Estimating River Discharge Using Multiple-Tide Gauges Distributed Along a Channel

Reliable estimation of freshwater inflow to the ocean from large tidal rivers is vital for water resources management and climate analyses. Discharge gauging stations are typically located beyond the tidal intrusion reach, such that inputs and losses occurring closer to the ocean are not included. Here, we develop a method of estimating river discharge using multiple gauges and time-dependent tidal statistics determined via wavelet analysis. The Multiple-gauge Tidal Discharge Estimate (MTDE) method is developed using data from the Columbia River and Fraser River estuaries and calibrated against river discharge. Next, we evaluate the general applicability of MTDE by testing an idealized two-dimensional numerical model, with a convergent cross-sectional profile, for eighty-one cases in which nondimensional numbers for friction, river flow, and convergence length scale are varied. The simulations suggest that MTDE is applicable to a variety of tidal systems. Model results and data analyses together suggest that MTDE works best with at least three gauges: a reference station near the river mouth, and two upstream gauges that respond strongly to distinct portions of the observed range of flow. The balance between tidal damping and amplifying factors determines the favorable location of the gauges. Compared to previous studies, the MTDE method improves the time resolution of estimates (from 2.5 to \u3c 1 week) and is applicable to systems with mixed diurnal/semidiurnal tides. However, model results suggest that tide-induced residual flows such as the Stokes drift may still affect the accuracy of MTDE at seaward locations during periods of low river discharge

Avustralya’da Halk Kütüphaneleri ve Eğitim İlişkisi: 1996-2011

In general, public libraries and education in all developed countries are two important items. In this study, public libraries in Australia were evaluated quantitatively based on education, the number of libraries, staff, materials, lending rates, the number of schools, teacher-student ratio, school enrollment rates and per pupil expenditure data. Findings showed that there is not a relation between public libraries and education in Australia between 1996-2011.Genel olarak tüm gelişmiş ülkelerde halk kütüphaneleri ve eğitim iki önemli ögedir. Bu çalışmada Avustralya’daki halk kütüphaneleri; eğitim, kütüphane sayısı, personel, materyal sayısı, ödünç verme oranları, okul sayısı, öğretmen-öğrenci oranı, okullaşma oranı ve öğrenci başına harcama verileri esas alınarak niceliksel olarak değerlendirilmiştir. Elde edilen bulgular, 1996-2011 yılları arasında, Avustralya’da halk kütüphaneleri ile eğitim arasında herhangi bir ilgi olmadığını göstermiştir

The Effect of Task Type and Task Orientation on L2 Vocabulary Learning

This study was conducted to investigate the effect of meaning-focused versus form-focused input-oriented and output-oriented task-based instruction on elementary level Iranian EFL Learners’ vocabulary comprehension and recall. For this purpose, a sample of 120 male students from a private school in Tehran was selected through convenience sampling and based on availability. The participants were divided into four groups, and each group was given a different treatment. The first group was taught through meaning-focused input-oriented vocabulary tasks; the second group was instructed through meaning-focused output-oriented tasks; the third group received form-focused input-oriented vocabulary tasks, and the fourth group received form-focused output-oriented vocabulary instruction. At the end of the treatment, the participants in all the four groups were given a vocabulary comprehension and a vocabulary recall posttest. The results indicated that meaning-focused tasks were more effective than form-focused tasks on both vocabulary comprehension and recall. At the same time, input-oriented tasks turned out to be more effective than output-oriented tasks on only vocabulary comprehension. In vocabulary recall, input-oriented tasks were more effective when they were form-focused, while output-oriented tasks were more effective when they were meaning-focused. The results of this study can have implications for teachers, learners, and curriculum designers

The Public Libraries of Iran: A Quantitative Evaluation

Halk kütüphaneleri dijital uçurumun azaltılmasında önemli roller üstlenen toplumsal kuruluşlardır. On­ların, bu rollerini gerçekleştirebilmeleri için niceliksel açıdan yeterli durumda olmaları gerekmektedir. Ayrıca, halk kütüphanelerine ilişkin niceliksel göstergeler niteliklerini ve nitelikli hizmet vermelerini doğrudan belirler. İran, 30 ilde yaşayan 71 milyon nüfusa sahip bir Ortadoğu ülkesidir. Bu çalışmada, İran’daki halk kütüphanelerine ilişkin niceliksel durum kütüphane sayısı, kullanıcı, derme ve personel unsurları açısından ortaya konulmaya çalışılmıştır. Elde edilen sonuçlara göre, İran’da ele alınan söz konusu unsurlar açısından genelde bir yetersizlik olduğu anlaşılmıştır. Çalışma sonunda bazı önerilerde bulunulmuştur.Public libraries as social organizations play a significant role in reducing the digital divide. In order to perform this role, their quantitative aspects need to be sufficient. In addition, the quantitative indicators of public libraries reveal their qualities and qualified services. Iran has a population of 71 million, in 30 provinces. In this paper, the public libraries of Iran are studied with respect to number of libraries, us­ers, collections and staff. The results suggest that the abovementioned factors are generally insufficient as regards public libraries in Iran. In the conclusion of the study, some suggestions are made

A Novel Approach to Flow Estimation in Tidal Rivers

Reliable estimation of river discharge to the ocean from large tidal rivers is vital for water resources management and climate analyses. Due to the difficulties inherent in measuring tidal-river discharge, flow records are often limited in length and/or quality and tidal records often predate discharge records. Tidal theory indicates that tides and river discharge interact through quadratic bed friction, which diminishes and distorts the tidal wave as discharge increases. We use this phenomenon to develop a method of estimating river discharge for time periods with tidal data but no flow record. Employing sequential 32 day harmonic analyses of tidal properties, we calibrate San Francisco (SF), CA tide data to the Sacramento River delta outflow index from 1930 to 1990, and use the resulting relationship to hindcast river flow from 1858 to 1929. The M2 admittance (a ratio of the observed M2 tidal constituent to its astronomical forcing) best reproduces high flows, while low-flow periods are better represented by amplitude ratios based on higher harmonics (e.g.). Results show that the annual inflow to SF Bay is now 30% less than before 1900 and confirm that the flood of January 1862 was the largest since 1858

Quantifying Anthropogenic Stress on Groundwater Resources.

This study explores a general framework for quantifying anthropogenic influences on groundwater budget based on normalized human outflow (hout) and inflow (hin). The framework is useful for sustainability assessment of groundwater systems and allows investigating the effects of different human water abstraction scenarios on the overall aquifer regime (e.g., depleted, natural flow-dominated, and human flow-dominated). We apply this approach to selected regions in the USA, Germany and Iran to evaluate the current aquifer regime. We subsequently present two scenarios of changes in human water withdrawals and return flow to the system (individually and combined). Results show that approximately one-third of the selected aquifers in the USA, and half of the selected aquifers in Iran are dominated by human activities, while the selected aquifers in Germany are natural flow-dominated. The scenario analysis results also show that reduced human withdrawals could help with regime change in some aquifers. For instance, in two of the selected USA aquifers, a decrease in anthropogenic influences by ~20% may change the condition of depleted regime to natural flow-dominated regime. We specifically highlight a trending threat to the sustainability of groundwater in northwest Iran and California, and the need for more careful assessment and monitoring practices as well as strict regulations to mitigate the negative impacts of groundwater overexploitation

The evolving landscape of sea-level rise science from 1990 to 2021

As sea-level rise (SLR) accelerates due to climate change, its multidisciplinary field of science has similarly expanded, from 41 articles published in 1990 to 1475 articles published in 2021, and nearly 15,000 articles published in the Web of Science over this 32-year period. Here, big-data bibliometric techniques are adopted to systematically analyse this large literature set. Four main research clusters (themes) emerge: (I) geological dimensions and sea-level indicators, (II) impacts, risks, and adaptation, (III) physical components of sea-level change, and (IV) coastal ecosystems and habitats, with 16 associated sub-themes. This analysis provides insights into the evolution of research agendas, the challenges and opportunities for future assessments (e.g. next IPCC reports), and growing focus on adaptation. For example, the relative importance of sub-themes evolves consistently with a relative decline in pure science analysis towards solution-focused topics associated with SLR risks such as high-end rises, declining ecosystem services, flood hazards, and coastal erosion/squeeze

Climate-informed environmental inflows to revive a drying lake facing meteorological and anthropogenic droughts

The rapid shrinkage of Lake Urmia, one of the world\u27s largest saline lakes located in northwestern Iran, is a tragic wake-up call to revisit the principles of water resources management based on the socio-economic and environmental dimensions of sustainable development. The overarching goal of this paper is to set a framework for deriving dynamic, climate-informed environmental inflows for drying lakes considering both meteorological/climatic and anthropogenic conditions. We report on the compounding effects of meteorological drought and unsustainable water resource management that contributed to Lake Urmia\u27s contemporary environmental catastrophe. Using rich datasets of hydrologic attributes, water demands and withdrawals, as well as water management infrastructure (i.e. reservoir capacity and operating policies), we provide a quantitative assessment of the basin\u27s water resources, demonstrating that Lake Urmia reached a tipping point in the early 2000s. The lake level failed to rebound to its designated ecological threshold (1274 m above sea level) during a relatively normal hydro-period immediately after the drought of record (1998–2002). The collapse was caused by a marked overshoot of the basin\u27s hydrologic capacity due to growing anthropogenic drought in the face of extreme climatological stressors. We offer a dynamic environmental inflow plan for different climate conditions (dry, wet and near normal), combined with three representative water withdrawal scenarios. Assuming effective implementation of the proposed 40% reduction in the current water withdrawals, the required environmental inflows range from 2900 million cubic meters per year (mcm yr−1) during dry conditions to 5400 mcm yr−1 during wet periods with the average being 4100 mcm yr−1. Finally, for different environmental inflow scenarios, we estimate the expected recovery time for re-establishing the ecological level of Lake Urmia