithium â can have positive effects. Other contaminants, like iron and manganese, can be troublesome.
Older groundwater is also sometimes too salty to drink without expensive treatment. This problem can be worse near the coasts: Overpumping creates space that can draw seawater into aquifers and contaminate drinking supplies.
Flow timescales of groundwater through different layers. USGS
Ancient groundwater can take thousands of years to replenish naturally. And, as California saw during its 2011-2017 drought, natural underground storage spaces compress as they empty, so they canât refill to their previous capacity. This compaction in turn causes the land above to crack, buckle and sink.
Yet people today are drilling deeper wells in the West as droughts deplete surface water and farms rely more heavily on groundwater.
What Does It Mean for Water to Be âOldâ?
Letâs imagine a rainstorm over central California 15,000 years ago. As the storm rolls over whatâs now San Francisco, most of the rain falls into the Pacific Ocean, where it will eventually evaporate back into the atmosphere. However, some rain also falls into rivers and lakes and over dry land. As that rain seeps through layers of soil, it enters slowly trickling âflowpathsâ of underground water.
Some of these paths lead deeper and deeper, where water collects in crevices within the bedrock hundreds of meters underground. The water gathered in these underground reserves is in a sense cut off from the active water cycle â at least on timescales relevant to human life.
In Californiaâs arid Central Valley, much of the accessible ancient water has been pumped out of the earth, mostly for agriculture. Where the natural replenishment timescale would be on the order of millennia, agricultural seepage has partially refilled some aquifers with newer â too often polluted â water. In fact, places like Fresno now actively refill aquifers with clean water (such as treated wastewater or stormwater) in a process known as âmanaged aquifer recharge.â
Average turnover times for groundwater in the U.S. Alan Seltzer, based on data from Befus et al 2017, CC BY-ND
In 2014, midway through their worst drought in modern memory, California became the last western state to pass a law requiring local groundwater sustainability plans. Groundwater may be resilient to heat waves and climate change, but if you use it all, youâre in trouble.
One response to water demand? Drill deeper. Yet that answer isnât sustainable.
First, itâs expensive: Large agricultural companies and lithium mining firms tend to be the sort of investors who can afford to drill deep enough, while small rural communities canât.
Second, once you pump ancient groundwater, aquifers need time to refill. Flowpaths may be disrupted, choking off a natural water supply to springs, wetlands and rivers. Meanwhile, the change in pressure underground can destabilize the earth, causing land to sink and even leading to earthquakes.
Pumping accelerates groundwater flow to a well, delivering dissolved chemicals. USGS
Third is contamination: While deep, mineral-rich ancient groundwater is often cleaner and safer to drink than younger, shallower groundwater, overpumping can change that. As water-strapped regions rely more heavily on deep groundwater, overpumping lowers the water table and draws down polluted modern water that can mix with the older water. This mixing causes the water quality to deteriorate, leading to demand for ever-deeper wells.
Reading Climate History in Ancient Groundwater
There are other reasons to care about ancient groundwater. Like actual fossils, extremely old âfossil groundwaterâ can teach us about the past.
Envision our prehistoric rainstorm again: 15,000 years ago, the climate was quite different from today. Chemicals that dissolved in ancient groundwater are detectable today, opening windows into a past world. Certain dissolved chemicals act as clocks, telling scientists the groundwaterâs age. For example, we know how fast dissolved carbon-14 and krypton-18 decay, so we can measure them to calculate when the water last interacted with air.
Younger groundwater that disappeared underground after the 1950s has a unique, man-made chemical signature: high levels of tritium from atomic bomb testing.
The various components and properties of an unconfined aquifer. USGS
Other dissolved chemicals behave like tiny thermometers. Noble gases like argon and xenon, for instance, dissolve more in cold water than in warm water, along a precisely known temperature curve. Once groundwater is isolated from air, dissolved noble gases donât do much. As a result, they preserve information about environmental conditions at the time the water first seeped into the subsurface.
The concentrations of noble gases in fossil groundwater have provided some of our most reliable estimates of temperature on land during the last ice age. Such findings provide insight into modern climates, including how sensitive Earthâs average temperature is to carbon dioxide in the atmosphere. These methods support a recent study that found 3.4 degrees Celsius of warming with each doubling of carbon dioxide.
Groundwaterâs Past and Future
People in some regions, like New England, have been drinking ancient groundwater for years with little danger of exhausting usable supplies. Regular rainfall and varied water sources â including surface water in lakes, rivers and snowpack â provide alternatives to groundwater and also refill aquifers with new water. If aquifers can keep up with the demand, the water can be used sustainably.
Out West, though, over a century of unmanaged and exorbitant water use means that some of the places most dependent on groundwater â arid regions vulnerable to drought â have squandered the ancient water resources that once existed underground.
How water use and recharge fit into the hydrological cycle. State of California
A famous precedent for this problem is in the Great Plains. There, the ancient water of the Ogallala Aquifer supplies drinking water and irrigation for millions of people and farms from South Dakota to Texas. If people were to pump this aquifer dry, it would take thousands of years to refill naturally. It is a vital buffer against drought, yet irrigation and water-intensive farming are lowering its water levels at unsustainable rates.
As the planet warms, ancient groundwater is becoming increasingly important â whether flowing from your kitchen tap, irrigating food crops, or offering warnings about Earthâs past that can help us prepare for an uncertain future.
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This is such a successful project and gets such little exposure! I was looking at a sat map of Gabiley and was drawn to a body of water. Couldnât believe its still full.
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Haffir Dam project Faraweyne
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We need one or two of this huge catchments built in every region if not district. That will go a long way to water security.
2 million dollars is what this costed. If the Govât comes up with a plan to invest 20 million dollars over a 5 year period - that is 4 million dollars each year. I think the donor countries could fund another 20 million dollars - total of 40 million over 5 years. We could commission up to 4 dams each year.
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Surely, Humboweyne dam is in the wrong place, have never seen it hold water for more than a few days/weeks. Gabiley dam has held water for over 7 months and can hold between rainy seasons!
The wells near the surrounding area of the Gabiley dam have fully replenished thanks to the dam!
The nutrient silt that will eventually fill the dam can be extracted for farming as necessary.
Glad to see home grown expertise at work.
Every region needs this for sure. They donât even need to be as big smaller scale will do.
Every rainy season we have this
Donor countries know the solutions, they just donât want to solve anything. Itâs up to us.
Not necessarily. It just shows that the water is replenishing the underground water systems. Which is good in the longer run.
With Gabiley, it looks like it has good ground water (water table) which means the water are not going into the ground very fast.
Absolutely. They wonât fund anything until they see that you have the plan, you have costed and you done the ground work (i.e. engaged the community etc).