various aspects of the problem of ungauged basins. Almost all riverbasins, particularly in sub-Saharan Africa, are ungauged, or poorlygauged, with respect to some of the components of the hydrologi-cal cycle. Consequently, a considerable effort is put into overcom-
data for validation and may be highly complex thus making modelselection a difcult task especially in Africa where monitoring net-works are inadequate. Trambauer et al. evaluate 16 commonhydrological models and their applicability to drought forecastingin Africa and conclude that only 5 of the models that were analysedcan be applied with some degree of condence.
The evaporation process is one of the dominant processes in thehydrological cycle. However, there are few locations where evapo-ration is measured or with the required meteorological data (wind
groundwater for irrigation purposes. Hlophe et al. and Rapatsaet al. both discuss suitable environments for the performance oftilapia species (oreochromis). In the former study, Hlophe et al. out-lines the potential of oreochromis rendalli in aquaculture environ-
societies to work tirelessly to control the anthropogenic pollutionof our limited water resources.
4. Water and land sub-theme
The sub-Saharan region is confronted with the challenge of foodsecurity as the majority of communities rely on rainfed agriculture.The prediction of less rainfall in the region due to climate change(IPCC, 2007) highlights the need for more innovative techniques
Physics and Chemistry of the Earth 66 (2013) 13
w.eing water resources management problems due to river basinshaving limited data and, usually, of questionable quality. Model-ling tools are increasingly used to analyse existing conditions andpredict system performances. Again, these models require sound
ments in relation to its feeding habits, while the study byRapatsa et al. looks at the potential of various manure sources inincreasing sh food in aquadams.
These studies taken as a whole illustrate the need for AfricanEditorial
Putting science into practice
This is the 13th Special Issue of Physics and Chemistry of theEarth comprising papers presented at the 14th WaterNet/WAR-FSA/GWP-SA annual symposium held in Johannesburg, South Afri-ca between 31 October 2012 and 2 November 2012. The theme ofthe symposium was Putting Science into Practice. During theconference, 208 high quality presentations were made throughoral and poster displays spread over the six symposium sub-themes of Hydrology, Water & Environment, Water & Land, WaterResources Management, Water & Society and Water Supply & San-itation. These presentations were subsequently invited for submis-sion to this Special Issue which, after peer review, are published inthis volume. At close of call, 82 submissions were received and thisvolume contains 21 papers that had passed the peer review andproduction stage by the cut-off date.
Papers in this volume are spread over the following themes:Hydrology (2), Water & Environment (9), Water & Land (5), WaterResources Management (1) andWater Supply & Sanitation (4). Thisdistribution by theme has become the trend in the recent past andsignies the attention given to issues of water quality, water sup-ply, sanitation and the environment ahead of other IWRM focusareas.
Highlights of the research published in this special issue arepresented in the section below.
2. Hydrology sub-theme
The hydrology sub-theme is dominated by papers examining
Contents lists avai
Physics and Chem
journal homepage: ww1474-7065/$ - see front matter 2013 Published by Elsevier Ltd.http://dx.doi.org/10.1016/j.pce.2013.10.011speed, solar radiation or sunshine duration) for evaporation esti-mation. Temperature based methods for estimating evaporationhave therefore been developed to overcome the challenge of lackof measurements of evaporation or elements required for estima-tion. The Hargreaves and Samani (1985) method has gained wideacceptance. The performance of this method requires evaluatingin different hydroclimatological settings. Moeletsi et al. assessedthe performance of this method in the Free State Province of SouthAfrica. Evaporation rates estimated using the Hargreaves andSamani method were highly correlated with those obtained usingthe PenmanMonteith method except during the winter months(MayJuly). Calibration of the Hargreaves and Samani method im-proved estimation of evaporation rates. The work by Moeletsi et al.highlights the need for evaluating and improving generally ac-cepted hydrological estimation methods so that these methodsare applicable to different conditions.
3. Water and environment sub-theme
In this issue a variety of articles on water and environment havebeen submitted, from articles investigating groundwater safety, tothose looking at monitoring of heavy metals in aquatic environ-ments, municipal water treatment plants and protection of aqua-culture facilities from anthropogenic contamination. Seanegoet al. discuss the effect of sewage efuent on the physicochemicaland biological characteristics of the Sand River, and the need forcontinued monitoring. Moyo andWanda et al. discuss microbiolog-ical analysis of shallow groundwater wells and boreholes inZimbabwe, whereas the latter paper analyses the suitability of
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stry of the Earth
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blend of b-cyclodextrin and polyethersulfobe respectively. Both
the old doctrine of increasing the supply), as well as sustainable
shows that even for scientists, the concept of integration and
strytechniques proved to be effective in removing nitro-phenol fromwaste water and were deemed to be relatively cheap and couldbe synthesized rapidly. Hamza et al. describe the application of asugarcane bagasse/multi-walled carbon nanotube composite to re-move lead from an aqueous solution. They studied the lead adsorp-tion capacity of the composite under different physico-chemicalconditions and how these relate to the conditions that would beexperienced in waste water treatment plants (WWTPs). Howeverthe ecological risks of these new nanomaterials remain unknownsince the pristine material reacts differently and ultimately has adifferent toxicity prole than the material in an environmentallyrelevant matrix (Thwala et al., 2013).
With all the challenges highlighted here, communities, bothrural and urban, are increasingly resorting to groundwater use asan alternative to the increasing scarcity of surface water due toto improve crop yields under increasing water scarcity (Makuriraet al., 2009). The performance of these techniques require soundmonitoring of soil moisture; preferably using non-destructivemethods as applied by Bhme et al. Bulcock and Jewitt; Mhizhaand Ndiritu studied the effectiveness of some rainwater harvestingtechniques. Bulcock and Jewitt found out that some of these tech-niques appear in places that are outside of suitable site conditions.This partly explains why the potential benets of rainwater har-vesting are not well understood. Based on these ndings, theauthors have updated suitability ranges for selected techniques.Slaughter and Mantel developed a simple model to link river waterpollution to land use changes. Kiptala et al. classied land usesusing phenology to determine land suitability within the PanganiRiver Basin.
5. Water supply and sanitation sub-theme
The target of the Millennium Development Goals for water sup-ply and sanitation was to reduce by half the proportion of peoplewithout sustainable access to safe drinking water and basic sanita-tion (WHO/UNICEF, 2012). The good news is that, by 2010, two bil-lion people have gained access to safe drinking water since 1990.However, 780 million people are still without access. Althoughthere was an improvement in access to sanitation it is estimatedthat 2.6 billion people still do not have access to adequate sanita-tion. It is particularly in sub-Saharan Africa where the majority ofcountries are lagging behind the provision of sanitation and safedrinking water targets. Most of these countries have less than50% provision of drinking water due to the large rural populations.It is ironic since many countries in sub-Saharan Africa have accessto latest technologies such as cellular telephones, nanotechnology,hydro-electrical power, etc. but lack the infrastructure to providesafe drink water and sanitation. This provides unique challengesto the region in order to assure the safe provision of drinking waterand sanitation services.
The papers in this section focus on two broad topics, i.e. moni-toring of wastes (in both natural and waste water treatmentplants) and the development of technologies to clean wastewater.Wanda et al. applied a water quality index to assess the microbialand geochemical characteristics of shallow wells in Mzuzu City,Malawi. Faecal coliforms were present in most of the wells andthe WQI index results revealed that all of the wells were at riskof further contamination due to their close proximity to high den-sity rural populations with poor sanitation facilities.
Phao et al. present cost effective alternatives to polymer nano-composites for removing organic substances from wastewater.These authors report on nitrogen-doped carbon nanotubes with a
2 Editorial / Physics and Chemiuncontrolled pollution and climate change. However, groundwateris also highly vulnerable with low recharge rates (Sibanda et al.,how to implement this has not been fully embraced.The editorial team is highly thankful to all contributors of arti-
cles contained in this Special Issue. Articles that failed to make itinto the current volume can still be processed if authors take theirtime to improve their submissions as advised during the reviewprocess. This way, we can maintain the high quality standards ex-pected of this journal.
Beekman, H.E., Sunguro, S., 2002. Groundwater recharge estimation Suitability andreliability of three types of rain gauges for monitoring chloride deposition. Talesof a Hidden Treasure, Somerset West, South Africa, pp. 225233.
Hargreaves, G.H., Samani, Z.A., 1985. Reference crop evaporation from temperature.Transactions of the American of Agricultural Engineers 1, 9699.
ICWE, 1992. The Dublin statement and report of the conference. In: InternationalConference on Water and the Environment: Development Issues for the 21stCentury; 2631 January 1992, Dublin.
IPCC, 2007. Climate change 2007: Impacts, adaptation and variability. CambridgeUniversity Press, UK, Contribution of the Working Group II to the fourthassessment report of the IPCC.
Makurira, H., Savenije, H.H.G., Uhlenbrook, S., Rockstrm, J., Senzanje, A., 2009.Investigating the water balance of on-farm techniques for improved cropproductivity in rainfed systems: a case study of Makanya catchment, Tanzania.Physics and Chemistry of the Earth 34 (12), 9398.
Savenije, H.H.G., Van der Zaag, P., 2008. Integrated water resources management:concepts and issues. Physics and Chemistry of the Earth, Parts A/B/C 33 (5),290297, ISSN 1474-7065. http://dx.doi.org/10.1016/j.pce.2008.02.003.development (i.e. ecological integrity, one of Postels policyprinciples).
The only paper in this issue is by Tambudzai et al. who describethe decentralization process in Zimbabwe and its impact on themanagement of an irrigation scheme. They highlight the majorweakness affecting locally managed schemes in areas of technicalcapacity and accountability.
7. Concluding statement
This Special Issue series from the annual Waternet/WARFSA/GWP-SA symposia has continued to publish high quality and rele-vant research mainly for the Eastern and Southern Africa region.The growing interest from authors beyond this region shows therecognition given to the wide range of IWRM research issues thatare contained in this journal. Obviously these contributions areplaying a part to inuence policy as evidenced by the increase inmomentum towards water sector reforms, particularly, in theSADC region.
The fact that most papers in this issue deal with individual top-ics related to IWRM (e.g. drinking water supply, hydrology, agricul-ture, etc.) and do not address more than two topics in a paper,2009; Beekman and Sunguro, 2002) and more difcult to clean,once it is polluted.
6. Water Resources Management sub-theme
The Integrated Water Resources Management concepts as pre-sented by Savenije and van der Zaag (2008) deal with a variety ofissues related to the implementation of IWRM. Starting with theDublin principles that encourage the integrated management ofthe nite and valuable resource, public participation, the inclusionof women in the management of the resource, as well as theappreciating that the resource should be dealt with as an eco-nomic good (ICWE, 1992). Secondary to these core concepts isthe concept of decision making at the lowest appropriate level(decentralization), emphasis on demand management (versus
of the Earth 66 (2013) 13Sibanda, T., Nonner, J.C., Ulenbrook, S., 2009. Comparison of groundwater rechargeestimation methods for the semi-arid Nyamandhlovu area, Zimbabwe.Hydrogeology Journal 17 (6), 14271441.
Thwala, M., Musee, N., Mamba, B., Wepener, V., 2013. The oxidative toxicity of Agand ZnO nanoparticles towards the aquatic plant Spirodela punctuta and the roleof testing media parameters. Environmental Science: Processes & Impacts 15,18301843.
WHO/UNICEF, 2012. Progress on Drinking Water and Sanitation: 2012 Update.WHO/UNICEF Joint Monitoring Programme for Water Supply and Sanitation.UNICEF, New York, p. 66.
Department of Civil Engineering,University of Zimbabwe,
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University of the Western Cape,Private Bag X17, Bellville, 7535 Cape Town,
South AfricaTel.: +27 21 959 2871; fax: +27 21 959 2438.
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Editorial / Physics and Chemistry of the Earth 66 (2013) 13 3
Putting science into practice1 Introduction2 Hydrology sub-theme3 Water and environment sub-theme4 Water and land sub-theme5 Water supply and sanitation sub-theme6 Water Resources Management sub-theme7 Concluding statementReferences