Land and water systems: managing the hydrological risk

The paper suggests that the expansion of irrigated agriculture in the 20th century has de-coupled the water user from the inherent risk of exploiting both surface and groundwater resources. The apparent reliability of storage and conveyance infrastructure and the, relative cheapness and flexibility of groundwater exploitation offered by mechanised drilling and pumping have sheltered the end user from natural hydrological risk. The imperative for in-field irrigation efficiency has been effectively removed since the physical and economic management of the resource is determined by command area authorities or, in the case of some groundwater pumping, by the performance of power utilities, who have no direct interest in integrated resource conservation. As a result, the resource base has been degraded, and in some cases irreparable damage has occurred. It is argued that the rigidity of the resource management in many irrigation systems is not attuned to the inherent variability of natural systems upon which they depend. Further, the paper argues that irrigation management systems can work toward sustainability by spreading risk equitably, and transparently, amongst the resource regulators, managers and users. This has to involve a much more flexible approach to natural resource management that is conditioned not only by natural parameters, but also by the socio-economic settings. A range of examples highlights the variability and scale issues involved.     

TRICKLE IRRIGATION OF WHEAT APPLYING RENOVATED WASTEWATER1

ABSTRACT: A preliminary field experiment was conducted for trickle irrigation of winter wheat raised for grain production under arid conditions. Treated waste water was applied for trickle irrigation via a trickle system. Mean total amount of effluent applied was about 5700 m³/ha. In one of the experimental treatments, which was irrigated once a week, a grain yield of over 10,000 kg/ha was obtained, whereas in the other treatments the yields were about 8,500 kg/ha, which are above the mean yield obtained under sprinkler irrigation.     

EFFECT OF CATCHMENT SIZE ON PHOSPHORUS EXPORT1

ABSTRACT: We tested the common assumption, made when expressing phosphorus export on an areal basis, that this export is a linear function of catchment area and found it wanting. The data show that in agricultural catchments, TP (total phosphorus) export varies as the 0.77 power of drainage basin area, resulting in a reduction in phosphorus delivery per unit area with increasing catchment size. Following further division of catchments according to agricultural practice, we found that this spatial scale effect is restricted to row crops and pastures. We present simple statistical models to allow a comparison of TP export from catchments of different size. Such models are not needed for nonrow crops, mixed agricultural and forested catchments, where TP export is a linear function of catchment size.     

Planning for future sea-level rise in Swedish municipalities

A warmer climate leads to rising sea levels. Despite uncertainties about how rapid and substantial future sea-level rise (SLR) will be, society needs to prepare and adapt. This study examines the state of planning for future SLR in Sweden by surveying 33 coastal municipalities in southern Sweden and interviewing local, regional and national authorities with relevant accountability. The results reveal that there are considerable gaps in current planning for SLR. Almost one-third of municipalities lack guiding planning documents for SLR, and more than two-thirds do not discuss SLR beyond 2100. We argue that the prevailing uncertainty and ambiguity in assessments of future SLR is problematic within a traditional “predict-then-act” paradigm, and that robust approaches, such as scenario planning, can reduce many of these problems.     

Chitosan-based beads as sustainable adsorbents for wastewater remediation: a review

Environmental Chemistry Letters - Water contamination is increasing worldwide, yet actual methods of water and wastewater treatment are limited, in particular by actual fossil-fuel derived...     

Turbulent kinetic energy budgets in a model canopy: comparisons between LES and wind-tunnel experiments

A comparative study of turbulence in a wind-tunnel model canopy is performed, using Large eddy simulation (LES) and experimental data from PIV and hot-wire anemometry measurements. The model canopy is composed of thin cylindrical stalks. In the LES, these are represented using a plant-scale approach, while the scale-dependent Lagrangian dynamic model is used as subgrid-scale model. LES predictions of turbulence statistics and energy spectra are found to be in good agreement with the experimental data. Turbulent kinetic energy (TKE) budgets from the LES simulation are analyzed to provide more information absent in the measurements. Results confirm that sloshing motions at the low levels of the canopy are mainly driven by pressure fluctuations. A difference between the energy flux obtained from the energy spectrum and the SGS dissipation rate is observed, consistent with a spectral bypass mechanism in which the real spectral flux due to cascade is smaller than that implied by the energy-spectrum level, due to direct drain by the canopy.     

Metal mixtures in pregnant women and umbilical cord blood at urban populations—Rio de Janeiro,Brazil

Environmental Science and Pollution Research - This study aims to assess interrelationships between serum lead (Pb), cadmium (Cd), arsenic (As), and mercury (Hg) concentrations in pregnant women in...     

Benefit‐Cost Analysis of Integrated Water Resource Management: Accounting for Interdependence in the Yakima Basin Integrated Plan

Integrated water resource management (IWRM) requires accounting for many interrelated facets of water systems, water uses and stakeholders, and water management activities. The consequence is that project analysis must account for the nonseparability among the component parts of IWRM plans. This article presents a benefit‐cost (B‐C) analysis of a set of projects included in the Yakima Basin Integrated Plan proposed for the Yakima Basin in south‐central Washington State. The analysis accounts for interdependence among proposed water storage projects and between water storage and water market development in the context of historical and more adverse projected future climate scenarios. Focusing on irrigation benefits from storage, we show that the value of a given proposed storage project is lower when other proposed storage projects in the basin are implemented, and when water markets are functioning effectively. We find that none of the water storage projects satisfy a B‐C criterion, and that assuring proposed instream flow augmentation is less expensive by purchasing senior diversion rights than relying on new storage to provide it.     

Land cover changes as impacted by spatio-temporal rainfall variability along the Ethiopian Rift Valley escarpment

Magnitudes of land cover changes nowadays can be assessed properly, but their driving forces are subject to many discussions. Next to the accepted role of human influence, the impact of natural climate variability is often neglected. In this paper, the impact of rainfall variability on land cover changes (LCC) is investigated for the western escarpment of the Raya Graben along the northern Ethiopian Rift Valley. First, LCC between 2000 and 2014 were analysed at specific time steps using Landsat imagery. Based on the obtained LCC maps, the link was set with rainfall variability, obtained by means of the satellite-derived rainfall estimates (RFEs) from NOAA-CPC. After a correction by the incorporation of local meteorological station data, these estimates prove to be good estimators for the actual amount of precipitation (ρ _RFE1.0 = 0.85, p = 0.00, n = 126; ρ _RFE2.0 = 0.76, p = 0.00, n = 934). By performing several linear regression analyses, a significant positive relationship between the precipitation parameter DIFF 5Y (i.e. the at-RFE pixel scale difference in five-year average annual precipitation for the two periods preceding the land cover maps) and the changes in the woody vegetation cover was found (standardised regression coefficient β = 0.23, p = 0.02, n = 108). Despite the dominance of direct human impact, further greening of the study area can be expected for the future concomitantly to a wetter climate, if all other factors remain constant.