Periods Of Water Scarcity Research Articles

Drought tolerance versus drought avoidance: A comparison of plant-water relations in herbaceous wetland plants subjected to water withdrawal and repletion

ABSTRACT Wetlands are the intermediate between terrestrial and open water systems, and are thus fundamentally tied to changes in water table. Under normal climate conditions, wetlands may experience short periods of water scarcity through seasonal variations in precipitation or surface water run-off. However, during anomalous drought episodes, wetland plants may experience elevated water stress resulting in considerable decreases of both productivity and survival. Despite the intricate relationship between wetland macrophytes and water supply, little is known about the physiological responses of these plants to short-term water deficits. Therefore, the purpose of this study was to evaluate the effects of simulated drought on plant water relations in five herbaceous wetland species (monocots Carex alata, Juncus effusus, Peltandra virginica, and dicots Saururus cernuus, Justicia americana). In general, plant response to water deprivation may include drought avoidance (e.g., changes in stomatal conductance, ...

Assessment of the effects of oil spillage on groundwater in an inland basin of southeastern Nigeria

The heavy presence of hydrocarbons, reduced dissolved oxygen and high conductivity values inform the contamination of a local groundwater resource by an oil pipeline spillage in Isukwuato Local Government Area of Abia State. Monitoring the impact on a spring water source 90m downstream of the spill point showed that the oil spill migrated advectively with the groundwater of a shallow unconfined aquifer below, and that the effects were heaviest within the first two months of the spill. The effects then began to diminish with time and became only traces in the nineteenth month of the spillage. This would mean a long uncomfortable period of water scarcity for a people with no alternative source of water supply. International Journal of Natural and Applied Sciences Vol. 2(1) 2006: 19-23

Effects of irrigation on the water and energy balances of the Colorado and Mekong river basins

An irrigation scheme, based on simulated soil moisture deficit, has been included in the variable infiltration capacity macroscale hydrologic model. Water withdrawals are taken from the nearest river, or, in periods of water scarcity, from reservoirs. Alternatively, water can be assumed freely available. The irrigation scheme successfully simulates crop consumptive water use in large river basins. In general, irrigation leads to decreased streamflow and increased evapotranspiration. The locally significant increases in evapotranspiration (or latent heat) results in lower surface temperatures, and hence decreased sensible heat flux. Simulations performed for a 20-year period for the Colorado and Mekong river basins indicate irrigation water requirements of 10 and 13.4 km 3 year −1, respectively, corresponding to streamflow decreases of 37 and 2.3%. The increase in latent heat flux is accompanied by a decrease in annual averaged surface temperatures of 0.04 °C for both river basins. The maximum simulated increase in latent heat flux averaged over the three peak irrigation months for one grid cell is 63 W m −2, where surface temperature decreases 2.1 °C. Simulated actual water use is somewhat less than simulated irrigation water requirements; 8.3 and 12.4 km 3 year −1 for the Colorado and Mekong river basin, respectively.

Two-dimensional modelling of habitat suitability as a function of discharge on two Colorado rivers

The quantity of water that should be retained in streams and rivers for the benefit of fish during periods of water scarcity is a question of considerable interest to river managers and biologists. Although instream flow methodologies have existed since the 1970s, no single method has been widely accepted for use on large warm-water rivers because of their high species richness and generalized fish habitat use patterns. In this paper, we present an approach similar to instream flow incremental methodology, but which uses two-dimensional flow models and biomass estimates derived from multiple sites on two Colorado rivers for predicting the effect of discharge on adult standing stocks of two native fish species. Suitability criteria are developed for bluehead and flannelmouth sucker (Catostomus discobolus and C. latipinnis) by comparing adult biomass in individual meso-habitat units with modelled depths and velocities. We find that roundtail chub (Gila robusta) biomass is not correlated with depth and velocity, but appears to be positively associated with indices of habitat heterogeneity. Species biomass and total usable habitat area are predicted as a function of discharge for each site and data show good correlation between predicted and measured biomass. Results suggest that the Colorado and Yampa Rivers have similar potential for native fish biomass, but low summer discharges limit native fish biomass on the Yampa River. Copyright © 2005 John Wiley & Sons, Ltd.

Informal network utilisation and water distribution in two districts in the Khorezm Province, Uzbekistan

This paper analyses informal networks and their utilisation during a period of water scarcity in an upstream and a downstream district in the Khorezm Province, Uzbekistan. The evaluation is based on an organisational theory approach on informal networks. Communication patterns between farm managers, district water departments and district governors in a year with a sufficient amount of water and in a year of water scarcity are compared with informal network structures. The analysis shows that in the year of water scarcity an informal network was utilised to receive water. The importance of the informal network increased with increasing experience and individual perception of water scarcity. The findings confirm the assumption that informal networks are utilised more frequently when formal networks fail or are not functional. The case study therefore confirms the importance of an informal network during a crisis.

Water needs and women's health in the Kumasi metropolitan area, Ghana

This paper examines the impact of water fetching by women and the quality of water during periods of water scarcity on the health of women in the Kumasi metropolitan area. A sample of 210 women drawn using systematic random procedure is used for the study. Formal interview is the main instrument used. The survey has established that income, quality of water, hours spent fetching water during scarcity and age are the main factors influencing women's health in the metropolis during water scarcity. In both the core and periphery, the water-related problem influencing health is hours spent fetching water during scarcity. An empirical model on water needs and women's health has emerged from the survey. Recommendations have been made on strategies to ensure regular volume of surface water, effective management of scarce water resources with the participation of women, and ensuring gender equity in domestic services.

THE OPPORTUNITY COST OF WATER FOR ENVIRONMENTAL USE DURING WATER SHORTAGES WITH REFERENCE TO THE VAAL RIVER SYSTEM

Optimal utilisation of water means inter aha that it must be allocated to the different usesiusers in such a way that the welfare of the community will be enhanced maximally. Necessary information for pursuing optimal allocation is knowledge about the value of water in different uses. An indirect method, the opportunity cost/alternative value method, is applied to assess the value of water for environmental use during a period of water scarcity.

The Effect of Water Deprivation on Renal Function in Conscious Unrestrained Gambel's Quail (Callipepla gambelii)

Adjustments of renal function can conserve significant amounts of water for terrestrial mammals and birds during periods of water scarcity. By measuring renal function in unanesthetized, unrestrained Gambel's quail (Callipepla gambelii) while normally hydrated (NH) and after 4-5 d of water deprivation (WD), we tested the hypothesis that these birds respond to water deprivation by decreasing their glomerular filtration rate (GFR), thus lowering urine flow and attendant water loss. Glomerular filtration rate averaged 17.7 mL/h in NH quail and declined to 7.7 mL/h in WD quail. Tubular reabsorption of fluids increased slightly as a result of water deprivation, but the primary renal mechanism for water conservation was reduction in GFR. When deprived of water, Gambel's quail did not reduce their GFR more, nor concentrate their urine more, than other avian species from more mesic habitats. Urine-to-plasma osmotic ratios averaged 1.6. Final adjustments in water content of the urine are likely made in the lower gastrointestinal tract because NH quail reflux urine from the cloaca into this region. However, as urine osmolality increases because of dehydration, the osmotic gradient between plasma and luminal contents of the lower intestine may eventually prevent solute-linked water flux from the intestine. We suggest that quail no longer reflux urine under such circumstances. We developed an allometric equation relating GFR to body mass for NH birds that predicts a GFR of 40.3 mL/h for a 158. O-g Gambel's quail, a value 2.3 times higher than measured. We suggest that the evolution of a conservative metabolic rate has permitted a reduction in GFR and attendant water loss by way of urine flow.