Geomorphic and Climatic Controls on Water Temperature and Streambed Scour, Copper River Delta, Alaska : Implications for Understanding Climate Change Impacts to the Pacific Salmon Egg Incubation Environment

Pacific salmon (Oncorhynchus spp.) face numerous challenges associated with climate change. Most research has emphasized the potential effects of elevated summer water temperatures; however, climatic changes are also projected to significantly alter incubation and rearing habitats during the late autumn, winter, and spring months ("the incubation period"). Along the southern coast of Alaska, projected climatic changes include increases in the frequency of above freezing winter temperatures and reductions in low elevation snowpack. These changes are expected to impact the hydrology of salmon streams by increasing both water temperatures and the magnitude and frequency of winter floods. Projected increases in water temperature may accelerate embryo development, impacting juvenile viability. More powerful and more frequent winter floods could reduce the survival of salmon eggs by increasing streambed scour. Here, I investigate climatic and geomorphic controls of water temperature and potential scour depth at salmon spawning and rearing sites on the Copper River Delta, a large coastal foreland in Southcentral Alaska. In chapter 2, I utilized surface water temperature data collected at 18 sites to test the abilities of regression models to project year-round water temperature metrics based on catchment characteristics (elevation, slope, area, percent lake area) and air-water temperature correlations. Considerable variability in water temperature was observed on spatial and temporal scales. Both temperature maxima and the frequency of freezing conditions were positively correlated with percent lake area and negatively correlated with catchment elevation and slope. Sites with upwelling groundwater and sites with high-relief, high elevation catchments exhibited lower thermal sensitivity and water temperatures are anticipated to be less impacted by projected climatic changes. In chapter 3, I utilized surface and streambed water temperature data collected at 8 spawning sites to compare water temperatures during incubation periods under climatological mean ("severe winter") and anomalously warm ("mild winter") conditions. I also collected stream stage and channel geometry data at a subset of 3 sites and calculated streambed scour at bankfull discharge. The magnitude and seasonality of accumulated thermal units (°C/day) (ATU) within spawning gravels varied significantly between severe and mild winters at shallow flowpath sites, but not at upwelling groundwater sites. When seasonal snow and ice was absent, increases in spring ATU at shallow flowpath sites were particularly significant. Modelled mean scour depths varied from 3 to 72 cm, suggesting the impacts of scour on egg mortality will be variable across the landscape. I conclude that the impacts of projected climatic changes are likely to vary in magnitude across the Copper River Delta, even at small spatial scales, due to heterogeneity in climatic and geomorphic controls

Southern-Tyrrhenian seismicity in space-time-magnitude domain

An analysis is conducted on a catalogue containing more than 2000 seismic events occurred in the southern Tyrrhenian Sea between 1988 and October 2002, as an attempt to characterise the main seismogenetic processes active in the area in space, time and magnitude domain by means of the parameters of phenomenological laws. We chose to adopt simple phenomenological models, since the low number of data did not allow to use more complex laws. The two main seismogenetic volumes present in the area were considered for the purpose of this work. The first includes a nearly homogeneous distribution of hypocentres in a NW steeply dipping layer as far as about 400 km depth. This is probably the seismological expression of the Ionian lithospheric slab subducting beneath the Calabrian Arc. The second contains hypocentres concentrated about a sub-horizontal plane lying atan average depth of about 10 km. It is characterised by a background seismicity spread all over the area and by clusters of events that generally show a direction of maximum elongation. The parameters of the models describing seismogenetically homogeneous subsets of the earthquake catalogue in the three analysis domains, along with their confidence intervals, are estimated and analysed to establish whether they can be regarded as representative of a particular subset

Southern-Tyrrhenian seismicity in space-time-magnitude domain

An analysis is conducted on a catalogue containing more than 2000 seismic events occurred in the southern Tyrrhenian Sea between 1988 and October 2002, as an attempt to characterise the main seismogenetic processes active in the area in space, time and magnitude domain by means of the parameters of phenomenological laws. We chose to adopt simple phenomenological models, since the low number of data did not allow to use more complex laws. The two main seismogenetic volumes present in the area were considered for the purpose of this work. The first includes a nearly homogeneous distribution of hypocentres in a NW steeply dipping layer as far as about 400 km depth. This is probably the seismological expression of the Ionian lithospheric slab subducting beneath the Calabrian Arc. The second contains hypocentres concentrated about a sub-horizontal plane lying at an average depth of about 10 km. It is characterised by a background seismicity spread all over the area and by clusters of events that generally show a direction of maximum elongation. The parameters of the models describing seismogenetically homogeneous subsets of the earthquake catalogue in the three analysis domains, along with their confidence intervals, are estimated and analysed to establish whether they can be regarded as representative of a particular subset

Architectural technologies for life environment: improving sustainability by reusing wastes in novel geopolymeric mortars

Recently, implementing construction to a more sustainable industry has become a focal point in the international debate due to the huge volume of non-renewvable raw materials and energy consumed every year, along with the significant emissions of green-house gases and global warming, often associated to the supplementing industries. Besides, valorisation and reuse of industrial wastes and by-products is a viable alternative to the traditional industrial system, becoming a compelling topic to improve processes and materials sustainability. This paper fo- cuses on the development of a novel class of green geopolymers, worldwide considered a solid and sustainable alternative to Portland cement. Among the most advanced studies on construc- tion materials, many are the accredited advantages in boosting geopolimers as such as excellent properties, optimal durability, low CO2 emissions, low-cost and reproducible manufacture, etc. More particularly, this work discusses an alternative recycling procedure of kraft pulp indus- trial wastes to manufacture the specimens. Requirement, mix design, manufacture and charac- terisation of the novel mortars are reported in light of the relevant application in construction. Furthermore, a preliminary industrial setup and product cost assessment are predicted in order to estimate the commercial feasibility of the operation. Tests indicate that the produced ge- opolymers may efficiently substitute the ordinary Portland cement and can be used as structural material in construction according to the most relevant regulations and technical requirement. More over, other applications may be hypothesised in light of the analysed materials features. Finally, this study indicates that these novel mortars represent an efficient solution to reduce the environmental footprint associated with waste disposal whose valorisation and reuse in geopol- ymers technology is a suboptimal way of gaining financial surplus for the involved industrial players, while contributes for the implementation of a desirable circular economy, centered in the EU and international debate