Thesis (MS )--Montana State University--Bozeman, 2008. / Typescript. Chairperson, Graduate Committee: Mark L. Taper. Includes bibliographical references (leaves 60-68).

Gully erosion has been damaging archaeological sites in Grand Canyon during the last several decades, and there is a need to protect these features through mitigation, monitoring, and better geomorphic understanding. The purpose of this study was to assess the effectiveness of erosion-control structures , determine the accuracy and utility of aerial photogrammetry for monitoring gullies , and understand the geomorphology of the erosion . We performed total-station surveys and other data collection during February and October , 2002, at nine study sites in eastern and western Grand Canyon. Erosion-control structures are more prone to be damaged by flow when they are placed in reaches of very high local gradient. Treatments are generally successful in slowing erosion or causing deposition of sediment, but damaged erosion-control structures were shown to be less effective than intact structures, and actually increase local erosion in cases. Aerial photogrammetry was performed on four eroding archaeological sites in western Grand Canyon in March and October 2002 in order to assess the accuracy and change-detection utility of this tool. Accuracy was assessed on several different levels by comparing photogrammetry data to ground-survey data, and mean absolute vertical error ranged from 6-10 cm. Error of manual photogrammetry digital terrain models (DTMs) increased with topographic ruggedness and decreased with greater photogrammetric point density. Mean error reached a minimum of 5 cm for March and 6.5 cm for October when the ratio of point density to topographic ruggedness was ~40. Ground surveys and repeat photography indicated that two study gullies eroded or aggraded during the study period by 10-20 cm, but these changes were mostly undetected in the photogrammetry DTMs. Repeat ground surveys showed that gullies erode most at knickpoints and in steep reaches , and that new knickpoints tend to form in relatively steep reaches of a given channel. An area-slope erosion threshold was identified for the study sites and applied in a GIS-based model at four sites to show areas that exceed the threshold and are sensitive to gully erosion . Overall results show an upcatchment control of gully erosion and suggest that baselevel changes due to Glen Canyon Dam operation are subordinate controls.

Tectonics and drainage evolution are controlling overall landscape incision in eastern Grand Canyon. Superimposed on downcutting are dynamic responses of hillslopes, tributary streams, and the Colorado River to glacial-interglacial climate cycles. Five tributary stream fill terraces have been identified, and luminescence dating indicates aggradation was occurring 50- 34 ka {S3), 12-7 ka (S2), and 5-3.5 ka (S1). Seven Colorado River fill terraces have been identified, and luminescence and U-series dating indicate deposition was occurring 343-322 ka (M5), 151-118 ka (M4), and 71-64 ka (M3). Aggradation by the Colorado River in eastern Grand Canyon begins during glacial advances and continues into the subsequent climate reversals. It appears to be driven by increases in sediment yield associated with glacial advances in headwater areas and glacial conditions elsewhere in the Colorado River drainage basin. Local catchments have buffered responses to climate change, with stream aggradation being driven by changes in sediment yield and hydrology of hillslopes. Tributary stream aggradation during full-glacial conditions (S3) is caused by a decrease in precipitation intensity and an increase in bedrock weathering. Aggradation during glacial-interglacial transitions (S2) and interglacial conditions (S1) is the result of increased erosion of older surficial deposits and decreases in vegetation cover. In the context of the current working model for the response of drylands to climate change, eastern Grand Canyon is distinct in that significant tributary stream aggradation occurs during full-glacial climate conditions and throughout the tributary drainage networks. This suggests that landscape response to climate change in semiarid environments may be slightly different than in arid settings. Bedrock incision by the Colorado River has been occurring at a rate of 0.13 mm/yr over middle-late Quaternary time. The technique used to make this calculation involves comparing snapshots of the river at analogous positions within its aggradation-incision cycles. The most accurate calculation results from tracing the elevation of the valley bottom through time. This method requires robust age control, but is advantageous because true bedrock incision is calculated and possible error associated with the use of short time intervals and thick fill deposits is eliminated.

This study of the rhetoric in the Sierra Club's Grand Canyon Campaign, 1963 to 1967 seeks to determine the decisive strategies in the success of the campaign. Criteria for examining the rhetoric are adapted from the fields of rhetoric and sociology. This analysis examines preconditions of this conservation campaign, its leaders, membership, strategies, and audience-speaker relationships, The campaign's turning point came when the club used public audiences to pressure Control into capitulating to Agitation's demands, Other factors in the campaign's success were the Sierra Club's purity of belief, suppression action by Control, and incomplete purity of belief in the leader of Control.

Humpback Chub Gila cypha are endangered cyprinids endemic to the Colorado River drainage and are adapted to live in fast currents of warm, turbid water. Although nine known aggregations of Humpback Chub currently exist in the main-stem Colorado River in the Grand Canyon, little is known about their reproduction. I hypothesized that Colorado River water temperatures below Glen Canyon Dam are too low due to hypolimnetic water releases from Lake Powell for female Humpback Chub to develop mature eggs for spawning. Ultrasonic imaging, also called ultrasound, is an effective, non-lethal method used to determine sex and maturity of a variety of freshwater, anadromous, and marine fishes. However, many previous studies have been performed in laboratory environments. I developed a standardized method for ultrasonically scanning endangered Humpback Chub Gila cypha in remote locations within Grand Canyon, Arizona, USA. This method minimized stress to individual fish and took less than 1 min to perform. I was able to identify female fish with eggs based on two jpeg images and one 10 s video clip collected in the field. I also used ImageJ®, a National Institute of Health image processing program, to develop a brightness index to evaluate the maturity of eggs in female fish. I collected ultrasonic scans of captive, ripe Humpback Chub held at the Southwestern Native Aquatic Resources and Recovery Center (SNARRC) to determine that female fish were potentially ripe when a subsample of their eggs exhibited a brightness value within the 32-44 range. Although I was able to estimate egg maturity, I was not able to estimate egg mass of female fish. I used ultrasound to evaluate reproductive condition of 751 Humpback Chub in Grand Canyon. I documented egg development in female fish from the main-stem Colorado River, Little Colorado River, Havasu Creek, and Shinumo Creek. Egg development in Humpback Chub varies by location and time of year. Potentially ripe (stage 3) female fish were found at all sample locations and dates except at Shinumo Creek in 2013 and 2014. Potentially ripe females were also detected in every main-stem aggregation except for Pumpkin Springs and in two locations outside of established aggregations. Fisheries managers can use ultrasound to collect vital information about the reproductive status of fishes that cannot be killed and that are found in remote or rugged field locations. My findings indicate that female Humpback Chub are able to produce eggs throughout the main-stem Colorado River and that internal egg development and egg production likely do not limit recruitment. However, female fish may never experience the environmental triggers they need to spawn or may not experience conditions that would allow eggs and larvae to survive.

The recreational use of the Colorado River within the Grand Canyon National Park and National Monument increased on the order of 60 to 70 per cent during each year of the interval 1967 to 1970. Consequently, the U. S. National Park Service instituted user limits to protect and preserve the area commencing with the 1971 season. This limit was established with limited data on the users of the river or about their perceptions of the trip experience. A need existed to collect and analyze this type of data, and to suggest possible management alternatives. This study used a mailed questionnaire to a random sample of past participants in order to collect basic socio-economic data. The analysis was based on a 65% response rate, and consisted of individual question tabulation and multivariate data -cluster analysis. The data show background characteristics of the participants, reasons for taking the trip, reactions to the experience, perceptions of problems associated with the trips, reactions to crowded conditions, and needs for regulatory policy concerning user intensities.

No description available.

Bison spp. (bison) fossils are scarce on the Colorado Plateau, especially within the greater Grand Canyon region. Because of the poor fossil record for bison on the plateau and in Grand Canyon National Park, various resource managers have surreptitiously designated bison a nonnative and human-introduced species. The lack of evidence for bison seems to be the result of collection bias rather than a true lack of bison remains. Today, Grand Canyon National Park has a neighboring herd of 350 bison that have meandered unwantedly onto National Park lands from neighboring Forest Service and State of Arizona lands. This study spatiotemporally illustrates bison are recently native to the greater Grand Canyon area based on previously misidentified specimens in archaeological collections. Data here may require resource managers to reconsider whether or not bison should be reconsidered a native species to the Grand Canyon National Park and elsewhere on the Colorado Plateau.

Understanding the nature of Colorado River deposits in Grand Canyon helps reveal how the river responds to changes in its Colorado Plateau tributaries and Rocky Mountain headwaters. This study focused on Holocene alluvial deposits associated with archaeological sites excavated near Ninemile Draw in Glen Canyon and at Tanner Bar in eastern Grand Canyon. Two previously-developed conceptual models of deposition were tested based on previous work. Previous researchers have suggested that Holocene alluvial deposits in Grand Canyon are a series of inset aggradational packages that correlate to valley fills and arroyo-cutting cycles in Colorado Plateau tributaries and are laterally consistent throughout the river corridor. An alternate hypothesis is that alluvial packages record paleoflood sequences along the Colorado River with no Holocene change in river grade. In this model, deposits are preserved more variably as a function of local hydrologic geometry, and they should be less correlatable. Detailed stratigraphic columns of terrace deposits and several stratigraphic panels of archaeological trenches, combined with facies interpretations, were used to reconstruct a high-resolution alluvial history at two locations. Optically stimulated luminescence (OSL) and radiocarbon dating methods were used at both locations with consistent results. At both sites, the sediment includes multiple depositional facies of mainstem and local-source material, and it consists of stratal packages bound by unconformities. These stratigraphic relations, combined with geochronology, lead to the interpretation that the alluvium is composed of six correlatable alluvial packages at overlapping heights above river level throughout the canyon. The four older packages include facies that imply aggradation throughout the river corridor, suggesting oscillations in river grade. The youngest two packages consist only of mainstem flood deposits. These packages suggest that preservation of deposits over the past ~1 ky has not been driven by aggradation, although incision since ~1 ky is possible. Comparison of the interpreted chronostratigraphy to climate records suggests that this large river's grade has not responded visibly to smaller century to millennial-scale climate oscillations. This work is the first to document that the alluvial record in Grand Canyon spans the entire Holocene, and conclusions support to both previous conceptual models of deposition.

Debris flows in at least 529 Grand Canyon tributaries transport poorly-sorted clayto boulder-sized sediment into the Colorado River, and are initiated by failures in weathered bedrock, the "fire-hose effect," and classic soil-slips often following periods of intense rainfall coincident with multi-day storms. Recent debris flows had peak-discharges from about 100-300 m3/s. Twentieth-century debris flows occurred from once every 10-15 years in eastern tributaries, to once in over a century in western drainage areas. Systemwide, debris flows likely recur about every 30-50 years, and the largest recent flows were initiated during Pacific-Ocean storms in autumn and winter. Three idealized hydrographs are inferred for recent debris flows based on deposits and flow evidence: Type I, has a single debris-flow peak followed by a decayed recessional streamflow; Type II, has multiple, decreasing debris-flow peaks with intervening flow transformations between debris flow and non-debris flow phases; and Type III, may have either a simple or complex debris-flow phase (begin as either Type I or II), followed by a larger streamflow peak that reworks or buries debris-flow deposits under streamflow gravel deposits. From 1987 through 1995, at least 25 debris flows constricted the Colorado River, creating 2 rapids and enlarging at least 9 riffles or rapids. In March-April, 1996, reworking effects of a 7-day controlled flood release (peak = 1,300 m³/s) on 18 aggraded debris fans in Grand Canyon were studied. Large changes occurred at the most-recent deposits (1994-1995), but several other older deposits (1987-1993) changed little. On the most-recent fan deposits, distal margins became armored with cobbles and boulders, while river constriction, flow velocity, and streampower were decreased. Partial armoring of fan margins by relatively-low mainstem flows since the debris flows occurred, was an important factor limiting fan reworking because particles became interlocked and imbricated, allowing them to resist transport during the flood. Similar future floods will accomplish variable degrees of fan reworking, depending on the extent that matrix-supported sediments are winnowed by preceding mainstem flows.