961 resultados para water use optimization
Resumo:
Ecological Water Quality - Water Treatment and Reuse
Resumo:
Abstract: Preferential flow and transport through macropores affect plant water use efficiency and enhance leaching of agrochemicals and the transport of colloids, thereby increasing the risk for contamination of groundwater resources. The effects of soil compaction, expressed in terms of bulk density (BD), and organic carbon (OC) content on preferential flow and transport were investigated using 150 undisturbed soil cores sampled from 15 × 15–m grids on two field sites. Both fields had loamy textures, but one site had significantly higher OC content. Leaching experiments were conducted in each core by applying a constant irrigation rate of 10 mm h−1 with a pulse application of tritium tracer. Five percent tritium mass arrival times and apparent dispersivities were derived from each of the tracer breakthrough curves and correlated with texture, OC content, and BD to assess the spatial distribution of preferential flow and transport across the investigated fields. Soils from both fields showed strong positive correlations between BD and preferential flow. Interestingly, the relationships between BD and tracer transport characteristics were markedly different for the two fields, although the relationship between BD and macroporosity was nearly identical. The difference was likely caused by the higher contents of fines and OC at one of the fields leading to stronger aggregation, smaller matrix permeability, and a more pronounced pipe-like pore system with well-aligned macropores.
Resumo:
Dissertação para obtenção do Grau de Mestre em Engenharia do Ambiente, Perfil de Gestão e Sistemas Ambientais
Resumo:
Dissertação para obtenção do Grau de Mestre em Engenharia Electrotécnica, Sistemas e Computadores
Resumo:
Introduction Schistosomiasis is endemic in 74 countries and is considered a serious public health problem in some locations. Methods A transverse study was performed of 13 landless settlements in southern Sergipe from February to December 2009. The study included 822 settlers, of whom 601 underwent stool testing. Results The prevalence of schistosomiasis in landless workers was 4.3%. The population has a low education level, and basic sanitation services are not available to all residents. Conclusions The prevalence of schistosomiasis was low in the population and among different settlements, possibly because of different forms of water use by the settlers.
Resumo:
In the Brazilian Amazon, large areas of abandoned lands may revert to secondary forest. In the process, pioneer tree species have an important role to restore productivity in old fields and improve environmental conditions. To determine potential photosynthesis (Apot), stomatal conductance (g), transpiration (E), and leaf micronutrient concentrations in Ochroma pyramidale (Cav. ex Lam.) Urban a study was carried out in the Brazilian Amazon (01o 51' S; 60o 04' W). Photosynthetic parameters were measured at increasing [CO2], saturating light intensity (1 mmol (photons) m-2 s-1), and ambient temperature. The rate of electron-transport (J), Apot,and water-use efficiency (WUE) increased consistently at increasing internal CO2 concentration (Ci). Conversely, increasing [CO2] decreased gs, E, and photorespiration (Pr). At the CO2-saturated region of the CO2 response curve (1.1 mmol (CO2) mol-1(air), J was 120 μmol (e-) m-2s-1 and Apot reached up to 24 μmol (CO2) m-2s-1. Likewise, at saturating C1 g and E were 30 and 1.4 mmol (H2O) m-2s-1, respectively, and P 2 r about 1.5 μmol (CO2) m-2s-1. Foliar nutrients were 185, 134, 50, and 10 μmol (element) m-2 (leaf area) for Fe, Mn, Zn, and Cu, respectively. It was concluded that [CO ] probably limits light saturated photosynthesis in this site. Furthermore, from a nutritional point of view, the low Fe to Cu ratio (15:1) may reflect nutritional imbalance in O. pyramidale at this site.
Resumo:
Dissertação de mestrado integrado em Engenharia Civil
Resumo:
Dissertação de mestrado integrado em Engenharia Civil
Resumo:
Dissertação de mestrado integrado em Engenharia Civil
Resumo:
Supplemental data for this article can be accessed at http://dx.doi.org/10.1080/07900627.2015.1070091. It includes an easy-to-use spreadsheet that calculates the efficiencies used in this paper, that is Sefficiency with energy considerations.
Resumo:
Syrian dry areas have been for several millennia a place of interaction between human populations and the environment. If environmental constraints and heterogeneity condition the human occupation and exploitation of resources, socio-political, economic and historical elements play a fundamental role. Since the late 1980s, Syrian dry areas are viewed as suffering a serious water crisis, due to groundwater overdraft. The Syrian administration and international development agencies believe that groundwater overexploitation is also leading to a decline of agricultural activities and to poverty increase. Action is thus required to address these problems.However, the overexploitation diagnosis needs to be reviewed. The overexploitation discourse appears in the context of Syria's opening to international organizations and to the market economy. It echoes the international discourse of "global water crisis". The diagnosis is based on national indicators recycling old Soviet data that has not been updated. In the post-Soviet era, the Syrian national water policy seems to abandon large surface water irrigation projects in favor of a strategy of water use rationalization and groundwater conservation in crisis regions, especially in the district of Salamieh.This groundwater conservation policy has a number of inconsistencies. It is justified for the administration and also probably for international donors, since it responds to an indisputable environmental emergency. However, efforts to conserve water are anecdotal or even counterproductive. The water conservation policy appears a posteriori as an extension of the national policy of food self-sufficiency. The dominant interpretation of overexploitation, and more generally of the water crisis, prevents any controversary approach of the status of resources and of the agricultural system in general and thus destroys any attempt to discuss alternatives with respect to groundwater management, allocation, and their inclusion in development programs.A revisited diagnosis of the situation needs to take into account spatial and temporal dimensions of the groundwater exploitation and to analyze the co-evolution of hydrogeological and agricultural systems. It should highlight the adjustments adopted to cope with environmental and economic variability, changes of water availability and regulatory measures enforcements. These elements play an important role for water availability and for the spatial, temporal, sectoral allocation of water resource. The groundwater exploitation in the last century has obviously had an impact on the environment, but the changes are not necessarily catastrophic.The current groundwater use in central Syria increases the uncertainty by reducing the ability of aquifers to buffer climatic changes. However, the climatic factor is not the only source of uncertainty. The high volatility of commodity prices, fuel, land and water, depending on the market but also on the will (and capacity) of the Syrian State to preserve social peace is a strong source of uncertainty. The research should consider the whole range of possibilities and propose alternatives that take into consideration the risks they imply for the water users, the political will to support or not the local access to water - thus involving a redefinition of the economic and social objectives - and finally the ability of international organizations to reconsider pre-established diagnoses.
Resumo:
Crans-Montana-Sierre is a tourist area locateci in Rhone valley in central Valais, cha-racterized by dry climate and scarce summer precipitations. More than other regions in Switzerland, this area has suffered the effects of the drought (heat wave) that affec¬ted all Western Europe during summer 2003. In the future, climate change together with societal and economic development will signicantly modify the water need of the region and, consequently, may increase the potential conflicts of interest. Within a long term planning strategy, decision-makers require precise information about the current amount of water needed in the region, with particular attention to temporal and spatial concentration, and the forecasted amount for 2050. This work therefore aims at estimating the variation of the water demand by taking into account the influence of climate change (CH2011) and socio-economic scenarios, developed in cooperation with the competent authorities. This thesis, whose aim is to study the water management and water uses is a core part of the MontanAqua project "Water management in times of scarcity and global change" mainly because of its interdisciplinary topic at the interface between water resources, land development and the socio-political structure. Results show that socio-economic development by 2050 could have a greater impact than expected climate changes (CH2011, A1B scenarios) for the same time horizon for water demand. Demography, spatial planning, tourism and economic development are just some of the factors that could significantly affect the water consumption of the Crans-Montana-Sierre region. Compared with the future water resources available, the maximal water demand forecasted by the socio-economic scenarios developed within the project MontanAqua, could not always be satisfied. This issue, like extreme climate phenomena (as it was the summer drought occurred in 2003 or in April / May 2011), could be mitigated adopting regional management policies relating to a more rational water use and preventive storage of water resource. - Crans-Montana-Sierre est une région touristique située dans la vallée du Rhône; dans le Valais central, qui se caractérise par un climat relativement pauvre en précipitations et qui plus que d'autres a subi les effets de la sécheresse qui a touché l'Europe occidentale durant l'été 2003. À l'avenir, les changements climatiques ainsi que le développement socio-économique modifieront de manière significative les besoins en eau de la région, ce qui risque de faire augmenter les rivalités d'usage concernant cette ressource. Afin de jouer à l'avance, les décideurs ont besoin d'informations précises sur la quantité d'eau nécessaire à la région, avec une attention particulière à sa concentration temporelle et spatiale, à l'heure actuelle et à l'horizon 2050. Ce travail vise donc à estimer la variation de la demande en eau en tenant compte de l'influence des changements climatiques (CH2011) et des scénarios socio-économiques, élaborés en collaboration avec les autorités compétentes. Cette thèse, qui met l'accent sur les usages de l'eau fait partie du projet Montan Aqua « Gestion de l'eau en temps de pénurie et de changement global », est à l'intersection entre les ressources hydriques, l'aménagement du territoire et son organisation socio-politique, fait qui la met, non pas par son importance, mais par son emplacement et ses interconnexions, au coeur de cette recherche. Les résultats obtenus montrent comment les développements socio-économiques d'ici à 2050 ont un impact potentiellement plus important que les changements climatiques prévus par les scénarios AlB de CH2011 pour le même horizon temporel sur la demande en eau. Démographie, aménagement du territoire et contexte économico-touristique, ne sont que quelques-uns des facteurs qui ont la capacité d'agir significativement sur les usages de l'eau en ce qui concerne les aspects qualitatif et quantitatif de la région de Crans-Montana-Sierre. Par rapport aux ressources en eau disponibles à l'avenir, la demande maximale d'eau prévue par les scénarios socio-économiques développés au sein du projet MontanAqua risque de ne pas être toujours satisfaite. Ce danger et la manifestation de phénomènes climatiques extrêmes, comme la sécheresse estivale survenue en 2003 ou celle d'avril/mai 2011, ne pourront être atténués que par l'adoption de politiques de gestion à l'échelle régionale favorisant une utilisation plus rationnelle et un stockage préventif de la ressource en eau.
Resumo:
The Summit Lake Watershed Improvement Project is a watershed-based sediment control project designed to greatly reduce to nearly eliminate sedimentation of an existing lake that is being renovated for use as a water source in southern Iowa. Summit Lake is owned by the City of Creston and was once a water source lake until around 1984. The watershed improvements will include lakeshore stabilization and erosion control practices as a precursor for related improvements to the lake and overall 4,900-acre watershed. Best practices included in this phase are the implementation of riprap, a rain garden, grade stabilization structures, grassed waterways, terraces, basins, water use and access ordinances, education and outreach, water monitoring, and other stream bank improvements. These improvements, along with leveraged work to be done by strategic partners, will enable the lake to be used for local and regional water supplies by sustaining the lake for many years to come. Without the lake rehabilitation, the lake will likely be filled with sedimentation to the point that it will have no recreational value. Key partners are the City of Creston, IDNR, Southern Iowa Rural Water Association, Union County, the Union County NRCS office, Southwestern Community College, and the Summit Lake Association, which is a non-profit group of landowners working to protect the lake. The project will address WIRB targets: a) streambank stabilization, b) livestock runoff, c) agricultural runoff and drainage, d) stormwater runoff, and e) a section of inadequately sewered community.
Resumo:
The objective of this work was to determine the critical irrigation time for common bean (Phaseolus vulgaris L. cv. Carioca) using infrared thermometry. Five treatments were analyzed. Canopy temperature differences between plants and a well-watered control about 1, 2, 3, 4, and 5±0.5ºC were tested. Physiological variables and plant growth were analyzed to establish the best time to irrigate. There was a significant linear correlation between the index and stomatal resistance, transpiration rate, and leaf water potential. Although significant linear correlation between the index and mean values of total dry matter, absolute growth rate, and leaf area index was found, no correlation was found with other growth index like relative growth rate, net assimilation rate, and leaf area ratio. Plants irrigated when their canopy temperature was 3±0.5ºC above the control had their relative growth rate mean value increased up to 59.7%, yielding 2,260.2 kg ha-1, with a reduction of 38.0% in the amount of water used. Plants irrigated when their canopy temperature was 4±0.5ºC yielded 1,907.6 kg ha-1, although their relative growth rate mean value was 4.0% below the control. These results show that the best moment to irrigate common bean is when their canopy temperature is between 3ºC and 4±0.5ºC above the control.
Resumo:
The objective of this work was to analyze gas exchange, photosynthetic characteristics, photochemical efficiency of photosystem II and anatomical characteristics of young plant leaves of two guarana (Paullinia cupana) clones (BRS-CG372RC and BRS-CG611RL) growing under open field. The variables of gas exchange and fluorescence of chlorophyll a were evaluated in mature leaves. The values of photosynthesis and transpiration found for BRS-CG372RC were 27% greater and 80% lesser than values found for BRS-CG611RL, respectively. The values of stomatal conductance found for the clones BRS-CG372RC and BRS-CG611RL were in the order of 224 and 614 mmol mm-2 s-1, respectively. The values of photorespiration, rate of carboxylation and rate electron transport were greater in BRS-CG372RC. The clone BRS-CG372RC exhibited stomatal density 26% greater than BRS-CG611RL. However, the area of ostiolar opening was 42% greater in BRS-CG611RL. The values of the water use efficiency in BRS-CG372RC were 134% greater than in BRS-CG611RL. High stomatal density and low stomatal conductance can be important characteristics in the selection of the clones with a good ability to assimilate carbon and optimize the use of water.