Household-specific barriers to citizen-led flood risk adaptation.

Adaptation is essential to mitigate the effects of climate change, such as increasing flood risk. In response to widespread maladaptation, citizen-led approaches are increasingly championed, whereby people on the frontline of climate change determine their own objectives and strategies of adaptation. Enabling equitable and effective citizen-led adaptation requires an understanding of the barriers for different groups of people but this is currently lacking, especially in low- and middle-income countries.

To mix or not to mix? A holistic approach to stratification-preserving and destratification aeration of drinking-water supply reservoirs.

Aeration is used globally as a remediation method for lakes and reservoirs with methods generally falling into two categories, those which preserve natural stratification (hypolimnetic aeration; HA) and those which destratify reservoirs through mixing of the water column (destratification aeration; DA). The United Kingdom and Australia largely focus on DA methods to manage harmful algal blooms and decrease trace metal concentrations, whereas the United States and Europe frequently focus on HA techniques to increase dissolved oxygen (DO) concentrations and decrease benthic nutrient and metal release from the sediment. A more holistic understanding of how the different techniques influence water quality in regard to raw water supply and ecosystem health should lead to more efficient treatment, reducing wasted energy and other costs during both reservoir management and the drinking-water treatment process.

Estimating the microbiological risks associated with inland flood events: Bridging theory and models of pathogen transport.

Flooding is known to facilitate infectious disease transmission, yet quantitative research on microbiological risks associated with floods has been limited. Pathogen fate and transport models provide a framework to examine interactions between landscape characteristics, hydrology, and waterborne disease risks, but have not been widely developed for flood conditions. We critically examine capabilities of current hydrological models to represent unusual flow paths, non-uniform flow depths, and unsteady flow velocities that accompany flooding.

Hypolimnetic oxygen depletion in eutrophic lakes.

The oxygen-consuming processes in the hypolimnia of freshwater lakes leading to deep-water anoxia are still not well understood, thereby constraining suitable management concepts. This study presents data obtained from 11 eutrophic lakes and suggests a model describing the consumption of dissolved oxygen (O(2)) in the hypolimnia of eutrophic lakes as a result of only two fundamental processes: O(2) is consumed (i) by settled organic material at the sediment surface and (ii) by reduced substances diffusing from the sediment. Apart from a lake's productivity, its benthic O(2) consumption depends on the O(2) concentration in the water overlying the sediment and the molecular O(2) diffusion to the sediment.

Long-term transformation and fate of manufactured ag nanoparticles in a simulated large scale freshwater emergent wetland.

Transformations and long-term fate of engineered nanomaterials must be measured in realistic complex natural systems to accurately assess the risks that they may pose. Here, we determine the long-term behavior of poly(vinylpyrrolidone)-coated silver nanoparticles (AgNPs) in freshwater mesocosms simulating an emergent wetland environment. AgNPs were either applied to the water column or to the terrestrial soils.

Response of sediment microbial community structure in a freshwater reservoir to manipulations in oxygen availability.

Hypolimnetic oxygenation systems (HOx) are being increasingly used in freshwater reservoirs to elevate dissolved oxygen levels in the hypolimnion and suppress sediment-water fluxes of soluble metals (e.g. Fe and Mn) which are often microbially mediated.

Solving the problem at the source: Controlling Mn release at the sediment-water interface via hypolimnetic oxygenation.

One of the primary goals of hypolimnetic oxygenation systems (HOx) from a drinking water perspective is to suppress sediment-water fluxes of reduced chemical species (e.g., manganese and iron) by replenishing dissolved oxygen (O(2)) in the hypolimnion.

Increased sediment oxygen uptake caused by oxygenation-induced hypolimnetic mixing.

Hypolimnetic oxygenation systems (HOx) are increasingly used in lakes and reservoirs to elevate dissolved oxygen (O(2)) while preserving stratification, thereby decreasing concentrations of reduced chemical species in the hypolimnion. By maintaining an oxic zone in the upper sediment, HOx suppress fluxes of reduced soluble species from the sediment into the overlying water. However, diminished HOx performance has been observed due to HOx-induced increases in sediment O(2) uptake.

Effect of hypolimnetic oxygenation on oxygen depletion rates in two water-supply reservoirs.

Oxygenation systems, such as bubble-plume diffusers, are used to improve water quality by replenishing dissolved oxygen (DO) in the hypolimnia of water-supply reservoirs. The diffusers induce circulation and mixing, which helps distribute DO throughout the hypolimnion. Mixing, however, has also been observed to increase hypolimnetic oxygen demand (HOD) during system operation, thus accelerating oxygen depletion.

Controlling soluble iron and manganese in a water-supply reservoir using hypolimnetic oxygenation.

Soluble metals such as iron (Fe) and manganese (Mn) often reach problematic levels in water-supply reservoirs during summer stratification following the onset of hypolimnetic hypoxia. The behavior of soluble and particulate Fe and Mn was studied following the installation of a hypolimnetic oxygenation system in Carvins Cove Reservoir, a water-supply impoundment managed by the Western Virginia Water Authority. During oxygenation, manganese concentrations were very low in the bulk hypolimnion (<0.