Surficial geology and distribution of post-impoundment sediment in Las Vegas Bay, Lake Mead

2001 ◽  
Author(s):  
David C. Twichell ◽  
VeeAnn A. Cross ◽  
Mark J. Rudin ◽  
Kenneth F. Parolski ◽  
Richard R. Rendigs
Keyword(s):  
Las Vegas ◽  
Lake Mead ◽  
Surficial Geology

Ongoing restoration and management of Las Vegas Wash: an evaluation of success criteria

Water Policy ◽  
2014 ◽  
Vol 16 (4) ◽  
pp. 720-738 ◽  
Author(s):  
Mahesh Gautam ◽  
Kumud Acharya ◽  
Seth A. Shanahan
Keyword(s):  
Las Vegas ◽  
Management Strategies ◽  
Management Program ◽  
Lessons Learned ◽  
Lake Mead ◽  
Channel System ◽  
Las Vegas Valley ◽  
Success Criteria ◽  
Southern Nevada ◽  
Channel Degradation

The Las Vegas Wash is a dynamic channel system that drains the Las Vegas Valley (3,950 km2) into Lake Mead and the lower Colorado River, which provides drinking water to southern California, Arizona, and southern Nevada. In the last few decades the Las Vegas Wash has undergone massive changes in terms of channel degradation and bank erosion followed by recovery and restoration efforts. The evolution of the Las Vegas Wash is interlinked with urbanization, water use, and wastewater discharge. This article reviews the historical dynamics of the Las Vegas Wash in the context of restoration: evaluates the ongoing activities in the Las Vegas Wash against an established framework and success criteria; summarizes lessons learned; and discusses challenges. The ongoing activities in the Las Vegas Wash differ from other regional restoration projects in that there is a lack of an appropriate historical reference to which restoration goals should be targeted. Keys to the success of the Las Vegas Wash restoration and management program appear to be strong interagency collaboration, funding availability, effective outreach and monitoring efforts, and adaptive management strategies based on pragmatic urban values. There is a potential for realignment of existing resources for more practical ecological restoration goals.

New 40Ar/39Ar isotopic dates from Miocene volcanic rocks in the Lake Mead area and southern Las Vegas Range, Nevada

1998 ◽  
Vol 35 (5) ◽  
pp. 495-503 ◽  
Author(s):  
Stephen S Harlan ◽  
Ernest M Duebendorfer ◽  
Jack E Deibert
Keyword(s):  
Las Vegas ◽  
Volcanic Rocks ◽  
Normal Fault ◽  
Vertical Axis ◽  
Lake Mead ◽  
Basin And Range Province ◽  
Red Sandstone ◽  
Las Vegas Valley ◽  
Western Lake ◽  
Southern Nevada

New 40Ar/39Ar dates on volcanic rocks interlayered with synextensional Miocene sedimentary rocks in the western Lake Mead area and southern end of the Las Vegas Range provide tight constraints on magmatism, basin formation, and extensional deformation in the Basin and Range province of southern Nevada. Vertical axis rotations associated with movement along the Las Vegas Valley shear zone occurred after 15.67 ± 0.10 Ma (2 sigma ), based on a 40Ar/39Ar date from a tuff in the Gass Peak formation in the southern Las Vegas Range. Basaltic magmatism in the western Lake Mead area began as early as 13.28 ± 0.09 Ma, based on a date from a basalt flow in the Lovell Wash Member of the Horse Spring Formation. Isotopic dating of a basalt from the volcanic rocks of Callville Mesa indicates that these rocks are as old as 11.41 ± 0.14 Ma, suggesting that volcanic activity began shortly after formation of the Boulder basin, the extensional basin in which the informally named red sandstone unit was deposited. The red sandstone unit is at least as old as 11.70 ± 0.08 Ma and contains megabreccia deposits younger than 12.93 ± 0.10 Ma. This result shows that formation of the Boulder basin was associated with development of topographic relief that was probably generated by movement along the Saddle Island low-angle normal fault. Stratal tilting associated with extension occurred both prior to and after 11.5 Ma.

Reproductive Responses of Common Carp (Cyprinus carpio) Exposed in Cages to Influent of the Las Vegas Wash in Lake Mead, Nevada, from Late Winter to Early Spring

2004 ◽  
Vol 38 (23) ◽  
pp. 6385-6395 ◽  
Author(s):  
Erin M. Snyder ◽  
Shane A. Snyder ◽  
Kevin L. Kelly ◽  
Timothy S. Gross ◽  
Daniel L. Villeneuve ◽  
...  
Keyword(s):  
Common Carp ◽  
Cyprinus Carpio ◽  
Las Vegas ◽  
Early Spring ◽  
Late Winter ◽  
Lake Mead ◽  
Common Carp Cyprinus Carpio ◽  
Carp Cyprinus Carpio

A PROACTIVE APPROACH TO MANAGING NUTRIENT LOADS IN LAS VEGAS BAY AND LAKE MEAD

2005 ◽  
Vol 2005 (6) ◽  
pp. 8414-8433
Author(s):  
Ira Rackley ◽  
Caroline Scruggs ◽  
Terry Johnson ◽  
Doug Karafa
Keyword(s):  
Las Vegas ◽  
Nutrient Loads ◽  
Lake Mead ◽  
Proactive Approach

Seismic study of earthquakes in the Lake Mead, Nevada-Arizona region

1976 ◽  
Vol 66 (5) ◽  
pp. 1657-1681
Author(s):  
A. M. Rogers ◽  
W. H. K. Lee
Keyword(s):  
Energy Release ◽  
Pore Pressure ◽  
Las Vegas ◽  
B Value ◽  
Tectonic Stress ◽  
Lake Mead ◽  
Triggered Release ◽  
Monitoring Period ◽  
High B Value ◽  
Elastic Energy Density

abstract A nine-station telemetered array was installed around the Boulder Basin portion of Lake Mead, Nevada-Arizona. During 112 years of monitoring, approximately 1,360 events were detected in the magnitude range −1.0 ≦ ML ≦ 2.9, and half this number were locatable. Many of the events, which ranged in depth from 0 to 13 km, can be associated with mapped faults. In particular, epicenter lineations clearly indicate activity on portions of steeply dipping faults on the east side of Boulder Basin, which generally confirms Carder's earlier work (Carder, 1945, 1948, 1970). The strike of these faults is approximately north. Focal mechanisms are in agreement with this strike and show right-lateral motion on near-vertical faults. The tension axis for this solution is oriented northwest-southeast in agreement with the stress pattern for other parts of the Basin and Range Province. Although lake load increased 20 per cent during the monitoring period, neither number of events nor energy release shows a correlation with this change. Carder (1970) found similar results for periods after 1949. A higher b value (1.45) was obtained than in the past, and lower monthly energy release was observed than in the late 1930's and 1940's when seismic activity at Lake Mead was first recorded. A 2-yr seismicity map of southern Nevada, including the monitoring period, shows that Lake Mead activity is now no greater than that of the surrounding area. The pre-Lake Mead seismic history is not well known because the founding of Boulder City occurred just a few years before Lake Mead was impounded. The existence of earthquakes in the region before the reservoir was filled has been questioned in the liteature. However, a search of the Las Vegas Review Journal for felt reports pre- and postimpoundment and compilation of a catalog of the largest events from the literature confirm that there was a significant increase in the number of felt events at Las Vegas after the reservoir was filled. The results indicate that the filling of Lake Mead has triggered release of tectonic stresses having the same orientation as the regional stress field. These stresses are probably being released in a way that is more dependent on tectonic stress buildup than on small changes in pore pressure (∼ 1 bar) due to fluctuating lake level. Given that the shear strength of rock decreases with increasing pore pressure, one might explain the decreasing energy release since the 1940's and the high b value as due to a decrease in elastic-energy density of the rock. A test of this hypothesis based on the order of magnitude of energy released seems to support it.

scholarly journals Paired city Cryptosporidium serosurvey in the southwest USA

2001 ◽  
Vol 126 (2) ◽  
pp. 301-307 ◽  
Author(s):  
F. J. FROST ◽  
T. MULLER ◽  
G. F. CRAUN ◽  
R. L. CALDERON ◽  
P. A. ROEFER
Keyword(s):  
Drinking Water ◽  
New Mexico ◽  
Blood Donors ◽  
Las Vegas ◽  
Tap Water ◽  
Bottled Water ◽  
Serological Response ◽  
Lake Mead ◽  
Southwest Usa

In 1996, serological responses to two Cryptosporidium antigens were determined for 200 Las Vegas (LV), Nevada, and 200 Albuquerque, New Mexico, blood donors to evaluate associations between endemic infections, water exposures, and other risk factors. LV uses chlorinated filtered drinking water from Lake Mead while Albuquerque uses chlorinated ground water. The intensity of serological response to both markers was higher for older donors (P < 0·05), donors who washed food with bottled water (P < 0·05) and donors from LV (P < 0·05). A decreased serological response was not associated with bottled water consumption, nor was an increased response associated with self-reported cryptosporidiosis-like illness or residence in LV at the time of a cryptosporidiosis outbreak 2 years earlier. Although these findings suggest the serological response may be associated with type of tap water and certain foods, additional research is needed to clarify the role of both food and drinking water in endemic Cryptosporidium infection.

Sign in / Sign up

Export Citation Format

Share Document