Lacustrine shore platforms at Lake Waikaremoana,North Island,New Zealand

This paper examines the morphology and processes governing the development of shore platforms at Lake Waikaremoana, North Island, New Zealand. Shore platforms at Lake Waikaremoana are recent features, and were formed when a new sequence of shoreline development was initiated, due to lowering of the lake by 5 m in 1946 for hydroelectric power development. Three predominant platform morphologies were identified around the lake. These include gently sloping platforms (c.1·5 to 3·9°), ramp platforms (c.6·8 to 9·2°), and concave ramp platforms (c.7·9 to 12°). Platform widths ranged from 11 to 31 m, with the gently sloping platforms characterized by the widest morphologies. Erosion rates were estimated using perched sandstone boulders and were found to range from 3·4 to 12·5 mm a^?1, with a mean erosion rate of 5·9 mm a^?1. Higher rates of erosion were identified at lower platform elevations, due to a greater frequency of wetting and drying cycles coincident with storm waves, while lower erosion rates were identified at higher elevations. Field evidence suggests that shore platforms at Lake Waikaremoana were likely initiated and continue to develop as a result of subaerial wetting and drying cycles. Waves, coincident with fluctuating lake levels, play an important role by removing the weathered material from the platforms, and appear to control the width of the platforms. A conceptual model of platform development is presented, and analogies are drawn between this model, and the formation of shore platforms in oceanic environments. Copyright © 2002 John Wiley & Sons, Ltd.     

Rock coast inheritance: an example from Galicia,northwestern Spain

A shore platform on the western coast of Galicia in northwestern Spain has been inherited from interglacial stages when sea level was similar to today. The wide, gently sloping intertidal platform is backed in places by supratidal rock ledges, and in other places by a steeper and narrower supratidal ramp. The gradient of the intertidal platform is consistent with the relationship between platform gradient and tidal range, but the slope of the ramp is much too high. The abandoned and degraded sea cliff is grass-covered along most of this coast, and the ledges and the ramp, which extend up to several metres above the highest tides, are covered by lichen and, in places, by salt-tolerant plants. Radiocarbon-dated sediments in the cliff, which range up to 36 000 years in age, lie on top of an ancient beach deposit. The former beach, remnants of which are found in situ on the ramp and rock ledges, as well as two caves that are filled with the dated sediments, are probably last interglacial in age. The morphological and sedimentary evidence suggests that the supratidal ramp and ledges were also formed during the last interglacial stage, whereas the wider intertidal platform is probably the product of several older interglacials, when sea level was generally similar to today. A general model is proposed for the inheritance of shore platforms in macro- and microtidal environments. Copyright © 1999 John Wiley & Sons, Ltd.     

DOWNVALLEY GRADIENTS IN FLOW PATTERNS,SEDIMENT TRANSPORT AND CHANNEL MORPHOLOGY IN A SMALL MACROTIDAL ESTUARY: DIPPER HARBOUR CREEK,NEW BRUNSWICK,CANADA

Dipper Harbour Creek's lower reaches run through a narrow salt marsh on the Bay of Fundy, New Brunswick, Canada. This 2 km long section of the creek constitutes an extreme example of a tide-dominated estuary exhibiting strong downvalley morphology and sedimentology gradients. Dipper Harbour Creek drains a basin of roughly 8.8 km², but except during the spring snowmelt freshet, tidal flow so overshadows freshwater flow within the salt marsh reach that the system essentially functions as a tidal creek. To identify and explain the main geomorphic processes controlling the creek system, records were collected in summer 1993 of tidal stage and velocity fluctuations, sand dune migration rates, bed material composition, channel cross-sectional geometry and channel sinuosity. Bed materials become progressively finer upvalley, with deposits of medium to coarse sands concentrated in the highly sinuous central reach of the creek during the summer. Current velocities within the creek are strongly flood-dominant, featuring a consistent low-stage peak in flood velocity, a secondary high-stage flood surge, and a weaker ebb peak occurring around bankfull stage. Under summer low freshwater discharge conditions, the predominant direction of bed sand transport is upvalley. The spring freshet, however, causes a major downvalley shift of sand deposits, suggesting a seasonal cycling of medium to coarse sands within Dipper Harbour Creek.     

下粗上细的苏20新井结构及其监测效能分析

本文介绍了苏20新井下粗上细结构及成井工艺,其中上部套管内径为146mm,下部套管内径为180mm。对其监测效能进行了分析,并从日潮差、峰谷出现时间、M_2波潮汐因子等角度比较不同井孔结构的响应能力。同时,对地震系统今后建井给出了借鉴性的建议,即按下粗上细新结构、新工艺施工成井,提高地震观测井对地壳应力应变的响应能力。     

Study of stream temperature dynamics and corresponding heat fluxes within Miramichi River catchments (New Brunswick,Canada)

Water temperature is a key physical habitat determinant in lotic ecosystems as it influences many physical, chemical, and biological properties of rivers. Hence, a good understanding of the thermal regime of rivers and river heat fluxes is essential for effective management of water and fisheries resources. This study dealt with the modelling of river water temperature using a deterministic model. This model calculated the different heat fluxes at the water surface and from the streambed using different hydrometeorological conditions. The water temperature model was applied on two watercourses of different sizes and thermal characteristics, but within a similar meteorological region, namely, the Little Southwest Miramichi River and Catamaran Brook (New Brunswick, Canada). The model was also applied using microclimate data, i.e. meteorological conditions within the river environment (1–2 m above the water surface), for a better estimation of river heat fluxes. Water temperatures at different depths within the riverbed were also used to estimate the streambed heat fluxes. Results showed that microclimate data were essential to get accurate estimates of the surface heat fluxes. Results also showed that for larger river systems, the surface heat fluxes were generally the dominant component of the heat budget with a correspondingly smaller contribution from the streambed. As watercourses became smaller and groundwater contribution more significant, the streambed contribution became important. For instance, approximately 80% of the heat fluxes occurred at the surface for Catamaran Brook (20% from the streambed) whereas the Little Southwest Miramichi River showed values closer to 90% (10% from the streambed). As was reported in previous studies, the solar radiation input dominated the contribution to the heat gain at 63% for Catamaran Brook and 89% for Little Southwest Miramichi River. Copyright © 2011 John Wiley & Sons, Ltd.     

Tidal Stress/Strain and the b-values of Acoustic Emissions at the Underground Research Laboratory, Canada

The correlation between the b-values of acoustic emissions (AEs) and the phase of the moon was investigated at the Underground Research Laboratory (URL) in Canada. The same data as those used in Iwata (2002) were examined, which showed that the occurrence of AEs is correlated with the phase of the moon. It was expected, therefore, that the b-value of the AEs would also be sensitive to tidal stress/strain fluctuations. We investigated the variation of the b-values as a function of the phase of the moon. Results show that b-values immediately following the times of full/new moon are higher than those at other times. Using AIC (Akaike Information Criterion) and random (Monte Carlo) simulations, it was confirmed that this feature is statistically significant. We also investigated whether or not there was a change in the b-values immediately before the times of full/new moon, but no statistically significant change was observed. The results suggest that the effect of stress/strain fluctuations on AE occurrences at the URL is asymmetric to the times of full/new moon.All authors are members of the Academic Robotics Group. In listing The Academic Robotics Group, the authors are endeavoring to place each of the participant institutions on an equal footing in terms of effort and authorship. M. A. Talamini is serving as presenter.     

River evaporation,condensation and heat fluxes within a first‐order tributary of Catamaran Brook (New Brunswick,Canada)

Stream temperature plays an important role in many biotic and abiotic processes, as it influences many physical, chemical and biological properties in rivers. As such, a good understanding of the thermal regime of rivers is essential for effective fisheries management and the protection aquatic habitats. Moreover, a thorough understanding of underlying physical processes and river heat fluxes is essential in the development of better and more adaptive water temperature models. Very few studies have measured river evaporation and condensation and subsequently calculated corresponding heat fluxes in small tributary streams, mainly because microclimate data (data collected within the stream environment) are essential and rarely available. As such, the present study will address these issues by measuring river evaporation and condensation in tributary 1 (Trib 1, a small tributary within Catamaran Brook) using floating minipans. The latent heat flux and other important fluxes were calculated. Results showed that evaporation was low within the small Trib 1 of Catamaran Brook, less than 0.07 mm day^?1. Results showed that condensation played an important role in the latent heat flux. In fact, condensation was present during 34 of 92 days (37%) during the summer, which occurred when air temperature was greater than water temperature by 4–6 °C. Heat fluxes within this small stream showed that solar radiation dominated the heat gains and long‐wave radiation dominated the heat losses. © 2015 Her Majesty the Queen in Right of Canada. Hydrological Processes. © 2015 John Wiley & Sons, Ltd.     

Long‐wave radiation and heat flux estimates within a small tributary in Catamaran Brook (New Brunswick,Canada)

River water temperature is an important water quality parameter that also influences most aquatic life. Physical processes influencing water temperature in rivers are highly complex. This is especially true for the estimation of river heat exchange processes that are highly dependent on good estimates of radiation fluxes. Furthermore, very few studies were found within the stream temperature dynamic literature where the different radiation components have been measured and compared at the stream level (at microclimate conditions). Therefore, this study presents results on hydrometeorological conditions for a small tributary within Catamaran Brook (part of the Miramichi River system, New Brunswick, Canada) with the following specific objectives: (1) to compare between stream microclimate and remote meteorological conditions, (2) to compare measured long‐wave radiation data with those calculated from an analytical model, and (3), to calculate the corresponding river heat fluxes. The most salient findings of this study are (1) solar radiation and wind speed are parameters that are highly site specific within the river environment and play an important role in the estimation of river heat fluxes; (2) the incoming, outgoing, and net long‐wave radiation within the stream environment (under the forest canopy) can be effectively calculated using empirical formula; (3) at the study site more than 80% of the incoming long‐wave radiation was coming from the forest; (4) total energy gains were dominated by solar radiation flux (for all the study periods) followed by the net long‐wave radiation (during some periods) whereas energy losses were coming from both the net long‐wave radiation and evaporation. Conductive heat fluxes have a minor contribution from the overall heat budget (<3·5%); (5) the reflected short‐wave radiation at the water surface was calculated on average as 3·2%, which is consistent with literature values. Results of this study contribute towards a better understanding of river heat fluxes and water temperature models as well as for more effective aquatic resources and fisheries management. Copyright © 2011 John Wiley & Sons, Ltd.     

Spatial and temporal distribution of heavy metal concentrations in mussels (Mytilus edulis) from the Baie des Chaleurs, New Brunswick, Canada

Previous studies on heavy metal contamination of the Baie des Chaleurs focus only on industrial centers and overlooked the ecosystem as a whole. To fill this gap, the objective of this study is to establish a baseline of the spatio-temporal distribution of heavy metals in mussels from the Baie des Chaleurs based on the ecosystem approach. Our results show, for the first time, a cadmium contamination in mussels across the south coast of the Baie des Chaleurs and not only in industrial centers. Our results also confirm previous studies showing heavy metal contamination of the Belledune area. This study demonstrates that the use of the ecosystemic approach is essential to obtain a comprehensive picture of environmental contamination in marine ecosystems.     

Sensitivity analysis of a deterministic water temperature model to forest canopy and soil temperature in Catamaran Brook (New Brunswick,Canada)

A coupled deterministic hydrological and water temperature model, CEQUEAU, was modified to include soil temperature and crown closure in its calculation of local advective terms in the heat budget. The modified model was than tested to verify its sensitivity to these modifications. An analysis of the heat budget of a small forested catchment in eastern Canada revealed that the advective term related to interflow plays a significant role in the daily water heat budget, providing on average 28% of the local advective budget (which also includes advective heat terms from surface runoff and groundwater) and nearly 14% of the total heat budget (which includes all radiative terms at the water surface, convection and evaporation, as well as the local advective terms). Relative sensitivity indices (RSIs) were used to verify the impact of the newly introduced parameters and variables. Among them, parameters related to the forest cover (crown closure and leaf area index) have a maximum RSI of ?0·6; i.e. a 100% increase in value produces a 60% decrease in the local advective term. Parameters with the greatest influence are the volume of water contributing to interflow and the amplitude of the net radiative flux at the soil surface, which, if doubled, would double the contribution of the local interflow advective term to the heat budget. Copyright © 2003 John Wiley & Sons, Ltd.     

Using GIS and a digital elevation model to assess the effectiveness of variable grade flow diversion terraces in reducing soil erosion in northwestern New Brunswick,Canada

Flow diversion terraces (FDT) are commonly used beneficial management practice (BMP) for soil conservation on sloped terrain susceptible to water erosion. A simple GIS‐based soil erosion model was designed to assess the effectiveness of the FDT system under different climatic, topographic, and soil conditions at a sub‐basin level. The model was used to estimate the soil conservation support practice factor (P‐factor), which inherently considered two major outcomes with its implementation, namely (1) reduced slope length, and (2) sediment deposition in terraced channels. A benchmark site, the agriculture‐dominated watershed in northwestern New Brunswick (NB), was selected to test the performance of the model and estimated P‐factors. The estimated P‐factors ranged from 0·38–1·0 for soil conservation planning objectives and ranged from 0·001 to 0·45 in sediment yield calculations for water‐quality assessment. The model estimated that the average annual sediment yield was 773 kg ha^?1 yr ^?1 compared with a measured value of 641 kg ha^?1 yr^?1. The P‐factors estimated in this study were comparable with predicted values obtained with the revised universal soil loss equation (RUSLE2). The P‐factors from this study have the potential to be directly used as input in hydrological models, such as the soil and water assessment tool (SWAT), or in soil conservation planning where only conventional digital elevation models (DEMs) are available. Copyright © 2009 John Wiley & Sons, Ltd.