Browsing by Subject "Water management"

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Domestic and agricultural water use by rural households in the Oueme River Basin (Benin): an economic analysis using recent econometric approaches
(2009) Arouna, Aminou; Dabbert, Stephan
Improving the management of water resources as well as an efficient use of available water are particularly important to address the increasing scarcity of water and the low level of water accessibility in many developing countries. However, better water management requires an understanding of the existing pattern of water use for domestic and agricultural activities. With a view towards contributing to such knowledge, this dissertation analyzes domestic and agricultural water use by rural households in the Oueme river basin of Benin. This is done within the scope of three research articles. The specific objectives of the dissertation were: 1) to analyze determinants of domestic water use in the rainy and dry seasons; 2) to estimate households? willingness to pay for water supply improvements and analyze its determinants; and 3) to quantify the efficiency of water use for agricultural production and identify factors explaining the differences in water use efficiency among households. The analyses are built on primary data collected from a household survey administrated to a sample of 325 households in the Oueme river basin, in 2007. To analyze domestic water demand, we identified three types of households: those that use only free water sources, those that use only purchased sources and those that combine both free and purchased sources. A system of two demand equations (one equation for free water and another for purchased water) was estimated using a Seemingly Unrelated Tobit (SURT) approach. The advantage of using the SURT approach is that it is appropriate to account simultaneously for the censored nature of water demand and the correlation between the error terms of two equations. In the analysis of households? willingness to pay (WTP) for water supply improvements, particular attention was given to the distribution of WTP, which has been addressed using (arbitrary) parametric assumptions in many previous studies. To avoid distributional assumptions, the dissertation introduced a semi-nonparametric bivariate probit approach to estimate WTP. To analyze water use efficiency, the dissertation combined an input-specific Data Envelopment Analysis (DEA) with a bootstrapped Tobit model. Bootstrapped Tobit takes care of the dependency problem between efficiency estimates. The analysis of water use efficiency focused on vegetable production in the dry season when water is scarce. Results showed that the average daily domestic water consumption per household during the rainy season (252 liters) is significantly higher than in the dry season (216 liters). SURT estimation results showed that water demand from purchased sources is perfectly price inelastic in the rainy season; indicating that rural households in Benin are very insensitive to changes in water price. This suggests that households are willing to pay more for water supply improvements, due not only to the necessity nature of water but also to its scarcity. Factors affecting domestic water use in the rainy season are household size and composition, education, time for fetching and accessibility to water sources. In the dry season, econometric analysis revealed that there is a positive relationship between wealth and the use of water from free and purchased sources. This result suggests that poverty reduces water use. Purchased water demand in the dry season is also perfectly price inelastic. However, a comparison of determinants of water use between seasons revealed that variables such as time for fetching water, access to water sources and wealth have differential influence on water use during the rainy and dry seasons. These results imply that policy makers must consider among other factors seasonal variation of the determinants of water use. The results of this dissertation provided the first evidence that, in rural Benin, households wanting to improve water supplies are willing to pay more than existing water prices. Households are willing to pay over one and a half times the present average water price. Furthermore, results revealed that estimated WTP would generate substantial revenue from the community, which can lead to significant reductions in subsidies. The supply of safe and adequate water based on estimated WTP will reinforce both the participation of the rural population in water supply management and the sustainability of water facilities. A related policy is that a demand-side management approach can be successfully implemented in rural areas for water supply improvements and sustainability. The important determinants of WTP for water supply improvements were education, age of household head, wealth, queue time at existing water sources and preferred improvements. The policy implication of these findings is that a combination of socio-economic factors affecting WTP, and a demand-side management approach, are likely to improve the sustainability of water projects in rural areas of Benin. Average water use efficiencies were 0.38 and 0.50 under constant and variable returns to scale specification, respectively. This implies that if vegetable farmers in the study area become more efficient in water use, significant amounts of water could be saved and made available for dry season farming land expansion. In addition, many farmers operated at an increasing return to scale (average scale efficiency is 0.70), revealing that most farms should be larger than they currently are to produce efficiently. Water use efficiency in vegetable production was determined by market access, land fragmentation, extension service, ratio of children to adults, water expenditure, water sources, off-farm income and wealth. Results suggest that policy makers should focus on improving farmers? access to input and output markets as well as their access to technical information and training through extension service or NGOs. The findings also showed that households paying for irrigation water or systems are more efficient in water use. However, any price policy should be combined with other policy options such as training and development of improved irrigation techniques adapted to socio-economic conditions of farmers. Overall, various socio-economic characteristic of households and institutional factors are found to explain water use for both domestic and agricultural activities. These factors must be carefully considered for the design and implementation of water management programs that can lead to sustainable accessibility to water. Although the research focuses on Benin, most of the conclusions and policy implications are relevant and could be applicable to many developing countries with similar socio-economics conditions. The dissertation also applies and extends recent econometric approaches that may be used for empirical studies on water management policy in developing countries.
Die Rolle des Porenraums im Kohlenstoffhaushalt anthropogen beeinflusster Niedermoore des Donaurieds
(2007) Höll, Bettina; Stahr, Karl
The use of peatlands in Central Europe for hundreds of years has led to their degradation (loss of organic matter) due to intensive mineralisation. Re-wetting of formerly drained peat aereas has been a popular method of retaining existing peatlands. The effect of re-wetting of degraded fens on their C-pools and C-fluxes is unknown. The protection of these natural resources combined with the creation of biological C-sinks might render the protection and conservation of peatland ecosystems more attractive. Water-logging leads to the accumulation of water in previously air-filled soil pores, something that might increase the C-pool of the soil. It is unknown whether the pore space, which possibly accounts for up to 90% of peatlands, contains carbon components that are similar to those found in the solid soil substance. It is also unknown how much the utilisation of peatlands affects the composition of C-components of the pore space. The major objectives of the present study were (1) to assess the temporal and spatial variability of the C-components in the pore space in fens undergoing different anthropogenic use (drainage, re-wetting) and (2) to assess the role of the pore space in the C-budget. In a Southern German area known as the Schwäbisches Donaumoos, carbon components of the gaseous phase (CO2, CH4) and the liquid phase (CO2/DIC, CH4, DOC, POC) were collected at different depths (5, 10, 20, 40, 60, 80 cm) from different drained (deep, moderately) fen sites and from a long-term re-wetted fen site. Sampling was done at weekly intervals between April 2004 and April 2006. The samples of the water phase and gas phase were collected at the respective sites using slotted PVC tubes and soil-air probes. Gas was analysed using a gas chromatograph and dissolved organic carbon was analysed using a TC water analyser. The fen sites were characterised by selected static parameters of the solid substance and dynamic parameters such as redox potentials, temperature, water level, soil-moisture tension and pH value. The specific use of the fens, which is closely related to the water budget of the area, was a decisive determinant of the amounts of carbon in pore space. Although the solid soil substance in fen sites accounted for less of 10% of the total substance (solid + pores), it still contained a higher amount of carbon (60 -152 kg C m-3) than the pore space. Furthermore the amount of time that the carbon remains is eventually longer in the solid soil substance than in the pore water. Assuming the pore water works only as a short time reservoir. Filling of the pore space with either air or water had a decisive effect on the amount of C. The investigations showed that the amount of C in the air-filled pore space contained an annual average of 15 g C m-3 (deep-drained area), whereas the water-filled pore space contained on average 263 g C m-3 (re-wetted area). The variable anthropogenic effects on fens led to area-specific situations (e.g. groundwater level) that not only affected the amount of C but also had a significant effect on the composition of C components. Dissolved inorganic carbon (DIC), with an average proportion of 55-72%, accounted for the largest proportion of dissolved carbon. Particulate organic carbon (POC) had similar concentrations to dissolved organic carbon (DOC), whereas dissolved methane (CH4) only accounted for a minor proportion (< 0.1%) of the entire carbon of the liquid phase. The DIC concentration was highest in the water from the pores of re-wetted fen. Independent from the use of the fens, different DIC isotope signatures of the ground, karst and spring waters (-11.7‰ to -14.3‰) in comparison to the pore waters (-16.7‰ to -18.4‰) were observed. The further differentiation into the 13C ratios of CO2 contained in the gaseous phase (-23.0‰ to -26.6‰) suggests that DIC ‘accumulated’ in the pore water by way of biogenic CO2. DOC concentrations were lowest in the re-wetted fen. The temporal variability of DOC was related to changes in the bioavailability of DOC. This was also observed in the moderately drained area. The low degree of aromatisation (= higher bioavailability) associated with higher DOC concentrations led to significantly lower values in the re-wetted area compared to the moderately drained area. The microbially easily available DOC proportion was not only temporally but also spatially limited and had a significant effect on the CO2 and CH4 concentrations. At similar depths, CO2 values 10- to 1000-fold higher than CH4 levels could be measured in the gaseous phase (2.7-67 mg CO2-C l-1 vs. < 5.3 mg CH4-C l-1). The highest concentrations were measured in the re-wetted fen. The CO2-C/CH4-C ratios rarely achieved ratios of below 100:1. Due to the higher concentrations of CO2, it can be assumed that the carbon dioxide could compensate for the effect of methane on the climate, on the condition that comparable CO2-C/CH4-C ratios are found in the emissions. The protection of fens as natural resources could be related to carbon uptake (results of the gas exchange to the atmosphere) and higher carbon amounts in the pore space. The amount of time that the carbon remains in the pore waters is correlated to carbon turnover and hydrological conditions. The latter are also important when assessing the indirect emissions, playing an important role in drained fens and rounding out carbon balances.
STAGE_W : an applied general equilibrium model with multiple types of water; technical documentation
(2014) Luckmann, Jonas; McDonald, Scott
This document provides a description of the STAGE_W computable general equilibrium (CGE) model, which is a development of the STAGE model and allows for the depiction of diverse water resources and qualities as well as the simulation of detailed water policy scenarios. The main extensions of STAGE_W are the integration of various water resources as factors, from which specific activities produce water commodities. These commodities are used as inputs in the production process of other activities or are consumed by households and other agents as final users. Thereby, the number and specification of water factors, activities and commodities are flexible and can be adjusted to the conditions of the country analyzed. Moreover the model allows for the substitution of water commodities by water consuming activities. Besides this, the addition of two water specific tax instruments, allows for various pricing schemes, including price differentiation according to water user. All other features of the STAGE model are carried over directly to STAGE_W.