Environmental Talk At UGPulse: Paving Roads
Flooding in Kampala.
NEMA

Environmental Talk At UGPulse: Paving Roads

Read this before you pave your land.

By Ivan Kibuka-Kiguli
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First published: September 20, 2006


We all hate dirt and hate its wet equivalent (mud) even more. So we usually set about putting it out of sight... forever. The most convenient way of doing this is by paving whatever piece of land the offending earth originates from, be it a road surface, driveway or courtyard. Problem solved. Or is it?


Let us consider the merits of paving. The all-important goal of reducing (you can never eliminate) dust is quite easily achieved. Of course the same follows for mud. You even get to prevent soil erosion in the paved area(s) and may use the paving material to re-design the area to suit your aesthetic taste. Lastly, your ego is soothed. You have just tamed the dust menace.

But effective paving comes at a financial cost. Not only the actual paving itself but any repairs to buried pipe work, cables, etc are rendered difficult and costly. Then come the environmental costs. The list is long but I will point out several of these.

  • Paving prevents natural seepage of rainwater at the soil surface and therefore increases run off volumes and speeds. It does not take rocket science to work out that severe soil erosion follows in the neighbouring unpaved areas.

  • By paving, you reduce the total area through which the soil absorbs rainwater. The water rushes off to lower ground. It meets more water on the way down and what you get is a water jam (rather like traffic jam). You have just created flooding because you are fighting nature!

  • The soil over which you pave absorbs very little water and consequently little water gets into the strata below it. The natural aquifers from which your water company, bore hole or well obtains its water dries up. This is the beginning of your potable water woes!

  • We all know paving prevents natural plant growth and destroys the natural habitat and therefore lives of plenty of organisms. Just imagine having your home being buried under concrete, you, the family and all.

    So, what alternatives have we got? Let us put our heads together and not only find but employ 'greener' options. Offhand, I can think of landscaping using techniques kinder to the environment. In my view, any technique without the disadvantages mentioned above is fine. People tend to find a few these alternatives a little more expensive especially since most of them are manufactured under patents, but hey, we must work out the environmental costs too. Besides, most of them in the end cost less in monetary terms.

    For those that really need to pave certain areas or cannot live without paving, there are some green alternatives for you to consider. If you happen to have visited the NEMA offices in Kampala via the gate leading to their basement garage, you will have noticed the honey comb shaped block work that was employed on the pavement. Some short grass has even grown over the area! I will not go into the details of the technology here but basically this kind of design eliminated the problems mentioned above. You can obtain more solutions by using Google to search for environmentally friendly paving alternatives. Here are some examples of the materials to be found.

    Grasscrete by Bomanite Grasscrete by Bomanite:
    A Functional "Green" Paving Solution

    Blending architecture and landscape is sometimes a complicated task when functionality, aesthetic appeal and eco-friendly criterion have to be considered. Grasscrete by Bomanite provides a variety of landscape solutions while maintaining a sustainable "green" product design.

    Grasscrete by Bomanite Grasscrete can also be employed as a stabilization product for areas that experience seasonal runoff, that require maximum water capacity to handle an adjacent hard surface or that require a structural base material prior to application.

    Grasscrete can be customized to suit a wide variety of applications where the elimination of retention ponds, swales or other storm water management devices is desired. Grasscrete does not contribute to the heat island effect like other hard surfaces such as asphalt, does not allow contaminants to runoff during "first flush" rainfall into potentially fragile eco-systems and allows for tree plantings in close proximity.

    Grasscrete is a very sustainable product that can employ a large recycled material content both in the form of aggregate and binder such as fly ash or slag- its lifespan is indefinite and can be recycled itself to form the aggregates for future Grasscrete applications.

    Read more

    Permeable Pavement Build It Green:
    Permeable Pavement

    Imagine looking down on a cityscape from a plane. You would likely note that a high percentage of the land is covered by impermeable surfaces: streets, parking lots, sidewalks, driveways, and rooftops. Instead of percolating into the ground, the majority of rain lands on these impermeable surfaces and flows into storm water sewers, picking up pollutants like motor oil, anti-freeze, and pesticides as it goes.

    In essence, our cities are enormous catch basins, collecting polluted water and diverting it into waterways. This stormwater is a major source of pollution in the San Francisco Bay. When stormwater is directed into streams, volumes are much greater than historic levels, substantially eroding stream beds and banks and flooding surrounding areas. To address these issues, municipalities typically widen channels and armor the banks with concrete, drastically disrupting the streams' ecological value.

    Read more

    In the end, unless we take care of mother earth, she will not provide our descendants with much other than a harsh welcome. It is time we stopped being complacent and started to act. The what-you-don't-see or what-you-haven't-seen attitudes will not do any more. Those of you that are privileged to visit or contribute to UGPulse, and are fortunate enough to come across information, I am sure you have at least the skills required to look this stuff up now that you are more aware of the problems involved. The hope is that you pass this awareness on to others to stop or prevent unwise paving.

    Join us and let us discuss more solutions to paving roads in Uganda.

  • By Ivan Kibuka-Kiguli
    more from author >>
    First published: September 20, 2006
    The author is a pollution control equipment engineer/consultant and a proud active member of UGPulse.