Automatic High Frequency Monitoring for Improved Lake and Reservoir Management.

Recent technological developments have increased the number of variables being monitored in lakes and reservoirs using automatic high frequency monitoring (AHFM). However, design of AHFM systems and posterior data handling and interpretation are currently being developed on a site-by-site and issue-by-issue basis with minimal standardization of protocols or knowledge sharing. As a result, many deployments become short-lived or underutilized, and many new scientific developments that are potentially useful for water management and environmental legislation remain underexplored. This Critical Review bridges scientific uses of AHFM with their applications by providing an overview of the current AHFM capabilities, together with examples of successful applications. We review the use of AHFM for maximizing the provision of ecosystem services supplied by lakes and reservoirs (consumptive and non consumptive uses, food production, and recreation), and for reporting lake status in the EU Water Framework Directive. We also highlight critical issues to enhance the application of AHFM, and suggest the establishment of appropriate networks to facilitate knowledge sharing and technological transfer between potential users. Finally, we give advice on how modern sensor technology can successfully be applied on a larger scale to the management of lakes and reservoirs and maximize the ecosystem services they provide.

Using detailed monitoring data to simulate spatial sediment loading in a watershed.

The use of watershed models as cost-effective tools to quantify the impact of conservation practices on water quality is often constrained by lack of data for model parameterization. This study uses short-term (3 years) detailed monitoring data to guide spatially distributed model parameterization and modeling analysis for suspended sediment in the Upper Esopus Creek Watershed (UECW) that is part of the New York City water supply. The calibrated Soil and Water Assessment Tool (SWAT) model simulated suspended sediment loading from tributary sub-basins and at the watershed outlet that were comparable to field measurements. Model simulations estimated that stream channels contributed the majority (85%) of stream sediment in the study watershed followed by upland erosion (11%) and point sources (4%), consistent with previous estimates and field observations. Long-term (12 years) simulation of the calibrated model was used to apportion the average annual sediment yields from tributary sub-basins which ranged between 12 and 161 t km(-2) year(-1). Model simulations were also used to understand the inter-annual variability and seasonality in suspended sediment loading in the study watershed. We demonstrate the wider applicability of short-term detailed monitoring for model parameterization and calibration, and long-term simulation of water quality using the SWAT model.

Modeling watershed-scale effectiveness of agricultural best management practices to reduce phosphorus loading.

Planners advocate best management practices (BMPs) to reduce loss of sediment and nutrients in agricultural areas. However, the scientific community lacks tools that use readily available data to investigate the relationships between BMPs and their spatial locations and water quality. In rural, humid regions where runoff is associated with saturation-excess processes from variable source areas (VSAs), BMPs are potentially most effective when they are located in areas that produce the majority of the runoff. Thus, two critical elements necessary to predict the water quality impact of BMPs include correct identification of VSAs and accurate predictions of nutrient reduction due to particular BMPs. The objective of this research was to determine the effectiveness of BMPs using the Variable Source Loading Function (VSLF) model, which captures the spatial and temporal evolutions of VSAs in the landscape. Data from a long-term monitoring campaign on a 164-ha farm in the New York City source watersheds in the Catskills Mountains of New York state were used to evaluate the effectiveness of a range of BMPs. The data spanned an 11-year period over which a suite of BMPs, including a nutrient management plan, riparian buffers, filter strips and fencing, was installed to reduce phosphorus (P) loading. Despite its simplicity, VSLF predicted the spatial distribution of runoff producing areas well. Dissolved P reductions were simulated well by using calibrated reduction factors for various BMPs in the VSLF model. Total P losses decreased only after cattle crossings were installed in the creek. The results demonstrated that BMPs, when sited with respect to VSAs, reduce P loss from agricultural watersheds, providing useful information for targeted water quality management.