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154 records · Page 9Linked to original sources
USGS1981

Deformation of host rocks and flow of magma during growth of minette dikes and breccia-bearing intrusions near Ship Rock, New Mexico

We have studied a small group of minette dikes and plugs that crop out within a flat-lying sequence of siltstone and shale near Ship Rock, a prominent volcanic throat of tuff breccia in northwestern New Mexico. Seven dikes form a radial pattern about Ship Rock we describe in detail the northeastern dike, which has an outcrop length of about 2,900 m, an average thickness of 2.3 m, and a maximum thickness of 7.2 m. The dike is composed of 35 discrete segments arranged in echelon; orientation. of dike segments ranges systematically from N. 52? E. to N. 66? E. A prominent joint set strikes parallel to the segments and is localized within several tens of meters of the dike. Regional joint patterns display no obvious relation to dike orientation. Small offsets of segment contacts, as well as wedge-shaped bodies of crumpled host rock within segments mark the sites of coalescence of smaller segments during dike growth. Bulges in the dike contact, which represent a nondilational component of growth, indicate that wall rocks were brecciated and eroded during the flow of magma. Breccias make up about 9 percent of the 7,176-m 2 area of the dike, are concentrated in its southwest half, and are commonly associated with its thickest parts. We also describe three subcircular plugs; each plug is smaller than 30 m in diameter, is laterally associated with a dike, and contains abundant breccias. Field evidence indicates that these plugs grew from the dikes by brecciation and erosion of wallrocks and that the bulges in the contact of the northeastern dike represent an initial stage of this process. From continuum-mechanical models of host-rock deformation, we conclude that dike propagation was the dominant mechanism for creating conduits for magma ascent where the host rock was brittle and elastic. At a given driving pressure, dikes dilate to accept greater volumes of magma than plugs, and for a given dilation, less work is done on the host rocks. In addition, the pressure required for dike growth decreases with dike length. From numerical solutions for dilation of cracks oriented like segments of the northeastern dike, we find that we can best model the form of the dike by treating it as composed of 10 cracks rather than 35. We attribute this result to coalescence of adjacent segments below the present outcrop and to inelastic deformation at segment ends. Using a driving pressure of 2 MPa (20 bars), we estimate a shear modulus of about 10^3 MPa for the host rocks, in agreement with laboratory tests on soft shale. A propagation criterion based on stress intensity at the segment ends indicates a fracture toughness of the host rocks of about 100 MPa-m^? , a hundredfold greater than values reported from laboratory tests. Segmentation of fractures is common in many materials and has been observed during fissure eruptions at Kilauea Volcano in Hawaii. At the northeastern dike, we attribute segmentation to local rotation of the direction of least principal compressive stress. From continuum-mechanical models of magma and heat flow in idealized conduits, we conclude that magma flows far more rapidly and with less relative heat loss in plugs than in dikes. Although dikes are the preferred form for emplacement, plugs are the preferred form for the flow of magma. We present a numerical solution for volumetric flow rate and wall heat flux for the northeastern dike and find that although the flow rate is extremely sensitive to conduit geometry, the rate of heat loss to wall rocks is not. During emplacement of the northeastern dike, local flow rate increased where wall rocks were eroded and reached a maximum of about 45 times the mean initial rate, whereas the maximum rate of heat loss to wallrocks increased to only 1.6 times the mean initial rate. An inferred progression from continuous magma flow along a dike to flow from a plug agrees well with observations of volcanic eruptions that begin from fissures and later are localized at discrete vents. We

Professional Paper↗
USGS1945

Ground-water conditions in the vicinity of Carlsbad, New Mexico

The area included in this investigation lies in Eddy County, New Mexico, largely between the foothills of the Guadalupe Mountains on the west and the Pecos River on the east, and extends from Carlsbad southward to Black River. The Pecos River drains the entire area, and in the growing season when water is diverted at Avalon Dam for irrigation its flow in this locality is maintained largely by the numerous springs emerging in the river channel north of Carlsbad. Carlsbad and vicinity depend on ground water fro a domestic water supply as the waters of the Pecos River are too highly mineralized for domestic use. About 1,120 acres of land was irrigation by ground water in the vicinity of Carlsbad in 1940. Valley fill, of Quaternary age, extends over most of the area, largely as a thin veneer, but it has a maximum known thickness of 256 feet. It is made up largely of clay with lenses of conglomerate, gravel, and sand. The Rustler formation, of upper Permian age, underlies the fills and is composed of gypsum and red beds with one persistent bed of limestone. The Salado formation, which is composed chiefly of halite (common salt), underlies the Rustler formation elsewhere buy it is absent over most of the area described in this paper. This Castile formations, which is predominantly anhydrite, underlies the Salado and overlies the Delaware Mountain group, of middle Permian age, which is deeply buried in most of the area. The upper part of the Delaware Mountain group grades into the Capitan and Carlsbad limestones to the north, east, and west, the latter being exposed near Carlsbad and in the foothills of the Guadalupe Mountain. The Carlsbad limestone in turn grades into the upper part of the Chalk Bluff formation. Ground water apparently moves eastward from the Guadalupe Mountains through the Carlsbad limestone to recharge the aquifers in the Delaware Mountain, Castile, and Salado units. In these formations the water soon becomes too highly mineralized for domestic or irrigation use. A large part of the water in the Carlsbad limestone emerges in the spring area north of Carlsbad, and a part of it moves into the valley fill in Dark Canyon Arroyo. The water in the fill of Dark Canyon Arroyo moves laterally into the limestone of the Rustier formation. The water moving eastward in the valley fill and Rustier limestone becomes progressively more mineralized and in the farmland area in the Carlsbad Irrigation Dstrict it is unfit for domestic use. In addition, highly mineralized water seeping from the farmlands and canals in the Carlsbad Irrigation District commingles with the water from the west, and the resulting mixture is undesirable even for watering stock, although if necessity it is much used for that purpose. Water occurs in channels of the Carlsbad limestone, and wells drilled into it generally obtain large yields id hard but potable water. The municipal supply of the city of Carlsbad is derived from 4 wells (1940) in the Carlsbad limestone. The aquifer has a high transmissibility in the vicinity of Carlsbad, as was shown by a test made on one of the wells owned by Southwestern Public Service Co. This well has a specific capacity of 275 gallons per minute per foot of drawdown. The present withdrawal of water from wells penetrating the aquifers in the Carlsbad limestone averages about 4 second-feet (about 2,600,00 gallons a day). The average flow emerging in the spring area in the Pacos River north of Carlsbad is about 60 second-feet (about 40 million gallons a day). It appears that about 12 second-feet of this flow (about 8 million gallons a day) comes from aquifers in the Carlsbad limestone and that the remainder represents leakage from Lake Avalon and the canal system. The valley fill is less permeable than the Carlsbad limestone but in some places sufficient yields are obtained for irrigation purposes. A test made on a well in the fill just south of Carlsbad showed the aquifer in that locality to have a transmissibility of about 60,000. Contamination of the household wells in West Carlsbad does not appear to be taking place at the present time although the juxtaposition of cesspools and outhouses on the one hand and poorly cased wells for domestic water supply on the other makes the situation dangerous.

New Mexico↗
USGS1987

Geologic map of the east part of the San Francisco Volcanic Field, north-central Arizona

The geologic map of the east part of the San Francisco volcanic field (called the East map area) is one of five adjoining geologic maps (fig. 1) prepared under the Geothermal Research Program of the U.S. Geological Survey as a basis for interpreting the history of magmatic activity in the volcanic field. This map is a revision of an earlier one (Moore and Wolfe, 1976). Detail of pyroclastic and alluvial deposits has been reduced for clarity on this uncolored version, and eolian deposits, represented by numerous active dunes of basaltic ash, have been completely omitted. Small cinder cones developed over rootless vents on the basalt flow (Qbb) of = vent 2019 have also been omitted. In addition, a few changes have been made in correlations of flows and vents. The stratigraphic classification has been modified because magnetic-polarity determinations and new K-Ar ages indicate that the physiographically defined Tappan and Woodhouse age groups (Moore and others, 1976) overlap significantly in age, and the rocks of those age groups are now assigned to the Brunhes or Matuyama Polarity Chronozones (Mankinen and Dalrymple, 1979). The San Francisco field, which is largely Pliocene and Pleistocene in age, is in northern Arizona, just north of the broad transition zone between the Colorado Plateau and the Basin and Range province. It is one of several dominantly basaltic volcanic fields of late Cenozoic age situated near the southern margin of the Colorado Plateau. The East map area encompasses approximately 1,220 km 2 . The volcanic field contains rocks ranging in composition from basalt to rhyolite--the products of eruption through Precambrian basement rocks and approximately a kilometer of overlying, nearly horizontal, Paleozoic and Mesozoic sedimentary rocks. About 500 km 3 of erupted rocks cover about 5,000 km 2 of predominantly Permian and locally preserved Triassic sedimentary rocks that form the erosionally stripped surface of the Colorado Plateau in northern Arizona. In the East map area, basalt, basaltic andesite and locally associated small dacite domes, and, in a few cases, andesite were extruded from numerous individual vents, each of which presumably erupted briefly and then became inactive. Such short-lived vents, represented mainly by cinder cones or tuff rings, are widely distributed over the map area, and their flows cover much of its surface. However, repeated eruption of andesite, dacite, and rhyolite domes and flows formed the O'Leary Peak eruptive center in the northwest part of the map area, and flows of andesite (Qa 1 and Qa 2 ) from the San Francisco Mountain stratovolcano entered the East map area from the west. A northeastward progression of volcanism during the past 15 m.y., from central Arizona into the San Francisco volcanic field, is shown by the compilation of Luedke and Smith (1978). Although complicated in detail, a general northeastward to eastward progression of volcanic activity is also apparent within the San Francisco volcanic field. Thus, much of the eruptive activity of the East map area occurred late in the development of the San Francisco field, and the East map area includes the youngest volcanic rocks of the field. These youngest rocks were formed during the Sunset Crater eruption, which occurred within the past 1,000 years (Smiley, 1958). A northeast-trending, faulted monocline occurs near Doney Mountain in the north-central part of the East map area, and a broad north- to northwest-trending anticline occurs at the east edge of the map area. Nearby volcanic rocks are not folded or faulted by either structure. Northwest-trending normal faults of small throw occur in the southern and northwestern parts of the map area. The faults in the northwestern part transect basalt flows of Matuyama and Brunhes ages (Tmb, Qmb, and Qbb). The volcanic rocks are not faulted elsewhere in the East map area. However, local northwestward elongation and alignment of vent deposits, as shown for example by the fissure deposits of the Sunset Crater eruption (Qbsbf), indicate the presence of a northwest-trending fracture system that apparently localized some of the eruptive feeders.

Arizona↗
USGS2012

Groundwater status and trends for the Columbia Plateau Regional Aquifer System, Washington, Oregon, and Idaho

Well information and groundwater-level measurements for the Columbia Plateau Regional Aquifer System in Washington, Oregon, and Idaho, were compiled from data provided by the U.S. Geological Survey and seven other organizations. From the full set of about 60,000 wells and 450,000 water-level measurements a subset of 761 wells within the aquifers of the Columbia River Basalt Group (CRBG) then was used to develop a simple linear groundwater-level trend map for 1968–2009. The mean of the trends was a decline of 1.9 feet per year (ft/yr), with 72 percent of the water levels in wells declining. Rates of declines greater than 1.0 ft/yr were measured in 50 percent of wells, declines greater than 2.0 ft/yr in 38 percent of wells, declines greater than 4.0 ft/yr in 29 percent of wells, and declines greater than 8.0 ft/yr in 4 percent of wells. Water-level data were used to identify groups of wells with similar hydraulic heads and temporal trends to delineate areas of overall similar groundwater conditions. Discontinuities in hydraulic head between well groups were used to help infer the presence of barriers to groundwater flow such as changes in lithology or the occurrence of folds and faults. In areas without flow barriers, dissimilarities in response of well groups over time resulted from the formation of groundwater mounds caused by recharge from irrigation or regions of decline caused by pumping. The areas of focus for this analysis included the Umatilla area, Oregon, and the Palouse Slope/eastern Yakima Fold Belt in the Columbia Basin Ground Water Management Area (GWMA) consisting of Adams, Franklin, Grant, and Lincoln Counties, Washington. In the Umatilla area, water levels from 286 wells were used to identify multiple areas of high hydraulic gradient that indicate vertical and horizontal barriers to groundwater flow. These barriers divide the groundwater-flow system into several compartments with varying degrees of interconnection. Horizontal flow barriers commonly correspond to mapped geologic structure and result in horizontal hydraulic gradients that progressively become steeper from north to south corresponding to an increase in structural complexity that may be impeding recharge from the uplands into the heavily developed areas. Most CRBG aquifers in the Umatilla area are declining and since 1970, cumulative declines range from about 100 to 300 feet. Significant vertical hydraulic gradients are documented for relatively small areas near Umatilla, and since the 1970s, downward vertical gradients in these areas have been increasing as hydraulic heads in the deeper units have declined. The absence of vertical gradients over much of the area may be a consequence of flow through commingling wells that results in the equilibration of the heads between aquifers. On the Palouse Slope in the central GWMA, large groundwater declines occurred during 1968–2009 along a north-south swath in the middle of the region. An analysis of 1,195 wells along major flow paths and through the area of persistent groundwater-level declines indicates that barriers to flow are not as evident in this area as in Umatilla. This is consistent with the geologic interpretation of the Palouse Slope as being a gently folded structure created by voluminous sheet flows of CRBG lavas. Groundwater discharge into the sediment-filled coulees, where the upper aquifers are intersected at land surface by incised canyons, is proposed as an alternative to explain local steepening of the hydraulic gradient along the Palouse Slope previously attributed to the presence of a groundwater dam. Comparison of generalized potentiometric surface maps developed for pre-development conditions and post-2000 conditions indicate that pre-development groundwater flow was from the uplands toward the Columbia and Snake River and that post-2000 flow patterns in the area are controlled by irrigation practices that have resulted in broad regions of elevated or depressed hydraulic head. In some cases, irrigation-related changes in head have reversed groundwater flow directions. Evidence of significant vertical hydraulic gradients exists, although much of the aquifer thickness is affected by commingling of wells. The effect of commingling and its relative contribution to problems related to groundwater-level declines remains unclear.

Washington, Oregon, Idaho↗
USGS2023

Roles of regional structures and country-rock facies in defining mineral belts in central Idaho mineral province with detail for Yellow Pine and Thunder Mountain mining districts

The central Idaho metallogenic province hosts numerous mineral deposit types. These include Late Cretaceous precious-polymetallic vein deposits, amagmatic Paleocene–Eocene breccia-hosted gold-tungsten-antimony deposits, and Eocene mercury deposits in metasedimentary roof pendants and in Late Cretaceous granitoids. Hot-springs gold deposits in Eocene volcanic rocks are also included in the central Idaho province. New sensitive high mass-resolution ion microprobe (SHRIMP) uranium-lead (U-Pb) ages for igneous rocks and for detrital zircon analyses of metasedimentary rocks along with geologic mapping clarify the geologic framework of the mineral deposits. This framework includes (1) structural controls for regional distribution of mining districts, (2) progressive structural development of individual districts, (3) regional sedimentary facies and their control of metals associations resulting in regional belts, and (4) influences of the several regional magmatic events. In central Idaho, 15 mining districts form two clusters that are grouped about a 200-kilometer (km) long system of normal faults. The northwestern cluster is in the regional hanging wall west of large, west-side-down faults, and the mineral deposits are located along smaller faults and fractures that cut the regional hanging wall. The southeastern cluster is in the regional hanging wall east of a linked large east-side-down fault and along and controlled by related hanging wall faults. At the southern extent of the regional fault system, the Yellow Pine-Thunder Mountain districts span a nearly 24-km-wide, east-tilted crustal block of normal-fault dominoes, exposing original crustal depths from 5 to 10 km deep on the west in the Late Cretaceous to shallow-surface depths on the east in the Eocene. Ore deposition in the northwestern district cluster was primarily Late Cretaceous and related to Idaho batholith plutons with only a single deposit related to a small Eocene intrusion; in the southeastern cluster, most deposits were initiated in the Late Cretaceous but with varying manifestations of overprinted Eocene mineralization activity. In the Yellow Pine-Thunder Mountain districts at the southern extent of the southern cluster, several mineralizing pulses occurred during hanging-wall collapse, such that (1) early deposits were multiply overprinted and (2) deposit depths, ages, and structural characteristics change progressively eastward. Originally deep-seated western Yellow Pine district deposits are Late Cretaceous viscoplastic mesothermal veins overprinted by Paleocene and Eocene breccia-hosted epithermal deposits. Central Yellow Pine district deposits contain early deeper vein systems but are primarily Paleocene and Eocene breccia-hosted epithermal deposits in Late Cretaceous plutonic rocks and Proterozoic–Paleozoic roof pendant rocks. Eastern district deposits are Eocene hot-springs-related deposits in the roof pendant. Thunder Mountain deposits farthest east are near-surface hot-springs deposits in Eocene volcanic and volcaniclastic rocks that overlie buried Cretaceous igneous and older roof pendant rocks. The mining district clusters are sited across several northwest-striking paleostratigraphic belts that are exposed in roof pendants and are offset by the regional normal fault system. A northeastern belt is Mesoproterozoic strata associated with gold-silver-copper±cobalt deposits. A central belt of Neoproterozoic rocks is not associated with mineral deposits in the central Idaho mineral province. A southwestern belt composed of probable Paleozoic deep-water miogeoclinal slope rocks and late Paleozoic epicratonic basinal rocks is thin and narrowly exposed but associated with gold-silver-antimony-tungsten±mercury deposits. These metasedimentary rocks (and their metal associations) are parts of regional mineral belts in which metal endowments are related to particular sedimentary facies belts and their Cretaceous thrust-fault juxtaposition and where these features have proximity to Late Cretaceous or Eocene igneous rocks. Offset and preservation or erosional stripping of these facies belts, thrust plates, igneous settings, and the associated regional mineral belts were controlled by the sense and magnitude of displacements across the regional normal-fault system.

Idaho↗
USGS2005

Evaluation of ground-water flow and land-surface subsidence caused by hypothetical withdrawals in the northern part of the Gulf Coast Aquifer system, Texas

During 2003–04 the U.S. Geological Survey, in cooperation with the Texas Water Development Board (TWDB) and the Harris-Galveston Coastal Subsidence District (HGCSD), used the previously developed Northern Gulf Coast Ground-Water Availability Modeling (NGC GAM) model to evaluate the effects of hypothetical projected withdrawals on ground-water flow in the northern part of the Gulf Coast aquifer system and land-surface subsidence in the NGC GAM model area of Texas. The Gulf Coast aquifer system comprises, from the surface, the Chicot and Evangeline aquifers, the Burkeville confining unit, the Jasper aquifer, and the Catahoula confining unit. Two withdrawal scenarios were simulated. The first scenario comprises historical withdrawals from the aquifer system for 1891–2000 and hypothetical projected withdrawals for 2001–50 compiled by the TWDB (TWDB scenario). The projected withdrawals compiled by the TWDB are based on ground-water demands estimated by regional water planning groups. The second scenario is a “merge” of the TWDB scenario with an alternate set of projected withdrawals from the Chicot and Evangeline aquifers in the Houston metropolitan area for 1995–2030 provided by the HGCSD (HGCSD scenario). Under the TWDB scenario withdrawals from the entire system are projected to be about the same in 2050 as in 2000. The simulated potentiometric surfaces of the Chicot aquifer for 2010, 2020, 2030, 2040, and 2050 show relatively little change in configuration from the simulated 2000 potentiometric surface (maximum water-level depths in southern Harris County 150–200 feet below NGVD 29). The simulated decadal potentiometric surfaces of the Evangeline aquifer show the most change between 2000 and 2010. The area of water levels 250– 400 feet below NGVD 29 in western Harris County in 2000 shifts southeastward to southern Harris County, and water levels recover to 200–250 feet below NGVD 29 by 2010. Water levels in southern Harris County recover to 150–200 feet below NGVD 29 by 2020 and remain in that range through 2050. A relatively small cone of depression in southern Montgomery County that did not appear in the 2000 surface develops and enlarges during the projected period, with a maximum depth of 250–300 feet below NGVD 29 in 2030, 2040, and 2050. The simulated decadal potentiometric surfaces of the Jasper aquifer each have a major cone of depression centered in southern Montgomery County that was minimally developed in 2000 but reaches depths of 550–650 feet below NGVD 29 in the 2020, 2030, 2040, and 2050 surfaces. Under the TWDB scenario the percentage of withdrawals supplied by net recharge increases from 75 percent in 2000 to 87 percent in 2050, and the percentage of withdrawals supplied by storage decreases from 25 percent in 2000 to 13 percent in 2050. Under the HGCSD scenario, withdrawals from the Chicot and Evangeline aquifers increase about 74 percent during 1995–2030; Jasper aquifer withdrawals are unchanged from those of the TWDB scenario. For the 2010, 2020, and 2030 potentiometric surfaces of the Chicot and Evangeline aquifers, the substantially greater withdrawals of the HGCSD scenario relative to those of the TWDB scenario result in progressively deeper cones of depression than those in the potentiometric surfaces associated with the TWDB scenario—for the Chicot aquifer in southern Harris County, 400–450 feet below NGVD 29 in 2030; for the Evangeline aquifer in southern Montgomery County, 700–750 feet below NGVD 29 in 2030. Although Jasper aquifer withdrawals are the same for both scenarios, the major cone of depression centered in southern Montgomery County in the 2030 potentiometric surface is 50 feet deeper at its center (600–700 feet below NGVD 29) than the cone in the 2030 surface under the TWDB scenario. Under the HGCSD scenario, the percentage of withdrawals supplied by net recharge decreases from 72 percent in 1995 to 57 percent in 2030, and the percentage of withdrawals supplied by storage increases from 28 percent in 2000 to 43 percent in 2030. About 85 percent of the increase supplied by storage is from the compaction of clay. Land-surface subsidence in the major area of subsidence centered in Harris and Galveston Counties during 2000–50 that results from simulating the TWDB withdrawal scenario expands slightly to the west and increases in places. The maximum change occurs in the Conroe area where subsidence increases from about 4 to about 13 feet during the projected period. Land-surface subsidence in the major area of subsidence during 1995–2030 that results from simulating the HGCSD withdrawal scenario increases substantially. For example, in east-central Harris County maximum subsidence increases from about 10–11 feet in 1995 to 22 feet in 2030. The hypothetical projected withdrawal scenarios are estimates of future withdrawals and might not represent actual future withdrawals. The simplifying assumptions that the downdip limit of freshwater flow in each hydrogeologic unit is a stable, sharp interface across which no flow occurs and that the base of the system is a no-flow boundary become less realistic and thus increase the uncertainty in results as drawdowns increase. The presence of uncertainty dictates that the results of the predictive simulations described in this report be used with caution in any decision-making process.

Texas↗
USGS2017

Suitability of river delta sediment as proppant, Missouri and Niobrara Rivers, Nebraska and South Dakota, 2015

Sediment management is a challenge faced by reservoir managers who have several potential options, including dredging, for mitigation of storage capacity lost to sedimentation. As sediment is removed from reservoir storage, potential use of the sediment for socioeconomic or ecological benefit could potentially defray some costs of its removal. Rivers that transport a sandy sediment load will deposit the sand load along a reservoir-headwaters reach where the current of the river slackens progressively as its bed approaches and then descends below the reservoir water level. Given a rare combination of factors, a reservoir deposit of alluvial sand has potential to be suitable for use as proppant for hydraulic fracturing in unconventional oil and gas development. In 2015, the U.S. Geological Survey began a program of researching potential sources of proppant sand from reservoirs, with an initial focus on the Missouri River subbasins that receive sand loads from the Nebraska Sand Hills. This report documents the methods and results of assessments of the suitability of river delta sediment as proppant for a pilot study area in the delta headwaters of Lewis and Clark Lake, Nebraska and South Dakota. Results from surface-geophysical surveys of electrical resistivity guided borings to collect 3.7-meter long cores at 25 sites on delta sandbars using the direct-push method to recover duplicate, 3.8-centimeter-diameter cores in April 2015. In addition, the U.S. Geological Survey collected samples of upstream sand sources in the lower Niobrara River valley. At the laboratory, samples were dried, weighed, washed, dried, and weighed again. Exploratory analysis of natural sand for determining its suitability as a proppant involved application of a modified subset of the standard protocols known as American Petroleum Institute (API) Recommended Practice (RP) 19C. The RP19C methods were not intended for exploration-stage evaluation of raw materials. Results for the washed samples are not directly applicable to evaluations of suitability for use as fracture sand because, except for particle-size distribution, the API-recommended practices for assessing proppant properties (sphericity, roundness, bulk density, and crush resistance) require testing of specific proppant size classes. An optical imaging particle-size analyzer was used to make measurements of particle-size distribution and particle shape. Measured samples were sieved to separate the dominant-size fraction, and the separated subsample was further tested for roundness, sphericity, bulk density, and crush resistance. For the bulk washed samples collected from the Missouri River delta, the geometric mean size averaged 0.27 millimeters (mm), 80 percent of the samples were predominantly sand in the API 40/70 size class, and 17 percent were predominantly sand in the API 70/140 size class. Distributions of geometric mean size among the four sandbar complexes were similar, but samples collected from sandbar complex B were slightly coarser sand than those from the other three complexes. The average geometric mean sizes among the four sandbar complexes ranged only from 0.26 to 0.30 mm. For 22 main-stem sampling locations along the lower Niobrara River, geometric mean size averaged 0.26 mm, an average of 61 percent was sand in the API 40/70 size class, and 28 percent was sand in the API 70/140 size class. Average composition for lower Niobrara River samples was 48 percent medium sand, 37 percent fine sand, and about 7 percent each very fine sand and coarse sand fractions. On average, samples were moderately well sorted. Particle shape and strength were assessed for the dominant-size class of each sample. For proppant strength, crush resistance was tested at a predetermined level of stress (34.5 megapascals [MPa], or 5,000 pounds-force per square inch). To meet the API minimum requirement for proppant, after the crush test not more than 10 percent of the tested sample should be finer than the precrush dominant-size class. For particle shape, all samples surpassed the recommended minimum criteria for sphericity and roundness, with most samples being well-rounded. For proppant strength, of 57 crush-resistance tested Missouri River delta samples of 40/70-sized sand, 23 (40 percent) were interpreted as meeting the minimum criterion at 34.5 MPa, or 5,000 pounds-force per square inch. Of 12 tested samples of 70/140-sized sand, 9 (75 percent) of the Missouri River delta samples had less than 10 percent fines by volume following crush testing, achieving the minimum criterion at 34.5 MPa. Crush resistance for delta samples was strongest at sandbar complex A, where 67 percent of tested samples met the 10-percent fines criterion at the 34.5-MPa threshold. This frequency was higher than was indicated by samples from sandbar complexes B, C, and D that had rates of 50, 46, and 42 percent, respectively. The group of sandbar complex A samples also contained the largest percentages of samples dominated by the API 70/140 size class, which overall had a higher percentage of samples meeting the minimum criterion compared to samples dominated by coarser size classes; however, samples from sandbar complex A that had the API 40/70 size class tested also had a higher rate for meeting the minimum criterion (57 percent) than did samples from sandbar complexes B, C, and D (50, 43, and 40 percent, respectively). For samples collected along the lower Niobrara River, of the 25 tested samples of 40/70-sized sand, 9 samples passed the API minimum criterion at 34.5 MPa, but only 3 samples passed the more-stringent criterion of 8 percent postcrush fines. All four tested samples of 70/140 sand passed the minimum criterion at 34.5 MPa, with postcrush fines percentage of at most 4.1 percent. For two reaches of the lower Niobrara River, where hydraulic sorting was energized artificially by the hydraulic head drop at and immediately downstream from Spencer Dam, suitability of channel deposits for potential use as fracture sand was confirmed by test results. All reach A washed samples were well-rounded and had sphericity scores above 0.65, and samples for 80 percent of sampled locations met the crush-resistance criterion at the 34.5-MPa stress level. A conservative lower-bound estimate of sand volume in the reach A deposits was about 86,000 cubic meters. All reach B samples were well-rounded but sphericity averaged 0.63, a little less than the average for upstream reaches A and SP. All four samples tested passed the crush-resistance test at 34.5 MPa. Of three reach B sandbars, two had no more than 3 percent fines after the crush test, surpassing more stringent criteria for crush resistance that accept a maximum of 6 percent fines following the crush test for the API 70/140 size class. Relative to the crush-resistance test results for the API 40/70 size fraction of two samples of mine output from Loup River settling-basin dredge spoils near Genoa, Nebr., four of five reach A sample locations compared favorably. The four samples had increases in fines composition of 1.6–5.9 percentage points, whereas fines in the two mine-output samples increased by an average 6.8 percentage points.

Nebraska, South Dakota↗
USGS2020

Recent planform changes in the Upper Mississippi River

Geomorphic changes in the Upper Mississippi River (UMR) have long been a concern of river agencies charged with maintaining and restoring river habitat (GREAT 1980; Jackson et al. 1981; USFWS 1992). Large meandering alluvial rivers like the UMR are expected to constantly change and adjust their fluvial landforms within their riparian corridors as a result of the natural interaction of hydrologic processes, sediment movement, and vegetation over time. However, present geomorphic changes in the UMR reflect altered hydrologic, hydraulic, and sediment conditions caused by regulated flows, constructed agricultural levees and navigation dams, altered land use in the watershed, and climate change. Levees reduce lateral hydrologic and sediment connectivity between channels and floodplains on many tributaries and on the Mississippi River downstream of Pool 13. Between each of the dams are a repeating series of landforms associated with tailwater, intermediate, and impounded conditions. The dams maintain a minimum water level, thus creating many off-channel areas that act as sediment traps. Whereas high-head dams cut off sedimentological connectivity longitudinally through the river corridor (Skalak et al., 2013), low head dams on the UMR only slightly altered transport longitudinally. Deltaic-like sedimentation can be common in the impounded sections of dammed rivers. Erosion of relict land surfaces that remained above the raised impounded water levels has been the dominant change in UMR impounded sections due to increased wind fetch leading to increased wave action. Even though upland sources of sediment from tributaries have decreased over the middle to late 20th century, increased annual precipitation, the interplay of increased variability in flood magnitudes from year to year, and more fall and winter flooding have likely changed erosion and sedimentation patterns in the UMR (Belby, et al., 2019). Paradoxically, monitoring and research indicates that the concentration of some water column constituents like total suspended solids and phosphorous has decreased during the 1991 to 2014 time period (Kreiling and Houser, 2016). In areas prone to increased sedimentation, bed elevations rise and thereby water depths are reduced at a given discharge, resulting in loss of fish habitat. Sediment deposition or erosion further influences water exchange rates between main channel and off-channel areas in the river by increasing resistance in connecting channels or enlarging existing connecting channels. Water depth and water exchange rates are the most prominent features describing habitat quality in the UMR (De Jager et al. 2018), and in some cases, the trajectory of planform change from heightened deposition promises to threaten deep backwater habitats particularly important for overwintering fish. Although information on the rate of vertical change in bed elevation is needed for a complete assessment of geomorphic change associated with the loss of deep backwater habitats, mapping planform changes over time (i.e., lateral changes between the land-water boundary) provide needed information on the location, potential cause, and progressive direction of deposition, especially in the mid sections between dams where deltaic processes are the most pronounced. Several types of planform changes have been observed and identified as concerns. For example, island loss in the large impounded areas of the upper part of the UMR was one of the concerns identified by river managers in the 1980s and 90s, and subsequently island construction became a common form of restoration implemented by the Upper Mississippi River Restoration (UMRR) Program (USACE 2012). Other subtler planform changes, such as channel bank erosion and delta formation in backwaters, are perceived to be important, but have largely gone unquantified. A systemwide reconnaissance of the UMR and IWW conducted in 1998 concluded that 14-percent of the river banks were eroding (Nakato and Anderson 1998). However, stabilization of existing river banks has never been widely pursued as a restoration measure, due to the high cost and uncertain benefits. Delta formation reduces the amount of backwater habitat; however, the deltas maintain and create a mix of riparian and aquatic habitats, and that is generally considered to be beneficial for wildlife and fish. If recent hydrologic trends of more frequent and longer duration flood events continue, a better understanding of planform changes can help in describing past changes, and then be used to forecast potential future trajectories of change. If UMR resource managers determine that past and forecasted conditions are undesirable, then UMRR projects could be identified and prioritized to address those concerns. Vegetative cover associations with landform changes have been used to detect and quantify planform changes in many rivers (Johnson 1985; Hiatt 2015; Volte et al. 2015). Freyer and Jefferson (2013) completed such a study in Pool 6 of the UMR using the landcover data from 12 dates over a 115-yr period, including the 1989, 2000, and 2010/2011 landcover/use (LCU) data from the UMRR Program. Planform change detected over the last 20 years represented by the UMRR Program data best reflect present-day geomorphic patterns, rates and processes. Changes occurring prior to dam construction and changes occurring soon after dam construction are likely not the same as those happening now, 50-70 years after dam construction and creation of the impoundments (McHenry et al., 1984; Bhowmik and Adams, 1986; WEST Consultants, 2000). The LCU data from each of the 1989, 2000, and 2010/2011 imagery was developed using similar methods and is available in a Geographical Information System (GIS) for the entire UMR and therefore provides the opportunity for a more comprehensive planform change analysis. This study used GIS overlays of LCU classes to map and quantify changes in planform features over two periods, looking specifically for depositional areas where terrestrial and wetland vegetation expanded at the expense of open water. The land expansion was grouped into four possible process-based types common in large floodplain rivers, some following that used by Lewin et al. (2017). The four types include: crevasse deltas emanating from a breach from a main channel through a natural levee or narrow floodplain into backwaters (crevasse deltas), tributary deltas expanding into backwaters (tributary deltas), deltaic bars at the upstream end of impoundments (impounded deltas), and linear-like bars extending from the downstream ends of narrow levees and remnant floodplains (bar-tail limbs). The methods deployed for change detection addressed possible errors from a variety of sources.

Illinois, Iowa, Minnesota, Missouri, Wisconsin↗
USGS1999

Fishes of Missouri River, chute, and flood plain habitats: Chapter 4 in Initial biotic survey of Lisbon Bottom, Big Muddy National Fish and Wildlife Refuge

The Lisbon Bottom Unit of the Big Muddy National Fish and Wildlife Refuge (Refuge) is approximately 2,200 acres and is the first complete unit of the Refuge. Primary objectives of the Refuge are to create and restore diverse riverine aquatic habitats and reconnect the Missouri River to its flood plain where feasible. Management seeks to accomplish these objectives by encouraging natural processes of erosion, deposition, and succession to the greatest extent possible. One of the most salient aquatic features of the Lisbon Bottom Unit is a newly created 2-mile-long free-flowing chute, or side channel (Fig. 1). This chute began forming as a levee breech scour hole during the Great Flood of 1993. The chute continued to develop during the 1995 flood and finally cut through to a flowing side channel during the 1996 flood. Extensive erosion and bank sluffing continued during 1997 due to sustained high flows that occurred throughout most of the year. The chute has progressively become wider and deeper with a developing meander pattern and channel bars have begun to form. Lisbon Bottom also contains several seasonal and permanent wetlands and is subject to periodic flooding at high Missouri River stages. Eight studies have been completed or are ongoing to evaluate Missouri River fishes associated with various habitat components of Lisbon Bottom and adjacent Missouri River reaches (Table 1). Several are part of much larger investigations to evaluate fish use of flood-created habitat features, basinwide fish assessment, and endangered or candidate species concerns. At the Lisbon Bottom Unit or in the Missouri River adjacent to the unit 54 fish species were collected (Table 2). Eight of these species have either a protected status under State or Federal laws or biologists consider them to potentially qualify for protected status. The status of the following fish is listed in Table 2: pallid sturgeon x shovelnose sturgeon hybrid, paddlefish, northern pike, sturgeon chub, sicklefin chub, ghost shiner, western silvery minnow, plains minnow, and blue sucker. Equally important to note are fish species that were not collected. The flathead chub, currently listed as State endangered and proposed for Federal listing, were not collected in any of the studies. Common fish species, collected in all seven sampling studies, included gizzard shad, common carp, river carpsucker, and freshwater drum. Paddlefish, skipjack herring, silver carp, white sucker, redfin shiner, western silvery minnow, bullhead minnow, and black bullhead were each collected in only one of the seven studies. Pflieger (1971) developed a guild system for the fishes of Missouri based on distribution patterns and centers of abundance. Fish were assigned to one of four primary faunal groups: Ozark, Big River, Lowland, and Prairie. Two secondary groups (Ozark-prairie and Ozark-lowland) were defined for species equally abundant and distributed in two of the primary areas. Two Ozark-prairie species, shorthead redhorse and white sucker, were collected on or near the Lisbon Bottom Unit. Big River species are found primarily in the Missouri and Mississippi Rivers. The environmental factors controlling fish distribution in these rivers appear to be substrate, current velocity, and turbidity. On or near the Lisbon Bottom Unit 18 Big River species were collected (Table 2). Lowland species are intolerant of siltation and high turbidity. They inhabit standing or slow-moving water with sand, fine gravel, and organic debris substrates. Two Lowland species, bullhead minnow and mosquitofish, were collected in connected scours on the Lisbon Bottom Unit. Prairie species have broader ecological tolerances than the Ozark and Lowland species. They are largely absent in high gradient streams and cool, clear waters. Prairie species make up a significant proportion of Missouri and Mississippi River fishes. Seven Prairie species were collected on or near the Lisbon Bottom Unit (Table 2). The last group, Wide-ranging, was defined as the species more widespread than the other faunal groups with broader environmental tolerances. Most Wide-ranging species occur at least occasionally in all sections of the state. Nineteen Wide-ranging species were collected on or near the Lisbon Bottom Unit (Table 2). Kubisiak (1997) found that isolated scours in the Lower Missouri River were dominated by Wide-ranging species. Connected scours also held Wideranging species but they contained Prairie species and were dominated by Big River species. Faunal group diversity and species richness were compared between isolated (Study l) and connected (Studies 4, 5, 7, and 8) scours of the Lisbon Bottom Unit. Species richness was similar with 22 species collected in isolated scours and an average of 24.8 species collected in connected scours. Isolated scour fish catches were dominated by Wide-ranging fish (59%) with 14% Big River fishes and 14% Prairie fishes. Connected scours had a larger percentage of Big River fish (32%) and fewer Wide-ranging (36%) and Prairie (13%) species than the isolated scours. In the combined studies, Wide-ranging fish dominated the connected scours. A similar comparison was made of fish from chute habitats and the Missouri River. Chute habitats include the Lisbon Bottom Chute, the chute between the right bank and island located at river mile 219, and a shallow channel running between a large sandbar complex and the channel border adjacent to Lisbon Bottom. Species richness in the chutes (35 species) was greater than that of the adjacent river (23 species). Big River species (40%) dominated the chute samples, followed by Wide-ranging at 31% Cand Prairie Cut 14%. The river samples contained equal numbers of Wide-ranging species (35%) and Big River species (35%) with 17% Prairie species. Differences in fish guild diversity and species richness may be due to numerous factors including sampling effort and sampling season. River samples were collected only in Study 3 in October; chute samples were collected in July, August, and October. Fish may have been using the chute in July and August to spawn, feed, or escape high river levels. The Lisbon Bottom Chute is a truly unique feature of the Lower Missouri River. It is the first naturally created side channel to develop since the U.S. Army Corps of Engineers tamed the river. The Corps eliminated 89% of the islands in the Missouri River between 1879 and 1954 (Funk and Robinson 1974). The chutes between the islands and the shore were shallower with less current than the main channel. These areas provided diversity to the Missouri River fish habitat, serving as nursery and feeding areas. The Lisbon Bottom Unit of the Big Muddy National Fish and Wildlife Refuge will continue to be studied in an effort to understand the complex role these areas play in river systems.

Missouri↗
USGS2020

Using advanced population genomics to better understand the relationship between offshore and spawning habitat use for Atlantic Sturgeon

Atlantic Sturgeon ( Acipenser oxyrinchus oxyrinchus ) are a large-bodied anadromous fish that historically supported important fisheries along the east coast of the United States. Following years of overharvest and habitat degradation, populations experienced severe declines. In 2012, the National Marine Fisheries Service listed Atlantic Sturgeon under the Endangered Species Act (ESA; 61 FR 4722). Their listing named five Distinct Population Segments (DPSs), predicated on genetic groups composed of geographically proximate populations. Federal management of Atlantic Sturgeon presents challenges, as sturgeon from each of the five DPSs mix extensively in coastal and marine habitats yet take and recovery progress must be evaluated separately for each unit. Genetic assignment testing based on mitochondrial and microsatellite markers allows individuals to be assigned back to their natal river and DPS. However, this approach is not perfect and some individuals may be incorrectly assigned. Recent advances in genomics offer the potential of a higher resolution approach to genetic assignment testing, and thus may reduce uncertainty associated with assignment testing. In addition, genomics allows a greater number of markers to be examined from across a broader portion of the sturgeon genome, thus may provide an enhanced perspective of population structure for the species, and potentially allow other previously intractable questions to be addressed (Bernatchez et al. 2017, Supple and Shapiro 2018). We used next-generation sequencing to develop a draft genome for Atlantic Sturgeon and identify single nucleotide polymorphisms (SNPs) that could be used to resolve the natal river and DPS of individual Atlantic Sturgeon. We identified 1,210 candidate SNPs within the nuclear genome as well as 49 SNPs within the mitochondrial genome. After filtering and review, we selected 161 nuclear SNPs and 39 mitochondrial SNPs for further testing and evaluation. We used genotyping-in-thousands by sequencing (GT-seq) to simultaneously sequence nuclear SNP loci, mitochondrial SNP loci, and the existing panel of twelve microsatellite loci. This effort required a pilot sequencing run on a single sturgeon sample to test marker amplification and refine primer strengths, followed by a series of sequencing runs to generate baseline data for 288 individuals representing nine populations of Atlantic Sturgeon in four DPSs. Using baseline data from the nine populations, we ran a series of genomic analyses to characterize diversity within and among populations, providing a benchmark for this species using the new SNP markers. Allelic richness was similar for all populations, although there was a general trend of more northern population containing greater levels of allelic richness. Interestingly, we observed linkage disequilibrium among many pairs of loci within many populations. This might be the result of physical linkage but could also suggest these populations are recovering from genetic bottlenecks and/or are effectively small, leading to specific haplotypes to be favored by chance. Pairwise differentiation among populations varied among the populations ( F ST range: 0.010-0.098) and was significantly correlated ( r = 0.771; P < 0.001) to pairwise F ST observed using microsatellite markers). Population clustering and ordination techniques using the new genomic data both support an overall population structure that is similar to the current DPS management units (which were developed primarily based on microsatellite genetic data). Overall, this suggests that existing microsatellite markers and the panel of SNP markers developed in this study provide similar information about the populations structure and ecology of Atlantic Sturgeon. Given the observed differences in allele frequencies among populations, our genomic baseline supports previous assertations that Atlantic Sturgeon show natal homing, despite mixing extensively in marine waters during non-breeding periods. Lower levels of differentiation between populations in the South Atlantic DPS suggest that populations in this region may have greater levels of gene flow relative to their more northerly conspecifics, which has also previously been suggested based on microsatellite data. The observed differentiation among populations provides the necessary foundation for determining the natal river and DPS of Atlantic Sturgeon using assignment testing. We tested the utility of our new genomic baseline for resolving the population and DPS of Atlantic Sturgeon. Our nuclear SNP markers showed utility for identifying the origin of unknown Atlantic Sturgeon samples, as 86.5% were assigned to the correct DPS and 66.3% were assigned to the correct natal river. However, since this study was funded the Conservation Genetics and Genomics Laboratory at Leetown Science Center has made significant improvements to their microsatellite genetic baseline, which now performs more effectively than our new genomic approach (the genetic baseline includes 12 populations and 5 DPSs, and correctly assigns 95.8% of individuals to DPS and 84.9% of individuals to their natal population using 12 microsatellite loci). We conducted an ad hoc exploration of how additional microsatellite or nuclear SNP loci may further improve the accuracy of assignment testing. We found that additional microsatellite markers are likely to result in greater improvements in assignment efficiency than additional nuclear SNPs. However, a much larger number of SNP loci (which if identified could be sequenced using other methods that are now available; e.g., the RAD-capture approach published by Ali et al. 2016) could produce assignment efficiencies that are greater than what is currently feasible using microsatellites. In the absence of further research and development of additional SNP markers for Atlantic Sturgeon (possibly using an approach other than GT-seq), the existing microsatellite loci are the most effective means available to determine the natal river and DPS of Atlantic Sturgeon encountered in offshore waters. Because our new genomic markers were less effective than the existing panel of 12 microsatellite markers, we chose to use the existing microsatellite markers to assign Atlantic Sturgeon captured in another BOEM-funded study (cooperative agreement M16AC00003; Monitoring endangered Atlantic Sturgeon and commercial finfish habitat use offshore New York) following consultation with our project officer. Using this approach, we genotyped and assigned 186 Atlantic Sturgeon captured in coastal waters off the Rockaway Peninsula, New York. The vast majority of these sturgeon were assigned to the New York Bight DPS (94.62%), and most appear to belong to the Hudson River population (87.10%) with smaller contributions from the Delaware River population (7.53%). Smaller contributions (2.15%) were observed from six other populations, including those from the James, York, Kennebec, Ogeechee, and Edisto rivers. Although most of the fish we assigned were assigned to the nearest spawning rivers (Hudson and Delaware), the contributions from distant rivers is consistent with the propensity of this species to move long distances and form mixed stock aggregations along the continental shelf. This finding indicates that spawning populations (and their corresponding DPS) from distant locations may potentially be impacted by offshore activities. In fact, activities in this region of the New York Bight could negatively impact Atlantic Sturgeon population from at least four different DPSs. Genetic or genomic assignment testing remains an essential tool to characterize potential impacts to Atlantic Sturgeon populations and should be applied more broadly to better characterize potential impacts of activities in other locations.

Atlantic Coast↗