Water storage recovery strategy to become blueprint for world's desert zones
Abu Dhabi: 16 January 2018: Abu Dhabi today unveiled the world's largest reserve of high quality desalinated water, se-cured in a network of 315 recovery wells lying up to 80 meters below the Liwa Desert. The wells are fed by one of United Arab Emirates' (UAE) longest water pipeline networks which runs the water from Shuweihat desalination plant at a rate of 7 million imperial gallons (ap-prox. 32,000 m3) / day over 27 months.
The reserve, which has at its core an infiltration and recovery system sitting atop a natural fresh water underground aquifer, was first investigated in 2002 and has been extensively researched by the Environment Agency - Abu Dhabi (EAD). The project was undertaken as a collaborative venture between EAD, delivering the vital scientific studies, feasibility, risk and mitigation scenarios as well as strategic planning Abu Dhabi Water and Electricity Authority (ADWEA) and its TRANSCO subsidiary, which managed the construction and on-the-ground implementation.
His Excellency Dr. Saif Saleh Al Seairi, Acting Director General of Abu Dhabi Water and Elec-tricity Authority (ADWEA), delivered a speech in which he thanked the President of the UAE, HH Sheikh Khalifa bin Zayed Al Nahyan, HH Sheikh Mohammed bin Zayed Al Nahyan, Crown Prince of Abu Dhabi, Deputy Supreme Commander of the UAE Armed Forces, and HH Sheikh Hamdan bin Zayed Al Nahyan, Ruler's Representative in Al Dhafra Region, for their continu-ous support of the water and electricity sector, a pivotal component of the cultural and ur-ban renaissance witnessed by Abu Dhabi. He also highlighted their impact on the develop-ment and contribution of the Authority and its group of companies through key infrastruc-ture projects. He added that the completion of the Liwa Strategic Water Reserve coincides with the celebration of the year 2018 as a result of the efforts of the late Sheikh Zayed bin Sultan Al Nahyan And for his vision of the future of the region, and call for the conservation of resources and secure access to future generations.
“The reserve acts as a safety net for the provision of water and is now being regarded as an excellent regional model for foresight and planning,” said His Excellency Saif Al Seairi, Acting Director General, ADWEA. “We applaud the efforts of the team that worked hard in some of the harshest desert conditions and in an environment of a constantly undulating landscape. The project team overcame considerable challenges to complete this one-of-a-kind scheme and lessons learned have been shared with our regional partners. This project has positioned Abu Dhabi”, he added.
“The entire project is testament to the power of multi-stakeholder collaboration, and an exemplary case study in inter-governmental cooperation driven by environmental pillars guiding sustainable economic imperatives,” said Her Excellency Razan Khalifa Al Mubarak, Secretary General, EAD.
The project has addressed Abu Dhabi's water security and its resilience through the re-charge of groundwater aquifers with high-quality desalinated water, which cannot be stored above ground due to contamination and other factors. The desalinated water is piped from the coast to create the secure, underground reserve system and was accomplished by a multi-national and multi-disciplinary team of experts from EAD, TRANSCO, ADWEA, RSB, the independent regulatory body for Abu Dhabi's water and electricity sector, GIZ International, Do. Rainer Consultancy and ACC-POSCO JV.
Established in one of the world's driest areas where rainfall rarely exceeds 10 cms a year, the project has been completed at an estimated cost of AED 1.61 billion equivalent to USD 435,616,000 to deliver a fallback pumping capacity of 100 million gallons of water / day to the emirate if required. The desalinated water percolates into the subsurface through basins with a system of semi-perforated underground pipes to recharge the aquifer using only gravity as a driving force.
The project ensures continuous water supply for Abu Dhabi city and Al Dhafra region and secures the reserve for future generations. Whenever needed, water from the 315 wells, lying up to 80 metres below ground, can be used to recover supplies at any time.
The reserve now holds more than 26 million m3 of water (equivalent to 5.6 billion imperial gallons) that can bolster drinking water supply when needed. “Long-term wellbeing of our communities is enhanced by the maintenance and enhancement of groundwater while be-ing conscious that we need to progress additional recharge and recovery projects to opti-mize flexible allocation of water as required,” said Razan Al Mubarak.
Hailed as a “breakthrough sustainable engineering feat”, the Liwa reserve attests to the emirate's commitment to “modern scientific knowledge and Abu Dhabi's future vision for a balanced approach between development and conservation, that started with the late Sheikh Zayed and is now part of his legacy; a legacy which continues to grow through our President HH Sheikh Khalifa Bin Zayed Al Nahyan, HH Sheikh Mohammed Bin Zayed Al Na-hyan, Crown Prince of Abu Dhabi and Deputy Supreme Commander UAE Armed Forces and HH Sheikh Hamdan Bin Zayed Al Nahyan, Ruler's Representative to Al Dhafra Region and EAD's Chairman of the Board. Their guidance, wisdom and unmitigated support continue to drive us forward,” according to Al Mubarak. “Their endorsement and insights are reflected in the Liwa Strategic Water Reserve, which represents a global benchmark for water man-agement in desert regions and could completely redefine international standards for re-charge and recovery projects”.
Throughout the implementation of the project, considerable attention was paid to the use of highly engineered, environment-friendly specification materials, which were deemed ap-propriate to the Liwa area. The infiltration basin was insulated with protective materials, including a gravel mix of large pore stones to evenly distribute water and ensure better fil-tration.
The 160-kilometre pipeline from the strategic water reserve site to the Madinat Zayed dis-tribution network in Abu Dhabi city consists of approximately 9,000 sections of welded pipes some of which measure 1.2 metres in diameter, and are up to 18 metres long. The sections had to be transported into the desert and pieced together through high precision welding which would take up to five continuous hours per section with stringent, follow-on X-ray inspection to ensure the system was leak-proof and could withstand the prevailing water pressure for a minimum of 50 years.
Concerns about aquifer contamination from large animals, such as roaming camels, were addressed by working with nature which resulted in the creation of a ‘groundwater protec-tion buffer zone' made from locally produced palm-frond while solar panels power wellhead monitoring instrumentation.
Reallocating the surplus from desalinated water into the reserve, addresses some of the challenges brought by dependence on desalination plants. “Desalination plants can be shut down by storms, a malfunction, a random sea raft and even the red tide phenomenon which has been exacerbated by climate change and negatively impacts water quality, the envi-ronment and ultimately the local economy. We need strategic reserves in the event of one or more stations being out of service and we need to ensure the availability of an alternative so that the population, industrial and commercial sectors are not negatively affected. The government realised the need for an alternative supply to cover our needs in the near or far term, and one which would also mitigate against climate risks and it is wisely investing in finding solutions” stated Al Seairi.
The Liwa desert was chosen for the project after it met strict specification criteria. These included an extremely light water basin trajectory to prevent leakage; capable of sustaining a ‘tank' thickness to handle significant storage volumes; safe surroundings free of human activities which could contaminate the reserve and where groundwater quality was of suffi-cient quality to allow for ‘recharge and mixing.'
“We decided to recharge the depleting ground aquifers with our surplus desalinated water and the result proved to be the most efficient way to store water at the lowest cost,” ex-plained Al Seairi. “We do not need to build and maintain water tanks. We do not need ener-gy to power their injection. We only re-inject water to replenish and restore what was pre-viously there.”
Water quality is ensured through strict control, heat and salinity monitoring equipment and a range of other metrics. “Running the expansive well network simultaneously is a complex process. Communication and inter-team information exchange is critical. All this data is connected to a master network that acts as the project's ‘brain' and is housed in a state-of-the-art electronic process centre from which technicians control pumps, wells and valves and water quality which complies with RSB drinking water standards, is ensured by auto-matically operating at least 20 wells per day”, stated Al Seairi.
Following the signing of a Memorandum of Understanding between EAD, represented by H.E. Razan Al Mubarak and TRANSCO, represented by H.E. Mohammed bin Omair Al Shamsi, Chairman of the Board TRANSCO at the International Water Summit which is running in the UAE capital as part of Abu Dhabi Sustainability Week, the strategic water reserve project will now be operated, managed and maintained by TRANSCO with scientific support by EAD. In readiness for the operation period, TRANSCO has prioritised the training of UAE nationals as project managers. “Their contact with this project vastly increases their experience, enriching their national pride and their sense of this project's value and they add their insight and viewpoint to achieve the project's objectives,” said H.E. Mohammed Bin Omair Al Shamsi.
For EAD, the project is a true visionary undertaking to address pressing realities. “The stor-age of huge reserves of fresh water in the desert was considered a dream for previous gen-erations. However, the nation's innovative vision, wise investment in the latest technologies and in global expertise balanced by a sustainable approach and environmental science have made that dream a reality,” said Al Mubarak. “As the Year of Zayed celebrates his achieve-ments and legacy, we honor and follow the path he set forth. Through inter-agency co-operation we have adopted a coherent approach to create real change in the management of our water resources to ensure the protection of our environment and our economic prosperity.”