A Search for Freshwater in the Saline Aquifer of Coastal Bangladesh.

In the polder region of coastal Bangladesh, shallow groundwater is primarily brackish with unpredictable occurrence of freshwater pockets. Delta building processes, including the codeposition of fresh-to-saline porewater and sediments, have formed the shallow aquifer. Impermeable clay facies and the lack of a topographical gradient limit the flow of groundwater and its mixing with surface water so controls on spatial variability of salinity are not obvious.

Minimizing irrigation water demand: An evaluation of shifting planting dates in Sri Lanka.

Climate change coupled with increasing demands for water necessitates an improved understanding of the water-food nexus at a scale local enough to inform farmer adaptations. Such assessments are particularly important for nations with significant small-scale farming and high spatial variability in climate, such as Sri Lanka. By comparing historical patterns of irrigation water requirements (IWRs) to rice planting records, we estimate that shifting rice planting dates to earlier in the season could yield water savings of up to 6%.

Impacts of management alternatives on rice yield and nitrogen losses to the environment: A case study in rural Sri Lanka.

Maintaining crop yields is vital as populations increase, but environmental degradation resulting from cultivation must be prevented. In particular, freshwater resources are at risk of nitrate leaching from superfluous fertilization. This research explores the tradeoffs between maximizing yield and limiting environmental impacts of rice production in Sri Lanka.

Drought planning and management: using high spatial resolution as part of the solution.

Water scarcity is intensified by drought, a phenomenon that impacts many sectors of society and affects virtually all climate zones. The Palmer drought indices are widely used by scientists and policy makers to understand drought and model its components. Despite the spatial heterogeneity and variability in variables required by the Palmer model, regional index values are most commonly used for real-time drought assessment.

Gaining perspective on the water-energy nexus at the community scale.

Water and energy resources are interrelated but their influence on each other is rarely considered. To quantify the water and energy portfolios associated with a community's water-energy nexus (WEN) and the influence of geographic location on resources, we present the WEN tool. The WEN tool quantifies a community's transport (consumed for or lost before delivery) and nexus (energy for water and water for energy) resources so communities can assess their resource flows.

Simulation of future stream alkalinity under changing deposition and climate scenarios.

Models of soil and stream water acidification have typically been applied under scenarios of changing acidic deposition, however, climate change is usually ignored. Soil air CO2 concentrations have potential to increase as climate warms and becomes wetter, thus affecting soil and stream water chemistry by initially increasing stream alkalinity at the expense of reducing base saturation levels on soil exchange sites. We simulate this change by applying a series of physically based coupled models capable of predicting soil air CO2 and stream water chemistry.

Anthropogenic sources of arsenic and copper to sediments in a suburban lake, Northern Virginia.

Mass balances of total arsenic and copper for a suburban lake in densely populated northern Virginia were calculated using date collected during 1998. Mass-balance terms were precipitation; stream inflow, including road runoff; stream outflow; and contributions from leaching of pressure-treated lumber. More mass of arsenic and copper was input to the lake than was output the 1998 lake-retention rates were 70% for arsenic and 20% for copper.

Aggregating Fine-Scale Ecological Knowledge to Model Coarser-Scale Attributes of Ecosystems.

As regional and global scales become more important to ecologists, methods must be developed for the application of existing fine-scale knowledge to predict coarser-scale ecosystem properties. This generally involves some form of model in which fine-scale components are aggregated. This aggregation is necessary to avoid the cumulative error associated with the estimation of a large number of parameters.