Consumptive water use

About: Consumptive water use is a research topic. Over the lifetime, 371 publications have been published within this topic receiving 32437 citations.

Crop evapotranspiration : guidelines for computing crop water requirements

Abstract: (First edition: 1998, this reprint: 2004). This publication presents an updated procedure for calculating reference and crop evapotranspiration from meteorological data and crop coefficients. The procedure, first presented in FAO Irrigation and Drainage Paper No. 24, Crop water requirements, in 1977, allows estimation of the amount of water used by a crop, taking into account the effect of the climate and the crop characteristics. The publication incorporates advances in research and more accurate procedures for determining crop water use as recommended by a panel of high-level experts organised by FAO in May 1990. The first part of the guidelines includes procedures for determining reference crop evapotranspiration according to the FAO Penman-Monteith method. These are followed by updated procedures for estimating the evapotranspiration of different crops for different growth stages and ecological conditions.

The New Blue and Green Water Paradigm: Breaking New Ground for Water Resources Planning and Management

Abstract: The production of biomass for direct human use—e.g., as food and timber—is by far the largest freshwater-consuming human activity on Earth. However, water policy and development concentrate on a fraction of the water for food challenge, namely, irrigated agriculture, which uses an estimated 25% of the global water used in agriculture, and on the industrial and domestic water supply, which corresponds to less than 10% of direct human water requirements considering only water for food, domestic use, and industry . The reason that biomass production so strongly outclasses other water-dependent processes is that water is one key element involved in plant growth. Simultaneous with the photosynthesis process, when stomata in the foliage open to take in carbon dioxide, large amounts of water are being consumed as transpiration flow and released as vapor from the plant canopy. Furthermore, this productive flow of vapor is accompanied by nonproductive evaporative losses of water from soil, ponded water, and intercepted water from foliage surfaces . Together, vapor fluxes as evaporation and transpiration, here defined as green-water flow, constitute the total consumptive water use in biomass production. Addressing the millennium development goal MDG of halving the proportion of malnourished people in the world by 2015, today amounting to a shocking 800 million people, is thus not only a tremendous agricultural endeavor but is also the world’s largest water-resource challenge. Hunger alleviation will require no less than a new Green revolution during the next 30 years, particularly in sub-Saharan Africa. As stated by Conway 1997 , the challenge is to achieve a green-green revolution, which compared with the first green revolution that lifted large parts of Asia out of an imminent hunger crisis in the 1960s and 1970s, will have to be founded on principles of environmental sustainability. As suggested by Falkenmark and Rockstrom 2004 , there is a third green dimension to a new agricultural revolution, since the focus will have to be on upgrading rain-fed agriculture, which entails increasing the use of the portion of rainfall that infiltrates the soil and is accessible by plants to generate vapor flow in support of biomass growth. This triply green revolution will require huge quantities of freshwater as vapor flow from the soil, through plants to the atmosphere. It raises the question of what eradicating hunger will in fact imply for water-resources planning and management.

The impacts of drought on freshwater ecosystems: an Australian perspective

Abstract: Southeastern Australia is presently experiencing one of the worst droughts observed in the region in the last 200 years. The consequences of drought have been far reaching both for human consumptive uses and for aquatic ecosystems, and serve to highlight several important aspects of the nature of droughts, their ecological impacts, and how humans respond to them. Running water ecosystems are the dominant form of freshwater ecosystem in Australia, yet, despite the high frequency of drought we lack a basic understanding of the consequences of long-term droughts (as distinct from seasonal droughts) as an ecosystem disturbance, and more is known about drought effects on flowing than on standing waters. Drought is well defined and characterised meteorologically, but hydrologically its characterisation is equivocal. While drought severely impacts natural aquatic ecosystems, its effects have been and are exacerbated by direct and indirect anthropogenic modifications to streams and their catchments. In streams the major impacts are the loss of water and habitat availability, and the reduction, if not severing, of connectivity (lateral, longitudinal and vertical). Despite the relative frequency of drought in Australia we have failed to develop long-term management strategies capable of contending with droughts and their impacts, particularly in catchments where human disturbances have reduced the natural resistance and resilience of aquatic ecosystems, and where the demand for consumptive water use is high and rising. Here, we provide a commentary on drought and its implications for the management of freshwater ecosystems. We begin with a general discussion of drought and its impacts on streams and rivers before discussing some of the more specific management issues and response strategies that have arisen in response to the current drought in Australia. Throughout we consider global as well as local examples. We conclude by highlighting important knowledge gaps and by providing some general principles for better incorporating droughts and their impacts into river management strategies.

Global modeling of withdrawal, allocation and consumptive use of surface water and groundwater resources

Abstract: . To sustain growing food demand and increasing standard of living, global water withdrawal and consumptive water use have been increasing rapidly. To analyze the human perturbation on water resources consistently over large scales, a number of macro-scale hydrological models (MHMs) have been developed in recent decades. However, few models consider the interaction between terrestrial water fluxes, and human activities and associated water use, and even fewer models distinguish water use from surface water and groundwater resources. Here, we couple a global water demand model with a global hydrological model and dynamically simulate daily water withdrawal and consumptive water use over the period 1979–2010, using two re-analysis products: ERA-Interim and MERRA. We explicitly take into account the mutual feedback between supply and demand, and implement a newly developed water allocation scheme to distinguish surface water and groundwater use. Moreover, we include a new irrigation scheme, which works dynamically with a daily surface and soil water balance, and incorporate the newly available extensive Global Reservoir and Dams data set (GRanD). Simulated surface water and groundwater withdrawals generally show good agreement with reported national and subnational statistics. The results show a consistent increase in both surface water and groundwater use worldwide, with a more rapid increase in groundwater use since the 1990s. Human impacts on terrestrial water storage (TWS) signals are evident, altering the seasonal and interannual variability. This alteration is particularly large over heavily regulated basins such as the Colorado and the Columbia, and over the major irrigated basins such as the Mississippi, the Indus, and the Ganges. Including human water use and associated reservoir operations generally improves the correlation of simulated TWS anomalies with those of the GRACE observations.