Water Resource

Knowledge of wetland hydrology and quantification of water inputs and outputs are Prerequisites to understanding wetland environments and determining their vulnerability to change. To get a better understanding of the dynamics of wetland change in the Usangu Plains, a study was conducted to: a) investigate the effects of human interventions on the wetlands, and b) determine the amount of dry season inflow required to maintain environmental flows downstream of the wetlands. The study integrated hydrologic data, remote sensing and GIS techniques to study the dynamics and spatial response of the wetlands. A monthly water balance model was developed for the wetlands to determine the major components of the water budget. The results of the analyses indicate that the wetlands have changed appreciably in size over recent years and the inflow volumes have decreased with time as a result of increased human interventions. The dry season vegetated swamp cover, a major component of the swamp, d...

This paper describes the methodologies adopted and the results obtained in assessing the groundwater resources of Metro Manila and Metro Cebu. Also some early and recent studies on the aquifer systems in the two metropolis are presented to draw some comparisons on the assessment and data acquisition methods and identify some gaps involved and the improvements needed. Some of the indicators used in assessing groundwater potential and associated problems include storage coefficient, transmissivity, safe yield, and salt water intrusion. The complex and expensive nature of actual field monitoring and analysis has encouraged the use of mathematical models in this study. Specifically, models adopted by NHRC and JICA were used and their respective capabilities, data requirements and modeling results for water balance are described. Although the two models have specific inputs unique to each model and the NHRC model used secondary 9 year data (i.e. 1982-1990) while JICA used one-year actual...

The objective of this research was to evaluate compaction of a Red-Yellow Latosol subjected to forestry traffic including two types of skidder: a wheeled-clambunk skidder and a tracked one. This study tries to remedy the lack of information on this subject, considering that mechanized traffic can result in several impacts on the environment. These impacts are related to soil compaction

Increasing demands on limited water resources have made wastewater reclamation for municipal irrigation an attractive option for extending water supplies in the semiarid Southwest. However, public concerns remain about the potential risks of human contact with reclaimed water used for irrigating public and recreational areas. This study focused on identifying public perceptions regarding wastewater reuse and how these may affect

Primary production on semiarid floodplains supports a diverse local and regional fauna. Reduced flooding from water resource development (WRD) may affect floodplain production by decreasing water and nutrient supply.We investigated the effects of reduced wetting on soil fertility by performing a regional soil survey across a gradient of flood frequency. Soil nitrogen (N), phosphorus (P) and carbon (C) were recorded over a soil-wetting event where heavy rainfall and flooding coincided.Soil nutrient concentrations indicate N limits plant growth and P does not.No spatial patterns in soil P were detected across the floodplain, suggesting that the principal mechanism controlling P fertility is the concentration of P in floodplain source material, and that flood mediated import and export of P are minor processes.Soil N concentrations rose following rainfall and flooding and the greatest increased occurred in flooded areas. Flood deposition of N accounted for only 9% of the boost in soil N in flooded areas, and N concentrations continued to rise when the floods and rains ceased. Elevated soil N levels do not appear to persist because at the start of a growth cycle, when soils were dry, soil N did not vary significantly with flood frequency. This suggests most of the boost in soil N was due to N-fixation, with the subsequent loss of N likely to have resulted from in situ processes such as denitrification.Agricultural export of nutrients appears to not be a significant process in the context of the high phosphorus fertility of floodplain source material and the apparently high rates of in situ processing of nitrogen.Synthesis and applications. Our data suggest that floodplain soil fertility is controlled by mechanisms other than flood frequency or agricultural export, meaning that WRD is unlikely to affect soil fertility; however, the biological implications of the brief pulse in soil N associated with wetting need further investigation.

In developing countries, the rapid urbanization in the second half of the twentieth century provoked radical changes in the cities with serious water related problems, such as freshwater scarcity, sewage and drainage problems. This growth produced several impacts on groundwater resources such as land impermeabilization and change in groundwater recharge, excessive exploitation and groundwater pollution. These facts have demanded better planning and management, especially in areas with high dense population. In Brazil, water legislation has been approved by parliament, a water agency has been created and technical knowledge of water resources has improved. Management strategies incorporated several issues: planning, legislation, zoning, licensing, concession and controlling. Monitoring, hydrochemical analyses and groundwater modeling have been performed to obtain more information for better management towards sustainability.

ORIGINAL ARTICLE Groundwater salinization processes in shallow coastal aquifer of Djeffara plain of Medenine, Southeastern Tunisia Rim Trabelsi • Kamel Abid • Kamel Zouari • Houcine Yahyaoui Received: 3 March 2010 / Accepted: 23 July 2011 Ó Springer-Verlag 2011 ...

Seventy-five percent of the available water resources in Malaysia are used for rice irrigation. Proper water management must be given due emphasis to effectively manage the water resources. This study analyzed field level practices, which could save irrigation water and thus increase area to be irrigated. The analyses were conducted for both the pre-saturation and normal supply periods using field data collected at the Besut irrigation scheme, Malaysia. Based on field water requirements and available flows at the intake structures, canal simulation was performed using the CanalMan model (Utah State University) together with water balance. The results have shown that pre-saturation should not be done continuously unless flow rates are at least 9.00 and 3.00 m3 s−1 for the Besut and Angga barrages, respectively. If the flow rate falls below these values, then pre-saturation should be done in two phases. However, when the flow rate is between 5.00 and 5.50 m3 s−1 at Besut barrage, pre-saturation should be done in three phases. The simulated schedules were compared with present pre-saturation schedules and it was observed that irrigable area could be increased by 10% than that at present. During the period of normal irrigation supply to the fields, there must be flow rates of at least 5.00 m3 s−1 and 1.50 m3 s−1 at the Besut and Angga barrages, respectively; in order to maintain irrigation supply to the whole irrigation scheme. Otherwise, selective irrigation or irrigation on a rotational basis will have to be enforced.

Water resources management is increasingly dealing with competing demands for fixed or diminishing available supplies. In this , the allocation and accounting of water consumption between competing users, including environmental uses, plays a critical role. Various software tools have been developed to cover aspects of water resources planning and allocation, operation, and catchment management. In line with the requirements of water management agencies, attention is turning to the development of integrated tools with a broad range of capabilities that include water resource planning under different climatic and allocation policies, water supply under various operating rules and user behaviour, and catchment management and ecosystem condition assessment under different management regimes. This paper describes a preliminary software structure for water allocation, planning and management, starting from the basic concepts of availability, supply, demand and accounting, and outlining t...

In southwestern Australia, karst features occur in geological formations other than the coastal calcarenites of the Tamala Limestone. The Noondine Chert was formed by the silicification of carbonate rocks and contains relict carbonate textures and palaeokarst features such as intense brecciation and the presence of subsurface voids. This geological formation is an important aquifer to the east of the Perth Basin where groundwater resources are otherwise limited, and the aquifer is highly vulnerable to contamination from agricultural land use. The Noondine Chert may also contain a rich stygofauna. This has not been taken into account in groundwater protection policies, and needs to be assessed as a matter of urgency. Karst in southwestern Australia is usually thought to be exclusively associated with variably lithified Quaternary calcarenites of the Tamala Limestone that are distributed near the coast between near Shark Bay and the south coast of Western Australia. Although the Tamal...

Efficient natural resources management, including continental water at watershed level, requires understanding the arrangement of landscape attributes in a region. The geographical analysis of landscape attributes is a useful approach to delineate relatively homogeneous watersheds or regions. This research was carried out in order to evaluate the effect of land cover through time on regionalisation modelling in the poorly-gauged Cuitzeo Lake Watershed, and to develop models to create two hydrogeographical regionalisations for the years 1975 and 2000. The inputs required by the regionalisation methodology were integrated in a GIS and validated before carrying out statistical regionalisation procedures (cluster analysis and PCA). GIS operations were done in Arc View 3.2 and statistical analyses in PC-ORD. Median Euclidean distances with mean distance linkage methods were used. A 75% of similarity was chosen as the threshold to generate regions. Importance rankings of regions were obtained using multicriteria evaluation methods. Based on the analysis, 38 of the 52 subwatersheds belonging to the Cuitzeo Lake Watershed were clustered; eight groups were defined in 1975 and nine in 2000. According to PCA, the strongest positive variables are associated to morphometric, geologic, land cover and soil attributes. Fourteen subwatersheds were never clustered. Four subwatersheds changed of cluster between 1975 and 2000. This change is explained because of rainfed agricultural parcel abandonment, and subsequent shrubland growth. This means that the hydrogeographical regionalisation is sensitive to land cover change processes. The methodological approach applied in this research is a low-cost and fast alternative for evaluating the impact of land cover and land use change on hydrogeographical regionalisation; in consequence, data and information generated during the analysis were made available to local authorities so that they can improve both water resources planning and their informational baseline for decision making and for development of environmental policies in the Cuitzeo Lake Watershed.

Diffuse pollution of water resources from agricultural sources is a major environmental issue in the European Union, and has been dealt with by specific legislation: the Nitrate Directive of 1991 and the Water Framework Directive of 2000. These attempts to provide a coordinated approach to solving environmental problems require methods and tools for spatial analysis and modelling on a continental scale, with river basins being used as spatial units. This paper presents a screening model (Ag-PIE), developed in a GIS environment, for the assessment of pressures from agricultural land use and the consequent impacts on surface and groundwater. Ag-PIE has been applied at the European scale (EU15), with focus on nitrogen pollution from chemical fertilisers and manure. The model adopts a multi-criteria evaluation procedure applied to spatial data layers which represent the variety of factors affecting the pollution process. The DPSIR (Driving forces, Pressures, State, Impact, Responses) approach is applied to provide the modelling approach with a conceptual framework and to further analyse and communicate results. Ag-PIE is ultimately aimed at providing a tool making use of state-of-the-art geographical databases to support policy-makers at the European level. The scale of reference adopted is the river basin, in particular those that extend across national boundaries. The quality of the results obtained has been assessed against existing related studies and monitoring reports and by means of sensitivity analysis. Conclusions are driven by considering the potential of Ag-PIE in devising policy support and its strengths and weaknesses in view of identifying future research needs.