Water Resources Engineering (WRE) connects engineering hydrology and hydraulics with global, economic, environmental, and societal issues. Our student Katie Mott makes this connection here…

On September 2, 2013, “Restoration Ecology” published an article by Matthew McConnachie, et al., titled “The Challenges of Alleviating Poverty through Ecological Restoration: Insights from South Africa’s ‘Working for Water’ Program.” This article relates to the WRE domain of hydrology and the specific issue of the distribution of water resources being threatened by invasive alien plants in regions of South Africa. Invasive alien plants have grown to become a significant issue for communities in South Africa, decreasing biological diversity and diminishing water resources. To decrease invasive alien plants and increase protection of water resources, the South African government created a program in the 1990’s called “Working for Water” (WFW). This article analyzes the efforts made by WFW to see if the program is meeting their objectives of protecting water resources by diminishing invasive alien plants and alleviating poverty. In this program, people are employed to clear invasive alien plants that interfere with water resources and biological diversity. Methods for ridding of invasive plants include hand pulling, stem injections, and creating catchment areas. Figure 1 shows the relationship between biomass and streamflow reduction (McConnachie et. al, 2013). To analyze the WRE article further, “Ecology and Society” published an article examining WFW’s effects on Table Mountain in Cape Town, SA. The article was in agreement that the implementation of WFW was necessary due to the national issue of invasive alien plants threatening water resources. If catchment areas were not regularly maintained, streamflow would decrease by the equivalent of 30% of the annual water supply to the city of Cape Town (van Wilgen et. al, 2012). A second source stated that these invasive alien plants escalate flooding events, redirect volumes of water from its initial path, and effect agriculture, fisheries, transport, recreation, and water supply (UNEP). What may be missing from this article are the effects some practices WFW uses to eliminate invasive alien plant species could have on the environment, such as stem injections and the use of herbicides.

In a broader economic context, Working for Water was created to give employment to people who were living in underdeveloped rural areas with low to no income. The issue of water resources scarcity in South Africa due to invasive alien plants has negatively affected the economy’s water supply, but positively affected the economy by creating more jobs for low-income communities. The creation of the program has economically and environmentally benefitted South Africa by creating more jobs and securing more water resources. An article published in 2001 in “Land Degradation & Development” commented on the economic effects of WFW. Shown in Table 1 below, the capital and annual costs of managing invasive alien species in South Africa are much higher than not managing the invasive alien species. Although these costs are higher, the management of invasive alien plant species have caused the above ground biomass 15 years after experiencing a fire, reduction in streamflow from biomass, water yield, and the unit cost of water to all be significantly improved (Binns et. al, 2001).

Figure 1 Biomass and Streamflow Reduction

Figure 1 Biomass and Streamflow Reduction

Table 1 Cost Analysis of WFW

With management of alien plants Without management of alien plants
Area (ha) 10000 10000
Mean annual rainfall (mm) 1500 1500
Capital cost of clearing initial infestations ($/ha) 830 0
Capital cost of developing water supply facility (million $) 67.7 0
Total capital cost of water supply facility including initial clearing (million $) 76 67.7
Annual interest on capital cost at 8% 6.1 5.4
Annual cost of continuing alien plant management 8 0
Annual operating cost of water supply facility 1.29 1.29
Total annual costs including operation, alien plant management, and interest 7.47 6.69
Above ground biomass 15 years post fire 3867 10964
Streamflow from rainfall without considering vegetation (mm equivalent) 742 742
Reduction in streamflow from biomass (mm equivalent) 114 256
Water yield (100,000 m3 per year) 62.7 48.6
Unit cost of water ($ per m3) 0.119 0.138

References:

Binns, J. A., Illgner, P. M., and Nel, E. L. Water Shortage, Deforestation, and Development: South Africa’s Working for Water Programme, Land Degradation & Environment, 12: 341-355. May 31, 2001

McConnachie, M. M., Cowling, R. M., Shackleton, C. M. and Knight, A. T. The Challenges of Alleviating Poverty through Ecological Restoration: Insights from South Africa’s “Working for Water” Program, Restoration Ecology, 21: 544–550. 2013

van Wilgen, Brian W. Evidence, Perceptions, and Trade-offs Associated with Invasive Alien Plant Control in the Table Mountain National Park, South Africa, Ecology and Society, 17. 2012

Working for Water: A South African Sustainability Case, United Nations Environment Programme (UNEP). N.D.

Advertisements