Options for improving water use efficiency under worsening scarcity: Evidence from the Middle Olifants Sub-Basin in South Africa

Following the political changes in the early 1990s, the South African government introduced a comprehensive reform process for the water sector with the goal of achieving an enhanced and more equitable water management system. This paper analyses the existing water allocation situations and applies a non-linear optimisation model to investigate the optimal intraand inter-regional allocation regimes in the Middle Olifants sub-basin of South Africa. Economic issues such as efficiency gains related to water transfers are discussed and calculated water price elasticities and estimated water demand functions provide necessary fundamentals for further modelling work. Social and environmental aspects are accounted for by including constant water demands in the model. Results show higher benefits from inter-regional water allocation. Reducing water supply levels to conform to the sustainable water supply policy, it can be shown that although water supply is reduced by approximately 50%, total benefits from water use are only reduced by 5% and 11% for inter- and intra-regional allocation regimes, respectively. These results indicate that alternative water allocation mechanisms can serve as policy instruments to offset the effects of water scarcity

Preferences for Domestic Water Services in the Middle Olifants Sub-Basin of South Africa

Using household survey data, this study investigates preferences for domestic water services in the Middle Olifants sub-basin of South Africa. Water is a relatively scarce resource in South Africa that is distributed unevenly both geographically and seasonally as well as sociopolitically. For a water management addressing the policy objectives of efficiency in use, equity in access and benefits and long-term sustainability, economic valuation of the different water uses is required. In order to detect households' preferences, a choice experiment of the various water services was conducted. Results suggested the presence of preference heterogeneity and therefore, a latent class model was applied, dividing households into homogeneous groups according to their preferences. Four distinct groups of households could be identified which differ significantly in terms of their socio-economic characteristics, their attitudes toward pricing of water and their satisfaction with current water service levels. Willingness to pay (WTP) estimates of different water service characteristics in all groups indicate that households are willing to pay higher prices for a better and more reliable water services provision. But the amount households are willing to pay differs among the groups. This information is helpful for policy-makers to enable the design of water services in the Middle Olifants according to preferences of local households. Besides, WTP estimation can provide a basis for setting water tariffs

Metacarpal trabecular bone varies with distinct hand-positions used in hominid locomotion

Trabecular bone remodels during life in response to loading and thus should, at least in part, reflect potential variation in the magnitude, frequency and direction of joint loading across different hominid species. Here we analyse the trabecular structure across all non-pollical metacarpal distal heads (Mc2-5) in extant great apes, expanding on previous volume of interest and whole-epiphysis analyses that have largely focussed on only the first or third metacarpal. Specifically, we employ both a univariate statistical mapping and a multivariate approach to test for both inter-ray and interspecific differences in relative trabecular bone volume fraction (RBV/TV) and degree of anisotropy (DA) in Mc2-5 subchondral trabecular bone. Results demonstrate that while DA values only separate Pongo from African apes (Pan troglodytes, Pan paniscus, Gorilla gorilla), RBV/TV distribution varies with the predicted loading of the metacarpophalangeal (McP) joints during locomotor behaviours in each species. Gorilla exhibits a relatively dorsal distribution of RBV/TV consistent with habitual hyper-extension of the McP joints during knuckle-walking, whereas Pongo has a palmar distribution consistent with flexed McP joints used to grasp arboreal substrates. Both Pan species possess a disto-dorsal distribution of RBV/TV, compatible with multiple hand postures associated with a more varied locomotor regime. Further inter-ray comparisons reveal RBV/TV patterns consistent with varied knuckle-walking postures in Pan species in contrast to higher RBV/TV values toward the midline of the hand in Mc2 and Mc5 of Gorilla, consistent with habitual palm-back knuckle-walking. These patterns of trabecular bone distribution and structure reflect different behavioural signals that could be useful for determining the behaviours of fossil hominins

The position of Australopithecus sediba within fossil hominin hand use diversity

The human lineage is marked by a transition in hand use, from locomotion towards increasingly dexterous manipulation, concomitant with bipedalism. The forceful precision grips used by modern humans probably evolved in the context of tool manufacture and use, but when and how many times hominin hands became principally manipulative remains unresolved. We analyse metacarpal trabecular and cortical bone, which provide insight into behaviour during an individual’s life, to demonstrate previously unrecognized diversity in hominin hand use. The metacarpals of the palm in Australopithecus sediba have trabecular morphology most like orangutans and consistent with locomotor power-grasping with the fingers, while that of the thumb is consistent with human-like manipulation. This internal morphology is the first record of behaviour consistent with a hominin that used its hand for both arboreal locomotion and human-like manipulation. This hand use is distinct from other fossil hominins in this study, including A. afarensis and A. africanus

Economic Analysis of Water Supply Cost Structure in the Middle Olifants Sub-Basin of South Africa

Using data gathered from the National Treasury of South Africa, we examine the structure of water supply costs and tariffs of Water Service Authorities (WSAs) in the Middle Olifants sub-basin of South Africa. Using the translog cost function method, the marginal cost of water supply and economies of scale are estimated. Comparison of tariffs and marginal costs show that the estimated marginal cost is higher than the actual tariff paid by consumers. This implies that WSAs in the Middle Olifants are not charging enough to recover the costs of the water services. Thus, among other things, pricing of water at its marginal cost would partly assist in solving the cost recovery problem. Raised tariffs would in turn contribute to improved efficiency of water use. As evidenced by estimation results of returns to scale (greater than one), merger of WSAs would be economically advantageous. Hence, reversing the process of transferring water services’ authority to ‘local’ municipality level and thus up-scaling WSAs into the ‘district’ municipality level is an important policy option for improving water services efficiency in the Middle Olifants sub-basin of South Africa

District-Level Spatial Analysis of Migration Flows in Ghana: Determinants and Implications for Policy

The present study investigates the determinants of inter-district migration flows over the 1995-2000 period in Ghana. A combination of socio-economic, natural and spatial ‘district-level’ attributes are considered as potential variables explaining the direction of migration flows. In addition to the ‘net’ migration model, ‘in’ and ‘out’ migration models are also employed within the context of the gravity model. Results in the three models consistently show that people move out of districts with less employment and choose districts with high employment rate as destinations. While shorter distance to roads encourages out-migration, districts with better water access seem to attract migrants. Generally, people move out of predominantly agrarian districts to relatively more urbanized districts