Evaluation of Storage Reallocation and Related Strategies for Optimizing Reservoir System Operations

Statement of the Problem Rapid population and economic growth combined with depleting groundwater reserves are resulting in ever increasing demands on surface water resources in Texas, as well as elsewhere. The climate of the state is characterized by extremes of floods and droughts. Reservoirs are necessary to control and utilize the highly variable streamflow. Due to a number of economic, environmental, institutional, and political considerations, construction of new reservoir projects is much more difficult now than in the past. Consequently, optimizing the beneficial use of existing reservoirs is becoming increasingly more important. Reservoir operation is based on the conflicting objectives of maximizing the amount of water available for conservation purposes and maximizing the amount of empty space available for storing future flood waters to reduce downstream damages. Common practice is to operate a reservoir for either flood control only, conservation only, or a combination of flood control and conservation with separate pools designated for each. The conservation and flood control pools, or vertical zones, in a multipurpose project are fixed by a designated top of conservation (bottom of flood control) pool elevation. Conservation pools may be shared by various purposes, such as water supply, hydroelectric power, and recreation, which involve both complementary and conflicting interactions. Public needs and objectives and numerous factors affecting reservoir operation change over time. An increasing necessity to use limited storage capacity as effectively as possible warrants periodic re-evaluations of operating policies. Reallocation of storage capacity between purposes represents a general strategy for optimizing the beneficial use of limited storage capacity in response to changing needs and conditions. A storage reallocation between flood control and conservation purposes typically involves a permanent or seasonal change in the designated top of conservation pool elevation. Reallocations between conservation purposes can be achieved by various modifications of operating policies. Although given relatively little consideration in the past, storage reallocations will likely be proposed more frequently as demands on limited resources increase. Scope of Study This report documents an investigation of: (1) the potential of storage capacity reallocation and other related modifications in operating policies as management strategies for optimizing the beneficial use of existing reservoirs in Texas and (2) modeling capabilities for formulating and evaluating such changes to operating policies. In general, storage reallocations can involve a variety of types of reservoir use. The present study focused primarily on flood control and water supply. Multiple purpose reservoir operations involving hydroelectric power were also investigated. Both permanent conversion of storage capacity between purposes and seasonal rule curve operations were addressed. Buffer pool operations were also considered. Multiple reservoir system operation was a major emphasis of the study. The literature was reviewed and several reservoir management agencies contacted to (1) identify experiences in studying and/or implementing storage reallocations and (2) evaluate the state-of-the-art of associated modeling and analysis capabilities. The feasibility of seasonal rule curve operation depends upon the seasonal characteristics of the various factors affecting reservoir operation. Precipitation, streamflow, reservoir evaporation, water demands, and reservoir storage content data for Texas were analyzed to identify seasonal characteristics. A 12-reservoir system operated by the U.S. Army Corps of Engineers and Brazos River Authority provided a case study for evaluating the potential for storage reallocations and related operating strategies. This system, located in the Brazos River Basin, is considered representative of major reservoirs in Texas. The existing operating policies and possible modifications were investigated. The case study includes (1) flood control storage frequency and conservation drawdown frequency analyses based on the results of monthly hydrologic period-of-record simulations of reservoir system operations and (2) firm yield and reliability analyses. The generalized computer programs HEC-3, HEC-5, STATS, and MOSS-IV, and several utility software packages were used in the modeling study. Simulation of reservoir system operations was based on an 85-year sequence of monthly hydrologic data. The case study provides a preliminary assessment of the viability of permanent storage conversions and/or adoption of seasonal rule curve operations as potential reservoir management strategies. The objective is to evaluate storage reallocation potentialities in general, not develop detailed reallocation plans. The case study is basically a reconnaissance-level hydrologic analysis of reservoir operations. The monthly period-of-record simulations provide a reasonably precise analysis of water supply considerations. However, the daily hydrologic data required for detailed analysis of flood control operations were not included in the study. Reallocation of reservoir storage capacity involves complex institutional, financial, economic, legal, political, and technical considerations not addressed in the case study. However, the hydrologic analyses provide a good starting point for determining what types of reallocation strategies and modeling approaches might be potentially effective and whether more detailed studies are worthwhile. Organization of the Report Chapter 2 is a general discussion of reservoir operation and institutional and technical aspects of storage reallocation and a review of reallocations which have been implemented or proposed throughout the nation. Chapter 3 addresses the seasonality of the hydrologic factors pertinent to seasonal rule curve operation in Texas. Chapter 4 reviews state-of-the-art modeling capabilities and describes the computer models adopted for use in the case study. The Brazos River Basin case study is presented in chapters 5 through 8. Study results are summarized, and conclusions are presented in chapter 9

Hydrologic and Institutional Water Availability in the Brazos River Basin

Statement of the Problem Effective management of its surface water resources is essential to the continued growth and prosperity of the state of Texas. Rapid population and economic growth combined with depleting ground water reserves are resulting in ever-increasing demands being placed upon the surface water resources. The climate of the state is characterized by extremes of floods and droughts. Reservoirs are necessary to control and utilize the highly variable streamflow. Numerous reservoirs have been constructed to facilitate management of the water resources of the various river basins of the state. Effective control and utilization of the water resource supplied by a stream/reservoir system requires an understanding of the amount of water which can be provided under various conditions. Estimates of reservoir yield are a key element in practically all studies and decisions involving development and management of surface water supplies. Yield is defined as the amount of water which can be supplied by an unregulated stream, reservoir, or multiple reservoir system during a specified period of time. The stochastic nature of streamflow must be reflected in methods for quantifying yield. The approaches for expressing yield which traditionally have been used in water supply planning and management are firm yield and, to a lesser extent, reliability. Firm yield is the estimated maximum release or withdrawal rate which can be maintained continuously during a repetition of the hydrologic period-of-record. A number of definitions of reliability are cited in the technical literature. A common definition is that reliability is the percentage of time that a stream/reservoir system is able to meet a specified demand. Precise textbook definitions of firm yield and reliability can be formulated for a simple river basin with one reservoir and one water user. However, in actual practice, for a complex multiple reservoir, multiple user system, firm yield and reliability must be defined in terms of the basic assumptions and approaches used in handling various complicating factors. Water supply planning and management involves complex institutional, environmental, hydrologic, and physical systems. Streamflow, reservoir sedimentation, evaporation, water demands, and other variables pertinent to yield determinations are highly stochastic. Measured historical data is limited in extent and accuracy. The future is always uncertain. Mathematical models only approximate the complexities of reality. Consequently, reservoir yield studies necessarily involve uncertainties and approximations. The availability of water to particular users depends upon legal rights and contractual commitments as well as physical facilities and hydrologic conditions. Reservoir yield is subject to institutional as well as hydrologic constraints. Evaluation of the relationships between water rights and reservoir yield is particularly important at this time in Texas with the recent completion of the water rights adjudication process. Scope of the Study The objective of the study documented by this report was to evaluate and improve state-of-the-art capabilities for estimating reservoir yield. Institutional as well as hydrologic aspects of water availability were investigated. Evaluation of increases in yield achieved by multiple reservoir system operation, rather than separate operation of individual reservoirs, was a major emphasis of the study. The river basin was viewed as an integrated system. The hydrologic and institutional availability of water was investigated for a case study reservoir system. However, the study approach and computer programs used are generally applicable to any reservoir system. Study findings have pertinent implications for water resources management throughout Texas and elsewhere as well as for the specific river basin studied. Water availability is dependent upon institutional constraints and capabilities. The study included a review of water law and other institutional aspects of surface water management in Texas. A literature review was made assessing modeling capabilities for estimating reservoir yield. The reservoir system simulation models HEC-3 and HEC-5 were adopted for use in the case study. These generalized computer programs provide comprehensive capabilities for analyzing the hydrologic aspects of reservoir system operations, but lack the capability to simulate water rights priorities. Consequently, a generalized water rights simulation computer program was developed in conjunction with the study. Other computer programs were used for developing input data and analyzing output from the HEC3, HEC-5, and water rights models. A system of twelve reservoirs in the Brazos River Basin provided a case study. Nine multiple purpose flood control and conservation reservoirs are owned and operated by the Fort Worth District (FWD) of the U.S. Army Corps of Engineers (USACE). The Brazos River Authority (BRA) has contracted for most of the water supply storage capacity of the nine federal projects. The BRA owns and operates three other conservation reservoirs. In addition to the 12-reservoir USACE/BRA system, Hubbard Creek Reservoir, owned by the West Central Texas Municipal Water District, was modeled in detail because of its relatively large storage capacity. The numerous other smaller reservoirs in the basin were considered primarily from the perspective of approximating their impacts on the 12 USACE/BRA reservoirs. Individual reservoir and system firm yields were computed based on alternative conditions of reservoir sedimentation and alternative assumptions regarding multiple reservoir and multiple user interactions. The sensitivity of firm yield estimates to these and other factors was evaluated. A series of yield analyses were made from a strictly hydrologic perspective, without consideration of water rights. Yield analyses were then repeated incorporating water rights constraints. In addition to the firm yield simulations, a basinwide water rights analysis simulation study was performed. The simulations were based on monthly historical period-of-record hydrologic data. The modeling studies provided a basis for evaluating the hydrologic and institutional availability of water in the Brazos River Basin. Organization of the Report An overview of water law and institutions in Texas, from the perspective of surface water Management, is presented in Chapter 2. Surface water Management in the Brazos River Basin is described in Chapter 3. Chapter 4 is 8 discussion of reservoir system yield analysis models in general and the models used in the present study in particular. The Brazos River Basin simulation studies are documented by Chapters 5 through 9. Chapter 5 describes the compilation of basic data used in the study. A detailed hydrologic yield study is documented by Chapter 6. The analyses outlined in Chapter 6 were performed with HEC-3 and HEC-5 and are from a strictly hydrologic perspective, without consideration of water rights. The water rights analyses, utilizing the TAMU Water Rights Analysis Progra , are presented in Chapters 7 and 8. Chapter 7 discusses the results of a simulation of hydrologic and water rights aspects of surface water management in the basin. Firm yields constrained by senior water rights are documented in Chapter 8. Chapter 9 provides a critical evaluation, including sensitivity analyses, of the key factors affecting firm yield estimates. The study summary and conclusions are presented as Chapter 10

Large-scale magnetic field in the Monoceros OB 1 east molecular cloud

Context. The role of large-scale magnetic fields in the evolution of star-forming regions remains elusive. Its investigation requires the observational characterization of well-constrained molecular clouds. The Monoceros OB 1 molecular cloud is a large complex containing several structures that have been shown to be engaged in an active interaction and to have a rich star formation history. However, the magnetic fields in this region have only been studied on small scales. Aims. We study the large-scale magnetic field structure and its interplay with the gas dynamics in the Monoceros OB 1 east molecular cloud. Methods. We combined observations of dust polarized emission from the Planck telescope and CO molecular line emission observations from the Taeduk Radio Astronomy Observatory 14-metre telescope. We calculated the strength of the plane-of-sky magnetic field using a modified Chandrasekhar-Fermi method and estimated the mass-over-flux ratios in different regions of the cloud. We used the comparison of the velocity and intensity gradients of the molecular line observations with the polarimetric observations to trace dynamically active regions. Results. The molecular complex shows an ordered large-scale plane-of-sky magnetic field structure. In the northern part, it is mostly orientated along the filamentary structures, while the southern part shows at least two regions with distinct magnetic field orientations. Our analysis reveals a shock region in the northern part right between two filamentary clouds that, in previous studies, were suggested to be involved in a collision. The magnetic properties of the north-main and north-eastern filaments suggest that these filaments once formed a single one, and that the magnetic field evolved together with the material and did not undergo major changes during the evolution of the cloud. In the southern part, we find that either the magnetic field guides the accretion of interstellar matter towards the cloud or it is dragged by the matter falling towards the main cloud. Conclusions. The large-scale magnetic field in the Monoceros OB 1 east molecular cloud is tightly connected to the global structure of the complex. In the northern part, it seems to serve a dynamically important role by possibly providing support against gravity in the direction perpendicular to the field and to the filament. In the southern part, it is probably the most influential factor governing the morphological structure by guiding possible gas inflow. A study of the whole Monoceros OB 1 molecular complex at large scales is necessary to form a global picture of the formation and evolution of the Monoceros OB 1 east cloud and the role of the magnetic field in this process.Peer reviewe

Modelling stochastic bivariate mortality

Stochastic mortality, i.e. modelling death arrival via a jump process with stochastic intensity, is gaining increasing reputation as a way to represent mortality risk. This paper represents a first attempt to model the mortality risk of couples of individuals, according to the stochastic intensity approach. On the theoretical side, we extend to couples the Cox processes set up, i.e. the idea that mortality is driven by a jump process whose intensity is itself a stochastic process, proper of a particular generation within each gender. Dependence between the survival times of the members of a couple is captured by an Archimedean copula. On the calibration side, we fit the joint survival function by calibrating separately the (analytical) copula and the (analytical) margins. First, we select the best fit copula according to the methodology of Wang and Wells (2000) for censored data. Then, we provide a sample-based calibration for the intensity, using a time-homogeneous, non mean-reverting, affine process: this gives the analytical marginal survival functions. Coupling the best fit copula with the calibrated margins we obtain, on a sample generation, a joint survival function which incorporates the stochastic nature of mortality improvements and is far from representing independency.On the contrary, since the best fit copula turns out to be a Nelsen one, dependency is increasing with age and long-term dependence exists

Structure and Magnetism of well-defined cobalt nanoparticles embedded in a niobium matrix

Our recent studies on Co-clusters embedded in various matrices reveal that the co-deposition technique (simultaneous deposition of two beams : one for the pre-formed clusters and one for the matrix atoms) is a powerful tool to prepare magnetic nanostructures with any couple of materials even though they are miscible. We study, both sharply related, structure and magnetism of the Co/Nb system. Because such a heterogeneous system needs to be described at different scales, we used microscopic and macroscopic techniques but also local selective absorption ones. We conclude that our clusters are 3 nm diameter f.c.c truncated octahedrons with a pure cobalt core and a solid solution between Co and Nb located at the interface which could be responsible for the magnetically inactive monolayers we found. The use of a very diluted Co/Nb film, further lithographed, would allow us to achieve a pattern of microsquid devices in view to study the magnetic dynamics of a single-Co cluster.Comment: 7 TeX pages, 9 Postscript figures, detailed heading adde

Is there an impact of public smoking bans on self-reported smoking status and exposure to secondhand smoke?

<p>Abstract</p> <p>Background</p> <p>Implementation of smoke free policies has potentially substantial effects on health by reducing secondhand smoke exposure. However little is known about whether the introduction of anti-smoking legislation translates into decreased secondhand smoke exposure. We examined whether smoking bans impact rates of secondhand smoke exposure in public places and rates of complete workplace smoking restriction.</p> <p>Methods</p> <p>Canadian Community Health Survey was used to obtain secondhand smoking exposure rates in 15 Ontario municipalities. Data analysis included descriptive summaries and 95% confidence intervals were calculated and compared across groups</p> <p>Results</p> <p>Across all studied municipalities, secondhand smoke exposure in public places decreased by 4.7% and workplace exposure decreased by 2.3% between the 2003 and 2005 survey years. The only jurisdiction to implement a full ban from no previous ban was also the only setting that experienced significant decreases in both individual exposure to secondhand smoke in a public place (-17.3%, 95% CI -22.8, -11.8) and workplace exposure (-18.1%, 95% CI -24.9, -11.3). Exposures in vehicles and homes declined in almost all settings over time.</p> <p>Conclusions</p> <p>Implementation of a full smoking ban was associated with the largest decreases in secondhand smoke exposure while partial bans and changes in existing bans had inconsistent effects. In addition to decreasing exposure in public places as would be expected from legislation, bans may have additional benefits by decreasing rates of current smokers and decreasing exposures to secondhand smoke in private settings.</p

Fluoromycobacteriophages for rapid, specific, and sensitive antibiotic susceptibility testing of Mycobacterium tuberculosis

Rapid antibiotic susceptibility testing of Mycobacterium tuberculosis is of paramount importance as multiple- and extensively- drug resistant strains of M. tuberculosis emerge and spread. We describe here a virus-based assay in which fluoromycobacteriophages are used to deliver a GFP or ZsYellow fluorescent marker gene to M. tuberculosis, which can then be monitored by fluorescent detection approaches including fluorescent microscopy and flow cytometry. Pre-clinical evaluations show that addition of either Rifampicin or Streptomycin at the time of phage addition obliterates fluorescence in susceptible cells but not in isogenic resistant bacteria enabling drug sensitivity determination in less than 24 hours. Detection requires no substrate addition, fewer than 100 cells can be identified, and resistant bacteria can be detected within mixed populations. Fluorescence withstands fixation by paraformaldehyde providing enhanced biosafety for testing MDR-TB and XDR-TB infections. © 2009 Piuri et al

Protein Kinase C Iota Regulates Pancreatic Acinar-to-Ductal Metaplasia

Pancreatic acinar-to-ductal metaplasia (ADM) is associated with an increased risk of pancreatic cancer and is considered a precursor of pancreatic ductal adenocarcinoma. Transgenic expression of transforming growth factor alpha (TGF-α) or K-rasG12D in mouse pancreatic epithelium induces ADM in vivo. Protein kinase C iota (PKCι) is highly expressed in human pancreatic cancer and is required for the transformed growth and tumorigenesis of pancreatic cancer cells. In this study, PKCι expression was assessed in a mouse model of K-rasG12D-induced pancreatic ADM and pancreatic cancer. The ability of K-rasG12D to induce pancreatic ADM in explant culture, and the requirement for PKCι, was investigated. PKCι is elevated in human and mouse pancreatic ADM and intraepithelial neoplastic lesions in vivo. We demonstrate that K-rasG12D is sufficient to induce pancreatic ADM in explant culture, exhibiting many of the same morphologic and biochemical alterations observed in TGF-α-induced ADM, including a dependence on Notch activation. PKCι is highly expressed in both TGF-α- and K-rasG12D-induced pancreatic ADM and inhibition of PKCι significantly reduces TGF-α- and K-rasG12D-mediated ADM. Inhibition of PKCι suppresses K-rasG12D–induced MMP-7 expression and Notch activation, and exogenous MMP-7 restores K-rasG12D–mediated ADM in PKCι-depleted cells, implicating a K-rasG12D-PKCι-MMP-7 signaling axis that likely induces ADM through Notch activation. Our results indicate that PKCι is an early marker of pancreatic neoplasia and suggest that PKCι is a potential downstream target of K-rasG12D in pancreatic ductal metaplasia in vivo