ï»¿ Over the past week, many people have speculated that the recent rain floods in Amman were the result of the unusually heavy rainfall. Others have hypothesized that it is in fact the drastic increase in the city’s population.
Meanwhile, the Greater Amman Municipality (GAM), and a few other authorities, depended on similar arguments, attributing the floods to unusual rainfall in an unexpectedly overpopulated city. However, aside from the arguments and speculation on the street, if we are to look at what happened from a very basic engineering perspective, we would have to understand a critical fact about the design of the city’s stormwater drainage infrastructure.
The system’s design is based on the probability of occurrence of an expected peak discharge during its shelf life, which can range from 50 to 100 years or sometimes 20-25 years, based on sufficient scientific and hydrologic data. When designing any master plan, or a new development, you need to always refer back to the topography and hydrologic history. For example, constructing a road down a hillside should be shifted or elevated if possible, or else a proper drainage component should be added, such as a pipe or box culverts that meet the expected runoff. This scientific viewpoint is supported by other official authorities like the Ministry of Interior and the Meteorological Department.
If we base our next steps on careful scientific examination and decision making, then we will quickly come to the conclusion that unless further evidence suggests otherwise, today, we are in no need for amending the current design codes. Today, we are also in no need for investing the time and money that comes with a full upgrade of Amman’s storm water infrastructure network.
So, if not the infrastructure, then what?
Aside from the general inefficient readiness of the drainage network and GAM’s staff, a few factors we can easily observe simply as residents of Amman can be summed up in the following recommendations:
1. Mandatory Regulations
We lack the proper mandatory regulations on all site development projects, including buildings, roads, facilities, etc, based on the city’s master plan. Project designers must take into consideration the hydrologic factors when locating roads or buildings that will affect the natural surface and subsurface drainage pattern or characteristics of the topography.
2. Integrate Stormwater Management In Design
Another mid-to-long term problem we’re not seriously considering is possible failure of the road network. GAM must adopt a master plan that reflects a totally different philosophy towards development design, one that integrates storm water management into the very core of site design, as opposed to being considered an afterthought. As such, provision for adequate drainage is of paramount importance in road design and cannot be overemphasized. Cut or fill failures, road surface erosion, and weakened subgrades, followed by a mass failure, are all products of inadequate or poorly designed drainage.
For example, when there’s a road cutting the stream of a hillside you should take into consideration how to fix the drainage. Aside from the flooding issue, severe damage can be caused if water changes the characteristics of constructional subgrade layers, which is more or less exemplified by the street collapse in Abdali back in October. Water flow will eventually find its way; you can never block it. It will go beneath or above the structure. The solution to this challenge, put simply: build it right from the beginning.
The solution to this challenge, put simply: build it right from the beginning.
3. Ensuring Regular Maintenance
Poor maintenance of the existing components of the existing stormwater and surface drainage network. GAM must continuously work on maintaining all inlets in functioning order and preventing contamination from unclean discharges to the storm drain, to enhance the ability to safely convey storm water away from residents and business owners and prevent localized flooding. Simply put, it is not enough to build it once and think it will last forever. To be in good condition, the infrastructure must be regularly maintained, not just exclusively before the winter season
4. Better Coordination & Better Regulation
There is little to no coordination between GAM – the sole owner and manager of the city’s infrastructure – and different utilities providers, such as the water authority, electric companies, and telecommunication companies. This lack of coordination results in GAM’s weak supervision of the maintenance and upgrade activities carried out by utilities providers. Subsequently, this sometimes causes unreported damages to the storm water and surface drainage infrastructure network. The same applies to GAM’s direct supervision of private sector construction activities. Residential real estate developers usually hire mediocre-skilled contractors, who would harm the infrastructure during excavation works, which usually goes unreported. Moreover, poor supervision over material stockpiling or when trucks get rid of excavated material, means that construction materials can easily clog drainage infrastructure components, with or without rain.
5. Develop A Conservation Ethic
The increased population of the city has only one major impact on the capacity of the storm water network. It is shameful design practice and bad engineering to connect both sewage and storm water flows in any country. In such bad design, what happens is that the more users (aka residents) connected to the sewage system, the less this system can take in storm water. This kind of bad engineering is particularly shameful in a country that ranks among the poorest in water resources. It is important to develop a conservation ethic that treats storm water runoff as a “resource” rather than a “by-product” of development.
GAM should develop a comprehensive and all-inclusive approach to recovery; an approach that takes into consideration the dynamic nature of recovery, with a focus on people, housing and property, infrastructure, and services. It is imperative GAM builds resiliency measures into projects and processes to decrease the city’s vulnerability to social, economic and environmental impact of similar future incidents. And they will happen – GAM has to anticipate them and plan for them. There is no way around that.
The recovery and planning timeframe is also critical. After the crises that happened, we now have a window of opportunity open to us for only a short while. In this window of opportunity, citizens feel a sense of belonging and are keen to make the future better through collective action. GAM must take advantage of that window.
We are not blaming individuals or officials; it is simply an institutional strategic process that must be revised in order to prevent the occurrence of such tragic events causing deaths and financial losses. A soul lost is irreplaceable and never compensable by any mean. Yes, climate change is real; it is here. But how can we measure its impact or severity if the basic evaluation reference point is not clearly identified? Unless GAM is fulfilling its duties and doing its homework immaculately, we will not accept GAM blaming such crises on acts of God, plastic bags, or even climate change.
*Anwar Majali is a civil engineer and Business Development Manager at GreEnergy Jordan, based in Amman.