Water productivity and water footprint: misguided concepts or useful tools in water management and policy?

Water productivity (WP) and water footprint (WFP) are popular concepts in research and discourses on water management. Yet there are concerns about their theoretical validity and practical value. This paper shows that the water production function, the concept with a sound theoretical foundation, is the basis for WP. Total WFP is the reciprocal of WP. The practical value of WP and WFP depends on the context of water use and stress. Maximizing WP, not a panacea to all water problems, mainly suits arid rainfed areas. In other regions, economic and marginal WP for increasing overall production should take precedence in water management and policy decisions.     

Reasons underlying behaviour of motorcyclists disregarding traffic regulations in urban areas of Indonesia

Over the last decade, motorcycle use has been rapidly increasing in Indonesia as have violations of traffic rules committed by motorcyclists. This study aims to explore the impacts of motorcyclists’ attitudes, habits, preferences, and travel patterns on their behaviour in disregarding traffic regulations in three cities in Indonesia. The theory of planned behaviour and structural equation modelling are employed to explore these relationships. Consistent with results from previous studies in developed countries, an individual’s beliefs and attitudes, social norms and perceived behaviour control significantly influence behaviour in disregarding traffic rules. Young adults and students are found to be more likely to frequently violate traffic regulations. However, unlike previous findings from developed countries, in Indonesia, males are less likely to disregard traffic rules than females. Overall, pushing the motorcycle through a (very) narrow gap, speeding, driving recklessly, and overtaking on the wrong side are the most frequent traffic violations that make up repetitive violation behaviour among urban motorcyclists in Indonesia. The results highlight the need to revisit Indonesian National Traffic Law traffic violation classification and penalties and separate violations that are likely to cause fatal results, thus requiring tougher law enforcement, from violations that are unlikely to have fatal consequences.     

Chemistry of tap water in Sri Lanka‐implications on health

A preliminary survey on the chemical quality of tap water in Sri Lanka has been carried out and has been grouped into three categories depending on the source of the water. It was revealed that in certain parts of Sri Lanka, the tap water does contain excess quantities of lead. The Piper trilinear diagram shows that much of the tap water of Sri Lanka belongs to the Ca#shMg‐HCO₃ type. Low pH values have also been observed in certain areas and could bring out excess dissolved ions into the tap water. In view of the fact, that only a small percentage of the population of Sri Lanka have access to piped water, no serious health hazards due to the poor quality of the tap water have been encountered.     

Improving Wheat Productivity in Pakistan: Econometric Analysis Using Panel Data from Chaj in the Upper Indus Basin

Abstract

Increasing water scarcity, degradation of land and water resources, continuing low agricultural productivity, and increasing populations are posing the largest ever challenges for development of agricultural economies in many developing countries including Pakistan. Using panel data from irrigated settings in Chaj sub-basin of the Indus basin in Pakistani Punjab, we attempt to: (a) analyze the causes of low productivity; (b) disentangle factors (both land, water and other factors) contributing to productivity variations; and (c) identify limits and opportunities for narrowing productivity gaps and increasing overall wheat production, with a view to enhance food security for the poor. The results of the study indicate that locational inequities in distribution of canal water, use of groundwater of varying quality, differences in use of seed varieties, and other inputs lead to significant variations in wheat productivity. Key implications are that large gains in wheat productivity are possible by (a) improving the production environment at the tail-end through integrated water management practices; (b) adjusting the mix of canal and groundwater use; and (c) using technological interventions to improve the adoption of modern wheat varieties and dissemination of knowledge on planting dates and timings and application rates of inputs, especially water and fertilizer. Not only such interventions are economically, financially, and environmentally desirable, they are also pro-poor. What is needed is a strong political will and commitment.     

Limnology and culture-based fisheries in non-perennial reservoirs in Sri Lanka

This study was carried out to investigate the possibility of using the limnological characteristics of non‐perennial reservoirs in Sri Lanka for the future management of culture‐based fisheries. Forty‐five reservoirs were randomly selected to study their limnology, out of which 32 were stocked with fish fingerlings of Chinese and Indian carps, tilapia and freshwater prawn at stocking densities ranging from 218–4372 fingerlings ha^?1. Of these, 23 reservoirs were harvested at the end of the culture period (6–10 months). Thirteen limnological parameters were measured during the water retention period of each of the 45 reservoirs between November 2001 and January 2004. The mean values of the limnological parameters were used to ordinate the reservoirs through principal component analysis. Ordination showed a productivity gradient among reservoirs where Secchi disc depth, total phosphorus, chlorophyll‐a, inorganic turbidity and organic turbidity were identified as key factors. The total fish yield of culture‐based fisheries was positively correlated to the scores of the first principal component axis. This study reveals that it is possible to classify non‐perennial reservoirs in Sri Lanka based on the above limnological parameters in order to develop culture‐based fisheries and that they could be applicable in comparable water bodies elsewhere in the tropics.     

Arsenic binding mechanisms on natural red earth: a potential substrate for pollution control

Natural red earth (hereafter NRE) was used as a novel adsorbent to examine its retention behaviour in different inorganic arsenic species (As (III) and As (V)) that are abundant in natural water. Adsorption isotherms were constructed at pH approximately 5.5 for As(III) and As(V) in 0.01 M NaNO(3) at 298K for 5 g/L NRE system. The initial arsenic [As(III) or As(V)] concentrations varied between approximately 10(-5) and approximately 10(-4) M. The experimental data were quantified using single site or stepwise Langmuir models. Sorption maximum, was observed at approximately 0.173 mM of As(V). To reach the maximum surface coverage of red earth at pH approximately 5.5 As(III) requires approximately 0.308 mM of initial loading. When compared to As (III), As(V) shows strong affinity for NRE surface sites. This study suggests the potential of NRE as a starting material in decontaminating water polluted with As species.     

Mineral‐induced degradation of halogentated organic pollutants from aquatic systems

Several laboratory tests were conducted to examine Fe(II) as an enhancing agent in the dehalogenation of CHC1₃ in batch mode. The CHC1₃ degradation was found to be negligible when only Fe(II) is present as a reductant in the (aqueous) reaction system. However, in the presence of Fe(II) coated goethite, the rate of CHC1₃ degradation was enhanced to some extent. This observation can be explained by considering a surface mediated electron transfer step in the overall process. Substantial increase of the degradation rate was observed when the goethite particles first coated with fulvic acid were employed in the adsorption of Fe(II) for the degradation of CHC1₃.     

Impact of molecular structure on the performance of methyl ester ethoxylates

Methyl ester ethoxylates are a new class of ethylene oxide (EO)-derived surfactants. Little is known about the impact of structural variations on their performance properties. The effects of carbon chain length, EO content, the degree of unsaturation of the methyl ester feedstock, and feedstock purity were examined for their impact on both physical properties and surfactant performance properties. Physical properties examined included surface properties (surface tension, critical micelle concentration, surface excess adsorption), melting point, water solubility, viscosity, foam stability, color, clarity, and odor. The impact of molecular structure on performance was examined for various applications, including laundry detergents, dishwashing detergents, and hard-surface cleaners. Presented at the AOCS Annual Meeting & Expo, May 1997, Seattle, Washington.     

Methyl ester propoxylates

Insertion of propylene oxide into methyl esters is accomplished using a proprietary alkoxylation catalyst. The alkoxylation mechanism is believed to involve transesterification between the alkoxylated metal-alkoxide of the catalyst and the ester. Optimal alkoxylation conditions are discussed. The effect of inserting propylene oxide prior to ethoxylation on surface properties and foam performance is examined. Presented at the annual meeting of the American Oil Chemists' Society, Seattle, WA, May 1997.