Development of an Integrated System for the Simulation and Assessment of Produced Water Discharges from Offshore Platforms

Techniques for modeling of marine pollution have been studied for decades. Specialized modeling methods have been used to simulate the dispersions of pollutants from offshore outfalls. Produced water, the largest volume waste stream discharged from offshore oil and gas production activities, is a complex mixture of dissolved and particulate organic and inorganic chemicals including metals and hydrocarbons. In recent years, the growing importance and interest in the ocean environment assessment has urged further evaluation of produced water impacts on the marine ecosystem. This thesis study describes an integrated system for the modeling and assessment of produced water discharges in coastal area. The system integrates ocean circulation simulation, pollutant fate and transport modeling that couples near field mechanisms and far field processes, and risk assessment approaches where exposure risks and probabilistic risks are evaluated. A literature survey is first introduced to review and present capabilities and limitations of the most widely used methods and models associated with assessment of the impact of marine pollution. This review identified the need for an integrated system with configurations of numerical schemes of Princeton Ocean Model (POM) for ocean circulation simulation, a Lagrangian method to simulate near field transport processes in three dimensional cross flows, and a numerical solution for far field transport modeling. The physical models are dynamically integrated to ensure mass and energy conservation. Furthermore to assess risks, a modified Monte Carlo method which uses a statistical model to establish the relationship between uncertainty parameters and output concentrations is integrated with physical modeling system along with risk characterization approaches to map risk levels. Evaluation and field validations are conducted for each individual sub-models and for the overall integrated modeling results. Specifically, the near field model is validated against a field study performed in USA platform located about 100 miles of New Orleans Louisiana. The computational efficiency and accuracy of the far field model are evaluated through test cases in comparison with concentration distribution results generated from an exact analytical solution and a RWPT (Random Walk Particle Tracking) method. Validations of ocean circulation results and the integrated produced water dispersion results are conducted in a case study carried out on the Grand Banks of Newfoundland, Canada. Validations show good performance of the developed modeling system which is used to provide satisfactory 3D simulation of marine pollutant dispersion for effective assessment and management of offshore waste discharges. Finally, a risk assessment is carried out to predict risks associated with predicted lead and benzene concentration resulting from potential future produced water discharges in the East Coast of Canada. This research study provide a tool for the modeling of complex transport processes in the coastal area, and improved methods for risk assessment of produced water impacts on the regional water environment

Quarterly literature review of the remote sensing of natural resources

The Technology Application Center reviewed abstracted literature sources, and selected document data and data gathering techniques which were performed or obtained remotely from space, aircraft or groundbased stations. All of the documentation was related to remote sensing sensors or the remote sensing of the natural resources. Sensors were primarily those operating within the 10 to the minus 8 power to 1 meter wavelength band. Included are NASA Tech Briefs, ARAC Industrial Applications Reports, U.S. Navy Technical Reports, U.S. Patent reports, and other technical articles and reports

NUTRIENTS AND EUTROPHICATION IN THE TAW ESTUARY

Increased inputs of nutrients to estuaries and coastal waters can cause undesirable effects associated with eutrophication, including nuisance and toxic algal blooms, reduced amenity value, changes in species composition, bottom anoxia and fish kills. The main sources of nutrients to estuaries are river runoff, sewage discharges, atmospheric inputs and possibly submarine groundwater discharges. For the UK, estuarine eutrophication has been shown to occur in at least 16 estuaries (including the Taw in North Devon). Consequently, these systems have been designated as '(Potential) Problem Area' under the OSPAR Common Procedure for the Identification of Eutrophication and also as a 'Eutrophic Water' under the EU's Nitrates Directive and I or a 'Sensitive Area (Eutrophic)' under the Urban Wastewater Treatment Directive or both. Significant reductions in N and P inputs have been realized following application of the EU's Urban Waste Water Treatment Directive. Atmospheric NOx and NHx emissions have also decreased and are expected to decrease further as implementation of existing legislation continues and new controls are introduced for activities such as shipping. The Nitrates Directive was introduced to tackle N discharges from agriculture but little change in N loads to estuaries has been recorded. Using the Taw Estuary as an example, data routinely collected by the Environment Agency for England and Wales (EA) over the period 1990-2004 were interrogated to identify the drivers of excessive algal growth. The estuary was highly productive with chlorophyll a concentrations regularly exceeding 100 µg Lˉ¹ , mostly during periods of low freshwater input from the River Taw when estuarine water residence times were longest. The reported approach demonstrates the value of applying conventional statistical analyses in a structured way to existing monitoring data and is recommended as a useful tool for the rapid assessment of estuarine eutrophication. However, understanding of primary production dynamics in the Taw was constrained because of the low temporal resolution, heterogeneity and gaps in the EA data. Therefore, a temporal high resolution monitoring campaign was conducted in summer 2008 to document the development and decline of three algal blooms. The significance of long water residence times following low freshwater inflow and neap tides was confirmed. During peaks in chlorophyll a concentration (max. 226 µg Lˉ¹ ) , nutrient limitation switched from P to Si and persisted for more than 2 weeks in the outer estuary. Signs of ammonium and phosphate ( <0.2 µM) and silicate ( <2 µM) depletion were also observed. Using multivariate statistics, five distinct sets of environmental conditions present in the Taw at different stages of algal growth were identified and directly linked to freshwater inflow. UK Climate Impacts Programme scenarios predict a 30-50% decrease in Q95 flows (the flow which is exceeded 95% of the time) of rivers in south Britain by 2050. Under the current nutrient regime, this is likely to severely increase the severity and duration of symptoms of eutrophication in the Taw and favour potentially hazardous phytoplankton groups instead of diatoms. To mitigate future eutrophication events in the Taw, it is recommended to further reduce N and P inputs. It is also crucial to perform a detailed assessment of potential climate change consequences for the Taw Estuary and similar systems

The measurement of reaeration in streams

PhD ThesisA detailed study of the several methods for the determination of reaeration rates in streams has been made. Particular attention has been given to the floating soluble solids technique which appears to be a simple and reliable method for the measurement of reaeration rates in small streams. A comprehensive review of both conceptual and empirical mathematical models for the prediction of the reaeration rate coefficient is presented in an attempt to identify the practical outcome and application of these models to- natural stream conditions. A critical review and discussion of the three primary methods usually employed for the reaeration measurement in streams, namely the oxygen balance, disturbed equilibrium and tracer techniques, is presented to allow the understanding of the main principles, related assumptions, degree of applicability and the errors involved in each of these methods. The theoretical basis of a new method, the floating soluble solids technique is introduced, and previous work results presented. The physico-chemical para'meters effect upon the reaeration rate coefficient are discussed in the last part of the literaýure review. An extensive laboratory programme has been conducted, during which the individual and interaction effects of three important hydraulic variables (velocity, depth and roughness) upon atmospheric reaeration, propane gas desorption and solids dissolution processes have been investigated using statistical experimental design and analysis techniques. The assumption that the ratio between the reaeration and propane desorption rate coefficients js constant and independent of mixing and turbulent conditions has been herein confirmed using a different approach (surface response methodology) from the previously reported tests. A weaker depth dependence of both reaeration and propane desorption rate coefficients has been verified at low velocity levels, and which becomes stronger as average water velocity increases. Natural stram data and energy dissipation response to the same hydraulic factors variation appear to further substantiate the above evidence. The common parameters and main 'limitations controlling both reaeration and dissolution processes have been identified and dimensionless correlation equations were developed for the determination of the reaeration coefficient from' velocity of solids dissolution measurements. Field trials, involving the disturbed equilibrium, steady state propane gas tracer, and floating soluble solids methods, appears to confirm the evidence that reaeration coefficients might be successfully estimated from, velocity of solids dissolution measurements in small streams.Conselho Nacional de Desenvolvimento Cientifico e Tecnologico: CNPq, Brazilian Government: Committee of Vice-Chancellors and Principals of the Universities of the United Kingdom

Abstracts of manuscripts submitted in 1989 for publication

This volume contains the abstracts of manuscripts submitted for publication during calendar year 1989 by the staff and students of the Woods Hole Oceanographic Institution. We identify the journal of those manuscripts which are in press or have been published. The volume is intended to be informative, but not a bibliography. The abstracts are listed by title in the Table of Contents and are grouped into one of our five deparments, marine policy, or the student category. An author index is presented in the back to facilitate locating specific papers

Earth Resources: A continuing bibliography with indexes, issue 15, October 1977

This bibliography lists 387 reports, articles, and other documents introduced into the NASA scientific and technical information system between July 1 and September 30, 1977. Emphasis is placed on the use of remote sensing and geophysical instrumentation in spacecraft and aircraft to survey and inventory natural resources and urban areas. Subject matter is grouped according to agriculture and forestry, environmental changes and cultural resources, geodesy and cartography, geology and mineral resources, hydrology and water management, data processing and distribution systems, instrumentation and sensors, and economic analysis

Earth Resources: A continuing bibliography with indexes, issue 6, December 1975

This bibliography lists 484 reports, articles, and other documents introduced into the NASA scientific and technical information system between April 1975 and June 1975. Emphasis is placed on the use of remote sensing and geophysical instrumentation in spacecraft and aircraft to survey and inventory natural resources and urban areas. Subject matter is grouped according to agriculture and forestry, environmental changes and cultural resources, geodesy and cartography, geology and mineral resources, hydrology and water management, data processing and distribution systems, instrumentation and sensors, and economic analysis

Ecological Impacts of Degassing From Masaya Volcano, Nicaragua

Persistent degassing is an unusual type of volcanic activity with considerable environmental impacts, although its effects on downwind ecosystems are poorly researched. Up to 1000 tonnes of SO2 per day are degassed from Masaya Volcano in Nicaragua, and trade winds blow the plume in a WSW direction. A cross-wind transect through this plume provides a natural laboratory for this study on volcanic gases and their impacts on the tropical dry forest. Measurements of gas concentration and deposition rates of SO2, HC1 and HF along the transect were described by Gaussian profiles. These were linked to gas emission at the crater and the wind direction estimated from the HYSPLIT model. SO2 concentration profiles were used to investigate the ecological response to exposure to the volcanic plume along the same transect at two scales: the vegetation community and individual plant traits. The plant community level study found high levels of volcanic SO2 were associated with low species richness, comprising mostly grasses and herbs, an acidic soil, an open canopy and a thin leaf litter layer. Local feedbacks with these environmental variables have likely slowed succession in this area, indicating long-term impacts of volcanic degassing. At the species level, Dalechampia scandens response to SO2 was surprising; its largest leaves were found where volcanic pollution was highest. Elevated H2O, CO2 or nutrient levels from the plume may have benefited these tolerant plants. Compared with vegetation composition, this likely shows a more short-term response to volcanic gas levels. As well as informing ecological studies, fitting Gaussian profiles to volcanic gas data has validated our understanding of plume dispersal. The first evidence of vegetation community and plant trait response to volcanic gases presented here may give useful insights into the impacts of other degassing volcanoes or future industrial pollution in the tropics

Remote Sensing of Earth Resources: A literature survey with indexes (1970 - 1973 supplement). Section 1: Abstracts

Abstracts of reports, articles, and other documents introduced into the NASA scientific and technical information system between March 1970 and December 1973 are presented in the following areas: agriculture and forestry, environmental changes and cultural resources, geodesy and cartography, geology and mineral resources, oceanography and marine resources, hydrology and water management, data processing and distribution systems, instrumentation and sensors, and economic analysis