Search results for "water resources."

New, Rare and Constant Habitats for Endangered Aquatic Plant Communities: The Importance of Microhabitats for Global biodiversity

2019

Natural water reservoirs are very valuable floristic sites, with springs particularly important for the preservation of floral biodiversity. This paper presents, as a case study, a community of water plants that is new to limnocrene karst springs in Europe: Potametum alpini (Potametea), found in Poland. The paper provides the floristic composition and ecological requirements of this plant association, which is rare and endangered in Europe. According to our knowledge, the habitat data presented here are unique as they are published for the first time for this plant community, and thus it is currently not possible to compare them with data from other authors. Our study confirms the importanc…

Desalination. From a questioned resource to a necessary and strategic resource during drought situations for the water supply in the Segura River Bas…

2018

En España, la desalinización ha cobrado un gran impulso en las dos últimas décadas gracias a la aprobación en 2001 del Plan Hidrológico Nacional y en 2004 del Programa A.G.U.A. Ello ha sido motivado por dos factores principales: 1) Las recurrentes e intensas sequías en las últimas décadas, en especial, la de los años noventa en la que se puso de manifiesto la necesidad de la búsqueda de nuevas fuentes y la apuesta por los recursos hídricos no convencionales (desalinización y aguas regeneradas depuradas); y 2) Cambio del antiguo paradigma hidráulico basado en el incremento de la oferta mediante las transferencias de aguas. El objetivo de esta investigación es analizar el rol que ha desempeña…

Simulation versus Optimization in the assessment of the resource opportunity cost in complex water resources systems.

2009

Comparison between energy balance and mass balance models for actual evapotranspiration assessment

2009

The assessment of the water needs for a specific crop has a fundamental importance in the management of water resources. The application of empirical models able to retrieve estimates of the actual evapotranspiration (ETa) to assess the need for water could give a valid tool for the planning of water supply, avoiding unnecessary water losses. In this context, two independent models for estimating actual evapotranspiration were compared. The first model is based on an energy balance and uses remotely sensed data and ancillary data from weather stations to assess the ETa. The second model also uses remotely sensed data and climatic data on a daily basis from a weather network. Field measureme…

On Infiltration and Infiltration Characteristic Times

2022

In his seminal paper on the solution of the infiltration equation, Philip (1969), https://doi.org/10.1016/b978-1-4831-9936-8.50010-6 proposed a gravity time, tgrav, to estimate practical convergence time and the time domain validity of his infinite time series expansion, TSE, for describing the transient state. The parameter tgrav refers to a point in time where infiltration is dominated equally by capillarity and gravity as derived from the first two (dominant) terms of the TSE. Evidence suggests that applicability of the truncated two-term equation of Philip has a time limit requiring higher-order TSE terms to better describe the infiltration process for times exceeding that limit. Since …

Willingness to pay to improve urban water supply: the case of Sucre, Bolivia

2014

In this study the contingent valuation method is applied in order to estimate the willingness to pay (WTP) of the inhabitants of Sucre (Bolivia) for an improvement in the urban water supply system. The study finds that about 55 per cent of households would be willing to pay an increase in their water bill for an improvement in the service. In order to deal with the problem of protest responses and the possible presence of a sample selection bias, a Heckman two-step model was estimated. More specifically, the econometric analysis undertaken reveals that there is no evidence of sample selection bias and that WTP positively relates to the respondents' household income, their level of education…

How much should customers be compensated for interruptions in the drinking water supply?

2017

Water supply interruptions directly affect customers, and customers should be compensated accordingly. However, few water regulators have applied compensation policies given the difficulty of estimating the economic value of compensation to customers. In this study, a pioneering approach based on the concept of shadow prices is proposed to determine the compensation that customers should receive for unplanned water interruptions. The Chilean water industry was selected as a case study because there is an ongoing policy discussion between the use of penalties or compensation as an incentive to prevent water supply interruptions. The estimated results indicate that for 2014, the value of comp…

A model of the filling process of an intermittent distribution network

2010

In many countries, private tanks are acquired by users to reduce their vulnerability to intermittent supply. The presence of these local reservoirs modifies the user demand pattern and usually increases user water demand at the beginning of the service period depending on the tank filling process. This practice is thus responsible for the inequality that occurs among users: those located in advantaged positions of the network are able to obtain water resources soon after the service period begins, while disadvantaged users have to wait much longer, after the network is full. This dynamic process requires the development of ad hoc models in order to obtain reliable results. This paper discus…

Strategic Master Plans

2013

The MEDIWAT Project (Sustainable management of environmental issues related to water stress in Mediterranean Islands) aims to provide innovative and sustainable technical, operational and managerial solutions for tackling problems caused by water resources-quality worsening and shortage in the Mediterranean insular context. The project brings together partners from six Mediterranean islands: Sicily, Cyprus, Corsica were considered large islands because of their area and hydrological behavior. Conversely Crete, Malta and Balearic Islands were considered small islands. A detailed analysis of current and future conditions relating to freshwater availability, quality and use has been carried ou…

Electrodialysis for water desalination: A critical assessment of recent developments on process fundamentals, models and applications

2018

Abstract The need for unconventional sources of fresh water is pushing a fast development of desalination technologies, which proved to be able to face and solve the problem of water scarcity in many dry areas of the planet. Membrane desalination technologies are nowadays leading the market and, among these, electrodialysis (ED) plays an important role, especially for brackish water desalination, thanks to its robustness, extreme flexibility and broad range of applications. In fact, many ED-related processes have been presented, based on the use of Ion Exchange Membranes (IEMs), which are significantly boosting the development of ED-related technologies. This paper presents the fundamentals…