Development of the sediment and water quality management strategies for the Salt-water River, Taiwan

The Salt-water River watershed is one of the major river watersheds in the Kaohsiung City, Taiwan. Water quality and sediment investigation results show that the river water contained high concentrations of organics and ammonia-nitrogen, and sediments contained high concentrations of heavy metals and organic contaminants. The main pollution sources were municipal and industrial wastewaters. Results from the enrichment factor (EF) and geo-accumulation index (Igeo) analyses imply that the sediments can be characterized as heavily polluted in regard to Cd, Cr, Pb, Zn, and Cu. The water quality analysis simulation program (WASP) model was applied for water quality evaluation and carrying capacity calculation. Modeling results show that the daily pollutant inputs were much higher than the calculated carrying capacity (1050 kg day(-1) for biochemical oxygen demand and 420 kg day(-1) for ammonia-nitrogen). The proposed watershed management strategies included river water dilution, intercepting sewer system construction and sediment dredging.     

The fluvial geochemistry, contributions of silicate, carbonate and saline-alkaline components to chemical weathering flux and controlling parameters: Narmada River (Deccan Traps), India

The Narmada River in India is the largest west-flowing river into the Arabian Sea, draining through the Deccan Traps, one of the largest flood basalt provinces in the world. The fluvial geochemical characteristics and chemical weathering rates (CWR) for the mainstream and its major tributaries were determined using a composite dataset, which includes four phases of seasonal field (spot) samples (during 2003 and 2004) and a decade-long (1990-2000) fortnight time series (multiannual) data. Here, we demonstrate the influence of minor lithologies (carbonates and saline-alkaline soils) on basaltic signature, as reflected in sudden increases of Ca²⁺-Mg²⁺ and Na⁺ contents at many locations along the mainstream and in tributaries. Both spot and multiannual data corrected for non-geological contributions were used to calculate the CWR. The CWR for spot samples (CWR_spot) vary between 25 and 63 ton km⁻² year⁻¹, showing a reasonable correspondence with the CWR estimated for multiannual data (CWR_multi) at most study locations. The weathering rates of silicate (SilWR), carbonate (CarbWR) and evaporite (Sal-AlkWR) have contributed ∼38-58, 28-45 and 8-23%, respectively to the CWR_spot at different locations. The estimated SilWR (11-36 ton km⁻² year⁻¹) for the Narmada basin indicates that the previous studies on the North Deccan Rivers (Narmada-Tapti-Godavari) overestimated the silicate weathering rates and associated CO₂ consumption rates. The average annual CO₂ drawdown via silicate weathering calculated for the Narmada basin is ∼0.032 × 10¹² moles year⁻¹, suggesting that chemical weathering of the entire Deccan Trap basalts consumes approximately 2% (∼0.24 × 10¹² moles) of the annual global CO₂ drawdown. The present study also evaluates the influence of meteorological parameters (runoff and temperature) and physical weathering rates (PWR) in controlling the CWR at annual scale across the basin. The CWR and the SilWR show significant correlation with runoff and PWR. On the basis of observed wide temporal variations in the CWR and their close association with runoff, temperature and physical erosion, we propose that the CWR in the Narmada basin strongly depend on meteorological variability. At most locations, the total denudation rates (TDR) are dominated by physical erosion, whereas chemical weathering constitutes only a small part (<10%). Thus, the CWR to PWR ratio for the Narmada basin can be compared with high relief small river watersheds of Taiwan and New Zealand (1-5%) and large Himalayan Rivers such as the Brahmaputra and the Ganges (8-9%).     

Subsurface ocean temperature indices for Central-Pacific and Eastern-Pacific types of El Ni?o and La Ni?a events

Subsurface ocean temperature indices are developed to identify two distinct types of tropical Pacific warming (El Ni?o) and cooling (La Ni?a) events: the Eastern-Pacific (EP) type and the Central-Pacific (CP) type. Ocean temperature anomalies in the upper 100?m are averaged over the eastern (80°W?C90°W, 5°S?C5°N) and central (160°E?C150°W, 5°S?C5°N) equatorial Pacific to construct the EP and CP subsurface indices, respectively. The analysis is performed for the period of 1958?C2001 using an ocean data assimilation product. It is found that the EP/CP subsurface indices are less correlated and show stronger skewness than the sea surface temperature (SST)-based indices. In addition, while both quasi-biennial (??2?years) and quasi-quadrennial (??4?years) periodicities appear in the SST-based indices for these two types, the subsurface indices are dominated only by the quasi-biennial periodicity for the CP type and by the quasi-quadrennial (??4?years) periodicity for the EP type. Low correlation, high skewness, and single leading periodicity are desirable properties for defining indices to separate the EP and CP types. Using the subsurface indices, major El Ni?o and La Ni?a events identified by the Ni?o-3.4 SST index are classified as the EP or CP types for the analysis period. It is found that most strong El Ni?o events are of the EP type while most strong La Ni?a events are of the CP type. It is also found that strong CP-type La Ni?a events tend to occur after strong EP-type El Ni?o events. The reversed subsequence (i.e., strong EP El Ni?o events follow strong CP La Ni?a events) does not appear to be typical. This study shows that subsurface ocean indices are an effective way to identify the EP and CP types of Pacific El Ni?o and La Ni?a events.     

The concept of diverse developments in port cities

This paper extends Alvin Toffler’s “three waves” concept into a classification framework that describes three stages and six types of port-city developments. These waterfront developments inject huge capital, but require a longer period for return on investment, and public-private partnership is commonly adopted as necessary for enhanced efficiency and risk sharing in many of the development projects. The concept of diverse developments is discussed, in which the content of development is first analyzed and then subdivided into development units grouped as having similar attributes. A corresponding leading organization for the given development unit is then chosen based upon the analyzed attributes. Using the series of steps in constructing the framework, the purpose of obtaining maximum social benefits and appropriate risk management is thus achieved. Waterfront development case studies are also included to explain advantages of adopting the concept of diverse developments. Finally, examples will be included to illustrate how this diverse development analysis can be applied in a flexible way so that competitive and high quality waterfronts can be created.     

Optimization of operation rule curves and flushing schedule in a reservoir

Flushing sediment through a reservoir has been practiced successfully and found to be inexpensive in many cases. However, the great amount of water consumed in the flushing operation might affect the water supply. To satisfy the water demand and water consumed in the flushing operation, two models combining the reservoir simulation model and the sediment flushing model are established. In the reservoir simulation model, the genetic algorithm (GA) is used to optimize and determine the flushing operation rule curves. The sediment‐flushing model is developed to estimate the amount of the flushed sediment volume, and the simulated results update the elevation‐storage curve, which can be taken into account in the reservoir simulation model. The models are successfully applied to the Tapu reservoir, which has faced serious sedimentation problems. Based on 36 years historical sequential data, the results show that (i) the simulated flushing operation rule curves model has superior performance, in terms of lower shortage index (SI) and higher flushing efficiency (FE), than that by the original reservoir operation; (ii) the rational and riskless flushing schedule for the Tapu reservoir is suggested to be set within an interval of every 2 or 4 years in the months of May or June. Copyright © 2003 John Wiley & Sons, Ltd.     

Experimental study of upstream influence in the two‐dimensional flow of a stratified fluid over an obstacle†

An experimental investigation was made of the upstream influence in front of two‐dimensional obstacles when they were towed in a linearly stratified fluid. The experiments were performed in a plexiglas channel 30.5 feet long, 2 feet high and 14 inches wide filled with a linearly stratified salt solution. Velocity measurements and flow visualization were obtained by neutrally buoyant liquid droplets and dye lines. Density measurements were made by a salinity probe.

The existence of unattenuated upstream influence in front of an obstacle was quantitatively documented for the first time. It occurred in the form of multiple unattenuated horizontal jets when there was a separated open wake behind the obstacle. These jets were identified to be the super‐position of “columnar disturbance modes”. The total number of columnar modes was determined solely by the Froude number of the flow and was equal to the number of lee‐wave modes excited. The drag due to upstream columnar modes was estimated and found to be lower than the drag due to the lee wave modes:     

Regional economic impact analysis of earthquakes in northern Taiwan and its implications for disaster reduction policies

The direct damage caused by earthquakes, such as impaired buildings, may interfere with normal business operations and disrupt the function of the industrial chain. Such economic impacts can be evaluated using the input–output analysis developed by Leontief. In this paper, two scenario earthquakes in northern Taiwan both with a return period of 475 years—the Hsinchu Hsincheng and the Yilan Nan-ao earthquakes—are simulated. The results show that the economic impact caused by the Hsincheng earthquake is greater than that resulting from the Nan-ao earthquake, which should be the major scenario considered for the disaster reduction plan. The industries affected the most are the manufacturing, food services and entertainment, storage and retail trade, and public and construction industries. The Nan-ao earthquake causes relatively more losses in the food services and entertainment industries. Most of the repercussion effects of these industries are in the central and southern parts of Taiwan. The loss to the manufacturing sector and its repercussion effects are enormous. Therefore, the government should make it a first priority to encourage the manufacturing sector to implement earthquake mitigations, such as a seismic retrofit, or to provide a seismic evaluation, which can enable firms to engage in mitigation voluntarily. The measure needed to reduce the loss in agriculture is that the government can purchase agricultural products in central and southern Taiwan following the disaster and offer them to survivors in northern Taiwan.     

Elastic behavior of vanadinite,Pb<Subscript>10</Subscript>(VO<Subscript>4</Subscript>)<Subscript>6</Subscript>Cl<Subscript>2</Subscript>, a microporous non-zeolitic mineral

The high-pressure behavior of a vanadinite (Pb₁₀(VO₄)₆Cl₂, a = b = 10.3254(5), c = 7.3450(4) Å, space group P6₃/m), a natural microporous mineral, has been investigated using in-situ HP-synchrotron X-ray powder diffraction up to 7.67 GPa with a diamond anvil cell under hydrostatic conditions. No phase transition has been observed within the pressure range investigated. Axial and volume isothermal Equations of State (EoS) of vanadinite were determined. Fitting the P–V data with a third-order Birch-Murnaghan (BM) EoS, using the data weighted by the uncertainties in P and V, we obtained: V ₀ = 681(1) Å³, K ₀ = 41(5) GPa, and K′ = 12.5(2.5). The evolution of the lattice constants with P shows a strong anisotropic compression pattern. The axial bulk moduli were calculated with a third-order “linearized” BM-EoS. The EoS parameters are: a ₀ = 10.3302(2) Å, K ₀(a) = 35(2) GPa and K′(a) = 10(1) for the a-axis; c ₀ = 7.3520(3) Å, K ₀(c) = 98(4) GPa, and K′(c) = 9(2) for the c-axis (K ₀(a):K ₀(c) = 1:2.80). Axial and volume Eulerian-finite strain (fe) at different normalized stress (Fe) were calculated. The weighted linear regression through the data points yields the following intercept values: Fe _a (0) = 35(2) GPa for the a-axis, Fe _c (0) = 98(4) GPa for the c-axis and Fe _V (0) = 45(2) GPa for the unit-cell volume. The slope of the regression lines gives rise to K′ values of 10(1) for the a-axis, 9(2) for the c-axis and 11(1) for the unit cell-volume. A comparison between the HP-elastic response of vanadinite and the iso-structural apatite is carried out. The possible reasons of the elastic anisotropy are discussed.