Stratigraphic analysis of the southwestern quadrant of the Cedar Hills Regional Landfill: Incorporating recent borehole explorations and radiometric dating with previous investigations.

This report presents the results of stratigraphic analysis of the southwestern quadrant of the Cedar Hills Regional Landfill (CHRLF). My report was intended to incorporate the recent Area 8 borehole data into the pre-existing analyses. This analysis was conducted during the preparation of the Area 8 Hydrogeologic Report, but is my independent investigation and does not represent the opinion of UEC or their associates. The CHRLF, in Maple Valley, WA, south of Squak Mountain, is a municipal solid waste landfill that has been in operation since the 1960s. A network of borings, the product of previous investigations, exists for the study area. I utilized the compiled boring logs, previous investigations, and the recently acquired data to produce a series of interpretative cross-sections for the study area. I recognized 9 distinct stratigraphic units, including fill. My interpreted stratigraphic units are similar to those identified in previous investigations such as the Area 7 Hydrogeologic investigation (HDR Engineering and Associates, 2008). These units include pre-Olympia aged non-glacial alluvium, glacial alluvium, and glacial till. Additionally, younger, Vashon-aged deposits of glacial till, recessional outwash, recessional lacustrine, and ice-contact were observed. An isolated “till-like” deposit was observed below the Vashon till. This could possibly represent an older till as mapped by Sweet Edwards (1985) and Booth (1995). I cite the continuity of the lower contact of the Vashon till (Unit 5, Table 2) and the upper contact pre-Vashon non-glacial fluvial deposits (Unit 9, Table 2) as evidence that faults or other structural features do not offset the deposits in the study area. This conclusion supports the findings of the pre-existing body of work within the landfill property and the nearby Queen City Farms property.

Channel Migration and Avulsion Hazards at Sunshine Point Campground, Mount Rainier National Park, Washington

In November 2006, the flood of record on the upper Nisqually River destroyed part of Sunshine Point Campground in Mount Rainier National Park, Washington. The Nisqually River migrated north and reoccupied five acres of its floodplain; Tahoma Creek partially avulsed into the west floodplain, topping banks of an undersized channel and flooding the campground. I assessed hazards to infrastructure at the old campground location, where the Park proposes to rebuild the remaining campground roads and sites. This assessment focuses on two major hazards: northward Nisqually River migration, which may reincorporate the floodplain into the river destroying infrastructure; and Tahoma Creek avulsions, which may flood the campgroud and deposit sediment burying campground infrastructure. I quantify northward migration by: estimating migration rates and changes to channel width; evaluating river occupation of the pre- and post-2006 campground; and estimating scour depths at revetments protecting the campground. I digitized the Nisqually River channels and channel centerlines from maps and images between 1955 and 2013 into a GIS, which I used to estimate migration rate and river width changes. Centerline migration rates average 9 ft/yr along the length of the Nisqually River study reach; at Sunshine Point lateral migration rates average 11 ft/yr. Maximum migration along the study reach was 19 ft/yr between 2006 and 2009. Greater than average migration rates and channel widths correspond to river confluences and include the Tahoma Creek confluence at Sunshine Point. To determine historical channel locations and the frequency that the river occupied different parts of its floodplain, I digitized the river from maps and images between 1903 and 2013. The Nisqually River flows through Sunshine Point Campground in eight out of 15 historical images. I assess scour at revetments protecting infrastructure from the Nisqually River during a 100-year recurrence interval flood using measured cross-sections. During a 100-year flood, the Nisqually River may scour up to 10 feet below the bed elevation. These scour depths can destabilize critical revetments leaving loose unconsolidated riverbanks exposed to Nisqually River flows. To determine the causes, locations, and frequency of flood hazards from Tahoma Creek avulsions, I field map avulsion channels and compare the results with imagery and channel width changes between 1955 and 2013. Mapped avulsion channels occur with swaths of dead vegetation or nascent vegetation; both dead and recent vegetation are visibly distinct from surrounding vegetation in aerial images. Times of changes to these vegetation anomalies correspond to increases in Tahoma Creek channel width. Avulsions have occurred at least three times in the study period: pre-1955, between 1979 and 1984, and in 2006. The 1984 and 2006 avulsions both occur after increases in Tahoma Creek reach averaged width. The NPS is considering two options to rebuild Sunshine Point Campground, both at the same location. The hazards posed by the Nisqually River and Tahoma Creek at Sunshine Point will affect both construction options equally. Migration hazards to the campground may be reduced by limiting the proposed campground infrastructure to an elevated ridge that has not been occupied by the Nisqually River since 1903. The hazards of damage from migration may be reduced by revetments, which were effective in preventing northward Nisqually River migration in 1959 and 1965. Tahoma Creek avulsions are related increased of Tahoma Creek reach averaged widths, which are near a 58- year maximum, and occurred during a 10-year flood in 1984. The campground may be as susceptible to flooding from avulsions during as little as a 10-year flood. A large avulsion may occur with the next significant Tahoma Creek width increase. Glacial retreat has been shown to increase debris flow activity and increase sediment delivery to Mount Rainier rivers. Increased sediment discharge has been correlated with aggradation, which will further encourage Tahoma Creek avulsions.

Geomorphic Impacts of the 2013 Colorado Front Range Flood on Black Canyon Creek and North Fork Big Thompson River

In September 2013, the Colorado Front Range experienced a five-day storm that brought record-breaking precipitation to the region. As a consequence, many Front Range streams experienced flooding, leading to erosion, debris flows, bank failures and channel incision. I compare the effects that debris flows and flooding have on the channel bar frequency, frequency and location of wood accumulation, and on the shape and size of the channel along two flood impacted reaches located near Estes Park and Glen Haven, Colorado within Rocky Mountain National Park and Arapaho-Roosevelt National Forest: Black Canyon Creek (BCC) and North Fork Big Thompson River (NFBT). The primary difference between the two study areas is that BCC was inundated by multiple debris flows, whereas NFBT only experienced flooding. Fieldwork consisted of recording location and size of large wood and channel bars and surveying reaches to produce cross-sections. Additional observations were made on bank failures in NFBT and the presence of boulders in channel bars in BCC to determine sediment source. The debris flow acted to scour and incise BCC causing long-term alteration. The post-flood channel cross-sectional area is as much as 7 to 23 times larger than the pre-flood channel, caused by the erosion of the channel bed to bedrock and the elimination of riparian vegetation. Large wood was forced out of the stream channel and deposited outside of the bankfull channel. Flooding in NFBT caused bank erosion and widening that contributed sediment to channel bars, but accomplished little stream-bed scour. As a result, there was relatively little damage to mid-channel and riparian vegetation, and most large wood remained within the wetted channel.

River and Hillslope Response to Localized Uplift Along a Left Bend of the San Andreas Fault, Santa Cruz Mountains, CA

Studying landscape evolution of the Earthís surface is difficult because both tectonic forces and surface processes control its response to perturbation, and ultimately, its shape and form. Researchers often use numerical models to study erosional response to deformation because there are rarely natural settings in which we can evaluate both tectonic activity and topographic response over appropriate time scales (103-105 years). In certain locations, however, geologic conditions afford the unique opportunity to study the relationship between tectonics and topography. One such location is along the Dragonís Back Pressure Ridge in California, where the landscape moves over a structural discontinuity along the San Andreas Fault and landscape response to both the initiation and cessation of uplift can be observed. In their landmark study, Hilley and Arrowsmith (2008) found that geomorphic metrics such as channel steepness tracked uplift and that hillslope response lagged behind that of rivers. Ideal conditions such as uniform vegetation density and similar lithology allowed them to view each basin as a developmental stage of response to uplift only. Although this work represents a significant step forward in understanding landscape response to deformation, it remains unclear how these results translate to more geologically complex settings. In this study, I apply similar methodology to a left bend along the San Andreas Fault in the Santa Cruz Mountains, California. At this location, the landscape is translated through a zone of localized uplift caused by the bend, but vegetation, lithology, and structure vary. I examine the geomorphic response to uplift along the San Andreas Fault bend in order to determine whether predicted landscape patterns can be observed in a larger, more geologically complex setting than the Dragonís Back Pressure Ridge. I find that even with a larger-scale and a more complex setting, geomorphic metrics such as channel steepness index remain useful tools for evaluating landscape evolution through time. Steepness indices in selected streams of study record localized uplift caused by the restraining bend, while hillslope adjustment in the form of landsliding occurs over longer time scales. This project illustrates that it is possible to apply concepts of landscape evolution models to complex settings and is an important contribution to the body of geomorphological study.

The role of large woody debris and riparian forest in channel avulsion in the Carbon River, Mount Rainier National Park, Washington

A specific type of natural log jam in the upper alluvial reach of the Carbon River was found to influence secondary channel avulsion, causing flooding hazards to the adjacent Carbon River Road in the northwest quadrant of Mount Rainier National Park, Washington. The fence-like natural log jam was characterized by large woody debris buttressed horizontally against standing riparian trees (i.e. ìfence railsî and ìfence postî). The objectives of this report are two-fold. First, physical characteristics and spatial distribution were documented to determine the geomorphic controls on the fence-like log jams. Second, the function and timing of the natural log jam in relation to channel avulsion was determined to provide insight into flooding hazards along the Carbon River Road. The fence-like log jams are most abundant in the upper reaches of the Carbon River between 3.0 and 5.5 kilometers from the Carbon Glacier terminus, where longitudinal gradient significantly decreases from about 0.06 to 0.03. Sediment impoundment can occur directly upstream of the fence-like log jam, creating vertical bed elevation difference as high as 1.32 meters, and can form during low magnitude, high frequency flood event (3.5-year recurrence interval). In some locations, headcuts and widening of secondary channel were observed directly to the side of the log jams, suggesting its role in facilitating secondary channel avulsions. Areas along the Carbon River Road more prone to damages from avulsion hazards were identified by coupling locations of the log jams and Relative Water Surface Elevation map created using the 1-meter 2012 Light Detection and Ranging Digital Elevation Map. Ultimately, the results of this report may provide insight to flooding hazards along the Carbon River Road from log jam-facilitated channel avulsion.

The terrestrial Miocene biota of southern New Zealand

Known Early-Middle Miocene terrestrial strata of southern New Zealand are represented by alluvial plain and lacustrine sediments. A vertebrate fauna including fish, ducks, and crocodiles populated Lake Manuherikia, with abundant mussels, gastropods, and stromatolites occupying the near-shore areas of the lake. A diverse vegetation covered the surrounding broad fluvial plains that extended to the coastal margins. Initially this was largely rainforest, which varied according to habitat and to changing climate. In particular, the climate and ecology appear to have fluctuated across the two major thresholds of fire/no-fire and of peat accumulation and no-peat. A major climate change, possibly the sharp global deterioration in conditions at about 14 Ma, profoundly changed the vegetation. Rainforest continuity fragmented, and herblands became widespread. Leaf fossils effectively disappear from the record at this time.

Early-Middle Jurassic stratigraphy of the Fortrose-Chaslands region, southernmost South Island, New Zealand

The 40 km of coastline from Fortrose to Chaslands Mistake (southeastern South Island, New Zealand) comprises sediments that are part of the Early-Middle Jurassic of the Murihiku Terrane. The sediments are dominantly fluvial with some marine beds and alluvial fan deposition, and display an evolution of fluvial style which progresses from perennial flow to seasonal flow. The McPhee Cove Conglomerate is a prominent unit to the north. It has been used to separate two formations which would otherwise, on inherent lithological grounds, be difficult to distinguish. This paper discusses several similar conglomerates which occur in the south, but which are separated from the type area of the McPhee Conglomerate by major tectonic disruption. Hence, the existing lithostratigraphic nomenclature to the north, including the McPhee Cove Conglomerate, cannot be simply extended southwards. The Fortrose-Chaslands area appears to consist of two tectonic blocks, the Slope Point Block and the Brothers Block, which are separated from each other and from the adjacent Papatowai Block by major strike faults (or fault zones). A change is proposed to the existing stratigraphy which involves recognising all terrestrial sediments as part of the False Island Formation. Four prominent clast-supported conglomerate horizons are named as members of the False Islet Formation: the White Head Conglomerate, Black Bluff Conglomerate. Hoiho Conglomerate, and Slope Point Conglomerate Members. The latter contains five named conglomerate beds.

Focused beam reflectance technique for in situ particle sizing in wastewater treatment settling tanks

Due to the complexities involved with measuring activated sludge floc size distributions, this parameter has largely been ignored by wastewater researchers and practitioners. One of the major reasons has been that instruments able to measure particle size distributions were complex, expensive and only provided off-line measurements. The Focused Beam Reflectance Method (FBRM) is one of the rare techniques able to measure the particle size distribution in situ. This paper introduces the technique for monitoring wastewater treatment systems and compares its performance with other sizing techniques. The issue of the optimal focal point is discussed, and similar conclusions as found in the literature for other particulate systems are drawn. The study also demonstrates the capabilities of the FBRM in evaluating the performance of settling tanks. Interestingly, the floc size distributions did not vary with position inside the settling tank flocculator. This was an unexpected finding, and seriously questioned the need for a flocculator in the settling tank. It is conjectured that the invariable size distributions were caused by the unique combination of high solids concentration, low shear and zeolite dosing. (C) 2004 Society of Chemical Industry.

Pollen transport and deposition in riverine and marine environments within the humid tropics of northeastern Australia

Mechanisms of pollen transport in the humid tropics region of northeastern Australia were investigated to support the interpretation of a long Quaternary pollen record from ODP Site 820 located on the adjacent continental slope. Pollen analysis of surface sediment samples from the channels of two major river catchments demonstrated internal consistency in pollen spectra and little fluvial pollen sorting in relation to sediment variation. Differences in modem pollen spectra between catchments reflect existing variation in vegetation cover that, in turn, reflects climatic differences between catchments. Recent pollen spectra from top samples of the ODP core have sufficient in common with the riverine samples to suggest that the rivers are contributing a major pollen component to the offshore sediments, but these have been size sorted by marine action. Recent pollen samples from core tops taken from the Grafton Passage on the continental shelf that was thought to be the major passage for pollen transport to ODP Site 820 show significant differences to both riverine and ODP samples and suggest that pollen are dispersed across the continental shelf and through the outer Great Barrier Reef system in a more complex way than anticipated. (c) 2004 Elsevier B.V. All rights reserved.

A worldwide correlation for exponential bed particle size variation in subaerial aqueous flows

The particle size of the bed sediments in or on many natural streams, alluvial fans, laboratory flumes, irrigation canals and mine waste deltas varies exponentially with distance along the stream. A plot of the available worldwide exponential bed particle size diminution coefficient data against stream length is presented which shows that all the data lie within a single narrow band extending over virtually the whole range of stream lengths and bed sediment particle sizes found on Earth. This correlation applies to both natural and artificial flows with both sand and gravel beds, irrespective of either the solids concentration or whether normal or reverse sorting occurs. This strongly suggests that there are common mechanisms underlying the exponential diminution of bed particles in subaerial aqueous flows of all kinds. Thus existing models of sorting and abrasion applicable to some such flows may be applicable to others. A comparison of exponential laboratory abrasion and field diminution coefficients suggests that abrasion is unlikely to be significant in gravel and sand bed streams shorter than about 10 km to 100 km, and about 500 km, respectively. Copyright (C) 1999 John Wiley & Sons, Ltd.

Triassic stratigraphy and sedimentology in central England

The Triassic rocks of Central England consist of three major stratigraphic units: Sherwood Sandstone Group, Mercia Mudstone Group, and Penarth Group. The lower part of the Sherwood Sandstone Group represented by the Kidderminster, Cannock Chase, and Polesworth Formations represents pebbly braided river deposits carried by a major fluvial system flowing to the North-Northwest. The upper part of the Sherwood Sandstone Group includes the Wildmoor and Bromsgrove Sandstone Formations, the deposits of a sandy alluvial system. The Mercia Mudstone Group represents quiet-water deposits of marginal palya type which were subjected to occasional marine flooding. The overlying Penarth Group represent shallow marine and lagoonal environment associated with the Rhaetian marine transgression. The mineralogy of the Triassic sandstones indicates that the main source was from medium to low rank metamorphic rocks with additional supplies from igneous and metamorphic rocks. The study of size-composition trends shows that the climate was semiarid in early Triassic time and became more humid later. The Triassic sandstones show a variety of diagenetic features typical of continental red beds; these include: 1. the dissolution of unstable ferromagnesian silicates, 2. the replacement of detrital grains by clay, 3. the pseudomorphism of biotite by haematite, and 4. the formation of a suite of authigenic minerals including quartz, illite, mixed-layer illite-montmorillonite, kaolinite, k-feldspar, haematite, titanium oxide and later carbonate cement. Palaeomagnetic studies of selected samples show that the magnetization is muticomponent with the various components being carried by different textural phases of haematite.

The sedimentology and diagenesis of Lower Permian (Rotliegend) sediments: (onshore U.K. and southern North Sea). Available in 2 volumes.

The thesis provides a comparative study of both sedimentology and diagenesis of Lower Permian (Rotliegend) strata, onshore and offshore U.K. (Southern North Sea). Onshore formations studied include the Bridgnorth, Penrith and Hopeman Sandstone, and are dominated by aeolian facies, with lesser amounts of interbedded fluvial sediments. Aeolian and fluvial strata in onshore basins typically grade laterally into alluvial fan breccias at basin margins. Onshore basins represent proximal examples of Rotliegend desert sediments. The Leman Sandstone Formation of the Ravenspurn area in the Southern North Sea displays a variety of facies indicative of a distal sedimentological setting; Aeolian, fluvial, sabkha, and playa lake sediments all being present. "Sheet-like" geometry of stratigraphical units within the Leman Sandstone, and alternation of fluvial and aeolian deposition was climatically controlled. Major first order bounding surfaces are laterally extensive and were produced by lacustrine transgression and regression from the north-west. Diagenesis within Permian strata was studied using standard petrographic microscopy, scanning electron microscopy, cold cathodo-Iuminescence, X-ray diffraction clay analysis, X-ray fluorescence spectroscopy, fluid inclusion microthermometry, and K-Ar dating of illites. The diagenesis of Permian sediments within onshore basins is remarkably similar, and a paragenetic sequence of early haematite, illitic clays, feldspar, kaolinite, quartz and late calcite is observed. In the Leman Sandstone formation, authigenic mineralogy is complex and includes early quartz, sulphates and dolomite, chlorite, kaolinite, late quartz, illite and siderite. Primary lithological variation, facies type, and the interdigitation and location of facies within a basin are important initial controls upon diagenesis. Subsequently, burial history, structure, the timing of gas emplacement, and the nature of sediments within underlying formations may also exersize significant controls upon diagenesis within Rotliegend strata.

Genetic studies of Cu-Pb-Zn mineralisation in Triassic red beds of Western Europe

Continental red bed sequences are host, on a worldwide scale, to a characteristic style of mineralisation which is dominated by copper, lead, zinc, uranium and vanadium. This study examines the features of sediment-hosted ore deposits in the Permo-Triassic basins of Western Europe, with particular reference to the Cu-Pb-Zn-Ba mineralisation in the Cheshire Basin, northwest England, the Pb-Ba-F deposits of the Inner Moray Firth Basin, northeast Scotland, and the Pb-rich deposits of the Eifel and Oberpfalz regions, West Germany. The deposits occur primarily but not exclusively in fluvial and aeolian sandstones on the margins of deep, avolcanic sedimentary basins containing red beds, evaporites and occasionally hydrocarbons. The host sediments range in age from Permian to Rhaetian and often contain (or can be inferred to have originally contained) organic matter. Textural studies have shown that early diagenetic quartz overgrowths precede the main episode of sulphide deposition. Fluid inclusion and sulphur isotope data have significantly constrained the genetic hypotheses for the mineralisation and a model involving the expulsion of diagenetic fluids and basinal brines up the faulted margins of sedimentary basins is favoured. Consideration of the development of these sedimentary basins suggests that ore emplacement occurred during the tectonic stage of basin evolution or during basin inversion in the Tertiary. ð34S values for barite in the Cheshire Basin range from 13.8% to 19.3% and support the theory that the Upper Triassic evaporites were the principal sulphur source for the mineralisation and provided the means by which mineralising fluids became saline. In contrast, δ34S values for barite in the Inner Moray Firth Basin (mean δ34S = + 29%) are not consistent with simple derivation of sulphur from the evaporite horizons in the basin and it is likely that sulphur-rich Jurassic shales supplied the sulphur for the mineralisation at Elgin. Possible sources of sulphur for the mineralisation in West Germany include hydrothermal vein sulphides in the underlying Devonian sediments and evaporites in the overlying Muschelkalk. Textural studies of the deeply buried sandstones in the Cheshire Basin reveal widespread dissolution and replacement of detrital phases and support the theory that red bed diagenetic processes are responsible for the release of metals into pore fluids. The ore solutions are envisaged as being warm (60-150%C), saline (9-22 wt % equiv NaCl) fluids in which metals were transported as chloride complexes. The distribution of δ34S values for sulphides in the Cheshire Basin (-1.8% to + 16%), the Moray Firth Basin (-4.8% to + 27%) and the German Permo-Triassic Basins (-22.2% to -12.2%) preclude a magmatic source for the sulphides and support the contention that sulphide precipitation is thought to result principally from sulphate reduction processes, although a decrease in temperature of the ore fluid or reaction with carbonates may also be important. Methane is invoked as the principal reducing agent in the Cheshire Basin, whilst terrestrial organic debris and bacterial reduction processes are thought to have played a major part in the genesis of the German ore deposits.

Vegetation dynamics and their implications for the management of wetlands in the lowlands of Nepal

The maintenance of species richness is often a priority in the management of nature reserves, where consumptive use of resources is generally prohibited. The purpose of this research was to improve management by understanding the vegetation dynamics in the lowlands of Nepal. The objectives were to determine vegetation associations in relation to environments and human-induced disturbances that affect vegetation dynamics on floodplains, where upstream barrages had altered flooding patterns, and consumptive use of plant resources was influencing natural processes. Floodplain vegetation in relation to physical environments and disturbances were studied along transects, perpendicular to the course of the Mahakali River in the western Terai, Nepal. Forest structural changes were studied for three years in ten plots. A randomized split-block experiment with nine burning and grazing treatments was performed in seasonally flooded grasslands. A semi-structured questionnaire was used to assess people's socio-economic status, natural resource use patterns and conservation attitudes. ^ Elevation, soil organic matter, nitrogen, percentage of sand and grazing intensity were significant in delineating herbaceous vegetation assemblages, whereas elevation and livestock grazing were significant in defining forest type boundaries. On the floodplain islands, highly grazed Dalbergia sissoo-Acacia catechu forests were devoid of understory woody vegetation, but the lightly grazed D. sissoo-mixed forests had a well-developed second canopy layer, comprising woody species other than D. sissoo and A. catechu. In grasslands, species richness and biomass production were highest at intermediate disturbance level represented by the lightly grazed and ungrazed early-burned treatments. Ethnicity, education and resource use patterns were important in influencing conservation attitudes. A succession towards the mixed forests would occur in D. sissoo-dominated floodplain forests, where dams and barrages reduce flooding and associated fluvial processes, and if livestock grazing is stopped, as occasionally suggested by nature conservationists. In seasonally flooded grasslands, early burning with moderate grazing would enhance the species diversity and productivity. There is a need to implement a participatory integrated wetland management plan, to include community development, education and off farm income generation, to assure participatory conservation and management of wetlands in Nepal. ^

Glaisdale Beck diversion scheme - channel change and suspended sediment response

This paper describes the implementation of a novel mitigation approach and subsequent adaptive management, designed to reduce the transfer of fine sediment in Glaisdale Beck; a small upland catchment in the UK. Hydro-meteorological and suspended sediment datasets are collected over a two year period spanning pre- and post-diversion periods in order to assess the impact of the channel reconfiguration scheme on the fluvial suspended sediment dynamics. Analysis of the river response demonstrates that the fluvial sediment system has become more restrictive with reduced fine sediment transfer. This is characterised by reductions in flow-weighted mean suspended sediment concentrations from 77.93 mg/l prior to mitigation, to 74.36 mg/l following the diversion. A Mann-Whitney U test found statistically significant differences (p < 0.001) between the pre- and post-monitoring median SSCs. Whilst application of one-way analysis of covariance (ANCOVA) on the coefficients of sediment rating curves developed before and after the diversion found statistically significant differences (p < 0.001), with both Log a and b coefficients becoming smaller following the diversion. Non-parametric analysis indicates a reduction in residuals through time (p < 0.001), with the developed LOWESS model over-predicting sediment concentrations as the channel stabilises. However, the channel is continuing to adjust to the reconfigured morphology, with evidence of a headward propagating knickpoint which has migrated 120 m at an exponentially decreasing rate over the last 7 years since diversion. The study demonstrates that channel reconfiguration can be effective in mitigating fine sediment flux in upland streams but the full value of this may take many years to achieve whilst the fluvial system, slowly readjusts.