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USGS1967

Observations on unmeasured rivers

An analysis of data on hydraulic parameters collected during a single boat trip down a river system is presented, plotted in form of the hydraulic geometry. A dimensionless rating curve is used to estimate bankfull and average discharge for basins of various sizes. When compared with gaging station data, estimates of bankfull discharge are as consistent and possibly equal in accuracy to estimates made from gaging station data. Estimates of average discharge are less consistent; within the range of drainage areas represented by the gaging stations, errors of estimate vary from 0 to 58 percent. Local variations of bed material size along the river are compensated mostly by changes in local channel slope and roughness and do not much affect the progressive downstream changes in width, depth, or velocity.

Geografiska Annaler, Series A: Physical Geography↗

USGS1991

Rockslides on the Terminus of "Jokulsargilsjokull", Southern Iceland

On 10 November 1976, a 1.5 km × 0.5 km rockslide deposit on the surface of an unnamed outlet glacier of Mýrdalsjökull ice cap, southern Iceland, was observed from an aircraft. Deposits from two different rockslides, including the larger one observed on 10 November 1976, were visible on a 10 September 1978 aerial photograph of the unnamed outlet glacier. An analysis of vertical and oblique aerial photographs, Landsat images, and seismological records was used to establish the time of occurrence of the larger rockslide to a 30-day period between 9 September 1972 and 9 October 1972. The trigger mechanisms for the rockslide activity appear to have been heavy precipitation prior to the event and the decrease of buttressing mass at the base of the valley wall resulting from recession of the glacier (decrease in width and thickness). The recession led to instability of highly altered hyaloclastite bedrock, talus, and morainal materials on an oversteepened slope. An earthquake as a trigger mechanism was considered to be unlikely from a thorough review of seismic records. Measurements of the downglacier movement of the larger rockslide deposit give an average speed of the glacier as 30±3 m a-1 between September/October 1972 and 10 September 1978. From measurements of aerial photographs taken on 10 September 1978 and 4 September 1984, the average speed of the glacier increased to 45 m a-1 during this 6-year interval. Although the terminus of the unnamed outlet glacier had not yet begun to advance in 1986, it had undergone thickening since 1978.

Geografiska Annaler, Series A: Physical Geography↗

USGS1993

Rainfall-threshold conditions for landslides in a humid-tropical system

Landslides are triggered by factors such as heavy rainfall, seismic activity, and construction on hillslopes. The leading cause of landslides in Puerto Rico is intense and/or prolonged rainfall. A rainfall threshold for rainfall-triggered landsliding is delimited by 256 storms that occurred between 1959 and 1991 in the central mountains of Puerto Rico, where mean annual rainfall is close to or in excess of 2,000 mm. Forty one of the 256 storms produced intense and/or prolonged rainfall that resulted in tens to hundreds of landslides. A threshold fitted to the lower boundary of the field defined by landslide-triggering storms is expressed as I = 91.46 D -0.82 where I is rainfall intensity in millimeters per hour, and D is duration in hours. Landslide-producing storms occurred at an average rate of 1.2 per year. In general the landslides triggered by short-duration, high-intensity rainfall events were mainly shallow soil slips and debris flows, while the long-duration, low-intensity rainfall produced larger, deeper debris avalanches and slumps. For storms that had durations of up to 10 h, landsliding did not occur until rainfall intensity was as much as three times as high as the rainfall intensity reported as sufficient to trigger landsliding in temperate regions. As storm durations approach 100 h, the rainfall conditions necessary to initiate landsliding in Puerto Rico converge with those defined for temperate regions. A comparison of the Puerto Rico threshold with rainfall data from other humid-tropical regions suggests that the threshold developed for Puerto Rico may be applicable to other similar environments throughout the world.

Geografiska Annaler, Series A: Physical Geography↗

USGS2013

Alpine treeline of western North America: Linking organism-to-landscape dynamics

Although the ecological dynamics of the alpine treeline ecotone are influenced by climate, it is an imperfect indicator of climate change. Mechanistic processes that shape the ecotone—seed rain, seed germination, seedling establishment and subsequent tree growth form, or, conversely tree dieback—depend on microsite patterns. Growth forms affect wind and snow, and so develop positive and negative feedback loops that create these microsites. As a result, complex landscape patterns are generated at multiple spatial scales. Although these mechanistic processes are fundamentally the same for all forest-tundra ecotones across western North America, factors such as prior climate, underlying geology and geomorphology, and genetic constraints of dominant tree species lead to geographic differences in the responses of particular ecotones to climate change.

Physical Geography↗

USGS2013

Influences of geomorphology and geology on alpine treeline in the American West - More important than climatic influences?

The spatial distribution and pattern of alpine treeline in the American West reflect the overarching influences of geological history, lithology and structure, and geomorphic processes and landforms, and geologic and geomorphic factors—both forms and processes—can control the spatiotemporal response of the ecotone to climate change. These influences occur at spatial scales ranging from the continental scale to fine scale processes and landforms at the slope scale. Past geomorphic influences, particularly Pleistocene glaciation, have also left their impact on treeline, and treelines across the west are still adjusting to post-Pleistocene conditions within Pleistocene-created landforms. Current fine scale processes include solifluction and changes on relict solifluction and digging by animals. These processes should be examined in detail in future studies to facilitate a better understanding of where individual tree seedlings become established as a primary response of the ecotone to climate change.

The Rocky Mountains↗

USGS2013

Debris flows resulting from glacial-lake outburst floods in tibet, China

During the last 70 years of general climatic amelioration, 18 glacial-lake outburst floods (GLOFs) and related debris flows have occurred from 15 moraine-dammed lakes in Tibet, China. Catastrophic loss of life and property has occurred because of the following factors: the large volumes of water discharged, the steep gradients of the U-shaped channels, and the amount and texture of the downstream channel bed and bank material. The peak discharge of each GLOF exceeded 1000 m3/s. These flood discharges transformed to non-cohesive debris flows if the channels contained sufficient loose sediment for entrainment (bulking) and if their gradients were >1%. We focus on this key element, transformation, and suggest that it be included in evaluating future GLOF-related risk, the probability of transformation to debris flow and hyperconcentrated flow. The general, sequential evolution of the flows can be described as from proximal GLOFs, to sedimentladen streamflow, to hyperconcentrated flow, to non-cohesive debris flow (viscous or cohesive debris flow only if sufficient fine sediment is present), and then, distally, back to hyperconcentrated flow and sediment-laden streamflow as sediment is progressively deposited. Most of the Tibet examples transformed only to non-cohesive debris flows. The important lesson for future hazard assessment and mitigation planning is that, as a GLOF entrains (bulks) enough sediment to become a debris flow, the flow volume must increase by at least three times (the "bulking factor"). In fact, the transforming flow waves overrun and mix with downstream streamflow, in addition to adding the entrained sediment (and thus enabling addition of yet more sediment and a bulking factor in excess of three times). To effectively reduce the risk of GLOF debris flows, reducing the level of a potentially dangerous lake with a siphon or excavated spillway or installing gabions in combination with a downstream debris dam are the primary approaches.

Physical Geography↗

USGS2013

Assessment of the geomorphic effects of large floods using streamgage data: The 1951 floods in eastern Kansas, USA

Data from 23 U.S. Geological Survey (USGS) streamgages were analyzed to assess the geomorphic effects (short-term change and subsequent recovery) of the record 1951 floods on streams in eastern Kansas. Flood-related, channel-bed elevation change was indicated for 17 gage sites, with substantial deposition at five sites and substantial erosion at two sites. An assessment of post-flood bed elevation recovery was possible for several sites. While recovery to pre-flood channel-bed elevation occurred over a period of months to years at some sites, at other sites recovery was incomplete or absent. Floodrelated channel widening with partial recovery was indicated for one site and possible channel widening was indicated for two sites. It was demonstrated that an analysis of streamgage data is a potentially useful technique for assessing the geomorphic effects of a large flood at a site, provided that the gage has a long period of record and is located on an alluvial channel. In the absence of other lines of evidence, streamgage data can provide an estimate of the direction and magnitude (net) of geomorphic change that otherwise might not be available or attainable.

Kansas↗

USGS2013

Contexts for change in alpine tundra

Because alpine tundra is responding to climate change, a need exists to understand the meaning of observed changes. To provide context for such interpretation, the relevance of niche and neutral theories of biogeography and the continuum and classification approaches to biogeographic description are assessed. Two extensive studies of alpine tundra, from the Indian Peaks area, Colorado and Glacier National Park, Montana, are combined. The data are ordinated to describe relations. The pattern that emerges is one of a continuum of vegetation, but with the distinctions one might expect from distant sites. The relationships of the similarity of vegetation on all possible pairs of sites to the environmental differences and geographic distances are analyzed using Mantel correlations. Because distance and environmental differences in climate between the two sites are correlated, partial correlations are weak but still significant. More advanced analyses are suggested for this environment prior to interpretation of monitoring efforts such as GLORIA.

Colorado, Montana↗

USGS2026

A new inventory and conservation assessment of United States islands

To support conservation-focused research and management we developed a new 30-m resolution polygon data layer of the nonlacustrine and nonriverine islands of the United States, with associated attributes describing key physical and conservation geography characteristics. Islands were grouped into a three-tiered hierarchy of island regions (twelve), island provinces (twenty-eight), and individual islands (19,023). Islands were classified as either continental or oceanic based on their physiographic position relative to the North America continental shelf, and estuarine versus nonestuarine depending on their location within or external to estuaries. For each island we assessed the diversity of terrestrial and coastal ecosystems, the number of threatened and endangered (T&E) species listed under the Endangered Species Act, the number of T&E species critical habitats, the number of migratory bird species listed under the Migratory Bird Treaty Act, the number of Key Biodiversity Areas, and the number of and management responsibility for protected areas. We conclude that the conservation importance of islands is disproportionate to their total area as, for example, islands contain 52 percent of the T&E species yet their total area is only 2 percent of the area of the continental mainland. Similarly, of the global total of 431 World Terrestrial Ecosystems, 201 (47 percent) occur on U.S. islands compared with 286 (66 percent) that occur on the U.S. continental mainland.

Annals of the American Association of Geographers↗

USGS1906

Twenty-seventh annual report of the Director of the United States Geological Survey

During the last fiscal year the character of the work and the organization of the force remained substantially the same as described in the Twenty-sixth Annual Report. Accounts of the work performed in geology and paleontology, chemistry and physics, topography and geography, and hydrography, hydrology, and hydro-economics, as well as in the lines of publication and administration, will be found on later pages. Appropriations and allotments .--A plan of operations, including an itemized statement of the appropriations, amounting to $1,513,482.30, and the allotments thereof, was approved by the Secretary of the Interior on May 15, 1905. The work of the year conformed to this plan, copies of which are on file at the Department and the Survey. State cooperation .--Many of the States, following a well-established policy, cooperated with the National Survey in geologic, topographic, and hydrographic work; details are given on pages 12, 29, 72, and 74.

Annual Report↗

USGS2009

A New Map of Standardized Terrestrial Ecosystems of the Conterminous United States

A new map of standardized, mesoscale (tens to thousands of hectares) terrestrial ecosystems for the conterminous United States was developed by using a biophysical stratification approach. The ecosystems delineated in this top-down, deductive modeling effort are described in NatureServe's classification of terrestrial ecological systems of the United States. The ecosystems were mapped as physically distinct areas and were associated with known distributions of vegetation assemblages by using a standardized methodology first developed for South America. This approach follows the geoecosystems concept of R.J. Huggett and the ecosystem geography approach of R.G. Bailey. Unique physical environments were delineated through a geospatial combination of national data layers for biogeography, bioclimate, surficial materials lithology, land surface forms, and topographic moisture potential. Combining these layers resulted in a comprehensive biophysical stratification of the conterminous United States, which produced 13,482 unique biophysical areas. These were considered as fundamental units of ecosystem structure and were aggregated into 419 potential terrestrial ecosystems. The ecosystems classification effort preceded the mapping effort and involved the independent development of diagnostic criteria, descriptions, and nomenclature for describing expert-derived ecological systems. The aggregation and labeling of the mapped ecosystem structure units into the ecological systems classification was accomplished in an iterative, expert-knowledge-based process using automated rulesets for identifying ecosystems on the basis of their biophysical and biogeographic attributes. The mapped ecosystems, at a 30-meter base resolution, represent an improvement in spatial and thematic (class) resolution over existing ecoregionalizations and are useful for a variety of applications, including ecosystem services assessments, climate change impact studies, biodiversity conservation, and resource management.

Professional Paper↗

USGS1979

Bibliography of geology and hydrology, eastern New Mexico

The High Plains of the eastern New Mexico region are recognized as an abundant and varied source of natural resources. The bibliography of over 1,900 references concerned with geology, hydrology, chemistry, and geography has been compiled to assist physical science researchers in their study of this region. (Kosco-USGS)

Water-Resources Investigations Report↗

USGS1980

Bibliography of geology and hydrology, southwestern New Mexico

The southwestern part of New Mexico is recognized as a source of abundant and varied natural resources. This bibliography of over 2,700 references concerned with geology, hydrology, chemistry, and geography has been compiled to assist physical science researchers in their study and development of this region.

New Mexico↗

USGS2021

Soils and paleosols

Soils are naturally occurring bodies that form in the interface between the geosphere, biosphere, hydrosphere , and atmosphere. They are the medium for much of the Earth's plant and animal growth. Soil morphology and how it evolves are functions of the soil-forming factors of climate, organisms, relief, parent material, and time. The expression of soil morphology takes the form of layers, called horizons, that differ in their color, particle size distribution, structure, chemistry, and organic matter content from the parent material. A fundamental soil mapping unit in the USA is the soil order and 12 soil orders have been defined on the basis of soil morphology, physical and chemical properties, and climate. Soil geography in the USA is explained by an examination of how these 12 soil orders are found in particular climates, under specific vegetation communities, how they develop from compositionally distinct parent materials, or how they are a result of the age of soil parent material. Paleosols are ancient soils, those that formed in the past. Three types of paleosols are recognized, buried soils (those covered by a younger sediment or rock), exhumed paleosols (formerly buried soils that are now exposed at the surface due to erosion of overlying materials), and relict paleosols (soils that occur at the land surface, but which formed in an environment, such as a climate or biome, very different from that at the present time). Paleosols can help define geologic contacts and can aid in elucidating past climates or vegetation regimes. Although there are rich geologic records of paleosols in the Quaternary, there is an increasing recognition of the importance of all these features in the longer, pre-Quaternary geologic record.

Book chapter↗

USGS2011

Stopover habitats of spring migrating surf scoters in southeast Alaska

Habitat conditions and nutrient reserve levels during spring migration have been suggested as important factors affecting population declines in waterfowl, emphasizing the need to identify key sites used during spring and understand habitat features and resource availability at stopover sites. We used satellite telemetry to identify stopover sites used by surf scoters migrating through southeast Alaska during spring. We then contrasted habitat features of these sites to those of random sites to determine habitat attributes corresponding to use by migrating scoters. We identified 14 stopover sites based on use by satellite tagged surf scoters from several wintering sites. We identified Lynn Canal as a particularly important stopover site for surf scoters originating throughout the Pacific winter range; approximately half of tagged coastally migrating surf scoters used this site, many for extended periods. Stopover sites were farther from the mainland coast and closer to herring spawn sites than random sites, whereas physical shoreline habitat attributes were generally poor predictors of site use. The geography and resource availability within southeast Alaska provides unique and potentially critical stopover habitat for spring migrating surf scoters. Our work identifies specific sites and habitat resources that deserve conservation and management consideration. Aggregations of birds are vulnerable to human activity impacts such as contaminant spills and resource management decisions. This information is of value to agencies and organizations responsible for emergency response planning, herring fisheries management, and bird and ecosystem conservation.

Journal of Wildlife Management↗

USGS2010

Effects of including surface depressions in the application of the Precipitation-Runoff Modeling System in the Upper Flint River Basin, Georgia

This report documents an extension of the Precipitation Runoff Modeling System that accounts for the effect of a large number of water-holding depressions in the land surface on the hydrologic response of a basin. Several techniques for developing the inputs needed by this extension also are presented. These techniques include the delineation of the surface depressions, the generation of volume estimates for the surface depressions, and the derivation of model parameters required to describe these surface depressions. This extension is valuable for applications in basins where surface depressions are too small or numerous to conveniently model as discrete spatial units, but where the aggregated storage capacity of these units is large enough to have a substantial effect on streamflow. In addition, this report documents several new model concepts that were evaluated in conjunction with the depression storage functionality, including: ?hydrologically effective? imperviousness, rates of hydraulic conductivity, and daily streamflow routing. All of these techniques are demonstrated as part of an application in the Upper Flint River Basin, Georgia. Simulated solar radiation, potential evapotranspiration, and water balances match observations well, with small errors for the first two simulated data in June and August because of differences in temperatures from the calibration and evaluation periods for those months. Daily runoff simulations show increasing accuracy with streamflow and a good fit overall. Including surface depression storage in the model has the effect of decreasing daily streamflow for all but the lowest flow values. The report discusses the choices and resultant effects involved in delineating and parameterizing these features. The remaining enhancements to the model and its application provide a more realistic description of basin geography and hydrology that serve to constrain the calibration process to more physically realistic parameter values.

Georgia↗

USGS2010

Quality of stormwater runoff discharged from Massachusetts highways, 2005-07

The U.S. Geological Survey (USGS), in cooperation with U.S. Department of Transportation Federal Highway Administration and the Massachusetts Department of Transportation, conducted a field study from September 2005 through September 2007 to characterize the quality of highway runoff for a wide range of constituents. The highways studied had annual average daily traffic (AADT) volumes from about 3,000 to more than 190,000 vehicles per day. Highway-monitoring stations were installed at 12 locations in Massachusetts on 8 highways. The 12 monitoring stations were subdivided into 4 primary, 4 secondary, and 4 test stations. Each site contained a 100-percent impervious drainage area that included two or more catch basins sharing a common outflow pipe. Paired primary and secondary stations were located within a few miles of each other on a limited-access section of the same highway. Most of the data were collected at the primary and secondary stations, which were located on four principal highways (Route 119, Route 2, Interstate 495, and Interstate 95). The secondary stations were operated simultaneously with the primary stations for at least a year. Data from the four test stations (Route 8, Interstate 195, Interstate 190, and Interstate 93) were used to determine the transferability of the data collected from the principal highways to other highways characterized by different construction techniques, land use, and geography. Automatic-monitoring techniques were used to collect composite samples of highway runoff and make continuous measurements of several physical characteristics. Flowweighted samples of highway runoff were collected automatically during approximately 140 rain and mixed rain, sleet, and snowstorms. These samples were analyzed for physical characteristics and concentrations of 6 dissolved major ions, total nutrients, 8 total-recoverable metals, suspended sediment, and 85 semivolatile organic compounds (SVOCs), which include priority polyaromatic hydrocarbons (PAHs), phthalate esters, and other anthropogenic or naturally occurring organic compounds. The distribution of particle size of suspended sediment also was determined for composite samples of highway runoff. Samples of highway runoff were collected year round and under various dry antecedent conditions throughout the 2-year sampling period. In addition to samples of highway runoff, supplemental samples also were collected of sediment in highway runoff, background soils, berm materials, maintenance sands, deicing compounds, and vegetation matter. These additional samples were collected near or on the highways to support data analysis. There were few statistically significant differences between populations of constituent concentrations in samples from the primary and secondary stations on the same principal highways (Mann-Whitney test, 95-percent confidence level). Similarly, there were few statistically significant differences between populations of constituent concentrations for the four principal highways (data from the paired primary and secondary stations for each principal highway) and populations for test stations with similar AADT volumes. Exceptions to this include several total-recoverable metals for stations on Route 2 and Interstate 195 (highways with moderate AADT volumes), and for stations on Interstate 95 and Interstate 93 (highways with high AADT volumes). Supplemental data collected during this study indicate that many of these differences may be explained by the quantity, as well as the quality, of the sediment in samples of highway runoff. Nonparametric statistical methods also were used to test for differences between populations of sample constituent concentrations among the four principal highways that differed mainly in traffic volume. These results indicate that there were few statistically significant differences (Mann-Whitney test, 95-percent confidence level) for populations of concentrations of most total-recoverable metals

Scientific Investigations Report↗

USGS2011

A GIS application for assessing, mapping, and quantifying the social values of ecosystem services

As human pressures on ecosystems continue to increase, research involving the effective incorporation of social values information into the context of comprehensive ecosystem services assessments is becoming more important. Including quantified, spatially explicit social value metrics in such assessments will improve the analysis of relative tradeoffs among ecosystem services. This paper describes a GIS application, So cia l V alues for E cosystem S ervices (SolVES), developed to assess, map, and quantify the perceived social values of ecosystem services by deriving a non-monetary Value Index from responses to a public attitude and preference survey. SolVES calculates and maps the Value Index for social values held by various survey subgroups, as distinguished by their attitudes regarding ecosystem use. Index values can be compared within and among survey subgroups to explore the effect of social contexts on the valuation of ecosystem services. Index values can also be correlated and regressed against landscape metrics SolVES calculates from various environmental data layers. Coefficients derived through these analyses were applied to their corresponding data layers to generate a predicted social value map. This map compared favorably with other SolVES output and led to the addition of a predictive mapping function to SolVES for value transfer to areas where survey data are unavailable. A more robust application is being developed as a public domain tool for decision makers and researchers to map social values of ecosystem services and to facilitate discussions among diverse stakeholders involving relative tradeoffs among different ecosystem services in a variety of physical and social contexts.

Applied Geography↗