By J. A. Omotayo, COREN (Council for the Regulation of Engineering in Nigeria) Registered Civil Engineer
Water distribution (WD) is an intermediate stage in the water production and supply chain. It comprises the distribution pipeline networks, service reservoirs, booster stations, valves, flow meters, chambers and indicator/marker posts. Safe for looping, it can be likened to the branches of a tree, transporting materials from the root (intake and waterworks/headworks) through the trunk (rising and trunk pipeline mains) to the leaves (consumers). Pundits1,2,3,4,5,6,7,8 have various categorisations for the challenges to water sector and their effects on distribution. Ali1 listed three: Technical, Commercial and Administrative. Speight2 noted three: Technical, Management and Climate change. Jegede3 noted four: Technical, Commercial, Policy Framework and Organisational. But Khatri & Vairamoorthy4 conceived nine water supply challenges that are applicable to WD: Population &urbanisation, Globalisation and economic development, Deteriorating infrastructure, Governance and privatisation, Changes in public behaviours, Emerging technology, Risks on critical infrastructure systems, Increase in fuel (energy) costs, and Climate change. One thing is clear. The challenges to WD and their corresponding solutions are multifaceted and cannot be exhaustively treated in a single write up of this nature. The best we can do is to identify and briefly describe or illustrate some of these challenges and their corresponding solutions.
Water Distribution Challenges
In my opinion, WD challenges come in many forms: technical, environmental, economic, political, social and administrative challenges, among others.
Technical challenges include design, construction and operations errors, leakages, aging pipelines, inappropriate technology, inadequately skilled workforce and water quality degradation, among others.
Design, Construction and Operations Errors: WD design is prone to errors coming mainly from wrong assumptions, inadequate statistics, computing input errors, inappropriate field changes during construction works and operational mistakes. Consequently, areas of low and high pressure regimes become unavoidable during operations. These often lead to frequent pipe bursts, loss of treated water, high repair and maintenance costs, traffic hold ups or diversions and reinstatement of roads before, during and after pipeline repairs. Another side effect is back siphonage of dirty and contaminated waters that impact negatively on the water qualities delivered to consumers.
In the developing countries of Africa, there is always the tendency to rehabilitate or expand existing waterworks/headworks based on the assumption that any increase in production translates to corresponding increase in the number of people served. As such, little consideration is given to re-sizing the existing pipeline trunk mains to convey the treated water. In Akure, Ondo State, Nigeria, for example, water production increased from 9x106m3/yr to 14.4x106m3/yr between 2003 and 2012 without any improvement to the consumers8. Another wrong assumption involves pipeline extensions. Many pipeline extensions were made in the 1990s to various parts of Ekiti State (then a part of Ondo State), Nigeria with the assumption that the available water at Ero Dam/headworks was sufficient to serve more than half of the state. The over 800km pipeline extensions in Lagos State, Nigeria in the mid-1990s fall into this category. But today, the pipelines and service reservoirs in most of those communities are empty. Similarly, the National Water Rehabilitation Project (NWRP), a World Bank (WB) sponsored water project all over the 36 States of Nigeria in the 1990s was based on those two assumptions above: increase in production and pipeline extensions. Only in very few towns were the existing rising (pumping) mains and trunk mains re-sized or replaced as pipeline hydraulics would normally dictate.
Leakages and Burst Pipelines: There is no WD system anywhere in the world without some leakages and burst pipelines. Speight noted that about 23 – 27 bursts occur per 100 miles of pipeline in the US2. Although production increased in Akure by 5.4x106m3/yr or 61 percent between 2003 and 2012, the volume of water available to the consumers remained almost constant at 5.9x106m3/yr and 5.8x106m3/yr respectively8. The increase was wasted. In existing Nsawam water distribution, Nsawam, Eastern Region of Ghana, 26 percent leakage was observed during investigation with a 53.2 percent Non-Revenue Water9. Some of these leakages often come from buried joints, valves, flow meters, aged and weak pipelines and are physically non-detectible until water starts to boil or sinkholes created. Instances abound. Until pipe burst occurred at the military barracks in Akure during the dry season in 1990, nobody reasoned that the green vegetation on the hill top was being watered underground by leakages from an underground pipeline. More than 100m stretch of Ogodu Road, Ojota, Lagos State, Nigeria collapsed in 1995 due to underground pipeline leakages. A sinkhole shut down three lanes of a major interstate highway for about two weeks in Denver in 2008, USA10.
Aging pipeline: The structural and hydraulic integrities of WD pipeline networks degrade with age. As corrosion progresses in steel and galvanised iron pipelines, they become weak and readily burst whilst still in service. Similarly, encrustation in cast iron and Asbestos Cement (AC) pipelines not only reduces their internal diameters leading to reduction in discharge but increases headloss and brings higher hoop stresses culminating in more frequent pipe bursts especially where booster pumps are involved.
Inappropriate Technology: In Africa, As-built drawings are often misplaced soon after operations start thus making line tracing and an appropriate modification a Herculean task. Also in Africa, most of the booster stations rely on power to operate high lift and booster pumps. Since power is erratic, WD is also erratic. Reducing dependency on power remains a challenge.
Inadequately skilled workforce: Most operatives do not know that transient pressure (water hammer) is induced with rapid closure of valves at reservoirs located on high grounds. And developing a team of skilled workforce is a problem as it takes time to assemble and train them. By the time they have gained sufficient technical knowhow and capabilities, some of them may be old and less agile, close to their retirement age or have been redeployed to other districts/zones. Some may even retire or join new employments thus creating a vacuum within the water agency.
Water Quality Degradation: Water quality degrades in WD in many ways: back siphonage of dirty and contaminated waters when pressures are low, dissolved corroded pipeline materials (iron, copper, etc), contamination during repairs, reduction in disinfectants residual due to oxidation and or formation of carcinogenic organic by-products, excessively long contact times and flows from sediments-laden service reservoirs, among others2,11. The problem becomes worse with the stringent imposition of chemical limitations (quantity & time) beyond which disinfection not only violates national and WHO standards but impacts negatively on health of consumers2.
Topography: Generally, service reservoirs are located on high grounds to be able to feed the adjoining WD system. The steeper the slope, the greater is the flow to low land areas in WD system and the worse the supply regime to consumers closer to the service reservoirs on higher grounds. For example, Ogbagi, Akoko, Ondo State, Nigeria on a hill top with a balancing reservoir that also supplied water to Ikare-Akoko, Ondo State, Nigeria on a low land used to complain of water shortages untill 1991 when Ondo State Water Corporation decided to install a valve on the Ikare line to control the flows. Even within the same zone in Agege area of Lagos State, Nigeria consumers at Alfa Nla Street on higher elevation do not enjoy as much regular water supply as those at Capitol Road. Operatives often have to divert flows to get consumers on higher grounds served.
In WD, operations managers and operatives are increasingly faced with meeting emergencies when the environment roars. These include how to minimise wastages, restore or divert water supply, and minimise damages to properties during flood. Others include how to cope with drought, rainfall variability and bush fire.
Flood: Flooding of urban communities can cause damages (disconnection, breakages, flotation, back siphonages, silting of chambers, destruction of indicator posts, etc.) to various connecting pipelines. The affected networks may have to be partly or totally shut off, repaired, flushed, disinfected, and reconnected as quickly as possible. In unpaved areas, gradual erosion of earth cover over pipelines laid on hilly slopes is common.
Drought: With drought comes water rationing (diversions) to serve various segments of the communities affected thereby creating a good condition for back siphonage of unwholesome and dirty waters from the surrounding in areas not served or having low pressures. During this time, Engineers, Managers and operatives may have sleepless nights figuring out solutions and implementing the needed diversions to ameliorate people’s sufferings. During this time also bush fires can touch and damage uPVC, PVC and HDPE pipelines that are not fully buried underground.
Cold: In the temperate regions, taps are run to waste when temperatures drop close to or below freezing to prevent blockage thus putting pressure on Engineers, Managers and operatives to ensure continuous flow.
Water availability: Another challenge caused by the environment is that water demand is now exceeding availability12 in some localities: “West Asia and Indo-Gangetic Plains in South Asia”7, and Florida and California in the US2. More urban centres WD systems will be affected as population grows, and coping with the new challenge may be a priority in future.
Economic challenges include:
Inadequate Networks: In developing countries, WD networks are inadequate to meet up with growing urbanisation and population increase. WD networks in Nairobi and eleven satellite towns showed 10 percent to 47 percent approx. coverage13. In ten urban centres surveyed in Ghana in 2007, only Accra had 82 percent coverage with others having 12 percent to 48 percent coverage5. Nigeria has 47 percent water supply coverage1 thus implying that WD might be about 30 percent.
Cost of investment: All over the world, every WD is known to be capital intensive. The pipes, valves, fittings, service reservoirs, booster stations, meters, etc. do not come cheap. Sydney water invests about $300 million annually in order to cope with growth in water demand6. Nigerian Federal Government spent over N800 billion ($5.16 billion approx.) between year 2000 and 2012, yet UNICEF estimated that only 47 percent coverage in water supply was achieved as at 20121. In 2006, WaterAid estimated that Nigeria needed $5.812 billion on water to meet the 2015 MDG (Millennium Development Goal) target14. A half of this might go into WD networks. In 2005, the US needed $11 billion to meet up with water infrastructure and projected a 20-year spending estimate of $276.8 billion that both federal budgetary provisions and consumer tariffs could not meet up2. Three-quarter of this cost were estimated for WD2. Deo’s survey showed that Ghana urban water required $1.692 billion in 19985.
All these huge costs of capital translate to so many challenges: how to determine which aged pipeline to rehabilitate or replace, how to get the unit price of water right to recover investments and operations costs, how to provide a buffer to take care of emergences and future growth, how to gather and manage adequate demand and supply data, and how to adapt to new technologies.
Foreign and Domestic Debts: In Africa, a part of the challenge has to do with debt burden and or inability to secure foreign loans. For instance, the second phase of the Nsawam Water Supply Rehabilitation and Expansion Project for which €7 million external funding has been secured (part of which could have expanded the Nsawam distribution networks) could not be implemented as the Ghanaian government had to place embargo on foreign loans due to existing huge foreign debt burden estimated at GHc63 billions ($18.5 billions approx.). There was an economic report that some states in Nigeria (Lagos, Ondo, etc) have over-borrowed beyond what they could repay. Consequently, the Federal Government of Nigeria would not be in a position to guarantee external loans to these states.
Absence of cost optimisation: To minimise capital cost, sizes of pipeline mains (rising, trunk and distribution mains), reservoirs, valves, etc. in the developing countries have to be limited. Most of the existing distribution mains in Nigerian towns are limited to DN100mm to DN150mm running through streets with DN200mm to DN250mm as trunk mains. In major capital cities, the trunk mains are limited to DN300mm to DN800mm. Even in cosmopolitan cities like Lagos, the trunk mains are limited to DN900mm to DN1200mm. Consequently, the flow carrying capacities of the trunk mains are readily exceeded by the exponentially growing water demand population. Unfortunately, when flow is increased in any WD pipeline network, the total head loss is increased thereby denying distant consumers of potable water supply.
Political challenges include: lack of political will, politics of contract awards and absence of common needs, among others.
Lack of political will: Only the political will can commit so much money into WD. Often this political will is lacking in most countries, whether developing or developed. The reason is not farfetched. Most of the political leaders in positions of authority do not come from the water industry, do not experience water shortages and cannot fathom why more funds should be committed into WD systems. In Nigeria, any such fund for WD must necessarily be for extension into areas previously unserved to gain political advantage (recognition in military regimes or votes in democraticregimes).
Politics of contract awards: Instances abound on contract awards to high ranking and favoured political party sponsors and or members at all three tiers (federal, state and local) governments in Nigeria. Gradually, the Nigerian water industry has been witnessing a surge in the influx of politicians, lawyers and accountants, among others. But this is an industry where expertise in the investigation, design, construction and operation of WD are required.
Absence of common needs: The needs of countries vary from one to another, and have created some gulfs in having common collective decisions. While in the developed world, the needs are centred primarily on maintaining continuous flows with adequate pressures, replacing aging WD pipeline networks, and gathering/analysing/managing field data, the needs in developing countries are centred primarily on extension to communities not yet served, tariff determinations, revenue collection and ownership structure (i.e. whether it should remain public, private or public-private). Also, the standards set by each country vis-à-vis the United Nations on “access to water” (i.e. safe tap water) vary from home taps in the developed countries to stand pipes located about 5km away15 in the developing countries.
Social challenges faced include:
Management structure: WD has been under public ownership in Africa for more than half a decade. Yet privatisation has been successful in the developed world and has encouraged a push for its implementation in Nigeria16 and in Africa. However, this move has been resisted by labour unions and the general public. Ghana tried it between 2006 and 2011 only to back out when it failed17. Ekiti State Nigeria tried concession (a form of privatisation) between 2008 and 2011 and had to scrap it for similar reason3. Uganda18 and Nigeria’s Cross Rivers State19 governments have embraced a middle way called the public-private partnership or public-private sector participation (PPP). But not many African countries have keyed in to it.
Poor communication: Water is a “blue gold” and “Water is life” are slogans in the water industry. But when a bill board shows a child drinking from a tap or bathing under a stand pipe, the impression given is that water is not only cheap but a free social obligation15. In Africa, WD is taken as a social responsibility of water agencies and governments to provide. Viewed in this perspective, pipe bursts and water wastages are not accepted as the responsibilities of the consumers. Thus pipe bursts before flow meters located within consumers’ premises may not be reported.
Illegal connections: Also based on this government social responsibility illusion, there exist many illegal connections to WD pipeline networks that are unreported. Nigeria is home to many illegal connections by water supply agents some of whom even install centrifugal pumps to draw water from distribution mains into their reservoirs and resell to the public.
Urbanisation: Expansion of pipeline networks to new settlements moves in stepwise arithmetic progression in Africa but both urbanisation and water demand move at geometric progressions. This creates a gulf. This will continue to go deeper. In addition, damages to WD pipelines, chambers, maker posts, etc. during road expansion programmes are becoming worrisome with displaced marker posts making line tracing a Herculean task. Also, some of the undamaged pipelines often lie entirely under roads and make monitoring operations very difficult as with the old distribution line under Oba Adesida Road, Akure, Ondo State, Nigeria.
Administrative challenges facing WD include the determination and implementation of adequate wages and allowances structures to motivate Engineers, Managers and operative; their training and re-training; provision of adequate tools and equipment; better work schedules; etc. Others include ability to gather and manage large scale volumes of data on consumers, supply, demand, tariff, revenue, repair and maintenance, water quality, volume, pressure, pipeline materials and age, etc.
Solutions To Water Distribution Challenges
Having noted the challenges under six different sub-headings, it is reasonable to address their corresponding solutions likewise.
Solution to technical challenges:
To mitigate high and low pressure regimes in WD today, analysis and design are facilitated using computer aided softwares: Waternet, Eparnet, etc. Installation of some tri-function modern air valves is able to dampen pressure surges and mitigate damages20. There is the need for water agencies to carry out water audit programmes: leakage detection programme, non-revenue water programme, head loss/pressure and flow monitoring programme, etc. This will enable water agencies understand the extent of losses in supply and in revenue, inability to meet consumer demands, high repair and maintenance costs, and how best to address them. For instance, Non-revenue water is estimated at 63 percent in Nigeria14. Nsawam water audit report9 showed that leakages accounted for about 26 percent while the non-revenue water was about 53 percent. The import is that for every 100 consumers supplied, leakages have denied 35 others. As for tariff, 46 consumers were bearing the burden of 100 consumers. Of course, this explains why water rates are high in the developing countries and also why so many consumers are unwilling to pay their bills.
At the end of the water audit, water agencies and government must address leakages by gradually replacing old meters and aging WD pipeline networks. There are smart meters21,22 (e.g. Neptune meters, Sensus AMI meters, iMeters, etc) that can relay leakages and bursts to a SCADA (Supervisory Control And Data Acquisition), GIS (Geographic Information System), water agency asset management, etc. There are now HDPE pipes with fussion welds at joints (thus mitigating leakages at joints) and are of 12m long (thus minimising the number of joints) that can be used. This pipe type has better flow characteristics: minimal headloss, high strength to withstand high hydrostatic pressures, non-corrosive and chemically inert for encrustations to form23,24.
The use of an appropriate technology means that advantage of economies of scale can be used to produce more water at the same capital and running costs, thereby bringing down the unit cost of potable water delivered to consumers. Kenya is advancing an appropriate technology that takes advantage of gravity flows from high hills with minimum power and pumping arrangements.
Water quality should be monitored continuously, and when necessary, pipelines and service reservoirs should be flushed/cleaned and disinfected periodically even if there are no bursts.
Solution to Environmental Challenges:
A good approach is to lay pipelines deep enough to avoid exposure to flooding, erosion and bush burning damages. In Nsawam, we laid OD400 HDPE pipeline below R. Densu bed. The work was executed during the dry season and protected against flotation with concrete u-caps. It has survived high floods since 2013. In addition, there is the need for Engineers and Managers in the water industry to start planning on how to cope with variability in rainfall, particularly how to use the available WD systems to ration supply in the near future. A new approach involves the laying of parallel lines for recycled water that can serve non-potable purposes2.
Solution to Economic Challenges:
Funding of water agencies should be given a top priority by governments and financial institutions. Consumers are often willing to pay for services that they enjoy. Any funding of water distribution pipeline networks is recoverable. It is a good and worthwhile investment. The success of Calabar, Cross River State of Nigeria water scheme complete with the distribution system under public-private sector participation (PPP) initiative and funded from the scratch with an initial $141 million African Development Bank (ADB) loan is noteworthy. This has attracted more funds/agencies: $495.3m from World Bank, €3.0m European Union donation, N5.4bn ($34.8 million apprx.) from First Bank of Nigeria, N8.9bn ($57.4 million approx.) by Cross River State Government, etc. thus making water available to more urban centres in the State19. The World Bank is a major pillar of fund and has been like that for Nigeria. Only recently, the Bank committed another $400 million to urban water supply in four towns in Nigeria25. In addition to international funding agencies, national governments and banks should set aside a certain percentage (say 10 percent) of their funds for WD.
There is need for water agencies to have the right to fix their tariffs to recover both capital and running costs. This could come through PPP or privatisation. At the same time, government should be prepared to support the underprivileged and poverty-stricken population in the developing countries using the Uganda PPP approach. Although privatisation may not be a panacea3,17 to WD in Africa, it could reduce monopoly, provide funding, increase competition through cost-benefit optimisation and improve delivery and availability of potable water16. But before privatisation takes its root in Africa, water agencies should thrive to lower their operating costs through economies of scale. Increase in volume of service delivery will result into reduction in operating costs.
Finally, computerised maintenance management system26 or Smart Water Grid systems27 can be deployed for cost – benefit optimisations, analysis of vast amount of data in WD as well as assist water agencies and governments to make better choices rather than the traditional recourse to conservative minimum cost approach.
Solutions to Political Challenges:
Most American heads of State were former military men. Hence, they never joked with defence budgets. The more Water Engineers in positions of authority at both Federal and State levels, the better water policy issues can be implemented. Thus, Water Engineers should not shy away from politics. This is also the stand of COREN (Council for the Regulation of Engineering in Nigeria)28.
There is the need for designers and consultants to properly advise political leaders to undertake a comprehensive review of water supply schemes (sources, intakes, water treatment plants, reservoirs and WD) before taking their political decisions. This will mitigate such experience noticed in Akure. The PPP strategy adopted in Calabar, Cross River State of Nigeria and Uganda has provided political pedestal to roll such exercise all over Nigeria, Africa and the developing world.
Inter-departmental fora to review master plans for towns, capital cities and cosmopolitan centres should take the front stage before any project implementation, be it on pipelines, road, etc. This will mitigate damages to WD networks during road expansion and rehabilitation programmes.
Solution to Social Challenges:
The solution to social challenges in WD still remains that of proper enlightenment. The slogan “Water is life” has been misunderstood by many and needed to be replaced with something like “Water is money”, “Water has a cost” or “Water is our wealth”. The import is that when people see water wasting through pipe bursts or leakages, they know money is being wasted and should be stopped. This may even encourage the reporting of illegal connections and their prosecution. Illegal connections can be detected easily where smart meters have been installed. To serve as a deterrent, the costs associated with illegal connections and the volume of water consumed should be compounded and recovered from culprits. In addition, water agencies should improve on maintenance culture.
Solutions to Administrative Challenges:
It is very important for Engineers, Managers and operatives involved in WD to have commensurate motivating remunerations, flexible and convenient work schedules, appropriate training and re-training programmes, etc. to motivate them to work. Management should thrive to provide SCADA, non-destructive flow meters29, GIS, etc. to enhance data analysis and management whilst facilitating decision making.
The challenges facing WD are numerous and cannot be exhausted and so do their corresponding feasible solutions. New challenges will crop up as the future unfolds, especially those relating to climate change. Governments and financial institutions should continue to invest in WD because such an action is worthwhile, reliable, profitable, recoverable and socially lifestyle enhancing.