- Receptivity to sustainable urban water management in the South West
- Authors: M. S. Poustie; R. R. Brown A. Deletic
Abstract: Small urban centres in the South West Pacific face many challenges regarding urban water management in the light of future uncertainties and climate change. Without implementing sustainable urban water management (SUWM), they risk adverse environmental and public health impacts, but little is known regarding the receptivity of urban water professionals towards its principles and practices. This paper assesses the willingness and ability of urban water managers from the region to implement SUWM. Results demonstrate that whilst aware of current failures, there was limited awareness of sustainable solutions, and a limited ability to identify benefits arising from SUWM implementation. There is a need to increase the opportunities for urban water professionals in the region to acquire skills and implement SUWM. This study identifies the capacity development needed in the region to increase receptivity to SUWM.
- An assessment of reservoir filling policies for the Grand Ethiopian
- Authors: Andrew King; Paul Block
Abstract: Africa's largest hydropower facility is currently under construction on the main stem of the Blue Nile River in Ethiopia. The Grand Ethiopian Renaissance Dam (GERD) is poised to facilitate regional development with a 63 billion cubic meter reservoir and 6,000 MW of power generating capacity. To date, however, no reservoir filling rate policy has been established. This policy will have clear implications on the GERD's ability to generate hydropower in the near-term and coincidentally impact people and livelihoods in Sudan and Egypt through reduced streamflow availability. Implications of climate variability and emerging climate change within Ethiopia cast further uncertainty on potential filling policies and system operations. To address this challenge, numerous filling policies are evaluated through a climate-sensitivity approach to estimate impacts on reservoir filling time, hydropower production, and downstream flows. This provides viable and timely points of comparison for regional water managers and politicians negotiating system operations in the midst of ongoing project construction.
- Climate change impact chains in the water sector: observations from
projects on the East India coast
- Authors: Sibylle Kabisch; Ronjon Chakrabarti, Till Wolf, Wilhelm Kiewitt, Ty Gorman, Ashish Chaturvedi Rachna Arora
Abstract: With regional variations, climate change has a significant impact on water quality deterioration and scarcity, which are serious challenges in developing countries and emerging economies. Often, effective projects to improve water management in the light of climate change are difficult to develop because of the complex interrelations between direct and indirect climate impacts and local perceptions of vulnerabilities and needs. Adaptation projects can be developed through a combination of participatory, bottom-up needs assessments and top-down analyses. Climate change impact chains can help to display the causal chain of climate signals and resulting impacts and thereby establish a system map as a basis for stakeholder discussions. This article aims to develop specific climate change impact chains for the water management sector in rural coastal India that combine bottom-up and top-down perspectives. Case studies from Tamil Nadu and Andhra Pradesh, India, provide a basis for the impact chains developed. Bottom-up data were gathered through a vulnerability and needs assessment in 18 villages complemented with top-down research data. The article is divided into four steps: (1) system of interest; (2) data on climate change signals; (3) climate change impacts based on top-down as well as bottom-up information; (4) specific impact chains complemented by initial climate change adaptation options.
- Methodology for risk assessment of flash flood events due to climate and
land-use changes: application to the Llobregat basin
- Authors: M. Velasco; À. Cabello, I. Escaler, J. I. Barredo A. Barrera-Escoda
Abstract: Global change, including climate, land-use and socio-economic changes, is expected to increase the stress on the entire water cycle. In the Mediterranean region, extreme events are likely to increase due to climate change. This work, framed in the EC Seventh Framework Programme project IMPRINTS, presents a methodology to obtain future flood risk maps using climate and land-use scenarios, identifying the new potential risk zones. The implementation of this methodology is applied to the Llobregat river basin case study. Two different special report on emission scenarios are used, and although the uncertainties are high, the results obtained are coincident: an increase of flood risk is observed in the whole Low Llobregat area. The climate changes affect the basin globally, increasing the risk homogeneously within the area considered. On the other hand, land-use changes represent urban growth in the floodplains, and hence, local risk increases are found in these spots.
- Assessing water demands and coverage sensitivity to climate change in the
urban and rural sectors in central Chile
- Authors: Francisco J. Meza; Sebastián Vicuña, Mark Jelinek, Eduardo Bustos Sebastián Bonelli
Abstract: Snow dominated basins in the subtropics are susceptible to climate change, since evaporation and streamflows are affected, impacting key water sectors and increasing the risk of water shortages. This paper shows an integrated assessment of the impacts of climate change on the major water users in the Maipo Basin of Chile, allowing a direct comparison between competing sectors, describing their sensitivity to future climate changes instead of focusing on individual scenarios, and assessing the effect of likely responses, such as pumping, that impact groundwater levels. We developed a statistical downscaling mechanism to correct biases in global circulation model projections and ran a hydrological model to determine the impacts of climate change on the ability of the system to meet water demands. Mean coverage and minimum coverage of urban and agricultural sectors are sensitive to climate change, particularly to larger changes in precipitation. The urban sector is less sensitive because of higher reliability standards and holds a greater fraction of water-use rights in comparison to actual withdrawals. In addition, groundwater pumping represents an additional source of water to meet population demands. However, this favorable condition could no longer be present if climate change also affects aquifer recharge dynamics.
- Effects of changes in climatic variables on maize crop water requirements
in Huang–Huai–Hai watersheds, China
- Authors: Xinli Mou; Xinghui Xia, Daoyi Gong, Qiang Liu, Qiong Wu Jia Guo
Abstract: The study of crop water requirements (CWR) under climate change is critical for reasonable crop irrigation. In the present study, the effects of changes in climatic variables from 1961 to 2010 on maize CWR in Huang–Huai–Hai (HHH) watersheds in China were investigated. Five daily climatic factors including maximum temperature (T
max), minimum temperature (T
min), wind speed (u
2), sunshine hours (n
sun), and relative humidity (RH) from 121 weather stations during the maize growing season were studied. The Penman–Monteith method was employed to calculate crop evapotranspiration (ETc
), and the spatiotemporal distribution characteristics of ETc
and climatic factors were investigated via singular value decomposition. Results showed that the ETc
of spring maize slightly increased by 0.4% during the past 50 years, which was primarily caused by the increase in T
max. The ETc
of summer maize decreased by 10.5%, which was primarily caused by the decrease in n
sun and u
2. Overall, the ETc
followed the same spatiotemporal change trend as those of T
sun, and u
2 in the HHH, whereas no coexisting spatiotemporal change between ETc
and RH, as well as T
min, was observed. This result suggests that changes in T
sun, and u
2 are the main climatic factors that influence maize CWR in the HHH.
- Water and energy futures for Melbourne: implications of land use, water
use, and water supply strategy
- Authors: S. J. Kenway; G. M. Turner, S. Cook T. Baynes
Abstract: This paper quantifies the effect of three policy levels on the water and energy futures of Melbourne, Australia. During a time of severe water shortages attributed to climate change, water strategies lacked consideration of energy consequences. Modeling, guided by urban metabolism theory, demonstrated that a compact urban form, reduced water consumption by 90 GL/a, compared with a sprawling city, and had greater water conservation impact than simulated demand management measures. Household water conservation, coupled with increased use of solar hot water systems, reduced grid energy use by some 30 PJ/a. Desalination, tripled water supply energy demand, growing to a total of 4.5 PJ/a, by 2045. While the increase is less than 1% of total Melbourne urban energy use, it contributes to a substantial increase in the energy bill for urban water provision. Importantly, the energy impact could be offset through demand management measures. Recommendations for the combined management of water and energy include improving energy characterization of the urban water cycle; impact-evaluation of regional plans; using total urban water and energy balances in analysis to provide context; and developing reporting mechanisms and indicators to help improve baseline data across the water and energy systems.
- Optimal sampling network for monitoring the representative water quality
of an entire reservoir on the basis of information theory
- Authors: Changhyoun Lee; Kyungrock Paik Yosang Lee
Abstract: This study presents a method for optimal selection of sampling stations for representative and effective water quality monitoring of a reservoir on the basis of information theory. We adopt an objective function used for the design of other hydrological monitoring networks such as rain gauge networks. Unlike rain gauges, in which only a single variable of rainfall is of interest, water quality monitoring stations measure multiple water quality variables. To consider this nature, a new concept of multi-variate weighted total information is proposed. This allows us to consider the relative importance between multiple water quality variables in the design of water quality monitoring networks. The proposed methodology is applied to Lake Yongdam, South Korea, where water quality has been extensively observed at several points. The optimal combination of sampling sites selected with the proposed method is found to show little redundancy in comparison with a previous independent study that presents statistical analysis of the same dataset. Further, the water quality data averaged over all stations are very close to those averaged over the selected sites only, implying that the optimal combination of sampling sites is representative of all sites.
- Irrigation demand modelling using the UKCP09 weather generator: lessons
- Authors: Michael Green; E. K. Weatherhead
Abstract: The determination of irrigation demand is typically based on crop modelling using a long historic record of local daily weather data. However, there are rarely adequate weather station records near to given sites; often any local records cover a limited number of years, are incomplete, costly or are of poor quality. This paper examines whether version 1 of the UKCP09 weather generator can provide a simpler and effective method of calculating irrigation demand with sufficient accuracy for regulatory and design purposes. The irrigation demands at seven sites distributed around England were modelled using the UKCP09 baseline climatology and compared with results modelled using daily observed weather records. For the design dry year used for irrigation planning, the weather generator replicated the observed conditions with reasonable accuracy. The weather generator was however less successful at replicating extreme dry years. These results are encouraging but also provide a note of caution for the use of these generated datasets for studying current irrigation demand and by implication for modelling future needs under climate change. The study also demonstrated a simple sub-sampling approach for reducing the processing demands if using the dataset in more complex models, though this would not remove any underlying error.
- A methodology for quantifying global consumptive water use of coffee for
sustainable production under conditions of climate change
- Authors: Nishadi Eriyagama; Yann Chemin Ranjith Alankara
Abstract: Coffee is the second most traded commodity in the world after oil. A sustainable coffee industry is crucial to maintaining global agriculture, trade, human and environmental well-being, and livelihoods. With increasing water scarcity and a changing climate, understanding and quantifying the risks associated with water, a primary input in coffee production, is vital. This methodological paper examines the means of quantifying: (a) ‘current’ consumptive water use (CWU) of green coffee (coffee beans at harvest time) globally; (b) coffee ‘hot spots’ and ‘bright spots’ with respect to levels of CWU, yields and water stress; and (c) possible impacts of climate change on the CWU of coffee. The methodology employs satellite-derived monthly evapotranspiration data and climate projections from two global circulation models for three future scenarios. Initial estimates suggest that currently (on average) 18.9 m3/kg of water is consumed in producing one unit of green coffee. The same estimate for irrigated coffee is 8.6 m3/kg, while that for rain fed coffee is 19.6 m3/kg. Climate scenarios show that effective mean annual rainfall in many major coffee areas may decrease by the 2050s. The generic methodology presented here may be applied to other crops, too, if crop data are available.