Olifants Basin Research Articles

Toward adaptive water governance: the role of systemic feedbacks for learning and adaptation in the eastern transboundary rivers of South Africa

This paper contributes to scholarship on adaptive water governance (AWG), following policy reforms in South Africa, through a focus on systemic feedbacks for learning and adaptation as critical aspects of AWG. We draw insights from three innovative and evolving water governance experiments. In 1998 South Africa adopted integrated water resources management (IWRM) as a transformative approach for achieving an equitable, sustainable, and decentralized stakeholder-centered water resources governance: all hallmarks of an enabling environment for a two-decade history of AWG, although not named as such. Progress in AWG is explored by using a longitudinal, evaluative exploration of three cases in two transboundary basins in South Africa, with a focus on the unfolding enabling environment for achieving sustainability and equity. Building on previous work, we present and discuss a range of enablers that are shown to function systemically to support feedbacks and build adaptive capacity and resilience in complex and uncertain river systems. In the Crocodile Basin, meta-governance arrangements that created an enabling space for collaborative experimentation and learning proved critical as feedbacks were progressively strengthened and embedded through evolving social and institutional arrangements. The enabling environment also supported a networked, blended system of stakeholder- and state-led platforms that have co-evolved through experimentation and learning. Despite progress, long-term persistence of action-learning feedbacks appears less certain in the Olifants Basin cases. We suggest that enabling meta-governance arrangements that offer an institutional home within which to embed learning is critical. The need to explore alternative networked governance arrangements and to explicitly manage for feedbacks that enhance learning at multiple scales is emphasized. We conclude with recommendations for future work on AWG, including reconciling differences between AWG and IWRM that originally framed South African reforms.

Redressing inequities of the past from a historical perspective: The case of the Olifants basin, South Africa

This paper analyses the continuities and changes in water management in the Olifants basin after the first decade of implementation of the National Water Act (1998). By taking a historical perspective of the basin development trajectory, the paper shows how the White minority rulers, who exerted power until 1994, systematically denied historically disadvantaged individuals (HDIs) the right to become significant water users, let alone 'economically viable' water users. In contrast, White water users undertook major water resource development, which, by the 1970s resulted in the emergence of a 'White water economy'. Under the new dispensation (post-1994), the Department of Water Affairs and Forestry (DWAF) took a two-pronged approach in the Olifants basin and elsewhere for redressing the inequities of the past. On the one hand, from the central top down, it opened up the 'White water economy' into a water economy serving especially 'economically viable water users', who rapidly ceased to be White only. As reflected in a range of new measures taken in the Olifants basin, in this new water economy DWAF better targets bulk domestic supplies to HDIs, has more public participation, and is strengthening its regulatory role in terms of cost-recovery, environmental issues, and pollution prevention. On the other hand DWAF seeks to fill the enormous backlog in water services delivery to HDIs, not only for domestic water uses, but increasingly also for productive uses. The major challenge of bottom-up coordinated service delivery for multiple uses through the newly established Provincial and Local Governments and the transforming line agencies is addressed under the recently launched Water for Growth and Development Initiative.

Evolutional characteristics of hydro-meteorological drought studied using standardized indices and wavelet analysis

The study presents a more recent historical analysis of hydro-meteorological droughts in the Olifants Basin, South Africa from 1980 to 2013 using the Standardized Precipitation Index (SPI), the Standardized Precipitation Evapotranspiration Index (SPEI) and the Streamflow Drought Index (SDI). Time series of SPI, SPEI and SDI were analyzed for drought intensity and duration using wavelet analysis. Results indicate different periodicity and temporal variability of drought with significant meteorological drought incidence in 1991–2004 within the 2–8-year band and hydrological drought in 1996–2004 within the 3–5-year band. Spearman correlation analysis revealed a significant correlation (p < 0.01) between SPI and SPEI irrespective of the timescale. However, the strongest correlation occurred at the same timescale for SPI and SPEI: 3-month timescale (r = 0.904, p < 0.01), 6-month timescale (r = 0.936, p < 0.01), 9-month timescale (r = 0.946, p < 0.01) and 12-month timescale (r = 0.947, p < 0.01). A significant relation also existed between SDI and SPI (r = 0.731, p < 0.01) as well as between SDI and SPEI (r = 0.631, p < 0.01). Findings further indicate varying degrees of drought ranging from near normal to extremely dry conditions during 1980–2013. It is expected that strategies and policy actions on drought factor in the recurring nature of droughts so as to minimize the negative impact on water resources and other human–hydro-ecological systems.

A framework for selecting crops for irrigation using mining contaminated water: An example from the Olifants basin of South Africa

Irrigated agriculture is adapting to viability challenges due to water contamination from mining in various ways. We explore the option of using crops that are able to tolerate the impacts of such water contamination as a short term adaptation strategy. We present a framework which enables the selection of crops suitable for irrigated production using mining contaminated water. The framework identifies key factors that should inform crop selection; and these include crop adaptation to climatic conditions, contaminants present in water, crop tolerance to contaminants, crop use and accumulation of toxic metals. A proposed process for screening and selecting a crop is described. Although considered a partial analysis due to incomplete and non-standardised information on crop tolerance levels, the framework narrows down choices which can be assessed in more detail or with field trials. The framework shows that interventions beyond the farm level are necessary to support the use of contaminant tolerant crops as a strategy for adapting to water contamination from mining. However, key questions regarding the risks associated with alternative crops and difficulties in selecting suitable crops remain.

Groundwater recharge modelling in a large scale basin: an example using the SWAT hydrologic model

Groundwater constitutes an essential resource that augments surface water resources in meeting the water supply needs of man and the ecosystem. Most importantly in arid and semi-arid environments where rainfall patterns are erratic, groundwater resources are often the preferred source of water. This causes enormous pressure on the resource leading to diminishing groundwater resources. Land use changes also impact on groundwater resources through alterations in the hydrologic regime. It is imperative therefore to evaluate groundwater recharge dynamics under changing land uses to provide for a better resource planning and allocation. We present in this study, an investigation into groundwater recharge dynamics of the Olifants Basin, a water stressed basin in Southern Africa over the past decade with considerations to land use changes. Three land use change scenarios were developed to simulate the groundwater recharge of the basin within the Soil and Water Assessment Tool (SWAT) environment. The SWAT model was calibrated (1988–2001) and validated (2002–2013) with good model performance statistics; NSE, R2, PBIAS, RSR of 0.88, 0.89, −11.49%, 0.34 and 0.67, 0.78, −20.69%, 0.57 respectively for calibration and validation stages. Findings indicate groundwater recharge declined by 10.37 mm (30.3%) and 2.34 mm (9.82%) during the periods 2000–2007 and 2007–2013 respectively. The decline in groundwater recharge was linked to the changes in urban (9.2%), agriculture (6.1%), rangelands (−16.8%) during the period 2000–2007 and urban (1.3%), agricultural (14%), rangelands (−14.8%) during 2007–2013. The SWAT model reveals it capabilities as a decision support tool (DST) in groundwater recharge assessment for large scale basins.

The Analysis of Transaction Costs in Water Policy Implementation in South Africa: Trends, Determinants and Economic Implications

Water is a complex economic good. It requires optimal management to control rising scarcity and competition for use. South Africa like many other parts of the world is in the process of implementing market-based water policy reforms to attain equity, efficiency, and sustainability in water use. However, these reforms have not been entirely successful and water allocation problems persist. This could be due to many contributing factors, certainly, but this paper narrows down to identify possible transaction costs that would arise from the policy process. Transaction costs can be great hindrances to policy formation and implementation especially if they constitute a large component of total policy costs. However, transaction costs remain generally unmeasured and this study fills in this gap for the Olifants basin of South Africa. Specifically, the study identifies and quantifies transaction costs incurred by various stakeholders in the water policy process in the Olifants basin in South Africa. Further, determinants of irrigation farmers’ transaction costs are assessed using regression approaches. Results from this study allow evaluating existing policies ex-post for improvement purposes.

Hydrological Responses to Land Use/Cover Changes in the Olifants Basin, South Africa

This paper discusses the hydrological impacts of land use changes on the Olifants Basin in South Africa using the Soil and Water Assessment Tool (SWAT). A three-phase land use scenario (2000, 2007 and 2013) employing the “fix-changing” method was used to simulate the hydrology of the Olifants Basin. Changes in land uses were related to different hydrological responses through a multi-regression analysis to quantify the effects of land use changes. Results reveal that from 2000 to 2013, a 31.6% decrease in rangeland with concomitant increases in agriculture lands (20.1%), urban areas (10.5%) and forest (0.7%) led to a 46.97% increase in surface runoff generation. Further, urbanization was revealed as the strongest contributor to increases in surface runoff generation, water yield and evapotranspiration (ET). ET was found to be a key water availability determinant as it has a high negative impact on surface runoff and water yield. Urbanization and agriculture were the most essential environmental factors influencing water resources of the basin with ET playing a dominant role. The output of the paper provides a simplistic approach of evaluating the impacts of land use changes on water resources. The tools and methods used are relevant for policy directions on water resources planning and adaptation of strategies.

Simulation of Sediment Yield in a Semi-Arid River Basin under Changing Land Use: An Integrated Approach of Hydrologic Modelling and Principal Component Analysis

Intensified human activities over the past decades have culminated in the prevalence of dire environmental consequences of sediment yield resulting mainly from land use changes. Understanding the role that land use changes play in the dynamics of sediment yield would greatly enhance decision-making processes related to land use and water resources management. In this study, we investigated the impacts of land use and cover changes on sediment yield dynamics through an integrated approach of hydrologic modelling and principal component analysis (PCA). A three-phase land use scenario (2000, 2007 and 2013) employing the “fix-changing” method was used to simulate the sediment yield of the Olifants Basin. Contributions in the changes in individual land uses to sediment yield were assessed using the component and pattern matrixes of PCA. Our results indicate that sediment yield dynamics in the study area is significantly attributed to the changes in agriculture, urban and forested lands. Changes in agriculture and urban lands were directly proportional to sediment yield dynamics of the Olifants Basin. On the contrary, forested areas had a negative relationship with sediment yield indicating less sediment yield from these areas. The output of this research work provides a simplistic approach of evaluating the impacts of land use changes on sediment yield. The tools and methods used are relevant for policy directions on land and water resources planning and management.

A Historical Analysis of Rainfall Trend in the Olifants Basin in South Africa

&lt;span style="font-size: 10.5pt; font-family: 'Times New Roman','serif'; mso-bidi-font-size: 12.0pt; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;" lang="EN-US"&gt;A set of homogeneity test methods and the Mann-Kendall trend test were applied on historical rainfall records of the Olifants Basin to detect changes in rainfall pattern under a changing climate. In total, historical rainfall records from 13 stations obtained from the South African Weather Service (SAWS) and the Department of Water Affairs (DWA) spanning the period 1975-2013 were used in the analysis. Results of the study indicate an insignificant declining rainfall trend in the Olifants Basin with a mean annual rainfall of 664 mm. Rainfall in the basin exhibits spatio–temporal variation with coefficient of variation of 24%. Inter-annual and seasonal variability is dominant in the records examined. Changes observed in rainfall over the years were therefore concluded to have resulted due to climate change impacts.&lt;/span&gt;

Application of SWAT Model to the Olifants Basin: Calibration, Validation and Uncertainty Analysis

The application of the Soil and Water Assessment Tool (SWAT) to the Olifants Basin in South Africa was the focus of our study with emphasis on calibration, validation and uncertainty analysis. The Basin was discretized into 23 sub-basins and 226 Hydrologic Response Units (HRUs) using 3 arc second (90 m × 90 m) pixel resolution SRTM DEM with stream gauge B7H015 as the Basin outlet. Observed stream flow data at B7H015 were used for model calibration (1988-2001) and validation (2002-2013) using the split sample approach. Relative global sensitivity analysis using SUFI-2 algorithm was used to determine sensitive parameters to stream flow for calibration of the model. Performance efficiency of the Olifants SWAT model was assessed using Nash-Sutcliffe (NSE), coefficient of determination (R2), Percent Bias (PBIAS) and Root Mean Square Error-Observation Standard deviation Ratio (RSR). Sensitivity analysis revealed in decreasing order of significance, runoff curve number (CN2), alpha bank factor (ALPHA_BNK), soil evaporation compensation factor (ESCO), soil available water capacity (SOIL_AWC, mm H2O/mm soil), groundwater delay (GW_ DELAY, days) and groundwater “revap” coefficient (GW_REVAP) to be the most sensitive parameters to stream flow. Analysis of the model during the calibration period gave the following statistics; NSE = 0.88; R2 = 0.89; PBIAS = -11.49%; RSR = 0.34. On the other hand, statistics during the validation period were NSE = 0.67; R2 = 0.79; PBIAS = -20.69%; RSR = 0.57. The observed statistics indicate the applicability of the SWAT model in simulating the hydrology of the Olifants Basin and therefore can be used as a Decision Support Tool (DST) by water managers and other relevant decisions making bodies to influence policy directions on the management of watershed processes especially water resources.

Sensitivity and uncertainty propagation in coupled models for assessing smallholder farmer food security in the Olifants River Basin, South Africa

Using family balance (i.e., combined net farm and non-farm incomes less family expenses), an output from an integrated model, which couples water resource, agronomic and socio-economic models, its sensitivity and uncertainty are evaluated for five smallholder farming groups (A–E) in the Olifants Basin. The crop management practiced included conventional rainfed, untied ridges, planting basins and supplemental irrigation. Scatter plots inferred the most sensitive variables affecting family balance, while the Monte Carlo method, using random sampling, was used to propagate the uncertainty in the model inputs to produce family balance probability distributions. A non-linear correlation between in-season rainfall and family balance arises from several factors that affect crop yield, indicating the complexity of farm family finance resource-base in relation to climate, crop management practices and environmental resources of soil and water. Stronger relationships between family balance and evapotranspiration than with in-season rainfall were obtained. Sensitivity analysis results suggest more targeted investment effort in data monitoring of yield, in-season rainfall, supplemental irrigation and maize price to reduce family balance uncertainty that varied from 42% to 54% at 90% confidence level. While supplemental irrigation offers the most marginal increase in yields, its wide adoption is limited by availability of water and infrastructure cost.

Hydrological impacts of climate change in gauged and ungauged watersheds of the Olifants basin: a trading-space-for-time approach

Robust projections of climate change impacts on regional hydrology are crucial for water resources management, especially in data-sparse regions. Impact projections have to: (a) be available at gauged and ungauged locations; (b) consider changes in watershed behaviour for different future climates and land uses; and (c) include estimates of uncertainty. We apply a novel water resources modelling framework which combines signature regionalization with the trading of space for time to obtain hydrological projections in ungauged basins and under climate change for the Olifants basin in southern Africa, a UNESCO HELP basin. We find that using statistically downscaled general circulation model (GCM) vs observed climate data leads to only slight deterioration in reliability of runoff projections for the historical period. The framework projects a decrease in regional runoff by –8.7% and –3.9% for A2 and B1 scenarios, respectively, by the end of the century, with, 80% and 67% of GCMs agreeing on the decrease in runoff, respectively.Editor Z.W. Kundzewicz; Associate editor C.-Y. XuCitation Singh, R., van Werkhoven, K., and Wagener, T., 2013. Hydrological impacts of climate change in gauged and ungauged watersheds of the Olifants basin: a trading-space-for-time approach. Hydrological Sciences Journal, 59 (1), 29–55.

The deep waters of land reform: land, water and conservation area claims in Limpopo Province, Olifants Basin, South Africa

Through investigating the reactions of commercial farmers to land and water reforms in the Trichardtsdal-Ofcolaco area, Limpopo Province, Olifants Basin, South Africa, from 1997 to 2006, it is shown that water claims are key to land redistribution processes, and that commercial farmers make strategic use of arguments for nature conservation and ecological stewardship to defend their claims to water. Given these observations, caution is warranted with respect to the implementation of land and water reforms as separate policy packages; it may be more effective to design water and conservation policies as an integral part of land reform programmes.

Comparative assessment of widespread irrigation with low quality mine-water in undisturbed and rehabilitated mine-lands in the upper Olifants using the ACRU2000 model

The ACRU agrohydrological model, in the form of ACRU2000 and its salinity module, ACRUSalinity, was employed in catchment-scale assessment of widespread irrigation with low quality mine-water in undisturbed (un-mined) and rehabilitated soils in the Upper Olifants basin of South Africa. The study area comprised a small catchment of 4.7 km2 located in a coal-mine environment, known as the Tweefontein Pan catchment. The catchment drained to a surface reservoir (Tweefontein Reservoir) of maximum capacity and surface area 4 000 Mℓ and 1.5 km2, respectively. The catchment was instrumented to measure hydrodynamic responses and simulated as a hydrological system. Consideration was given to runoff, groundwater storage, evapotranspiration, baseflow, interception, irrigation water supply and rainfall, thereby accounting for all the dominant hydrological components of the system. Three scenarios were simulated using the available records for 5 years (1999 to 2004). The first was a baseline scenario representing the prevailing condition in the study area and the other 2 scenarios represented widespread irrigation with the mine-water on undisturbed and rehabilitated soils. In simulating the widespread irrigation on rehabilitated soils, a distinction was made between a rehabilitated irrigated area before and after the re-establishment of the equilibrium water table. Comparison of the results from the simulated scenarios indicated that a greater undisturbed area (max of 160 ha) than rehabilitated area (max of 120 ha) could be irrigated with mine-water from the Tweefontein Reservoir. Irrigation on rehabilitated soils depleted the water in the reservoir more rapidly than irrigation on undisturbed soils, due to lower runoff and higher ingress to groundwater in rehabilitated areas.Keywords: mine-water, widespread irrigation, mined land irrigation, Upper Olifants, catchment scale, hydrological assessment, ACRU2000

Is normative integrated water resources management implementable? Charting a practical course with lessons from Southern Africa

At the seventh Waternet/WARFSA/GWP-SA Symposium, Lewis Jonker described the “perceived failure of implementing IWRM in South Africa.” This paper starts from Jonker’s observation – which can certainly be defended – and argues that attempts to implement full Integrated Water Resources Management (IWRM) are doomed to failure and disappointment. The paper therefore offers a more practical ‘expedient’ solution. The paper is based on research done in Tanzania (Ruaha Basin) and South Africa (Olifants Basin) that is further informed by a growing literature critical of the IWRM paradigm as currently understood and practiced. As a guide to actual policies and their implementation in developing countries, IWRM has led to mis-guided priorities and paralysis of development programmes. An alternative approach is one in which basin managers identify priority problem areas, and focus specifically on finding solutions to these problems within an integrated framework, rather than starting with a broad set of principles and trying to implement these. The paper proposes that a shift away from IWRM as a normative concept is now overdue, and argues for realism and action by focusing attention on and prioritizing the critical needs of poor people in Africa. People cannot wait forever .

Assessment of the Impact of Irrigation with Low-quality Mine Water on Virgin and Rehabilitated Soils in the Upper Olifants Basin

Low-quality mine water from collieries may be used in large quantities to irrigate agricultural crops on virgin (unmined) and rehabilitated soils in South Africa. Such a use could enhance crop production and allow environmentally sustainable mine water disposal. In this study, the volume and qualities of the runoff from two centre pivots irrigated with moderately saline mine water, as well as their soil water salinities, were monitored and used to determine water and salt balances, using the modified ACRU agrohydrological model, ACRU2000, and its salinity module, ACRUSalinity. At both sites, much of the water evaporated, while a significant part of the salt input either precipitated or remained with the water in the soil horizons. A higher percentage of drainage water (and salinity) were retained as ground water storage and a lower percentage of runoff occurred in the rehabilitated sandy loam soil, while a higher percentage of salts accompanied runoff in the virgin clayey soils. Simulated salt saturation values indicate that many crops could be successfully irrigated at 100% yield potential at either site. Electrical resistivity surveys were carried out at both sites. A general decrease in resistivities with depth in both the virgin and rehabilitated soils reflected the decreasing influence of the mine water used for irrigation with depth and the precipitation of salts in the soils close to the ground surface. The occurrence of a thicker, low-resistivity, near-surface layer near the exit of each pivot area indicates that the water and salt content of the subsurface increased in the direction that the surface and near-surface irrigation water flowed.