Pieter van der Zaag

Water as an Economic Good and Demand Management Paradigms with Pitfalls

Abstract In certain circles, demand management is seen as one and the same thing as economic pricing. This thinking is stimulated by the Dublin principle that water should be considered an economic good. But is this reasoning correct? Is economic pricing an adequate means to reach more desirable levels of demand? There is considerable misunderstanding about what the concept of water as an economic good implies. In this paper it is argued that water pricing should primarily serve the purpose of financial sustainability through cost recovery. Moreover, in water pricing, adequate attention should be given to equity considerations through, for example, increasing block tariffs. Instead of economic pricing there is a need for defining a reasonable price, which provides full cost recovery but which safeguards ecological requirements and access to safe water for the poor. Giving a reasonable price to water has the additional benefit that it sends out a clear signal to the users that water should be used wisely, but the prime target of water pricing remains cost recovery. A major argument of neoclassical economists is that economic pricing of water will facilitate the re-allocation of water from sectors with lower added value (such as agriculture) to sectors with a higher added value (such as urban water use). However, the value of alternative uses of irrigation water is often grossly over-estimated. Adequate and effective regulations may suffice in order to achieve the optimal allocation of water resources.

Conceptual framework for the management of shared river basins; with special reference to the SADC and EU ☆

1. Shared river basins, an introduction 1.1. SADC and the EU Climatic diAerences stand out when comparing the regions of the European Union (EU) and the Southern African Development Community (SADC). Southern Africa has a distinct dry and wet season, and, more importantly, its climate is characterised by a high variation between relatively wet and dry years, a phenomenon much less pronounced in the EU. In addition overall evaporative capacity in the SADC region is considerably higher than in EU countries. In general, the SADC region is a water scarce area in comparison with Europe. For SADC countries water is key to sustainable development (IHE, 1994). Table 1 shows that many SADC countries are rapidly approaching situations of water stress (generally defined as less than 1700 m 3 per capita per year), if not absolute water scarcity (less than 1000 m 3 per capita per year) (Engelman & LeRoy, 1993; Gleick, 1993). A striking diAerence between EU and SADC countries is that the per capita water availability in the SADC region, which is already low, is expected to reduce by half by the year 2025, whereas per capita water availability in Europe remains virtually constant. The rapid decline in SADC countries is mainly a result of population growth. Data on per capita water availability suAer from lack of relevant hydrological information. Traditionally, the computations are based on the availability of surface water. The data of Gardner-Outlaw and Engelman (1997), in Table 1, also suAer from that bias. Other resources, in particular the amount of rainfall that is directly available for vegetation (termed ‘green’ Water Policy 2 (2000) 9‐45

Adaptive and Integrated Water Management: Coping With Complexity and Uncertainty

Managing water is like trying to hit a moving target, and adaptive management of water resources is increasingly recognized as an important research field. Many variables impinge on the sociobiophysical water system, and they trigger complex responses due to nonlinear relations and thresholds that may suddenly push the system into another state. Simple (mental or numerical) models are inadequate to predict system response. More refined approaches are required, and adaptive management is one such promising approach.

Towards measurable criteria for the equitable sharing of international water resources

Equity is key to the allocation of international water resources. Six possible criteria and allocation algorithms that operationalise the equity concept, are developed and applied to the Orange, Nile and Incomati rivers. The criterion that considers all (blue and green) water resources and that uses the basin population as the main allocation variable yields the most equitable water allocation. Two important variables are identified over which the riparian countries should reach consensus:

Rainfall–interception–evaporation–runoff relationships in a semi-arid catchment, northern Limpopo basin, Zimbabwe

Abstract Characterizing the response of a catchment to rainfall, in terms of the production of runoff vs the interception, transpiration and evaporation of water, is the first important step in understanding water resource availability in a catchment. This is particularly important in small semi-arid catchments, where a few intense rainfall events may generate much of the seasons runoff. The ephemeral Zhulube catchment (30 km2) in the northern Limpopo basin was instrumented and modelled in order to elucidate the dominant hydrological processes. Discharge events were disconnected, with short recession curves, probably caused by the shallow soils in the Tshazi sub-catchment, which dry out rapidly, and the presence of a dambo in the Gobalidanke sub-catchment. Two different flow event types were observed, with the larger floods showing longer recessions being associated with higher (antecedent) precipitation. The differences could be related to: (a) intensity of rainfall, or (b) different soil conditions. Interception is an important process in the water balance of the catchment, accounting for an estimated 32% of rainfall in the 2007/08 season, but as much as 56% in the drier 2006/07 season. An extended version of the HBV model was developed (designated HBVx), introducing an interception storage and with all routines run in semi-distributed mode. After extensive manual calibration, the HBVx simulation satisfactorily showed the disconnected nature of the flows. The generally low Nash-Sutcliffe coefficients can be explained by the model failing to simulate the two different observed flow types differently. The importance of incorporating interception into rainfall–runoff is demonstrated by the substantial improvement in objective function values obtained. This exceeds the gains made by changing from lumped to semi-distributed mode, supported by 1 000 000 Monte Carlo simulations. There was also an important improvement in the daily volume error. The best simulation, supported by field observations in the Gobalidanke sub-catchment, suggested that discharge was driven mainly by flow from saturation overland flow. Hortonian overland flow, as interpreted from field observations in the Tshazi sub-catchment, was not simulated so well. A limitation of the model is its inability to address temporal variability in soil characteristics and more complex runoff generation processes. The model suggests episodic groundwater recharge with annual recharge of 100 mm year-1, which is similar to that reported by other studies in Zimbabwe. Citation Love, D., Uhlenbrook, S., Corzo-Perez, G., Twomlow, S. & van der Zaag, P. (2010) Rainfall–interception–evaporation–runoff relationships in a semi-arid catchment, northern Limpopo basin, Zimbabwe. Hydrol. Sci. J. 55(5), 687–703.

Estimation of Reservoir Discharges from Lake Nasser and Roseires Reservoir in the Nile Basin Using Satellite Altimetry and Imagery Data

This paper presents the feasibility of estimating discharges from Roseires Reservoir (Sudan) for the period from 2002 to 2010 and Aswan High Dam/Lake Nasser (Egypt) for the periods 1999–2002 and 2005–2009 using satellite altimetry and imagery with limited in situ data. Discharges were computed using the water balance of the reservoirs. Rainfall and evaporation data were obtained from public domain data sources. In situ measurements of inflow and outflow (for validation) were obtained, as well. The other water balance components, such as the water level and surface area, for derivation of the change of storage volume were derived from satellite measurements. Water levels were obtained from Hydroweb for Roseires Reservoir and Hydroweb and Global Reservoir and Lake Monitor (GRLM) for Lake Nasser. Water surface areas were derived from Landsat TM/ETM+ images using the Normalized Difference Water Index (NDWI). The water volume variations were estimated by integrating the area-level relationship of each reservoir. For Roseires Reservoir, the water levels from Hydroweb agreed well with in situ water levels (RMSE = 0.92 m; R2 = 0.96). Good agreement with in situ measurements were also obtained for estimated water volume (RMSE = 23%; R2 = 0.94) and computed discharge (RMSE = 18%; R2 = 0.98). The accuracy of the computed discharge was considered acceptable for typical reservoir operation applications. For Lake Nasser, the altimetry water levels also agreed well with in situ levels, both for Hydroweb (RMSE = 0.72 m; R2 = 0.81) and GRLM (RMSE = 0.62 m; R2 = 0.96) data. Similar agreements were also observed for the estimated water volumes (RMSE = 10%–15%). However, the estimated discharge from satellite data agreed poorly with observed discharge, Hydroweb (RMSE = 70%; R2 = 0.09) and GRLM (RMSE = 139%; R2 = 0.36). The error could be attributed to the high sensitivity of discharge to errors in storage volume because of the immense reservoir compared to inflow/outflow series. It may also be related to unaccounted spills into the Toshka Depression, overestimation of water inflow and errors in open water evaporation. Therefore, altimetry water levels and satellite imagery data can be used as a source of information for monitoring the operation of Roseires Reservoir with a fairly low uncertainty, while the errors of Lake Nasser are too large to allow for the monitoring of its operation.

Shatt al Arab River system under escalating pressure: a preliminary exploration of the issues and options for mitigation

ABSTRACT This paper provides a broad description of the current state of hydrological and geographical characteristics of the Shatt al Arab River (SAR), and analyses the severe decline in water quantity and escalating levels of salinity. The analyses cover SAR as well as all contributing rivers and Mesopotamian Marshlands, which is essential to present a holistic picture of the issues. The analyses are based on the most recent data, though limited, on water availability, water resources development and management infrastructure, and water quality status. The study shows that the water inflows have significantly reduced and the water quality status has deteriorated to alarmingly high levels, especially from Basra to the river mouth. The crisis can only be averted through the cooperative water management initiatives taken by all the riparian countries, which require a paradigm shift from the current approach of unilateral water management planning to international cooperation and management on the shared water resources. The crisis mitigation strategies should find ways of increasing inflows and improving water quality from the upstream source rivers. At the same time, local measures are required to avoid drainage of poor-quality domestic and industrial effluents and highly saline water from the marshes into the SAR. These efforts should be supported by sound scientific information, which is also limited at the moment.

The Politics of Water Science: On Unresolved Water Problems and Biased Research Agendas

Many serious water-related societal problems remain unresolved. Examples include (a) the number of people without access to potable drinking water (about 1 billion) and sanitation (more than 2 billion), located mainly in Africa and Asia; (b) the challenges of avoiding and abating environmental degradation and water pollution in many densely populated regions of the world; (c) the low crop yields obtained by the majority of smallholder farmers, especially in Sub-Saharan Africa; and (d) the tensions that simmer between rival water uses and users within water scarce catchment areas and river basins, which may also involve nation states. The need to address these serious problems, as recognized in the Millennium Development Goals, is made all the more difacult by (e) the need to enhance the capacity of water systems to respond to climate change impacts (increased variability of rainfall, increased intensity of extreme events, and, in many parts, a decrease in the utilizable amounts of surfaceand groundwater). Furthermore, the South is now faced with (f) a sudden increase in biofuel demand (from the EU and US as a way to mitigate their greenhouse gas emissions and reduce dependency on oil exporters), which leads to shifts towards biofuel production in the South and thereby causes competition with other existing uses of land and water resources. Is water science, where science includes knowledge claims from both social and natural sciences,1 doing enough to contribute to resolving these

Data-sharing bottlenecks in transboundary integrated water resources management: a case study of the Mekong River Commission’s procedures for data sharing in the Thai context

Integrated water resources management (IWRM) relies on co-ordination, co-operation and sharing of collected data amongst relevant organizations. This article presents the results of systematic research into non-technical barriers that influence IWRM-related data sharing in transboundary contexts, with a focus on the Mekong River Commission’s procedures for data sharing in Thailand. The current extent of data sharing is quite limited. The main bottlenecks hindering relevant Thai organizations’ sharing data across national boundaries appear to be a perception of limited gains, and concerns for national security. The article concludes that data sharing for IWRM implementation cannot be radically improved without significant changes in the mindsets of the relevant organizations, and suggests how to achieve this.

Roman water law in rural Africa: the unfinished business of colonial dispossession

This paper discusses four questions about the recent water law reforms in Sub-Saharan Africa, which strengthen permit systems. First, do permit systems continue to dispossess rural small-scale users, as intended by European colonizers who introduced principles of Roman law? Second, is it wrong to assume that one can convert one legal system (customary water rights) into another legal system (permits) in the short term? Third, do current permit systems discriminate against small-scale users? And lastly, do fiscal measures ingrained in permits foster rent seeking and strengthen water resources as a commodity for nationals and foreigners who can pay? As all the answers are positive, the paper concludes by recommending measures to recognize and protect small-scale water users and render state regulation more realistic.