Water Bankruptcy IV: Getting Beyond Rhetoric to Long-Term Integrated Water Management (Part of the Water Series)

In Parts I through III of this series on Water Bankruptcy, we saw how of the more than 972.8 billion cubic meters of water that Malaysia receives in average annual rainfall, 413.1 billion cubic meters (42.5%) is lost to the atmosphere through evapotranspiration, 64 billion cubic meters (6.5%) infiltrates into the ground to recharge our groundwater reserves, and 495.7 billion cubic meters of water (51%) remains as surface runoff. We also saw that, at least officially, a relatively small fraction of the surface runoff, 14.6 billion cubic meters (3.35%) is abstracted for either ‘Own Use’ (8.6 billion cubic meters) or ‘Water for Distribution’ (3.8 billion cubic meters), and that, regrettably, a very significant fraction (in excess of 2 billion cubic meters) is lost in distribution. The official designation of these losses as ‘nonrevenue water’ while technically accurate, completely fails to adequately describe the circumstances and, rather more importantly, the implications of this loss.

In part IV, we will first examine how climate change and unsustainable modes of development could potentially change the proportions of water that comprise these major water pools. We will then explore how the official abstraction may be grossly underestimating the actual amount of water abstracted, which has serious implications to water-critical services and industries.

We saw in Part I of this series that because a warmer atmosphere is capable of holding more water, it draws more water from plants and the soil surface (evapotranspiration). It follows, therefore, that as the average temperature of the atmosphere increases with global warming, that evapotranspiration rates will increase, leaving less water for infiltration and surface runoff. Also foreseeable is the fact that as higher atmospheric temperatures drive higher rainfall intensities, comparatively less rainfall will have time to infiltrate in to the soil, so that more of the rain will end up as surface runoff rather than groundwater.

Conventional urban development, which renders much of the land surface impervious to water infiltration, adds yet more to the runoff, and, unless detained by natural or artificial impoundments, will increase the likelihood of flash floods. This phenomenon extends to our larger drainage structures as well. As described in part II of this series, natural riverbanks and riverbeds interact closely and continuously with groundwater, either contributing to, or receiving from, groundwater along their entire length, helping to reduce flooding, keeping river ecosystems functioning, and, closer to the coast, helping stave off sea-water intrusion. But as more of our rivers are lined with concrete, they lose the capacity to interact with groundwater in real time. Effectively isolated from each other, both water bodies can no longer buffer each other from extremes, resulting in either flooding or low/intermittent flow.

In the long-term, therefore, the take-home impacts of climate change on our national water resources regime, regardless of rainfall effects are: first, increased evapotranspiration loss; second, reduced opportunity for infiltration; third, a relative increase in surface runoff; and fourth; greater extremes in river flow rates, and all of the above have very significant knock-on impacts.

As one might expect, the abstraction of water for treatment and distribution requires large, sophisticated and expensive infrastructure, along with energy, treatment chemicals, and labour inputs. It must also operate within strict water quality and water quantity thresholds. The loss of more than 2 billion cubic meters of mostly treated and potable water in the distribution phase is therefore, cause for great concern. But this only accounts for losses from the formal abstraction of water. Much further upstream, the informal abstraction of water is quietly redirecting significant quantities of water from our pristine montane streams and their ecosystems.