Use of nonwettable membranes for water transfer

Transfer of water through nonwettable vinyl fluoride membranes has two unique features - /1/ very low water transfer rates can be held constant by holding temperature and solute concentrations constant, /2/ the pressure gradient against which water is transported is limited only by solution breakthrough or membrane strength

Water-resource and land-use issues

Water resource managementWater useCase studiesCatchment areasLand useHydrologyModelsEvaporationSoil moistureDecision support toolsRunoffFlowForestryDeforestationErosionRain

Water Use Trends in the United States

Since 1950, the United States Geological Survey (USGS) has collected and released data on national water use every five years for each state, the District of Columbia, Puerto Rico, and the U.S. Virgin Islands. In November 2014, the USGS released water-use estimates for 2010. These data are collected from a variety of sources, including from national data sets, state agencies, questionnaires, and local contacts (Maupin et al. 2014). They include estimates of withdrawals of freshwater and saline water from groundwater and surface-water sources and water use by sector. Using these data and historic data from several other sources, this paper reviews national water-use trends, going as far back as 1900 in some cases. For this analysis, we use the term "water use" to refer to the amount of water withdrawn from the ground or diverted from a surface-water source for use. Our analysis finds that we have made considerable progress in managing the nation's water, with total water use less than it was in 1970, despite continued population and economic growth. Indeed, every sector, from agriculture to thermoelectric power generation, shows reductions in water use. National water use, however, remains high, and many freshwater systems are under stress from overuse. Moreover, climate change will exacerbate existing water resource challenges, affecting the supply, demand, and quality of the nation's water resources. In order to address these challenges, we must continue and even expand efforts to improve water-use efficiency in our homes, businesses, industries, and on our nation's farms

Radiation Use Efficiency and Soil Water Content on Maize-mungbean Intercropping

Mungbean is traditionally intercropped with maize by small-scale farmers which do widely in the tropics, including Southeast Sulawesi. This study aims to assess the radiation use efficiency (RUE) and soil water content (SWC) in maize intercropped with mungbean. The research was arranged on Split-Plot Design of two factors, i.e. dose of “komba-komba” compost as the main plot consists on 5 t ha-1 and 10 t ha-1 and planting time of mungbean as a subplot, consists on planting mungbean with maize at the same time, delayed planting of mungbean 7 and 14 days after planting (DAP) of maize. The results shown that the highest RUE of maize 2.69 g MJ-1 and 3.15 g MJ-1 obtained on komba-komba compost dose 10 t ha-1 and planting mungbean 7 DAP of maize, while highest RUE of mungbean 0.31 g MJ-1 and 0.60 g MJ-1 obtained on komba-komba compost dose 10 t ha-1 and planting mungbean and maize at the same time, respectively. The soil temperature has negatively correlated with (SWC) that at the komba-komba compost with rxy = - 0.7422 and at the time planting of mungbean in intercropping with maize with rxy = - 0.7922

Urban Water Conservation and Efficiency Potential in California

Improving urban water-use efficiency is a key solution to California's short-term and longterm water challenges: from drought to unsustainable groundwater use to growing tensions over limited supplies. Reducing unnecessary water withdrawals leaves more water in reservoirs and aquifers for future use and has tangible benefits to fish and other wildlife in our rivers and estuaries. In addition, improving water-use efficiency and reducing waste can save energy, lower water and wastewater treatment costs, and eliminate the need for costly new infrastructure

Control of common scab without the use of water

The most effective way to control common scab is by irrigating a potato crop at tuber initiation. With the introduction of legislation such as the Water Framework Directive this will become increasingly difficult. In this field experiment, we assessed the potential of a number of non-water measures for controlling this disease. Common scab on daughter tubers at harvest was reduced by applying rapeseed meal at 1 t ha-1 to the beds and then incorporating it into the soil, and adding a mixture of Trichoderma viride isolates into the furrow at planting. None of these treatments was as effective as using water

Land-use effects on soil-water retention characteristic

Tillage can negatively affect soil physical properties such as bulk density, organic matter content, and soil hydraulic properties, which in turn affect how plants grow. The objective of this study was to evaluate water retention characteristics of a Jay silt loam soil under cultivated agriculture and native tallgrass prairie in northwest Arkansas. Air-dry soil samples collected from 0-10 cm depth were re-wet with varying amounts of distilled water to create a range of water contents. After overnight equilibration, the water potential was measured on the re-wet soil samples using a dewpoint potentiameter. The relationship between water potential (Ψ) and water content (θv) for the cultivated agricultural and undisturbed prairie soil was modeled using the equation Ψ = aθv –b, where a and b are coefficients determined from fitting the data and represent the water retention characteristics for the soil of the two different land uses. The a and b coefficients did not differ significantly due to land use. Therefore, the results of this study did not support our hypothesis that agricultural land use significantly affects water retention characteristics. However, increasing the number of soil samples in which the water potential was measured could have sufficiently decreased the variability in the a and b coefficients so that significant differences in water retention characteristics as a result of land use could have been demonstrated

How Much Water Do You Use?

This activity is designed to make students aware of how much water individuals and families use on a weekly basis. They will analyze their family's water use with a focus on ways to reduce consumption. Students conduct the survey at home for a full week. In the next week students will look at their water use surveys and consider what their families could do to reduce their use. Students then calculate how much water would be saved in a year if the families of everyone in the class followed conservation practices. The site contains the documents required for the activity, including one entitled "Water Conservation Tips". Educational levels: High school, Middle school