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This paper illustrates the scope and contribution that the discipline of geomorphology can offer in environmental litigation. The case in question was filed by two plaintiffs who contended that the construction of a storage facility on an adjacent property had caused significant disturbance of the topsoil, and that runoff from the impermeable surfaces (e.g., roofs, driveways) had exacerbated the problem by eroding and transporting soil and fill material from the facility directly into three ponds owned by them. They sued for $1.6 million to cover dredging, restoration of the ponds, and disposal of the sediment. Utilizing a range of geomorphological techniques, I was able to determine the most likely source area(s) of eroded sediment within the basin and quantify the extent to which the defendant's property contributed runoff and sediment to the ponds. The lawsuit was dismissed before ever going to trial. In the paper, I discuss the steps involved in the process of being an expert witness and also share some of the advice I have received from attorneys with whom I have worked. I emphasize the importance of setting any case study within a larger spatial context and encourage my fellow geomorphologists to become involved as experts in litigation because, in most instances, we can contribute to an appropriate outcome. [ABSTRACT FROM AUTHOR]

We consider finite groups with a given number of subgroups. With a carefully chosen definition of "similar," we find that for each positive integer k, the groups with exactly k subgroups fall into a finite list of similarity classes. [ABSTRACT FROM AUTHOR]

Kennedy's (1972) short, but classic, paper examines the validity of the concept of ‘bankfull’ as the channel-forming discharge and how that may apply to underfit streams. She argues that the 1.5 year recurrence interval equals bankfull assumption is invalid in many settings and leads to unnecessarily complex explanation of underfit meander wavelengths. Kennedy, who passed away in February 2014, is also remembered as a demanding educator who loved geomorphology, but even more so, her students. [ABSTRACT FROM AUTHOR]

Abstract: Channel characterization and instream wood surveys demonstrate the spatial complexity of an ungauged, tropical headwater stream (HWS) in the Tilarán Mountains of Costa Rica. Throughout the stream course, we characterized 29 individual reaches based on their morphological organization and instream wood occurrences. Bifurcated reaches were the most numerous and consistently distributed. They also had the highest values of wood abundance and loading and contained the majority of unattached instream wood. We selected two bifurcated reaches for ultrahigh resolution terrestrial laser scanning (TLS) surveys. Orthographic TLS produced millimeter-resolution point cloud data sets from which 2cm, planimetric-resolution digital elevation models (DEMs) of the channel surface were derived for both reaches. Cross-sectional surveys of these DEMs, using the River Bathymetry Toolkit (RBT), produced hydraulic geometries at two flow levels (high and low) for every meter-length of channel reach. We input these geometries into a one-dimensional, analytical model to demonstrate the downstream evolution of mean stream power through varying morphology elements. Mean stream power variation displays a regular pattern through the vertical modulation of step-pool sequences, but this regular pattern is lost through channel widening and bifurcation. Reach geometric data indicates that increasing width-to-depth ratio is the most notable feature of channel bifurcation and corresponds to a reduction in slope and roughness variation. This primary understanding of channel dynamics denotes the complex organization of a tropical HWS and promotes further research into tropical HWS systems. [Copyright &y& Elsevier]

Abstract: Wind energy is one of the fastest growing sources of power generation in the world. While general public and political support for wind energy is often high, siting wind farms frequently raises concerns in local communities, and individual projects often fail because of effective public opposition. This paper presents the results of a postal and online survey questionnaire that explores public perceptions of wind energy in two of the most important states for wind development, Texas and Iowa. The goal is a better understanding of public reactions to large-scale wind developments as a prerequisite of more widespread use of renewable energy resources. We found a high level of public support for wind energy, with more than two-thirds of respondents being in favor of building more wind farms either in their community or within the U.S. as a whole. Given that the majority of respondents had a very high level of concern for the general environment, we also found that almost two-thirds of respondents counter-intuitively indicated that producing electricity using fossil fuels is not detrimental to the environment, and that they had little concern for global climate change. Our results suggest that arguing for more renewable sources of energy based on reducing our carbon footprint is less persuasive in these communities than simply approaching it from the perspective of wind being a clean and safe source of energy. More than two-thirds of respondents felt their county had benefited economically from the wind farms and that they were a source of job creation in the county. Support for wind power in these communities is associated far more with socioeconomic factors than foundational aesthetic or moral values, with wind farms perceived as the vehicle that will reverse economic decline. [Copyright &y& Elsevier]

Rivers crossing coastal plains are often inefficient conveyors of sediment, so that changes in upstream sediment dynamics are not evident at the river mouth. Extensive accommodation space and low stream power often result in extensive alluvial storage upstream of estuaries and correspondingly low sediment loads at the river mouth. However, gaging stations with sediment records are typically well upstream of the coast, and thus tend to overestimate sediment yields by under-representing the lower coastal plain and because there is often a net loss of sediment in lower coastal plain reaches. Studies of alluvial sediment storage have generally focused on accommodation space, but, using examples from Texas, we show that low transport capacity controlled largely by slope is a crucial factor. [Copyright &y& Elsevier]

Abstract: Algorithms are described for the enumeration and recognition of groups whose order is a product of distinct primes. The focus is on providing access to isomorphism classes of such groups by computing representatives as needed rather than storing a large database of precomputed groups. [Copyright &y& Elsevier]

Summary: Conceptual models of river-estuary interaction are typically based on a notion of systematic downstream change in the intensity of fluvial processes. Low slopes, backwater effects, and effects of antecedent topography and landforms may complicate downstream tends in water and sediment flux in coastal plain rivers. An analysis of the lower Trinity River, Texas shows no consistent downstream pattern of increases or decreases in the discharge, stream power, or water surface slope. Flows may decrease downstream due to coastal backwater effects in the lowermost reaches, and due to diversion of flow into valley-bottom depressions during high flows in both the fluvial and fluvial-estuarine transition reaches. In general, however, stream power and slope decrease in the lower reaches, consistent with earlier findings of limited fluvial sediment delivery to the coastal zone. Some tributaries may become distributaries at high but sub-bankfull flows, as backwater effects reverse flows into depressions associated with paleomeanders. The paleomeanders, and possibly the locations of these “reversible” channels, are related to antecedent topography associated with aggradation/degradation cycles over the past 100Ka. Low-gradient coastal plain rivers may not function as simple conduits from land to sea. Further, the transition from fluvial to coastal dominance may be variable along the river, with the variability controlled not just by the relative magnitude of river and tidal or backwater forcing, but also by valley topography controlled in part by antecedent landforms. [Copyright &y& Elsevier]

Coastal and marine sedimentary archives are sometimes used as indicators of changes in continental sediment production and fluvial sediment transport, but rivers crossing coastal plains may not be efficient conveyors of sediment to the coast. Where this is the case, changes in continental sediment dynamics are not evident at the river mouth. Stream power is typically low and accommodation space high in coastal plain river reaches, resulting in extensive alluvial storage upstream of estuaries and correspondingly low sediment loads at the river mouth. In some cases there is a net loss of sediment in lower coastal plain reaches, so that sediment input from upstream exceeds yield at the river mouth. The lowermost sediment sampling stations on many rivers are too far upstream of the coast to represent lower coastal plain sediment fluxes, and thus tend to overestimate sediment yields. Sediment which does reach the river mouth is often trapped in estuaries and deltas. Assessment of sediment flux from coastal plain rivers is also confounded by the deceptively simple question of the location of the mouth of the river. On low-gradient coastal plains and shelves, the location of the river mouth may have varied by hundreds of kilometers due to sea-level change. The mouth may also differ substantially according to whether it is defined based on channel morphology, network morphology, hydrographic or hydrochemical criteria, elevation of the channel relative to sea level, or the locus of deposition. Further, while direct continent-to-ocean flux may be very low at current sea-level stands, sediment stored in estuaries and lower coastal plain alluvium (including deltas) may eventually become part of the marine sedimentary package. The role of accommodation space in coastal plain alluvial sediment storage has been emphasized in previous work, but low transport capacity controlled largely by slope is also a crucial factor, as we illustrate with examples from Texas. [ABSTRACT FROM AUTHOR]

Abstract: As human population worldwide has grown, so has interest in harnessing and manipulating the flow of water for the benefit of humans. The Trinity River of eastern Texas is one such watershed greatly impacted by engineering and urbanization. Draining the Dallas–Fort Worth metroplex, just under 30 reservoirs are in operation in the basin, regulating flow while containing public supplies, supporting recreation, and providing flood control. Lake Livingston is the lowest, as well as largest, reservoir in the basin, a mere 95 km above the Trinity''s outlet near Galveston Bay. This study seeks to describe and quantify channel activity and flow regime, identifying effects of the 1968 closure of Livingston dam. Using historic daily and peak discharge data from USGS gauging stations, flow duration curves are constructed, identifying pre- and post-dam flow conditions. A digital historic photo archive was also constructed using six sets of aerial photographs spanning from 1938 to 1995, and three measures of channel activity applied using a GIS. Results show no changes in high flow conditions following impoundment, while low flows are elevated. However, the entire post-dam period is characterized by significantly higher rainfall, which may be obscuring the full impact of flow regulation. Channel activity rates do not indicate a more stabilized planform following dam closure; rather they suggest that the Trinity River is adjusting itself to the stress of Livingston dam in a slow, gradual process that may not be apparent in a modern time scale. [Copyright &y& Elsevier]

Livingston Dam on the Trinity River in SE Texas, USA disrupts the transport of sediment to the lower Trinity River and the Trinity Bay/Galveston Bay estuary. However, a sediment budget of the lower basin shows that the effects of this disruption are undetectable in the lower river. Sediment trapped in Lake Livingston is partly offset by channel erosion downstream of the dam and by inputs from the lower basin. Most importantly, however, the lower coastal plain reaches of the Trinity are characterized by extensive alluvial storage and are a bottleneck that buffers the bay from effects of upstream changes in sediment flux. Storage is so extensive that the upper Trinity basin and the lowermost river reaches were essentially decoupled (in the sense that very little upper-basin sediment reached the lower river) long before the dam was constructed. Whereas sediment storage in Lake Livingston is extensive, alluvial storage on the Trinity flood plain is even more extensive. Dam-related sediment starvation effects are noted for about 52 km downstream, and the sediment budget suggests that a majority of the sediment in this reach is likely derived from channel scour and bank erosion. The capacious alluvial storage in the lower Trinity not only limits flux to the bay, but the large amount of remobilizable alluvium also allows the system to adjust to localized sediment shortages, as illustrated in the dam-to-Romayor reach. Internal adjustments within the lower Trinity River valley thus buffer the bay from changes in sediment supply upstream. [Copyright &y& Elsevier]

Information on the nature and relative contribution of different watershed sediment sources is recognized as a key requirement in the design and implementation of targeted management strategies for sediment control. A direct method of assessing sediment sources in a watershed that has attracted attention in recent years is sediment fingerprinting. The aim of this article is to describe the development of sediment fingerprinting as a research tool and to consider how the method might be transformed from a research tool to a management tool within a regulatory framework, with special reference to the United States total maximum daily load (TMDL) program. When compared with the current source assessment tools in developing sediment TMDLs, sediment fingerprinting offers considerable improvement as a tool for quantifying sources of sediment in terms of source type (e.g., channel vs. hillslope) as well as spatial location (subwatershed). While developing a conceptual framework for sediment TMDLs, we recognize sediment fingerprinting along with sediment budgeting and modeling as valuable tools in the TMDL process for developing justifiable sediment TMDLs. The discussions presented in this article may be considered as a first step toward streamlining the sediment fingerprinting approach for its wider application in a regulatory framework. [ABSTRACT FROM AUTHOR]