Suchergebnisse

The increasing demand of water for different uses, together with the variable availability of this resource, which is due to the increasingly frequent periods of drought, make necessary to undertake a set of structural and contextual actions to cope with the permanent or temporary scarcity situations. Within the search for solutions to the progressively more widespread situation of limited water availability for agriculture, this paper aims to state the role that engineering can play to face up this deficit, taking into account the social, economic, and environmental issues of water, together with the priority of uses. Structural measures can help to:1) increase the water availability (increased or more flexible supply through reservoirs, water transfers, water rights interchange centres, desalination, reuse, aquifer recovery, and conjunctive use of surface water and groundwater), and 2) rationalize water consumption by improving demand management, including the irrigation management improvement, as well as maximizing the efficiency of irrigation systems. In addition to these measures, other social issues can be implemented through public awareness and education, adequate economic policies, legislative adaptation, and technical support to municipalities and water use associations. Thus, to face up water scarcity in a region it is necessary to identify the different water sources, including alternative sources such as desalination and reuse, and develop an appropriate model of management as well as infrastructure for water storage and regulation. ; La creciente demanda de agua para los distintos usos, junto con la variabilidad en la disponibilidad de este recurso debido a los cada vez más frecuentes periodos de sequía, hacen necesario llevar a cabo un conjunto de acciones estructurales y coyunturales para poder hacer frente a las situaciones de escasez temporal o permanente que se producen. Dentro de la búsqueda de soluciones a la situación cada vez más generalizada de limitada disponibilidad de agua para la agricultura, el presente trabajo pretende incidir en el papel que puede jugar la ingeniería a la hora de hacer frente a esta situación de déficit, teniendo en cuenta los aspectos sociales, económicos y ambientales del agua y sus prioridades de uso. Las medidas estructurales pueden contribuir a: 1) aumentar los recursos (aumento o flexibilidad de la oferta mediante embalses, trasvases, centros de intercambio de derechos de agua, desalinización, reutilización, recarga de acuíferos, o el uso conjunto de aguas superficiales y subterráneas), o 2) racionalizar los consumos (mejorando la gestión de la demanda, incluyendo la mejora de la gestión del regadío y la mejora de la eficiencia del riego en parcela). Además de estas medidas puede llevarse a cabo otras de carácter social como la concienciación y educación ciudadana, el fomento de políticas económicas adecuadas, la adecuación de la legislación, o la asistencia técnica a municipios y comunidades de regantes. En definitiva, para poder hacer frente a la escasez de agua en una región es necesario identificar las diversas fuentes de agua, incluidas las fuentes alternativas como la desalación y la reutilización, y disponer de un modelo adecuado de gestión, así como de las infraestructuras necesarias para su almacenamiento y regulación.

37 Pags.- 2 Tabls.- 10 Figs. The definitive version is available at: http://elibrary.asabe.org ; The experimental data used in the paper are OA available (http://hdl.handle.net/10261/127635) ; A variety of techniques have been proposed for sprinkler drop characterization. Two of them, the disdrometer method (D) and the low-speed photographic method (P), have recently been applied in the literature. A statistical method for the improvement of disdrometer measurements (DM) has been proposed to improve D measurements. The aims of this study were: (1) to compare the disdrometer and photographic methods under indoor conditions, (2) to produce a drop characterization data set, (3) to assess the effect of the statistical treatment of disdrometer data, and (4) to gain insight into the relationship between drop variables. The drops resulting from an impact sprinkler operating at 200, 300, and 400 kPa were characterized at distances of 3, 6, 9, and 12 m from the sprinkler. In each method, diameters responded to operating pressure and distance from the sprinkler according to the expected trends. The difference in volumetric diameter estimation between methods P and D amounted to -4% of the average P volumetric diameter. The application of DM to this data set increased the difference in volumetric diameter with method P to 15%. Drop velocity and angle could be measured with method P and showed clear relationships with drop diameter. Finally, regression equations are presented relating the most relevant experimental variables. The disdrometer resulted in fast measurements of drop diameter, while the photographic method provided additional variables but required intense work in the laboratory and particularly in the office. ; This research was funded by the Plan Nacional de I+D+i of the Government of Spain (Grant No. AGL2007‐66716‐ C03). Carlos Bautista‐Capetillo received a scholarship from the Agencia Española de Cooperación Internacional para el Desarrollo (AECID). ; Peer Reviewed