Effect of Climate Change on Streamflows in the Mahanadi River Basin,India

ABSTRACT

In wet tropical regions, study of climate warming effects on water resources is important due to the socioeconomic and ecological implications. Observed changes in river flows of a major Indian river basin called the Mahanadi during the period 1926–1980 arepresented in relation to climatic changes that have occurred there. The Mahanadi River Basin is located in the monsoon region of India; its area is 141,600 km² and its mean annual flow is 66,640 million m³ . An earlier study by the author revealed that the surface air temperature over the basin has increased at a rate of 1.1 C° per century, which is highly significant However there has been no considerable change in the precipitation regime, though a slight decreasing trend is observed. In this article, an analysis of the trends in the runoff of the upper catchment and the whole catchment gauged at Hirakud and Naraj is presented. The results show a steady decrease in the river flows at these locations during the 55 year period of the study; this is significant statistically at the 1 per cent level. In order to increase confidence in this result, the moisture indices for the catchment have been computed and examined. Time series of these indices also show a clear declining trend during the period 1901–80. The main result obtained here is that climate warming that occurred over the basin, without being offset by an increase in precipitation (in fact a slight decrease in precipitation was observed), has resulted in a gradual decrease of river flows of the upper catchment as well as of the entire basin during the period 1926–1980. As a backdrop to future climate change scenarios over the Indian region, studies related to its impacts on water resources in the basin are important. However General Circulation Models (GCMs) at present are not capable of simulating adequately at regional and subregional scales. Nevertheless, it is hoped that recent efforts toward development of nested regional climate models may soon make it possible to have acceptable climate simulations for regions and subregions of this scale. The results of this article may be useful at that stage in hydrological forecasting studies for the basin.     

Unraveling transboundary water security in the arid Americas

ABSTRACT

Transboundary waters are characterized by diverse and complex socio-politico-economic obstacles to effective water management. We examine five distinct cases in the arid Americas – in locations from the US–Mexico border to the Andes mountains – employing water security as a conceptual prism to unravel the multiple and varied attributes of transboundary water challenges. We describe how borders complicate water security in arid regions and explore how institutional arrangements and practices – within and across jurisdictions – respond to these challenges. We find that institutional capacity is needed on multiple levels for effective water management, and institutions must be responsive and flexible to change.     

Bacteriological Quality of Rainwater in Roof and Ground Catchment Systems in Botswana

ABSTRACT

Bacteriological analyses were conducted on water samples from 13 roof tanks and 8 ground catchment tanks in Botswana in 1983. The results show that rainwater collected from corrugated iron roofs and stored in covered tanks is of high quality compared with traditional water sources and could provide a safe drinking water supply. The results for the ground catchment tanks, however, indicated that the water posed a serious health hazard. This is significant since several hundred ground tanks are already being used to provide water for other things besides human consumption. Since more ground tanks are planned both in Botswana and elsewhere in Africa the fencing of the catchment area and the use of simple sand and charcoal filters are recommended as the most practical means of insuring improved water quality in ground tanks.     

Water security and the pursuit of food,energy, and earth systems resilience

ABSTRACT

This article addresses the emergence and interrelation of food, energy, and water security in terms of resource use and the ensuing societal and environmental outcomes. For decades, food security and energy security have been well-accepted, operational concepts. Water security is the latest entrant, yet the implications of water insecurity for food, energy and earth systems resilience have not been adequately considered. This article examines how and why this is so – particularly with growing water scarcity and insecurity that may compete with energy and food security – and emphasizes the critical need to link water-energy-food nexus approaches to earth systems resilience.     

GIS and Multi-Criteria Evaluation: Robust Tools for Integrated Water Resources Management

Abstract

Integrated water resources planning and management are considered very complex issues. These issues are usually addressed through the multi-sectoral, interdisciplinary and hierarchal decomposition approaches. In general, integrated resource management indicates the consideration of water, social, socio-economic, economic and environmental issues. The current study aims at merging the GIS and Multi-Criteria Evaluation (MCE) techniques for the integrated water resource management of a cropped area. An area of about 120,000 Hectares located in the Northern Nile River Delta area with a coastal zone on the Mediterranean was selected and GIS was applied to represent the area's different environment, social, economic, and water factors. Different randomization cropping pattern distribution scenarios were proposed. Through the merging of GIS and MCE approaches, three scenarios were run and evaluated at three different levels: farm, canal catchment area and whole area. This merging resulted in a very powerful tool for the evaluation of different plans. The merging of GIS and MCE really facilitated the decision making process for these types of integrated water management problems.     

Reservoir Sedimentation in India—Its Causes,Control, and Future Course of Action

ABSTRACT

A survey of Indian reservoirs has shown that they receive on an average about 200 percent more sediment than the design inflow. The causes are the usual, except that they are operating very intensely. In brief ‘misuse and mismanagement’ of the catchment area will describe the causes of higher rates of sedimentation.

Fortunately India is very much aware of this problem and a lot is being done by identifying the priority areas for treatment and implementation of programmes to reduce soil erosion and sediment generation.

While techniques and efficacy of various biological and structural control measures are well known, it is the policy and planning aspects which need greater attention at present. Some of them are:

—It is important that policy and planning should aim at developing the catchment area, reservoir and command area as a package.

—In the developing world sediment is the greatest pollutant and it must be recognised and treated as such.

—A policy for effective water resource and hydropower development, watershed and command area development must take into account the short term and long term, direct and indirect, private and social benefits, and endeavour to involve the people and the employees in such a way that they feel committed to efficient and effective implementation.     

Synthetic Unit Hydrograph for Al Fara'a Catchment in the West Bank

Abstract

Synthetic unit hydrographs are frequently used to estimate hydrograph characteristics when observed data are not available. A number of synthetic unit hydrograph approaches are available, but the ones that found widespread use are those based on models of Snyder, Clark, and the U.S. Soil Conservation Services (SCS). The major goal of the study is to develop a synthetic unit hydrograph for Wadi Al Fara'a Catchment, which is un-gauged and considered one of the West Bank's most important catchments. Unfortunately, none of the wadis in the West Bank are gauged and flow records are not available; therefore, it is hoped that this method will be applied successfully for Wadi Al Fara'a catchment and the results can hopefully to be applied to all West Bank catchments, which will facilitate estimation of potential runoff in the whole West Bank.     

GIS Based Estimation of Sediment Discharge and Areas of Soil Erosion and Deposition for the Torrential Lukovska River Catchment in Serbia

In the present study the SHETRAN river basin modelling system was used in conjunction with Geographic Information System (GIS) to estimate potential erosion and deposition rates within the catchment and the concentrations of sediment in a flow at the catchment outlet on the example of the 114.31 km² mountainous torrential Lukovska River catchment in Serbia. The streams in the Lukovska River catchment are short, steep and often produce hazardous torrential floods as a consequence of strong rainfall of short duration. The soil erosion and sediment discharge were analysed in view of the catchment response to physical characteristics of the catchment. Considering that the most of total annual sediment discharge in watersheds of torrential character is achieved during storm events, the SHETRAN modelling system was calibrated on the example of a storm event in 1986 and validated for three other storm events in 1974, 1976 and 1979. The simulated results of discharges and sediment concentrations at the catchment outlet for both calibration and validation events were compared with the observed data and found to be reasonable. The changes of erosion and deposition rates within the catchment and in the course of time were estimated for the calibration event in 1986. The simulated erosion rates were within the range of 1 to 10.5 t/ha and corresponded to the observed rates of erosion in Europe during extreme rain events. The presented methodology is useful in identifying the erosion vulnerable regions in a catchment where erosion control measures should be implemented.     

Integrated Catchment Management in China

Abstract

As industries develop and waste discharge increases in China, the water quality in many rivers becomes a serious issue. Although the Chinese government has taken river pollution control as the top priority in enviornmental management, pollution still occurs in many locations regularly. One of the reasons is that the policy used for pollution control in China is more or less like “cure the problems, but not take radical measures.” An integrated catchment management (ICM) approach has been implemented in Australia as a fundamental measure for resource management and water pollution control since the 1980s. The ICM approach has been proved to be an effective means for pollution control in Australia. Is it possible to use the ICM approach in China? This paper describes an investigation on the possibility by comparing the conditions for implementing ICM programs in Australia and China. It is suggested that the Australian ICM model cannot be directly used in China because of: (1) difficulty of coordinating authorities at different levels, (2) unclear ownership of resources, (3) small farming scales, and (4) poor education of resources users. However, it may be possible to implement the ICM approach in China by: (1) establishing a clear ownership system of resources (land, water, and vegetation), (2) extending the function of existing catchment management committees, (3) establishing strong acts of catchment management, and (4) establishing monitoring and audit systems for resource use andconservation. The detailed implementation procedure for China needs to be further studied.     

Regional Water Supply Planning with Renewable Energy Technologies: The Case of Senegal

ABSTRACT

In order to plan for the installation of renewable energy technologies in the water supply sector in developing countries, an evaluation of the countries' renewable energy resources must first be made. It is then necessary to match the energy resources with the operating characteristics of the appropriate technologies. When these two stages have been completed, planning can proceed for a national program of renewable energy technology development. The example of Senegal is presented in terms of wind, solar and rainfall resources. Technologies considered are wind energy conversion systems (WECS), rainwater catchment systems (RWCS), hand pumps and solar pumping systems     

Management of Sediment in New South Wales,Australia

ABSTRACT

The amount of sediment in major New South Wales rivers and reservoirs is relatively low compared to world averages. This is a result of relatively low erosion rates, the sediment coarseness and numerous sediment sinks between the erodingparts of catchments and the rivers and reservoirs. However, in some locations several problems have required attention. These include: sediment blockage of roads and culverts; sedimentation of small reservoirs and recreational lakes; sedimentation on large alluvial fans; river channel damage casued by low sediment supply; and lack of effective government control over soil erosion and sedimentation in the past. Strategies to overcome these problems start with information collection to pinpoint major problems. This enables the preparation of total catchment management plans. These require proper land-use policies, legislation and education of the public for effective implementation.     

Design and Implementation Experience of an Australian Prototype Catchment Information Exchange Program

Abstract

Information access and exchange for catchment management is problematic. There are problems about how people use information in decision-making, who makes the decisions, and how information should be organized, located, and accessed to help decision makers. There is uncertainty about how catchment management organizations access, use, exchange, and spread information to people in their catchment. This paper outlines a solution to this problem. It is the second of two papers and presents the results of a research project reported earlier in Water International. This paper discusses how a prototype Catchment Information Exchange Program (CIEP) was developed as a result of the needs articulated by stakeholders and the outcomes of the research undertaken in two Australian field sites. The CIEP includes a Catchment Information System (CIS) which includes relational databases located on the Internet and CD-ROM. The paper also discusses issues and the lessons learned in the process of prototype design, field testing, and implementation. Implementation issues included: lack of coordination mechanisms, lack of long term funding, lack of leadership to build regional information exchange protocols and processes, institutional lethargy, and the scepticism by government of farmers' best practices, loss of scientific ownership of project results by researchers, and unwillingness to handle co-managed, co-owned information management systems. However, in the catchments where the program was piloted, there was considerable enthusiasm for the CIEP. A critical issue is to get a long-term sustained funding mechanism in place to enable expansion of the program.     

Appraisal and Assessment of World Water Resources

Abstract

A critical analysis of the present situation on the global water resources assessment is made. Basic data and methodological approaches used by the author for the assessment and prediction of water resources, water use and water availability on the global scale are briefly described. On the basis of data generalization of the world hydrological network new data are given on the dynamics of renewable water resources of the continents, physiographic and economic regions, selected countries as well as on the river water inflow to the world ocean. The results of the assessments for the 20^th century and for the future before 2010–2025 on the water supply for municipal, industrial and agricultural needs as well as an additional evaporation from reservoirs are presented. Loads on water resources and water availability depending on socio-economic and phisiographic factors are analyzed; regions of water scarcity and water resources deficit are discovered. Possible ways of water supply improvement and elimination of water resources deficit in different regions and countries are discussed     

Overland Flow on a Pervious Surface

ABSTRACT

This article presents the analytical solutions for overland runoff hydrographs produced by a uniform rainfall with decay soil infiltration rates. It was found that the kinematic wave travel time through a catchment under such a nonuniform rainfall excess is not a constant, but varies between the time of concentration and the time of equilibrium according to the soil moisture condition. The analytical solutions reveal that kinematic wave travel times are part of the hydrograph convolution process and can hardly be measured from observed hydrographs. The findings of this article suggest that the time of concentration of a small catchment shall be estimated by velocity-based methods rather than those empirical formulas developed for and calibrated by the time difference between the center of mass of the rainfall excess and the inflection point on recession of the observed runoff hydrograph.     

Guyana, “Land of Waters,” Moves to Harness Hydro Potential

ABSTRACT

Heavy metal concentrations (cadmium, chromium, lead, zinc) in 46 cistern water supply systems from single-family dwellings on St. Maarten, Netherlands Antilles were considerably below US drinking water limits in most cases. Release of zinc, lead, and cadmium in the distribution system, which is not related to the corrosiveness of the cistern water, caused lead and cadmium to exceed the US Public Health Service standard for 3 (6.5%) and 1 (2.2%) of the cisterns, respectively.

The following recommendations are suggested for protecting the roof catchment drinking water supply against heavy metal contamination:

? engineer the withdrawal of cistern water to exclude the metal-laden sediment

? identify appropriate paints to be used for cistern collection systems

? install substituted materials, protective coatings, and replacement of corroded metal parts in the distribution system

? discourage the usage of metal containers (e.g., oil) for prolonged water storage

? expand cistern water quality analyses to include lead

? exercise plumbosolvency control by treating the cistern water before distribution.

These recommendations, based on the case study, also apply to other areas of the world where cisterns of similar construction are used or are being planned.     

Catchment Flood Management

Abstract

In recent years, there has been a growing concern worldwide about climate change and the corresponding apparent increase in the risk and frequency of flooding and about the implications for a wide range of river basin management issues. This paper describes the United Kingdom government's approach to implementing Catchment Flood Management Plans (CFMPs), which will provide a large-scale strategic planning framework for the integrated management of flood risk to people and the development of the natural environment in a sustainable manner. This unified approach is to be adopted across England and Wales, with a view to establishing a unified framework to study flood management in each major catchment. Following on from this introduction to the U.K. approach to high-level flood management, details are given of a study where better water quality management during flood flow conditions has been shown to require a catchment-wide approach to reducing diffuse source pollution from agricultural regions. This study also shows that without this holistic approach to water management, a major cause of non-compliance with an EU Directive would not have been established for this river basin.     

FingerPro: an R Package for Tracking the Provenance of Sediment

Soil loss by erosion processes is one of the largest challenges for food production and reservoir siltation around the world. Information on sediment, nutrients and pollutants is required for designing effective control strategies. The estimation of sediment sources is difficult to get using conventional techniques, but sediment fingerprinting is a potentially valuable tool. This procedure intends to develop methods that enable to identify the apportionment of sediment sources from sediment mixtures. We developed a new tool to quantify the provenance of sediments in an agroforest catchment. For the first time, the procedure for the selection of the best combination of tracers was included in the tool package. An unmixing model algorithm is applied to the sediment samples to estimate the contribution of each possible source. The operations are compiled in an R package named FingerPro, which unmixes sediment samples after selecting the optimum set of tracers. An example from a well-studied Mediterranean catchment is included in the package to test the model. The sediment source apportionments are compared with previous results of soil redistributions where ¹³⁷Cs derived rates validate the unmixing results, highlighting the potential of sediment fingerprinting for quantifying the main sediment provenance. Fingerprinting techniques will allow us to better comprehend sediment transport to water ecosystems and reservoirs and its detrimental effect on the quality of the water and aquatic habitats. The FingerPro package provides further understanding of the unmixing procedure through the use of graphical and statistical tools, offering a broader and easier application of the technique.

     

The storage and provenance of fine sediment on the channel bed of two contrasting lowland permeable catchments,UK

Fine sediment (<63 µm) storage in river channels frequently represents a significant term in catchment sediment budgets and plays an important role in diffuse pollution problems. A combination of a sediment remobilization technique and the fingerprinting approach was used to examine the storage and provenance of fine sediment on the channel bed of two contrasting lowland permeable catchments in the UK. In the upper Tern (∼231 km²) study catchment, estimates of mean fine sediment storage on the channel bed ranged between 860–5500 g m⁻², with an overall average of 2391 g m⁻², compared to 470–2290 g m⁻² and 1065 g m⁻² in the Pang (∼166 km²) and 770–1760 g m⁻² and 1255 g m⁻² in the Lambourn (∼234 km²) sub‐catchments. Mean total fine sediment storage on the bed of the main channel was equivalent to 37% (upper Tern), 38% (Pang) and 21% (Lambourn) of the mean annual suspended sediment loads measured at the catchment outlets. Over the study period, the total gain (1427 t) and loss (1877 t) to fine sediment storage on the channel bed in the upper Tern catchment were equivalent to 82% and 108% of the mean annual suspended sediment load, respectively, compared to 149% (740 t) and 136% (678 t) in the Pang sub‐catchment, and 39% (422 t) and 49% (528 t) in the Lambourn sub‐catchment. The source of the fine sediment stored on the channel bed within each study area varied. In the upper Tern catchment, the weighted mean relative contributions from individual source types were estimated to be 35 ± 5% (pasture), 51 ± 5% (cultivated) and 14 ± 3% (channel banks and subsurface sources). The corresponding estimates were 49 ± 8%, 33 ± 5% and 18 ± 5% for the Pang sub‐catchment, compared to 19 ± 6%, 64 ± 5% and 17 ± 5% for the Lambourn sub‐catchment. These sediment source estimates have important implications for the design and implementation of targeted sediment control policies within the study areas. Copyright © 2007 John Wiley & Sons, Ltd.     

Estimation of Potential Soil Erosion for River Perkerra Catchment in Kenya

River Perkerra catchment with an area of 1207 km² is drained by River Perkerra, which is one of the rivers flowing into Lake Baringo whose drainage area is 6820 km². The lake is in a semi-arid area of Kenya. Its depth has reduced from 8 m in 1972 to 2.5 m in 2003 due to siltation resulting from high erosion rates in the catchment. The entire catchment is characterised by very steep slopes on the hillsides and gentle slopes in the middle and lower reaches where the surface is bare with very little undergrowth. Interventions to control soil erosion in this fragile ecosystem have been limited partly because of lack of data on erosion and its spatial distribution. In the present study, Universal Soil Loss Equation (USLE) was used in conjunction with GIS Arc/Info and Integrated Land and Water Information Systems (ILWIS) to estimate potential soil loss from River Perkerra catchment. Various physical parameters of the equation were derived by analysing spatial data and processing Landsat TM satellite imagery of the catchment. The estimated potential soil erosion from the catchment was 1.73 million tonnes/year while the sediment yield at the catchment outlet was found to be 1.47 million tonnes/year. The sediment delivery ratio derived using an empirical equation was 0.83. This figure indicates that a higher proportion of sediments generated in the catchment is delivered at the outlet. The use of GIS enabled the results of erosion potential to be mapped back onto the catchment. This is useful in identifying priority areas that require urgent management interventions in controlling soil erosion.