East Branch Research Articles

Low‐frequency radar sounding of temperate ice masses in Southern Alaska

We present the Warm Ice Sounding Explorer (WISE), a low‐frequency (2.5 MHz) radar for the sounding of temperate ice. WISE deployment in southern Alaska in 2008 and 2012 provides comprehensive measurements of glacier thickness, reveals deep valleys beneath glaciers and the full extent of zones grounded below sea level. The east branch of Columbia Glacier is deeper that its main branch and remains below sea level 20 km farther inland. Ice is 1000 m deep on Tazlina Glacier. On Bering glacier, two sills separate three deep bed depressions (>1200 m) that coincide with the dynamic balance lines during surges. The piedmont lobe of Malaspina Glacier and the lower reaches of Hubbard Glacier are entirely grounded below sea level 40 and 10 km, respectively, from their termini. Knowledge of ice thickness in these regions helps better understand their glacier dynamics, mass balance, and impact on sea level.

Rapid decrease of observed mass balance in the Urumqi Glacier No. 1, Tianshan Mountains, central Asia

The mass balance of Urumqi Glacier No. 1 located in Tianshan Mountains of central Asia has been monitored since 1959. Based on the long-term climate and glacier mass balance observation data for the period 1959–2010, analyses show that the glacier mass balance has decreased rapidly, the equilibrium line altitude (ELA) has ascended significantly and the glacier terminus has retreated continuously in response to climate change. The cumulative mass balance was −14,883 mm w.e., equivalent to glacier thinning of 16.5 m, with a mean value of 0.32 m/y. The ELA showed a significant ascending trend, ascending about 90 m. The averaged ELA was 4067 m a.s.l., and analysis shows the steady-state ELA (ELA0) was 4018 m a.s.l., with the mass-balance gradient α = 5.9 mm/m. The glacier terminus retreated by 199.3 m at the east branch and 241.3 m at the west branch. Linear regression analysis results suggest that 1 C° summer temperature increases leads to 440.6 mm mass balance decrease. Mass balance increases by 120 mm when annual precipitation increases by 100 mm. Mass balance decrease was controlled mainly by summer temperature. If such increased warming continues in the future, the glacier mass balance will form a strongly negative balance, the glacier will shrink, and the glacier terminus will continue to retreat.

History of the spruce-fir forest in the Catskill Mountains of New York.

Red spruce (Picea rubens Sarg.) and balsam fir (Abies balsamea (L.) Mill.) were present by 13,700 years B.C.E. in the Catskills Mountains of southeastern New York State. These conifers were, and still are, largely confined to the eastern and far western portions of the region. A gap in the distribution exists between these populations. Both species are absent from the intervening East Branch Delaware River watershed. No red spruce macrofossils were found in this watershed, suggesting that this conifer never colonized the gap postglacially. Rare macrofossils of balsam fir were found in only three of the 24 peatlands in this watershed, the conifer having disappeared between 11,300 and 8,200 years B.C.E.

Flowering and pollination of the native daylily species (Hemerocallis) in the Botanical Garden Institute, Far East Branch, Russian Academy of Sciences

The opening time of the flower and duration of blooming, as well as the anther opening time and type of pollination, have been studied in five species of the genus Hemerocallis L. under different weather conditions. It is found that weather conditions do not affect the flowering of mesophytic species. Xerophytic species start to bloom later under adverse weather conditions, and the life of their flower increases. The main type of pollination in daylilies is xenogamy, which is combined with geytonogamy. The pollen collected in a sunny weather at an air humidity of 65% is characterized by high vitality.

New replacement generic names for Ordovician ostracodes of Siberia

455 The generic name Kurenkovia was introduced by myself (Melnikova, 1981) for a new ostracod from the Middle Ordovician of the Moiero River (Middle Siberia). D.A. Sidorov paid attention to the fact that this name was earlier used by Sokolskaya (1969) to designate an oligochaete genus from the Kamchatka Peninsula. Therefore, according to Article 60.3 of the International Code ... (1999), I introduce the new generic name Kurenkovina to replace the preoccu pied name Kurenkovia, which is also given in honor of the micropaleontologist V.G. Kurenkova (with the type species Kurenkovia mononodosa Melnikova, 1981). ACKNOWLEDGMENTS I am sincerely grateful to D.A. Sidorov (Institute of Biology and Soil Sciences, Far East Branch, Russian Academy of Sciences), who indicated the homonymy.

Cenozoic structural deformation and expression of the “Tan-Lu Fault Zone” in the West Sag of Liaohe Depression, Bohaiwan basin province, China

Based on the interpretation of 3D seismic data and structural mapping we analyzed the geometry and kinematics of the fault system and validated the expression of the “Tan-Lu Fracture Zone” in the West Sag of Liaohe Depression, Bohaiwan basin province. The Cenozoic structural deformation within the West Sag of Liaohe Depression can be divided into extensional structure system and dextral structure system. The extensional system is constituted by numerous NNE-NE trending Paleogene normal faults, where the Taian-Dawa fault (F1) is the master boundary fault (MBF) dominating the deposition during Paleogene so that the sag shows a complex half-graben with “boundary fault in the east and overlap in the west”. The dextral system is constituted by 2–3 dextral basement faults in NNE-NE trending (F2, F3, F4) and associated structure, and the time of structural action started in Oligocene and continued to Quarternary so that some associated secondary faults of the dextral system cut off the Neogene and Quaternary. Under the influence of the position and attitude of NNE-NE trending basement strike-slip faults, the central north part and the south part of the West Sag show obviously different structural features. The former appears to be a complex “graben” structure limited by the reversed strike-slip fault in the west and bounded by the inverted normal fault in the east, the latter remains the complex half-graben structure with “boundary fault in the east and overlap in the west”, and the graben was mildly reconstructed by one or two normal strike-slip faults. The dextral system within the West Sag is the element of the west branch fault of the Tan-Lu Fracture Zone, which is a deep fracture zone extending along the east of the Liaodongwan Gulf. The deep fracture zone branches off into two separate faults within the Liaohe Depression. The east branch goes through from northern part of the Liaodongwan Gulf to the East Sag of Liaohe Depression and links with the Denghua-Mishan Fault near Shenyang, and the west branch passes from northern part of the Liaodongwan Gulf to the West Sag and Damintun Sag of Liaohe Depression and links with the Yilan-Yitong Fault. The principal displacement zone of the west branch of the Tan-Lu Fracture Zone cuts off the master extensional fault (F1) within the West Sag of Liaohe Depression and induces many cover faults in EW trending within the Neogene and Quaternary.

Подготовка легированных стеклянных литий-боратных дисков для рентгенофлуоресцентного анализа горных пород на плавильной установке VULCAN 4

A new fusion method is developed using VULCAN 4 plant to make litium-borax glass beads for XRF analysis of rocks. The sample-flux mass ratio is 1:2; the NH 4 Br, NH 4 F and LiF alloying additions are used to provide for a sustained molding process of igneous rocks. As it is established, the upper flat surface of the glass bead can be a criterion for the optimal mass of alloying substance. According to the results of electron scanning of samples, glass beads are homogeneous and do not contain any alloying substance, which could affect the distribution of other elements. According to the XRF spectrometer measurements, the principal elements of rocks and samples with different additions display some insignificant difference in their analytical line intensities. Preparation of glass beads is a well-reproduced process. Key words : rocks, XRF analysis, glass lithium-borax bead, alloying (Russian) DOI: http://dx.doi.org/10.15826/analitika.2013.17.2.002 V.Ya. Borkhodoev, S.D. Penievsky, O.T. Sotskaya North-East Interdisciplinary Science Research Institute n.a. N.A. Shilo, Far East Branch, Russian Academy of Sciences, Magadan

Comparative study on observed mass balance between East and West Branch of Urumqi Glacier No. 1, Eastern Tianshan, China

Comparative study on observed mass balance between East and West Branch of Urumqi Glacier No. 1, Eastern Tianshan, China

Application of LiDAR Data for Hydrologic Assessments of Low-Gradient Coastal Watershed Drainage Characteristics

Documenting the recovery of hydrologic functions following perturbations of a landscape/watershed is important to address issues associated with land use change and ecosystem restoration. High resolution LiDAR data for the USDAForestServiceSanteeExperimentalForestin coastalSouth Carolina,USAwas used to delineate the remnant historical water management structures within the watersheds supporting bottomland hardwood forests that are typical of the re- gion. Hydrologic functions were altered during the early1700’s agricultural use period for rice cultivation, with changes to detention storage, impoundments, and runoff routing. Since late1800’s, the land was left to revert to forests, without direct intervention. The resultant bottomlands, while typical in terms of vegetative structure and composition, still have altered hydrologic pathways and functions due to the historical land use. Furthermore, an accurate estimate of the watershed drainage area (DA) contributing to stream flow is critical for reliable estimates of peak flow rate, runoff depth and coefficient, as well as water and chemical balance. Peak flow rate, a parameter widely used in design of channels and cross drainage structures, is calculated as a function of the DA and other parameters. However, in contrast with the upland watersheds, currently available topographic maps and digital elevation models (DEMs) used to estimate the DA are not adequate for flat, low-gradient Coastal Plain (LCP) landscape. In this paper we explore a case study of a 3rd order watershed (equivalent to 14-digit hydrologic unit code (HUC)) at headwaters of east branch of Cooper River draining to Charleston Harbor, SC to assess the drainage area and corresponding mean annual runoff coefficient based on various DEMs including LiDAR data. These analyses demonstrate a need for application of LiDAR-based DEMs together with field verification to improve the basis for assessments of hydrology, watershed drainage characteristics, and modeling in the LCP.

Sensitivity of Thermal Habitat of a Trout Stream to Potential Climate Change, Wisconsin, United States1

Abstract: Airborne thermal remote sensing from four flights on a single day from a single‐engine airplane was used to collect thermal infrared data of a 10.47‐km reach of the upper East Branch Pecatonica River in southwest Wisconsin. The study uses a one‐dimensional stream temperature model calibrated with the longitudinal profiles of stream temperature created from the four thermal imaging flights and validated with three days of continuous stream temperature data from instream data loggers on the days surrounding the thermal remote‐sensing campaign. Model simulations were used to quantify the sensitivity of stream thermal habitat to increases in air and groundwater temperature and changes in base flow. The simulations indicate that stream temperatures may reach critical maximum thresholds for brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta) mortality, particularly if both air temperature increases and base flow declines. The approach demonstrates that thermal infrared data can greatly assist stream temperature model validation due to its high spatial resolution, and that this spatially continuous stream temperature data can be used to pinpoint spatial heterogeneity in groundwater inflow to streams. With this spatially distributed data on thermal heterogeneity and base‐flow accretion, stream temperature models considering various climate change scenarios are able to identify thermal refugia that will be critical for fisheries management under a changing climate.

Gornotaezhnoe geophysical system

A geophysical system has been built on the territory of the Ussuriisk astrophysical observatory of the Far East Branch, Russian Academy of Sciences. It includes a laser deformograph intended to detect variations of deformations of the Earth’s crust with an accuracy of 0.3 nm in a frequency range of 0–1000 Hz and GPS millimeter-accuracy stations.

Prediction and assessment of multiple glacial lake outburst floods scenario in Pho Chu River basin, Bhutan

AbstractIn this study, the characteristic of multiple glacial lake outburst floods (GLOFs) in the Pho Chu River basin in Bhutanese Himalayas is evaluated to help assess the potential impact. Thorthormi Cho (TC) and Lugge Cho (LC) in the east branch and two unnamed lakes labelled A and B in the west branch of Pho Chu are chosen for the study. Numerical models were employed to simulate different involved processes. The results show that the peak sediment discharge in the east branch of the Pho Chu River by the TC dam breach reached about 5000 m3/s (during the first GLOF) at 4 km whereas by the LC dam breach is about 600 m3/s (second GLOF) at 6 km. However, the highest peak hydrographs (sediment and water mixture) calculated during the first and second GLOF are about 10 000 m3/s at the 18‐km section and about 23 000 m3/s at the 10‐km section, respectively. In the west branch of Pho Chu, erosion and depositions are the frequent intermittent local processes during the first GLOF event from Lake A. Because the first event stabilized the irregular river bed profile, there is not much sediment discharge developed during the second GLOF from Lake B. At the 17‐km section of the west branch, the peak hydrograph reached about 9000 m3/s during the first event against the peak of about 800 m3/s during the second event. The results suggest that even if multiple dam breaches occur simultaneously, GLOF surges pass through the main river channel at different times with very different flood characteristics. The differences in travel time and flood characteristics mostly depend on the distributions of bed slope and potential erosion depth along the reach. Further, the amount of sediment accumulated in and transported by each surge is reliant on the temporal geomorphologic setting of the river and therefore on the impact of the previous GLOF on riverbed profile and potential erosion depth. The robustness in peak GLOF hydrographs is associated with sediment flow dynamics. As a consequence, serious inundation of Punakha, Lobeysa and major portion of Wangdue Phodrang is anticipated. Copyright © 2011 John Wiley & Sons, Ltd.

Information development around the world again

Once again this issue of Information Development takes us around the world, with articles on themes as varied as their geographical spread. We begin in South Asia with a general review of the role of information in rural development – a frequently-discussed topic in these pages. In ‘Role of information for rural development in Bangladesh: A sector-wise review’, Kazi Mostak Gausul Hoq of the University of Dhaka provides an overview of the roles information could play in various socio-politico-economic sectors in the rural areas of Bangladesh. Against a backdrop of the enactment of a Right to Information Act and the government’s recent efforts towards establishing a Digital Bangladesh by the year 2021, the country has been witnessing a revival of information-focused activities in its rural and farflung areas. Covering diverse areas including agriculture, health, human rights, education, employment, market and finance and disaster management, the article indicates how an informed and knowledgeempowered rural people could work towards ensuring the socio-economic advancement of the country, thereby recognizing the role of information for sustainable rural development. The preservation of the documentary heritage in Africa is the subject of the next paper, ‘Availing the liberation struggle heritage to the public: Some reflections on the use of Web 2.0 technologies in archives within the East and Southern Africa Regional Branch of the International Council on Archives (ESARBICA)’, by Francis Garaba of the Lutheran Theological Institute Library in Scottsville, South Africa. This paper addresses the extent to which Web 2.0 technologies may be used to make the liberation struggle heritage available to the public in archival institutions in the ESARBICA region, noting that the advent of web technologies provides an opportunity for these institutions to improve their public image. Social media technologies can have a transformative influence, but have to be the right technology for the right place and the right people, and archivists need to find innovative strategies to use these technologies. We remain in Africa, but with a change of theme, in the next paper. In ‘Information use and policy decision-making by district assembly members in Ghana’, David Kobla Fiankor of Ho Polytechnic and Harry Akussah of the University of Ghana report on a study to investigate information utilization for policy decision-making by assembly members in Ghana’s local government system. The study revealed that assembly members had little access to relevant and reliable information when making decisions about policies, programmes and policy implementation, and often made decisions based on what could be remembered. The study makes a number of recommendations for improving the situation. We return to Southern Africa and another complete change of content with the next paper. In ‘An investigation of institutional repositories in state universities in Zimbabwe’, Esther Nyambi and Sally Maynard of Loughborough University examine the current state of institutional repositories in Zimbabwe and the challenges and enablers for institutional growth, whilst evaluating the operational issues that might be affecting the setting up of institutional repositories. The current state of repositories has largely been influenced by the political and economic situation in Zimbabwe. Partnerships forged between the libraries and INASP are playing a significant role in supporting research and the setting up of repositories, but the issue of still requires attention and financial assistance from the government and from the universities themselves. Perhaps the most widespread ICT application in developing countries is the mobile phone. The final paper in this issue, ‘A voice for the voiceless: Peerto-peer mobile phone networks for a community radio service’ by Kavitha Ranganathan and Ankur Sarin of the Indian Institute of Management, Ahmedabad, proposes a new application for mobile ad hoc networks Information Development 28(1) 3–4 a The Author(s) 2012 Reprints and permission: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0266666911432984 idv.sagepub.com

Application of a degree-day model for determination of mass balance of Urumqi Glacier No. 1, eastern Tianshan, China

In order to verify the feasibility and stability of a degree-day model on simulating the long time series of glacier mass balance, we apply a degree-day model to simulate the mass balance of Urumqi Glacier No. 1 for the period 1987/1988–2007/2008 based on temperature and precipitation data from a nearby climate station. The model is calibrated by simulating point measurements of mass balance, mass balance profiles, and mean specific mass balance during 1987/1988–1996/1997. The optimized parameters are obtained by using a least square method to make the model fit the measured mass balance through the model calibration. The model validation (1997/1998–2007/2008) indicates that the modeled results are in good agreement with the observations. The static mass balance sensitivity of Urumqi Glacier No. 1 is analyzed by computing the mass balance of the glacier for a temperature increase of 1 °C, with and without a 5% precipitation increase, and the values for the east branch are −0.80 and −0.87 m w.e. a−1·°C−1, respectively, and for the west branch, the values are −0.68 and −0.74 m w.e. a−1·°C−1, respectively. Moreover, the analysis of the parameter stability indicates that the parameters in the model determined from the current climate condition can be applied in the prediction of the future mass balance changes for the glacier and provide a reference for extending the model to other small glaciers in western China.

Stratigraphic context, geochemical, and isotopic properties of magmatism in the Siluro-Devonian inliers of northern Maine: Implications for the Acadian Orogeny

This paper reports detailed stratigraphic analysis, whole rock geochemistry and Nd isotopic ratios of basalts from the northern Maine inliers. These data place constraints on first-order controversies about the tectonic conditions leading up to and during the early stages of the Acadian Orogeny in northern Maine. Late Silurian and early Devonian stratigraphic sequences indicate a progressive change from shallow water and subaerial exposure (Ripogenus and The Forks formations, East Branch Group) to a rapidly subsiding basin prior to the onset of Acadian deformation. Subsidence was accompanied by mafic to intermediate volcanism of the West Branch, Spider Lake, and Fish Pond volcanics, and that continued with intrusion of the syn-deformational Greenville Plutonic Belt, including the Flagstaff Lake Igneous Complex, whose properties we report in this paper. Trace element geochemistry indicates that magmatism is transdiscriminant, showing aspects of within-plate, volcanic arc, and back-arc affinities and Nd isotopic ratios are moderately positive (+2.3 to +3.8) indicating either an uncontaminated and moderately enriched mantle source, or a depleted mantle source contaminated by continental crust. Four possible tectonic models of the Acadian Orogeny and the Siluro-Devonian sedimentary-volcanic sequences of northern Maine are evaluated in the context of a subsiding basin associated with this magmatism developed on the amalgamated Laurentian plate. These include 1) slab detachment during southeast-directed subduction of the Laurentian continental margin; 2) “Laramide-style” thrust basins above a shallow, northwest-dipping subduction zone; 3) back-arc extension followed by thin-skinned shortening above a northwest-dipping subduction zone; and 4) “Moluccan-style” dual-dipping subduction zones.

Nature, genesis and provenance of silt pellets on the ice surface of Glacier No. 1, upper Urumqi River, Tian Shan, Northwestern China

This paper reports silt pellets found at the terminus of the east branch of Glacier No. 1, Tian Shan, Northwestern China. These pellets of approximately 1 mm in diameter appeared as layers on glacier surface. Two pellet samples were collected for microscope examination, grain-size measurement, and geochemical analysis to understand their nature, origin and provenance. Observations of thin sections show that the pellet is comprised of an inner structureless core and an outer concentric thin layer, explained by a two-stage process: a nucleus-forming stage and a concentric growth stage. The pellet is mainly comprised of poorly sorted ( σ = 1.7–1.8) silts (mean grain grain-size = 6.2–6.5 φ) with quartz, feldspar, biotite, pyroxenes, clay, and other minerals. The chemical compositions of the silt and clay portions are very similar to that of the Upper Continental Crust (UCC) except for a few elements (e.g., enrichments of Li, Mo, and clay-sized particles’ P, Zn, Cu, and Pb, and depletion of Ca and silt-sized particles’ Bi). The pellet materials are derived mainly from atmospheric dusts. Therefore, the silt pellets may provide insights into details of the large-scale fine sediment recycling between the atmospheric, glacial and alluvial systems.

Using barnacle and pigmentation characteristics to identify gray whale calves on their feeding grounds

Marine Mammal ScienceVolume 27, Issue 3 p. 644-651 Notes Using barnacle and pigmentation characteristics to identify gray whale calves on their feeding grounds Amanda L. Bradford, Amanda L. Bradford School of Aquatic and Fishery Sciences,University of Washington,P. O. Box 355020,Seattle, Washington 98195-5020, U.S.A.E-mail: [email protected]Search for more papers by this authorDavid W. Weller, David W. Weller Southwest Fisheries Science Center, NMFS, NOAA,3333 North Torrey Pines Court,La Jolla, California 92037-1022, U.S.A.Search for more papers by this authorAlexander M. Burdin, Alexander M. Burdin Kamchatka Branch of Pacific Institute of Geography,Far East Branch of the Russian Academy of Sciences,Pr. Rybakov, 19-a,Petropavlovsk-Kamchatsky, 683024, RussiaandAlaska SeaLife Center,301 Railway Avenue,Seward, Alaska 99664, U.S.A.Search for more papers by this authorRobert L. Brownell, Jr., Robert L. Brownell, Jr. Southwest Fisheries Science Center, NMFS, NOAA,1352 Lighthouse Avenue,Pacific Grove, California 93950, U.S.A.Search for more papers by this author Amanda L. Bradford, Amanda L. Bradford School of Aquatic and Fishery Sciences,University of Washington,P. O. Box 355020,Seattle, Washington 98195-5020, U.S.A.E-mail: [email protected]Search for more papers by this authorDavid W. Weller, David W. Weller Southwest Fisheries Science Center, NMFS, NOAA,3333 North Torrey Pines Court,La Jolla, California 92037-1022, U.S.A.Search for more papers by this authorAlexander M. Burdin, Alexander M. Burdin Kamchatka Branch of Pacific Institute of Geography,Far East Branch of the Russian Academy of Sciences,Pr. Rybakov, 19-a,Petropavlovsk-Kamchatsky, 683024, RussiaandAlaska SeaLife Center,301 Railway Avenue,Seward, Alaska 99664, U.S.A.Search for more papers by this authorRobert L. Brownell, Jr., Robert L. Brownell, Jr. Southwest Fisheries Science Center, NMFS, NOAA,1352 Lighthouse Avenue,Pacific Grove, California 93950, U.S.A.Search for more papers by this author First published: 26 August 2010 https://doi.org/10.1111/j.1748-7692.2010.00413.xCitations: 4Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume27, Issue3July 2011Pages 644-651 RelatedInformation

How Geology Changed the Design of Cedar Springs Dam San Bernardino County, California

Research Article| August 01, 2010 How Geology Changed the Design of Cedar Springs Dam San Bernardino County, California ARTHUR B ARNOLD; ARTHUR B ARNOLD 1607 Acebo Road NE, Rio Rancho, NM 87124 1. During design of Cedar Springs Dam Arthur B. Arnold was Chief, Southern California Project Geology Group for California Department of Water Resources, California Aqueduct Project, Palmdale California. Frank C. Kresse led the East Branch Geology Unit. Search for other works by this author on: GSW Google Scholar FRANK C KRESSE FRANK C KRESSE 21926 Page Court, Petaluma, CA 94954 1. During design of Cedar Springs Dam Arthur B. Arnold was Chief, Southern California Project Geology Group for California Department of Water Resources, California Aqueduct Project, Palmdale California. Frank C. Kresse led the East Branch Geology Unit. 2Corresponding Author Search for other works by this author on: GSW Google Scholar Author and Article Information ARTHUR B ARNOLD 1. During design of Cedar Springs Dam Arthur B. Arnold was Chief, Southern California Project Geology Group for California Department of Water Resources, California Aqueduct Project, Palmdale California. Frank C. Kresse led the East Branch Geology Unit. 1607 Acebo Road NE, Rio Rancho, NM 87124 FRANK C KRESSE 1. During design of Cedar Springs Dam Arthur B. Arnold was Chief, Southern California Project Geology Group for California Department of Water Resources, California Aqueduct Project, Palmdale California. Frank C. Kresse led the East Branch Geology Unit. 2Corresponding Author 21926 Page Court, Petaluma, CA 94954 Publisher: Association of Environmental & Engineering Geologists First Online: 02 Mar 2017 Online ISSN: 1558-9161 Print ISSN: 1078-7275 Copyright © 2010 EEGS Environmental & Engineering Geoscience (2010) 16 (3): 291–298. https://doi.org/10.2113/gseegeosci.16.3.291 Article history First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation ARTHUR B ARNOLD, FRANK C KRESSE; How Geology Changed the Design of Cedar Springs Dam San Bernardino County, California. Environmental & Engineering Geoscience 2010;; 16 (3): 291–298. doi: https://doi.org/10.2113/gseegeosci.16.3.291 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyEnvironmental & Engineering Geoscience Search Advanced Search Abstract Cedar Springs Dam, San Bernardino County, CA, was first conceived as a zoned earth-fill dam, based on the use of on-site materials. Final design investigations revealed clear evidence of recent active faulting, trending approximately parallel to the dam centerline within the dam footprint. No appropriate alternative dam location was available. Therefore, a complete re-design of the dam was made to accommodate offset without catastrophic failure of the dam. This potential offset of 3 to 5 ft (1 to 1.5 m), either vertical or horizontal, was termed the Maximum Credible Accident. The re-design required an intense off-site search for suitable impervious construction materials. Among the several new design features was an impervious core that could deform plastically without excessive cracking. Filter and rockfill zones were provided for piping and downstream embankment erosion protection. All zones were made thick enough to accommodate 5 ft (1.5 m) of offset and to still maintain a substantial thickness. The dam was re-positioned so that potential offset would occur up the abutment instead of beneath the maximum section. A large downstream open-graded rock section was added, the crest was widened and paved, and additional freeboard was provided, all to add protection from overtopping. The spillway was re-positioned so that identified faulting would cross the downstream spillway weir. During the 40 years since construction, no significant nearby earthquakes and faulting have affected the dam. The dam continues to perform within the intent of the design, which was based on the recognition of geologic conditions. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Evaluation of Seepage, Internal Erosion, and Remedial Alternatives for East Branch Dam, Elk County, Pennsylvania

East Branch Dam is a Pittsburgh District U.S. Army Corps of Engineers (COE) dam that nearly failed in 1957, several years after construction. The dam is a zoned embankment that is 56 m (184 ft) high and 526 m (1,725 ft) long. Its primary purpose is flood control. Following the observation of muddy water flowing from a rock drain at the downstream toe of the dam, soon after construction, emergency drilling through the embankment exposed a void that demanded lowering the pool and subsequent grouting. Localized grouting was accomplished to treat the void but did not involve a comprehensive repair of the dam. The 1957 near failure of East Branch Dam represents an excellent case history that provides dam designers and operators today insight into the mechanisms of internal erosion within an embankment dam, and it underscores the need to quickly take all necessary actions to protect the public. Since the 1957 emergency, the project has performed satisfactorily and has been closely monitored with a network of piezometers, weirs, and alignment-settlement pins. Even though evidence of further internal erosion has not reappeared, the fundamental conditions that caused the original problem were not corrected by the 1957 emergency repairs. Recently, the dam was evaluated under the COE Screening Portfolio Risk Assessment (SPRA) program. In light of the 1957 incident, conditions of active seepage, and high phreatic pressures within the embankment, the SPRA program assigned East Branch a Dam Safety Action Classification (DSAC) rating of II, generally indicating that failure could begin during normal operations or be initiated as the consequence of an event. A potential failure mode analysis (PFMA) was conducted in 2008 by the U.S. Bureau of Reclamation (USBR) as requested and participated in by the Pittsburgh District. The PMFA identified the potential for re-initiation of internal erosion at or near the cavity repair as the highest risk failure mode and a primary threat to public safety. Given these findings, the Pittsburgh District implemented a set of non-structural interim risk reduction measures (IRRM) in February 2008, including lowering of the pool to reduce risk of failure by an estimated 60 percent. The interim measures will allow the dam to operate safely until the COE determines the appropriate long-term remedy to address the structural deficiencies of East Branch Dam. In 2009, a joint COE–USBR PFMA was undertaken using procedures from both agencies. Current dam safety efforts involve reassessing potential failure modes, preparing a Dam Safety Modification Report, evaluating various remedial alternatives, and recommending a long-range repair plan for East Branch Dam. This paper examines the history of the dam, investigations performed, potential failure modes examined, and the range of remedial alternatives being considered.

Responses of two branches of Glacier No. 1 to climate change from 1993 to 2005, Tianshan, China

Clear understanding of how alpine glaciers respond to climate change is critical to accurately evaluate water resources and to retrieve climate information from the alpine glaciers. However, different glaciers may have different responses to climate change. This study focuses on two branches of Glacier No. 1 at the head of Urumqi River, Tianshan, China. These two branches, West Branch (WB) and East Branch (EB), have experienced the same pattern of climate warming since their separation in 1993. However, these glaciers have responded differently as observed by fieldwork and analysis of their annual mass balances, lengths, areas, equilibrium line altitudes (ELAs). To illustrate the different responses of climate change (increase in both temperature and precipitation), the glacier length response time ( T rl) and climate sensitivity ( C) are calculated for the two branches. The length response time and climate sensitivity are 1.89 y and 8.81 for the EB, and 1.63 y and 5.92 for WB. The different responses are interpreted to be controlled by glacial/topographical features with larger slopes and smaller areas, making the WB more sensitive to the recent climate warming.