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At least 1,477 records · Page 82Linked to original sources
USGS2002

Historic bluff retreat and stabilization at Flag Harbor, Chesapeake Bay, Maryland

Studies of bluff erosion and slope stability along the western shore of Chesapeake Bay suggest relative evolution from steep, eroding coastal bluffs to stable slopes at angles of repose ca. 35 degrees over decades. Because of the dating methods in those studies, it was impossible to precisely define rates of change. The present study provides historic age control. A pair of small harbor structures were constructed in the early 1950's at Chesapeake Beach, MD to maintain a dredged channel to a small marina occupying a ravine in the Calvert Cliffs. Prior to construction, this section of shoreline was comprised of eroding steep bluffs cut into Miocene-age sediments. Downdrift erosion is now apparent south of the structures as is updrift deposition behind the northern jetty. Since construction the updrift sand body has prograded northward and progressively deposited protective beaches along the toes of the bluffs. Former eroding bluffs nearest the harbor are now stable, vegetated slopes at angles near 35 degrees. Slope angles widen to the north and to the northern limit of the sand body. Beyond this are eroding bluffs standing at angles of 70-80 degrees. The relative time required for eroding bluffs to reach stability is estimated by interpolating the distance and time for the sand body to prograde northward since harbor construction. We measured slope angles at intervals northward from the updrift structure for a distance of 2000 feet. A least squares regression of slope angle vs distance showed progressive decrease in angle from north to south. Actively eroding 70-80 degree bluffs gave way to vegetated, but slumping slopes, and finally to stable 35-degree slopes at the harbor. A relationship between time and distance along the shore allowed us to estimate a stabilization time for this location of 35-40 years. The shortness of this time scale allows us to suggest that attempts to artificially stabilize eroding bluffs along this coast is not a simple task of protecting the toes of slopes from wave action. Once shoreline retreat ends, sloughing of sediment from bluff faces gives way to longer-term landslide processes. The bluff top recedes until a stable 35-degree slope is attained. Thus, simple shoreline protection methods may not preserve property at the bluff edge.

Open-File Report↗
USGS2017

Geologic map of the northern White Hills, Mohave County, Arizona

Introduction The northern White Hills map area lies within the Kingman Uplift, a regional structural high in which Tertiary rocks lie directly on Proterozoic rocks as a result of Cretaceous orogenic uplift and erosional stripping of Paleozoic and Mesozoic strata. The Miocene Salt Spring Fault forms the major structural boundary in the map area. This low-angle normal fault separates a footwall (lower plate) of Proterozoic gneisses on the east and south from a hanging wall (upper plate) of faulted middle Miocene volcanic and sedimentary rocks and their Proterozoic substrate. The fault is part of the South Virgin–White Hills Detachment Fault, which records significant tectonic extension that decreases from north to south. Along most of its trace, the Salt Spring Fault dips gently westward, but it also has north-dipping segments along salients. A dissected, domelike landscape on the eroded footwall, which contains antiformal salients and synformal reentrants, extends through the map area from Salt Spring Bay southward to the Golden Rule Peak area. The “Lost Basin Range” represents an upthrown block of the footwall, raised on the steeper Lost Basin Range Fault. The Salt Spring Fault, as well as the normal faults that segment its hanging wall, deform rocks that are about 16 to 10 Ma, and younger deposits overlie the faults. Rhyodacitic welded tuff about 15 Ma underlies a succession of geochemically intermediate to progressively more mafic lavas (including alkali basalt) that range from about 14.7 to 8 Ma, interfingered with sedimentary rocks and breccias in the western part of the map area. Upper Miocene strata record further filling of the extension-formed continental basins. Basins that are still present in the modern landscape reflect the youngest stages of extensional-basin formation, expressed as the downfaulted Detrital Valley and Hualapai Wash basins in the western and eastern parts of the map area, respectively, as well as the north-centrally located, northward-sagged Temple Basin. Pliocene fluvial and piedmont alluvial fan deposits record postextensional basin incision, refilling, and reincision driven by the inception and evolution of the westward-flowing Colorado River, centered north of the map area.

Arizona↗
USGS2022

Field-trip guide to continental arc to rift volcanism of the southern Rocky Mountains—Southern Rocky Mountain, Taos Plateau, and Jemez Mountains volcanic fields of southern Colorado and northern New Mexico

The southern Rocky Mountains of northern New Mexico and southern Colorado preserve the Oligocene to Pleistocene record of North American continental arc to rift volcanism. The 35–23 million year old (Ma) southern Rocky Mountain volcanic field (SRMVF), spectacularly preserved in the San Juan Mountains of southern Colorado, records the evolution of large andesitic stratovolcanoes to complex caldera clusters, from which at least 22 major ignimbrite sheets (each 150–5,000 cubic kilometers) were erupted. Outflow deposits of the SRMVF preserved along the broadly uplifted northwest flank of the northern Rio Grande rift basin (the San Luis Valley) provide critical structural and temporal constraints on the inception of crustal extension. Coincident with waning stages of SRMVF caldera-forming volcanism (~25.4 Ma), extensional tectonism was accompanied by a transition from bimodal early Miocene to intermediate-composition late Miocene and dominantly basaltic Pliocene rift volcanism of the Taos Plateau in the southern San Luis Basin. Concomitant rift volcanism in the Española Basin and bordering Jemez Mountains of northern New Mexico records a similar Miocene eruptive history dominated by intermediate-composition volcanism that transitioned locally to Pliocene rift-related basaltic volcanism of the Cerros del Rio volcanic field and culminated in eruptions of the iconic rhyolitic Pleistocene Bandelier Tuff and formation of the Valles Caldera along the northwestern rift-basin margin. This 6-day, 7-night field trip will focus, in broadly equal proportions, on rift-related extensional volcanism of the Jemez Mountains and Taos Plateau regions during the first half of the trip, and on caldera-forming volcanism of the southern Rocky Mountain volcanic field during the second half of the trip. The 35-million-year volcanic history of the region highlighted by new geologic mapping, high-resolution geochronology, petrologic, geochemical, and geophysical data facilitates discussion of (1) the magmatic response to the tectonic transition from subducted-slab arc to continental-rift volcanism; (2) the nature and temporal evolution of rift magmas; (3) fault controls on the spatial evolution of rift magmatism; (4) the diversity of continental-arc ignimbrite volcanism and associated lavas; (5) ignimbrite caldera structure and associated intrusions in three-dimension; (6) the role of recycled crystal mush and magmatic cumulates during growth of Cordilleran batholiths; and (7) high-precision geochronologic contributions to interpretation of relations between regional tectonic and volcanic processes. Most stops will be along roads, but there will be moderate hikes on trails of less than 1-hour duration covering 1–2 kilometers (0.6–1.2 miles) with modest elevation gain of <150 meters (<492 feet). The route will progress in reverse stratigraphic order, starting in the Jemez Mountains of New Mexico and proceed northward to San Luis Basin and San Luis Hills before turning west to the southeast and central San Juan Mountains. Our last full day takes us to the little-visited and only recently mapped, Bonanza caldera of the northeastern San Juan Mountains and on the final day, we leave the San Luis Valley to briefly explore the Tertiary subvolcanic plutons of the Collegiate Range along the west side of the Arkansas Valley rift valley, en route to Denver. The authors of all daily contributions acknowledge the helpful reviews by Amy Gilmer and Joe Colgan and thank Christine Chan and Jeremy Havens for assistance with figures, tables, and guidebook text.

Colorado, New Mexico↗
USGS2019

Movements of immature bald eagles: Implications for bird aircraft strike hazard

Bald eagle (Haliaeetus leucocephalus) aircraft strikes have increased dramatically over the last 20 years as their populations have recovered to near historic sizes. Their attraction to airfields and their large body size makes them a danger to aircraft and therefore important to airfield wildlife managers. However, their management is complicated by their special protected status and the iconic place they hold in the eyes of the public. To help airfield wildlife managers plan monitoring efforts and make informed management decisions, we studied the movements of 32 bald eagles telemetered as nestlings in the Chesapeake Bay of Virginia, USA. Managers often need to know when fledged eagles are most likely to move enough to encounter airfields near nests. As fledglings aged they moved progressively farther from the nest and spent more time away from the nest. Twenty-eight days after fledging, eagles spent most of the day (81±10%, 95% confidence interval) near the nest (<500 m) and only 7±7% of the daytime away from the nest (>1 km). By day 53 fledglings ventured beyond 2.5 km from the nest and spent 30 ± 15% the day >1 km away from their nest. However, distances moved were influenced by proximity of the nest to water, the quality and salinity of that water, and human population density. Eagles left their natal areas and generally migrated out of the Chesapeake Bay 60.5 ± 7.7 days (4 August) after fledging and returned to the Chesapeake Bay approximately 225 days later (March-April). Eighty-four percent (27 of 32) of the eagles that we tracked encountered 164 airfields across the east coast with 91% of those airfields located within 10 km of the Chesapeake Bay. Encounters with airfields outside the Chesapeake Bay occurred mainly during the first 1.5 years of life, peaking in late fall and early spring. Eagles were recorded on Chesapeake Bay airfields during each year, but encounters peaked in April of the first year of the bird’s life. This month coincides with the height of reported strikes of eagles by aircraft in the region. Our results suggest that eagles fledging from the Chesapeake Bay are not only an issue for airports near the Chesapeake Bay, but for airports across the east coast. Given the continued growth of the population, this issue is likely to continue and grow in significance.

Virginia↗
USGS2006

GFDL's CM2 global coupled climate models. Part I: Formulation and simulation characteristics

The formulation and simulation characteristics of two new global coupled climate models developed at NOAA's Geophysical Fluid Dynamics Laboratory (GFDL) are described. The models were designed to simulate atmospheric and oceanic climate and variability from the diurnal time scale through multicentury climate change, given our computational constraints. In particular, an important goal was to use the same model for both experimental seasonal to interannual forecasting and the study of multicentury global climate change, and this goal has been achieved. Tw o versions of the coupled model are described, called CM2.0 and CM2.1. The versions differ primarily in the dynamical core used in the atmospheric component, along with the cloud tuning and some details of the land and ocean components. For both coupled models, the resolution of the land and atmospheric components is 2?? latitude ?? 2.5?? longitude; the atmospheric model has 24 vertical levels. The ocean resolution is 1?? in latitude and longitude, with meridional resolution equatorward of 30?? becoming progressively finer, such that the meridional resolution is 1/3?? at the equator. There are 50 vertical levels in the ocean, with 22 evenly spaced levels within the top 220 m. The ocean component has poles over North America and Eurasia to avoid polar filtering. Neither coupled model employs flux adjustments. The co ntrol simulations have stable, realistic climates when integrated over multiple centuries. Both models have simulations of ENSO that are substantially improved relative to previous GFDL coupled models. The CM2.0 model has been further evaluated as an ENSO forecast model and has good skill (CM2.1 has not been evaluated as an ENSO forecast model). Generally reduced temperature and salinity biases exist in CM2.1 relative to CM2.0. These reductions are associated with 1) improved simulations of surface wind stress in CM2.1 and associated changes in oceanic gyre circulations; 2) changes in cloud tuning and the land model, both of which act to increase the net surface shortwave radiation in CM2.1, thereby reducing an overall cold bias present in CM2.0; and 3) a reduction of ocean lateral viscosity in the extratropics in CM2.1, which reduces sea ice biases in the North Atlantic. Both models have be en used to conduct a suite of climate change simulations for the 2007 Intergovernmental Panel on Climate Change (IPCC) assessment report and are able to simulate the main features of the observed warming of the twentieth century. The climate sensitivities of the CM2.0 and CM2.1 models are 2.9 and 3.4 K, respectively. These sensitivities are defined by coupling the atmospheric components of CM2.0 and CM2.1 to a slab ocean model and allowing the model to come into equilibrium with a doubling of atmospheric CO2. The output from a suite of integrations conducted with these models is freely available online (see http://nomads.gfdl.noaa.gov/). ?? 2006 American Meteorological Society.

Journal of Climate↗
USGS1979

Progress in remote sensing as it applies to missions of Committee for Coordination of Joint Prospecting for Mineral Resources in Asian Offshore Areas

The major thrusts of investigations of the use of space data for understanding our Earth continue to focus on the land and near-shore environments. This is expectable; people live on the land, draw most of their resources from the land or near-shore areas, and in these areas environmental degradation or improvement are most clearly observable. An exception to this focus of investigation was the launch of Seasat, a satellite dedicated to marine investigations. Seasat was short lived but the data produced strongly supported the use of imaging radar for land investigation, and, although studies are incomplete, suggest eventual benefits for the navigator, searchers for marine resources, and mariners--provided that the data and/or interpretations can be available to the marine users shortly after collection. In this regard, the positive steps now being taken in Southeast Asia to establish reception, processing, and interpretation centers are a major development.

Open-File Report↗
USGS1992

Sedimentology, behavior, and hazards of debris flows at Mount Rainier, Washington

Mount Rainier is potentially the most dangerous volcano in the Cascade Range because of its great height, frequent earthquakes, active hydrothermal system, and extensive glacier mantle. Many debris flows and their distal phases have inundated areas far from the volcano during postglacial time. Two types of debris flows, cohesive and noncohesive, have radically different behavior that relates empirically to clay content. The two types represent the observable end members of a continuum of debris flow characteristics at Mount Rainier. Cohesive flows exhibit behavior affected by the cohesion and adhesion of particles; noncohesive flows are dominated by particle collisions to the extent of extensive particle cataclasis during near-boundary shear. Cohesive debris flows contain more than 3 to 5 percent of clay-size sediment. The composition of these flows changed little during flow for more than 100 kilometers from Mount Rainier where they inundate parts of the now-populated Puget Sound Lowland. They originate as deep-seated failures of sectors of the volcanic edifice at a frequency indicating that such failures are the major destructional process of its morphologic evolution. In several deposits of large cohesive flows, a lateral, megaclast-bearing facies (with a mounded or hummocky surface) contrasts with a more clay-rich facies in the center of valleys and downstream. Cohesive flows at Mount Rainier do not correlate strongly with volcanic activity and thus can recur without warning, possibly triggered by nonmagmatic seismicity or by destabilization associated with the hydrothermal system. Noncohesive debris flows contain less than 3 to 5 percent of clay-size sediment. They form most commonly by hulking of sediment in water surges, but some originate directly or indirectly from shallow slope failures that do not penetrate the hydrothermally altered core of the volcano. In contrast with cohesive flows, most noncohesive flows transform both from and to other flow types, so that the debris flows are the middle segments of flow waves beginning and ending as flood surges. Proximally, through the bulking of poorly sorted, volcaniclastic debris on the flanks of the volcano, flow waves expand rapidly in volume by transforming from water surges through hyperconcentrated streamflow (20 to 60 percent sediment by volume) to debris flow. Distally, the transformations occur more slowly in reverse order--from debris flow, to hyperconcentrated flow, and finally to normal streamflow with less than 20 percent sediment by volume. During runout of the largest noncohesive flows, hyperconcentrated flow has occurred for as much as 40 to 70 kilometers. Lahars (volcanic debris flows and their deposits) occurred at Mount Rainier throughout later postglacial time and not as groups of closely time-related flows during discrete eruptive periods as at Mount St. Helens. An exception is a period of large noncohesive flows during and after construction of the modern summit cone. Laharrunout flows, the hyperconcentrated flows forming the distal phases of lahars, document the frequency and extent of noncohesive lahars. Deposits record the following transformations of debris flows: (1) the direct, progressive dilution of debris flow to hyperconcentrated flow, (2) deposition of successively finer grained lobes of debris until only the hyperconcentrated tail of the flow remains to continue downstream, and (3) dewatering of coarse debris flow deposits to yield fine-grained debris flow or hyperconcentrated flow. Three planning or design case histories represent different lengths of postglacial time. Case I is representative of large, infrequent (500 to 1,000 years on average) cohesive debris flows. These flows need to be considered in long-term planning in valleys around the volcano. Case II generalizes the noncohesive debris flows of intermediate size and recurrence (100 to 500 years). This case is appropriate for consideration in some structural design. Case III flows are relatively small but more frequent (less than 100 years on average).

Washington↗
USGS1989

Use of stable carbon and nitrogen isotopes to trace the larval striped bass food chain in the Sacramento-San Joaquin Estuary, California, April to September 1985

To assess one potential cause for the decline of the striped bass fishery in the Sacramento-San Joaquin Estuary, stable carbon and nitrogen isotope ratios were used to examine the trophic structures of the larval striped bass food chain, and to trace the flux of these elements through the food chain components. Study results generally confirm a food chain consisting of the elements, phytoplankton/detritus-->zooplankton/Neomysis shrimp-->larval striped bass. The stable isotope ratios generally become more positive as one progresses from the lower to the higher trophic level food chain components, and no unusual trophic structure was found in the food chain. However, the data indicate an unidentified consumer organism occupying an intermediate position between the lower and higher trophic levels of the larval striped bass food chain. Based on expected trophic interactions, this unidentified consumer would have a stable carbon isotope ratio of about 28/mil and a stable nitrogen isotope ratio of about 8/mi. Three possible feeding stages for larval striped bass also were identified, based on their lengths. The smallest length fish seem to subsist on their yolk sac remnants, and the largest length fish subsist on Neomysis shrimp and zooplankton. The intermediate-length fish represent a transition stage between primary food sources and/or use of a mixture of food sources. (USGS)

Water-Resources Investigations Report↗
USGS1963

Ground-water geology of Bexar County, Texas

The investigation in Bexar County was part of a comprehensive study of a large area in south-central Texas underlain by the Edwards and associated limestones (Comanche Peak and Georgetown) of Cretaceous age. The limestones form an aquifer which supplies water to the city of San Antonio, several military installations, many industrial plants, and many irrigated farms. The geologic formations that yield water to wells in Bexar County are sedimentary rocks of Mesozoic and Cenozoic age. The rocks strike northeastward and dip southeastward toward the Gulf of Mexico. In the northern part of the county, in an erosional remnant of the Edwards Plateau, the rocks are nearly flat and free from faulting. In the central and southern parts of the county, however, the rocks dip gulfward at gentle to moderately steep angles and are extensively faulted in the Balcones and Mexia fault zones. Individual faults or shatter zones were traced as much as 25 miles; the maximum displacement is at least 600 feet. In general, the formations are either monoclinal or slightly folded; in the western part of the county the broad Culebra anticline plunges southwestward. Most of the large-capacity wells in Bexar County draw water from the Edwards and associated limestones, but a few draw from the Glen Rose limestone, the Austin chalk, and surficial sand and gravel. The Hosston formation, Glen Rose limestone, Buda limestone, and Austin chalk, all of Cretaceous age, generally yield small to large supplies of water; the Wilcox group and Carrizo sand of Tertiary age yield moderate supplies and alluvium of Pleistocene and Recent age generally yield small supplies. The Edwards and associated limestones are recharged primarily by groundwater underflow into Bexar County from the west, and secondarily by seepage from streams that cross the outcrop of the aquifer in Bexar County. During the period 1934-47 the recharge to the aquifer in Bexar County is estimated to have averaged between 400,000 and 430,000 acre-feet per year. Discharge from the aquifer takes place by means of wells and springs and by underflow into Comal and Guadalupe Counties on the northeast. During the period 1934-47 the estimated average discharge from wells and springs was about 174,000 acre-feet per year. The discharge by underflow out of the county during the same period is estimated to have averaged between 220,000 and 260,000 acre-feet per year. Probably only a small amount of water moves downdip southeast of San Antonio. The presence of highly mineralized water in that area suggests that the circulation of water is poor because of the low permeability of the aquifer. During the period 1934-56 the discharge from the Edwards and associated limestones greatly exceeded the recharge; consequently, water levels in wells declined. The decline was greatest in the northwestern part of the county, where the water levels in wells dropped as much as 100 feet. The decline was progressively less toward the east, averaging 40 feet along the Bexar-Comal County line. The area of the greatest concentration of discharge, which includes San Antonio and extends to the southwest and northeast, coincides with the area of maximum faulting and maximum recorded yields from wells and is not the area of greatest decline. The ability of the Edwards and associated limestones to transmit and store water in the San Antonio area apparently is so great that the discharge from wells results in much smaller declines of water level than do similar or even smaller discharges in other areas. The water from the Edwards is almost uniformly a calcium bicarbonate water of good quality, although hard. In the southern part of the San Antonio area the water is charged with hydrogen sulfide; farther downdip it becomes highly mineralized.

Water Supply Paper↗
USGS2026

Advancing monitoring approaches to enhance tidal Chesapeake Bay habitat assessment for submerged aquatic vegetation, water clarity, chlorophyll a and dissolved oxygen

Water quality monitoring capacity has been declining for the Chesapeake Bay Program (CBP) at a time when information needs are growing, and data gaps exist to address critical decision-support for managers. The CBP Scientific Technical Assessment and Reporting Team is leading a Principal’s Staff Committee requested gap analyses toward understanding support needed to improve water quality monitoring and analysis programming. Advanced technologies and alternative monitoring approaches in the form of satellite-based measurements, Artificial Intelligence/Machine Learning (AI/ML) algorithms for data interpretation, continuous water quality in-situ sensor arrays, and community science efforts offer a growing portfolio of valuable opportunities for expanding data collections and analysis program capacities. However, since 1985, each of these options are examples of growing opportunities to enhance water quality assessments yet has seen limited adoption into elements of Chesapeake Bay water quality monitoring programs. Where new technologies have been adopted (e.g., shallow water continuous water quality monitoring), such temporally rich data streams have supported Bay health insights yet had limited use in regulatory water quality criteria assessment. This Scientific Technical Advisory Committee (STAC) supported workshop provided the ideal forum for engaging our CBP partnership regarding the maturity of new and evolving monitoring and analysis capacities to address program information needs while appreciating limitations with adopting new tools and approaches. Improving natural resources monitoring efficiency and effectiveness will expand the scientific and technical foundations for making robust, strategic choices on decisions for CBP Partnership community-based priorities, policies, and management actions. Workshop findings and recommendations reflect progress in science, technology, and analyses addressing long-standing programmatic limitations in data collection and analysis capacities. State-of-the-science updates highlighted in the workshop span the spectrum of efforts representing improvements, successes, remaining challenges toward operationalizing protocols, and guidance toward research, or adoption and implementation by monitoring programs.

Maryland, Pennsylvania, Virginia↗
USGS2012

Bathymetry and digital elevation models of Coyote Creek and Alviso Slough, South San Francisco Bay, California

In 2010, the U.S. Geological Survey (USGS), Pacific Coastal and Marine Science Center completed three cruises to map the bathymetry of the main channel and shallow intertidal mudflats in the southernmost part of south San Francisco Bay. The three surveys were merged to generate comprehensive maps of Coyote Creek (from Calaveras Point east to the railroad bridge) and Alviso Slough (from the bay to the town of Alviso) to establish baseline bathymetry prior to the breaching of levees adjacent to Alviso and Guadalupe Sloughs as part of the South Bay Salt Pond Restoration Project ( http://www.southbayrestoration.org ). Since 2010, the USGS has conducted fourteen additional surveys to monitor bathymetric change in this region as restoration progresses. The bathymetric surveys were conducted using the state-of-the-art research vessel R/V Parke Snavely outfitted with an interferometric sidescan sonar for swath mapping in extremely shallow water. This publication provides high-resolution bathymetric data collected by the USGS. For the 2010 baseline survey we have merged the bathymetry with aerial lidar data that were collected for the USGS during the same time period to create a seamless, high-resolution digital elevation model (DEM) of the study area. The series of bathymetric datasets are provided at 1 m resolution and the 2010 bathymetric/topographic DEM at 2 m resolution. The data are formatted as both X, Y, Z text files and ESRI Arc ASCII files that are accompanied by Federal Geographic Data Committee (FGDC) compliant metadata.

California↗
USGS1925

Notes on the geology of Green River Valley between Green River, Wyoming, and Green River, Utah

During July, August, and part of September, 1922, I had the privilege of accompanying a party sent out jointly by the Utah Power & Light Co. and the United States Geological Survey to gather such data as were still needed to complete a study of the power resources of Green River between Green River, Wyo., and Green River, Utah. The chief deficiency to be supplied was a continuous topographic map of the valley in sufficient detail to permit calculation of the storage capacity of any reservoir site that might be used, the stream gradient, and similar features. Maps on a satisfactory scale of a number of isolated stretches of the river had already been made by public or private agencies, and it was necessary to verify them and connect them on a uniform datum. Inasmuch as it was deemed unlikely that a dam higher than 300 feet would be constructed anywhere on the part of the river to be examined, a plane 300 feet above the water surface was made the upper limit of mapping. Over such parts of the valley as had been mapped already the progress of the party was naturally very rapid, and even where no mapping had previously been done, the 300-foot limit set upon the work and the usual narrowness of the valley combined to reduce the extent of the area to be mapped, so that the speed maintained was relatively high. Under this condition of rapid movement it was seldom possible to make more than the most cursory examination of the rocks, though occasionally circumstances permitted more or less detailed observation. The notes here recorded are therefore mostly of a rather generalized character, but as they pertain in part to localities that are difficult of access and not often visited by geologists, and that are at the same time classic in the history of American geology, I venture to to record them for whatever value they may have to other geologists.

Utah;Wyoming↗
USGS2016

The Integrated Landscape Modeling partnership - Current status and future directions

The Integrated Landscape Modeling (ILM) partnership is an effort by the U.S. Geological Survey (USGS) and U.S. Department of Agriculture (USDA) to identify, evaluate, and develop models to quantify services derived from ecosystems, with a focus on wetland ecosystems and conservation effects. The ILM partnership uses the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) modeling platform to facilitate regional quantifications of ecosystem services under various scenarios of land-cover change that are representative of differing conservation program and practice implementation scenarios. To date, the ILM InVEST partnership has resulted in capabilities to quantify carbon stores, amphibian habitat, plant-community diversity, and pollination services. Work to include waterfowl and grassland bird habitat quality is in progress. Initial InVEST modeling has been focused on the Prairie Pothole Region (PPR) of the United States; future efforts might encompass other regions as data availability and knowledge increase as to how functions affecting ecosystem services differ among regions. The ILM partnership is also developing the capability for field-scale process-based modeling of depressional wetland ecosystems using the Agricultural Policy/Environmental Extender (APEX) model. Progress was made towards the development of techniques to use the APEX model for closed-basin depressional wetlands of the PPR, in addition to the open systems that the model was originally designed to simulate. The ILM partnership has matured to the stage where effects of conservation programs and practices on multiple ecosystem services can now be simulated in selected areas. Future work might include the continued development of modeling capabilities, as well as development and evaluation of differing conservation program and practice scenarios of interest to partner agencies including the USDA’s Farm Service Agency (FSA) and Natural Resources Conservation Service (NRCS). When combined, the ecosystem services modeling capabilities of InVEST and the process-based abilities of the APEX model should provide complementary information needed to meet USDA and the Department of the Interior information needs.

Iowa, Minnesota, Nebraska, North Dakota, South Dak↗
USGS1969

Geologic history of the Colorado River: Chapter C in The Colorado River region and John Wesley Powell (Professional Paper 669)

John Wesley Powell clearly recognized that the spectacular features of the Colorado River - its many grand canyons - were dependent upon the structural history of the mountainous barriers crossed by the river. He conceived of three different historical relationships between rivers and structural features: (1) Newly uplifted land surfaces have rivers that flow down the initial slope of the uplift; these relationships he termed consequent. (2) A river may be older than an uplift that it crosses because it has been able to maintain its course by eroding downward as the uplift progresses; this relationship he named antecedent. (3) An uplifted block may have been buried by younger deposits upon which a river becomes established. The river, in cutting downward, uncovers the uplifted block and becomes incised into it; this relationship he called superimposed. The geologic history of the Colorado River involves all three relationships. In addition, although the position of the river course through a particular structural barrier may have been the result of superposition, the depth of the canyon at that point may be largely due to renewed uplift of the barrier; such deepening of the canyon, therefore, is due to antecedence. The problem of the Colorado River remains today very much as G. K. Gilbert stated it nearly 100 years ago: "How much is antecedent and how much is superimposed?" The question must be asked separately for each stretch of the river.

Colorado River↗
USGS2009

Alligators and crocodiles as indicators for restoration of Everglades ecosystems

Alligators and crocodiles integrate biological impacts of hydrological operations, affecting them at all life stages through three key aspects of Everglades ecology: (1) food webs, (2) diversity and productivity, and (3) freshwater flow. Responses of crocodilians are directly related to suitability of environmental conditions and hydrologic change. Correlations between biological responses and environmental conditions contribute to an understanding of species' status and trends over time. Positive or negative trends of crocodilian populations relative to hydrologic changes permit assessment of positive or negative trends in restoration. The crocodilian indicator uses monitoring parameters (performance measures) that have been shown to be both effective and efficient in tracking trends. The alligator component uses relative density (reported as an encounter rate), body condition, and occupancy rates of alligator holes; the crocodile component uses juvenile growth and hatchling survival. We hypothesize that these parameters are correlated with hydrologic conditions including depth, duration, timing, spatial extent and water quality. Salinity is a critical parameter in estuarine habitats. Assessments of parameters defined for crocodilian performance measures support these hypotheses. Alligators and crocodiles are the charismatic megafauna of the Everglades. They are both keystone and flagship species to which the public can relate. In addition, the parameters used to track trends are easy to understand. They provide answers to the following questions: How has the number of alligators or crocodiles changed? Are the animals fatter or thinner than they should be? Are the animals in the places (in terms of habitat and geography) where they should be? As surely as there is no other Everglades, no other single species defines the Everglades as does the American alligator. The Everglades is the only place in the world where both alligators and crocodiles exist. Crocodilians clearly respond to changes in hydrologic parameters of management interest. These relationships are easy to communicate and mean something to managers, decision makers, and the public. Having crocodilians on the list of system-wide, general indicators provides us with one of the most powerful tools we have to communicate progress of ecosystem restoration in Greater Everglades ecosystems to diverse audiences.

Florida↗
USGS1940

Formalin for external protozoan parasites: A report on the prevention and control of Costia necatrix

The smallest and most destructive of the ectoparasitic protozoans infecting salmon and trout, Costia necatrix , has unfortunately been relegated to virtual obscurity during the past few years. Few references to this parasite can be found in the recent literature and, where such things are discussed, one seldom hears a mention of Costia necatrix . This apparent lack of interest in Costia certainly does not result from the infrequency of its appearances nor from any lack of pathogenicity on its part when it does occur. Preserved specimens of ailing trout an dsalmon submitted to the Seattle Pathology Laboratory for diagnosis have yielded very surprising indications concerning the frequency, intensity, and geographic distribution of Costiasis - surprising in that a parasite should be so widespread, so pathogenic, and yet so seldom mentioned. The answer undoubtedly lies in the fact that Costia , being small in size and usually sedentary in its habits, is being overlooked during parasitic examinations. Although Costia is not at all difficult to recognize, even well-trained workers unfamiliar with its appearance almost invariably pass it by.

Progressive Fish-Culturist↗
USGS1985

Hydrogeologic data from a test well in east-central Duval County, Florida

A 2,112-foot test well was drilled in east-central Duval County, Florida, to obtain geologic, hydrologic, and water chemistry data. Drill cuttings and water samples were collected, and water-level measurements and lithologic and geophysical logs were made. Deposits to a depth of 575 feet consist of sand, clayey sand, phosphatic sandy clay, coquina, sandy limestone, and dolostone. Below 575 feet, the deposits consist of fragmented and granular limestone, dolomitic limestone, and massive to finely crystalline dolostone, which comprise the Floridan aquifer system in the area. Water levels were measured near or at the bottom of the drill hole through the drill stem and in the annular space between the drilled hole and drill stem at the well head as drilling progressed from 770 to 2,112 feet in depth. Water levels measured through the drill stem ranged from 1.17 feet above land surface at a depth of 2,107 feet to 15.0 feet above land surface at a depth of 1,574 feet. Water levels measured in the annular space ranged from 7.5 feet above land surface at a depth of 770 feet to 14.9 feet at various depths from 1,574 to 1,721 feet. Chloride concentrations of water sampled through the drill stem from a depth of 711 to 1 ,616 feet ranged from 22 to 150 milligrams per liter at 1,648 feet. Chloride concentrations then ranged from 345 to about 800 milligrams per liter to a depth of 2,071 feet and then increased to a maximum of 5,450 milligrams per liter at 2,107 feet. (USGS)

Open-File Report↗
USGS1972

Electric analog studies of flow to wells in the Punjab aquifer of West Pakistan

A series of experiments was performed with a steady-state electric analog simulating a cylindrical segment of the aquifer underlying the plains of the Punjab region of West Pakistan. In most of the experiments recharge was assumed to be from the surface, within a specified radius of influence, and distributed uniformly over the area within this radius. Experiments were made with different anisotropies (ratios of lateral to vertical resistance) so that various possible combinations of aquifer thickness and effective radius or radius of influence and combinations .of lateral and vertical permeability could be included in the models. Flow nets were constructed to show distribution of potential in the vertical section and intersections of stream surfaces with the vertical plane. The series of experiments in which the screened interval is in the upper part of the aquifer shows that flow decreases and stream tubes shift progressively toward the upper part of the aquifer as anisotropy increases. Another series illustrates that total yield increases and yield per foot of screen decreases as screen length increases. The experiments indicate that, under conditions prevalent in the Punjab, the Distance-drawdown method for determining permeability gives results with an error of 10 percent or less provided that at least one piezometer or observation well is within a few feet of the pumped well and that no observation well or piezometer used is more than 100 feet from the pumped well. Relative traveltime for each of 10 stream tubes is given for three models. Relative traveltimes for one-fourth and one-half the effective radius are given for selected stream tubes. By substituting values for the aquifer parameters, actual traveltimes are computed from the relative-traveltime data.

Water Supply Paper↗