Cyberinfrastructure and Web Apps for Managing and Disseminating the National Water Model

Hydrologic modeling can be used to provide warnings before, and to support operations during and after floods. Recent technological advances have increased our ability to create hydrologic models over large areas. In the United States (U.S.), a new National Water Model (NWM) that generates hydrologic variables at a national scale was released in August 2016. This model represents a substantial step forward in our ability to predict hydrologic events in a consistent fashion across the entire U.S. Nevertheless, for these hydrologic results to be effectively communicated, they need to be put in context and be presented in a way that is straightforward and facilitates management‐related decisions. The large amounts of data produced by the NWM present one of the major challenges to fulfill this goal. We created a cyberinfrastructure to store NWM results, “accessibility” web applications to retrieve NWM results, and a REST API to access NWM results programmatically. To demonstrate the utility of this cyberinfrastructure, we created additional web apps that illustrate how to use our REST API and communicate hydrologic forecasts with the aid of dynamic flood maps. This work offers a starting point for the development of a more comprehensive toolset to validate the NWM while also improving the ability to access and visualize NWM forecasts, and develop additional national‐scale‐derived products such as flood maps.     

Integrating Temporal Inequality into Conservation Planning to Improve Practice Design and Efficacy

In contrast to spatial inequality, there are currently no methods for leveraging information on temporal inequality to improve conservation efficacy. The objective of this study was to use Lorenz curves to quantify temporal inequality in surface runoff and tile drainage, identify controls on nutrient loading in these flowpaths, and develop design flows for structural conservation practices. Surface runoff (n = 94 site‐years) and tile drainage (n = 90 site‐years) were monitored on 40 fields in Ohio. Results showed, on average, 80% of nitrate‐nitrogen, soluble reactive phosphorus (P), and total P loads occurred between 7 and 12 days per year in surface runoff and between 32 and 58 days per year in tile drainage. Similar temporal inequality between discharge and load provided evidence that loading was transport‐limited and highlighted the critical role hydrologic connectivity plays in nutrient delivery from tile‐drained fields. Design flow criterion for sizing structural practices based on load reduction goals was developed by combining Lorenz curves and flow duration curves. Comparing temporal inequality between fields and the Maumee River, the largest tributary to the western Lake Erie Basin, revealed challenges associated with achieving watershed load reduction goals with field‐scale conservation. In‐field (i.e., improved nutrient and water management), edge‐of‐field (i.e., structural practices), and instream practices will all be required to meet nutrient reduction goals from tile‐drained watersheds.     

The limits to risk aversion: Part 1. The point of indiscriminate decision

The paper uses utility theory to investigate how much should be spent to avert all costs from an industrial accident apart from direct human harm. These “environmental costs” will include those of evacuation, clean-up and business disruption. Assuming the organisation responsible will need to pay such costs, the difference between its expected utility with and without an environmental protection system constitutes a rational decision variable for whether or not the scheme should be installed. The value of utility is dependent on the coefficient of relative risk aversion, “risk-aversion” for short. A model of an organisation's decision-making process has been developed using the ABCD model, linking the organisation's assets, A, the cost of the protection scheme, B, the cost of consequences, C, and the expected utility difference with and without the scheme, D. Increasing the organisation's risk-aversion parameter will tend to make it less reluctant to invest in a protection system, but can bring about such investment only when the scheme is relatively close to financial break-even. For such borderline schemes, the amount the organisation is prepared to spend on the protection system will rise as the risk-aversion increases. The ratio of this sum to the break-even cost is named the “Limiting Risk Multiplier”, the maximum value of which is governed by the maximum feasible value of risk-aversion. However, the mathematical model shows that increasing the risk-aversion will reduce the clarity of decision making generally. Although the reluctance to invest in a protection scheme may change sign and turn into a positive desire to invest as the risk-aversion increases, the absolute value of this parameter is a continuously decreasing function of risk-aversion, tending asymptotically to zero. As a result, discrimination will gradually diminish, being lost altogether at the “point of indiscriminate decision”. Here the decision maker will be able to distinguish neither advantage in installing the scheme nor disadvantage in installing its inverse. There is a close correspondence between this mathematically predicted state and that of panic, where an individual has become so fearful that his actions become random. The point of indiscriminate decision provides a natural upper bound for the value of risk-aversion. This bounds the Limiting Risk Multiplier in turn, and so sets an objective upper limit on the amount that it is rational to spend on an environmental protection system.     

Towards an alternative criterion for the shipping safety of activated carbons: Part 4. The role of times to ignition

To the previously developed and implemented new criterion for the shipping safety of activated carbons is added a consideration of ignition times. It is shown that there is considerable support for the view that in the past shipments of such materials deemed on the basis of the IMCO/ISO test procedures to be subcritical have actually been supercritical, but that the long ignition times, exceeding voyage times, have prevented fire from developing.     

LAND COVER AS A FRAMEWORK FOR ASSESSING RISK OF WATER POLLUTION1

ABSTRACT: A survey of numerous field studies shows that nitrogen and phosphorous export coefficients are significantly different across forest, agriculture, and urban land‐cover types. We used simulations to estimate the land‐cover composition at which there was a significant risk of nutrient loads representative of watersheds without forest cover. The results suggest that at between 20 percent and 30 percent nonforest cover, there is a 10 percent or greater chance of N or P nutrient loads being equivalent to the median values of predominantly agricultural or urban watersheds. The methods apply to environmental management for assessing the risk to increased nonpoint nutrient pollution. Interpretation of the risk measures are discussed relative to their application for a single watershed and across a region comprised of several watersheds.     

FOG AND ACIDIFICATION IMPACTS ON ION BUDGETS OF BASINS IN NOVA SCOTIA,CANADA1

ABSTRACT: We examined hydrogeochemical records for a dozen watersheds in and near Kejimkujik National Park in southwestern Nova Scotia by relating stream ion concentrations and fluxes to atmospheric deposition, stream type (lake inlet versus outlet; brown versus clear water), and watershed type (catchment area, topography, soils, and dominant forest cover type). We found that fog and dry deposition make important contributions to S, N, Cl, H, Ca, Mg, K, and Na inputs into these watersheds. Seasalt chloride deposition from rain, snow, fog, and dry deposition equal total stream outputs on a region‐wide basis. Chloride outputs, however, differ among watersheds by a factor of about two, likely due to local differences in air flow and vegetational fog interception. We found that most of the incoming N is absorbed by the vegetation, as stream water NO3^‐ and NH4⁺ are very low. Our results also show that the vegetation and the soils absorb about half of the incoming SO4². In comparison with other North American watersheds with similar forest vegetation, Ca outputs are low, while Mg and K outputs are similar to other regions. Soil exchangeable Ca and soil cation exchange capacity are also very low. We found that first‐order forest streams with no upstream lakes have a distinct seasonal pattern that neither corresponds with the seasonal pattern of atmospheric deposition, nor with the seasonal pattern of downstream lake outlets.     

Assessment of the benefits of climate model weights for ensemble analysis in three urban precipitation frequency studies

In hydrology, projected climate change impact assessment studies typically rely on ensembles of downscaled climate model outputs. Due to large modeling uncertainties, the ensembles are often averaged to provide a basis for studying the effects of climate change. A key issue when analyzing averages of a climate model ensemble is whether to weight all models in the ensemble equally, often referred to as the equal-weights or unweighted approach, or to use a weighted approach, where, in general, each model would have a different weight. Many studies have advocated for the latter, based on the assumption that models that are better at simulating the past, that is, the models with higher hindcast accuracy, will give more accurate forecasts for the future and thus should receive higher weights. To examine this issue, observed and modeled daily precipitation frequency (PF) estimates for three urban areas in the United States, namely Boston, Massachusetts; Houston, Texas; and Chicago, Illinois, were analyzed. The comparison used the raw output of 24 Coupled Model Intercomparison Project Phase 5 (CMIP5) models. The PFs from these models were compared with the observed PFs for a specific historical training period to determine model weights for each area. The unweighted and weighted averaged model PFs from a more recent testing period were then compared with their corresponding observed PFs to determine if weights improved the estimates. These comparisons indeed showed that the weighted averages were closer to the observed values than the unweighted averages in nearly all cases. The study also demonstrated how weights can help reduce model spread in future climate projections by comparing the unweighted and weighted ensemble standard deviations in these projections. In all studied scenarios, the weights actually reduced the standard deviations compared to the equal-weights approach. Finally, an analysis of the results' sensitivity to the areal reduction factor used to allow comparisons between point station measurements and grid-box averages is provided.     

A simple soil organic-matter model for biomass data assimilation in community-level carbon contracts.

Soil carbon (C) sequestration has been proposed as a transitional win-win strategy to help replenish organic-matter content in depleted agricultural soils and counter increases in atmospheric greenhouse gases. Data assimilation and remote sensing can reduce uncertainty in sequestered C mass estimates, but simple soil organic carbon (SOC) models are required to make operational predictions of tradeable amounts over large, heterogenous areas. Our study compared the performance of RothC26.3 and a reduced compartmental model on an 11-year fertilizer trial in subhumid West Africa. Root mean square error (RMSE) differences of 0.05 Mg C/ha between models on total SOC predictions suggest that for contractual purposes, SOC dynamics can be simulated by a two-pool structure with labile and stable components. Faster (seasonal) and slower (semicentennial and beyond) rates can be approximated by constants as instantaneous and infinite decay. In these systems, simulations indicate that cereal residue incorporation holds most potential for mitigation of transient C loss associated with recent land conversion to agriculture.     

Exploited species impacts on trophic linkages along reef-seagrass interfaces in the Florida Keys

The removal of fish biomass by extensive commercial and recreational fishing has been hypothesized to drastically alter the strength of trophic linkages among adjacent habitats. We evaluated the effects of removing predatory fishes on trophic transfers between coral reefs and adjacent seagrass meadows by comparing fish community structure, grazing intensity, and invertebrate predation potential in predator-rich no-take sites and nearby predator-poor fished sites in the Florida Keys (USA). Exploited fishes were more abundant at the no-take sites than at the fished sites. Most of the exploited fishes were either omnivores or invertivores. More piscivores were recorded at no-take sites, but most (approximately 95%) were moderately fished and unexploited species (barracuda and bar jacks, respectively). Impacts of these consumers on lower trophic levels were modest. Herbivorous and smaller prey fish (< 10 cm total length) densities and seagrass grazing diminished with distance from reefs and were not negatively impacted by the elevated densities of exploited fishes at no-take sites. Predation by reef fishes on most tethered invertebrates was high, but exploited species impacts varied with prey type. The results of the study show that, even though abundances of reef-associated fishes have been reduced at fished sites, there is little evidence that this has produced cascading trophic effects or interrupted cross-habitat energy exchanges between coral reefs and seagrasses.     

Incorporating private lands in conservation planning: protected areas in Britain.

Evaluations of the effectiveness of protected areas often report their inadequate representation of regional variation in environmental conditions, land cover, and biological diversity. One frequent contributory explanation is the heavy reliance placed upon the designation of public as opposed to private lands for statutory protection. Given that protected area designation in Britain has no such constraint, and indeed that more than half of such areas are on private lands, we tested the a priori assumption that within this region the representation of environmental conditions and land cover within statutory protected areas would be more equitable. Despite the reduction in land ownership constraints on where protected areas can be established, a marked bias in protected area coverage remains. Protected areas in Britain tend toward regions of higher elevation, soils of lower economic potential, and coastal/estuarine habitat and fail adequately to represent areas of lower elevation and woodland habitats. Improving the current situation requires not only a more systematic approach to site selection, but a more equitable and diverse portfolio of incentives for private landowners to facilitate the decision to manage sites for conservation.