Complete Bouguer gravity anomaly map of the Santa Ana 1° by 2° quadrangle, California
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The Dos Palos-Kettleman City area of this report includes approximately 1,350 square miles on the central-western side of the San Joaquin Valley, California. Large-scale farming operations in the area have used ground water as the major source of irrigation water for nearly three quarters of a century. In 1968, completion of the San Luis Canal part of the California Aqueduct, made surface water available to farmers. In time the widespread use of this imported water may cause chemical-quality changes in the native ground water. To document conditions prior to any possible changes, 361 samples of ground water were taken before deliveries of surface water were begun. The data will serve as a base to which future investigations can be compared. To establish any trends, the results were compared to earlier chemical data for the area. The results indicated that only minor changes in chemical quality had occurred between 1951 and 1968. Water from an upper water-bearing zone is markedly different from water in a lower water-bearing zone. Water in the upper zone is of various chemical types, and the concentration of dissolved solids increases from east to west across the area. Water in the lower zone is a sodium sulfate type and is fairly consistent throughout the zone.
This compilation of ground-water references was prepared as an aid to the field men engaged in ground-water investigations in the Missouri River Basin. It is thought that an acquaintance with the available literature on the area in which a field man is working may on occasion not only save him the effort of duplicating work that has already been done in his area but that he will find the reports of other workers on the same problem both informative and challenging. It is suggested that each field man make every effort to obtain copies of the literature on his area from nearby sources before he calls on superior for help in obtained copied of the desired references. It is not presumed that this bibliography is complete. In order that it may be improved upon at a later date, the field man is requested to enter on the blank pages at the end of the listed reference all other references he may discover from time to time. Then, if the demand for a revision of the bibliography is sufficiently great, these added references can be inserted in the appropriate places. Suggestions as to an improved arrangement of the material will be welcomed by the Missouri Basin Ground-Water Headquarters Office.
Many coarse-grained calcium- aluminum-rich inclusions (CAIs) contain features that are inconsistent with equilibrium liquid crystallization models of origin. Spinel-free islands (SFIs) in spinel-rich cores of Type B CAIs are examples of such features. One model previously proposed for the origin of Allende 5241, a Type B1 CAI containing SFIs, involves the capture and assimilation of xenoliths by a liquid droplet in the solar nebula (El Goresy et al ., 1985; MacPherson et al ., 1989). This study reports new textural and chemical zoning data from 5241 and identifies previously unrecognized chemical zoning patterns in the melilite mantle and in a SFI. These zoning patterns are identified by large-scale elemental mapping techniques. The compositional zoning is completely independent of, and cross-cuts individual melilite crystals in the mantle, a relation that suggests the mantle was deposited or accreted onto a preexisting core of the inclusion. Lack of correlation with individual mantle crystals also suggests that the mantle totally recrystallized at subsolidus temperatures. Sodium distribution maps demonstrate that most of the Na in 5241 was introduced during the secondary alteration process. Major- and trace-element data from the SFI boundary in a second type B1 CAI, Allende 3529Z, were obtained. The boundary bisects a large fassaite crystal. If the SFI is a relict xenolith, then chemical differences are likely to be present across the boundary. Electron microprobe analysis of the fassaite crystal reveals concentric zoning of Ti, which is unrelated to the SFI boundary, as well as distinct zones enriched in Al and depleted in Ti +3 . Ion microprobe analyses at the SFI boundary show no significant variation in Ba, Sc, V, Cr, Sr, Zr, Nb and REE in fassaite. There is no evidence that requires the capture of a xenolith in 3529Z. Based on chemical zoning and textural arguments, it is suggested that both of these CAIs formed by a process of partial melting of precursors, which contained either vesicles or spinel-free grains. Allende 5241 shows evidence for vapor condensation and accretion and/or introduction of a second liquid to form the melilite mantle. Chemical zoning patterns in the mantles of the inclusions indicate that 3529Z experienced a higher degree of partial melting than 5241, but it was not high enough to melt spinel or completely melt and homogenize relict fassaite components.
The National Map's 2-year goal, as described in this plan, is to provide a range of geospatial products and services that meet the basic goals of the original vision for The National Map while furthering the National Spatial Data Infrastructure that underpins U.S. Geological Survey (USGS) science. To accomplish this goal, the National Geospatial Program (NGP) will acquire, store, maintain, and distribute base map data. The management team for the NGP sets priorities for The National Map in three areas: Data and Products, Services, and Management. Priorities for fiscal years 2008 and 2009 (October 1, 2007 through September 30, 2009), involving the current data inventory, data acquisition, and the integration of data, are (1) incorporating current data from Federal, State, and local organizations into The National Map to the degree possible, given data availability and program resources; (2) collaborating with other USGS programs to incorporate data that support the USGS Science Strategy; (3) supporting the Department of the Interior (DOI) high-priority geospatial information needs; (4) emergency response; (5) homeland security, natural hazards; and (6) graphics products delivery. The management team identified known constraints, enablers, and drivers for the acquisition and integration of data. The NGP management team also identified customer-focused products and services of The National Map. Ongoing planning and management activities direct the development and delivery of these products and services. Management of work flow processes to support The National Map priorities are identified and established through a business-driven prioritization process. This tactical plan is primarily for use as a document to guide The National Map program for the next two fiscal years. The document is available to the public because of widespread interest in The National Map. The USGS collaborates with a broad range of customers and partners who are essential to the success of The National Map, including the science community, State and Federal agencies involved in homeland security, planners and emergency responders at the local level, and private companies. Partner contributions and data remain a primary input and foundation of The National Map. Partnership strategies for each of The National Map's component data themes are outlined in this plan. Because of the importance of The National Map customers, a reassessment of customer needs will be completed during 2008. Results of the assessment will be incorporated into future decisions and priorities. A performance milestone matrix has been developed that contains the full list of milestones, major deliverables, and major tasks. The matrix forms the basis for reporting on accomplishments and issues. However, a number of risks, dependencies, and issues have been identified that could affect meeting milestones in the matrix, such as: the USGS is not the Circular A-16 lead for boundaries, transportation, and structures; availability of sufficient and sustainable funding; availability of Federal workforce and contractors with necessary skills, and numerous competing customer and stakeholder requirements.
This report is a joint effort of the Biological Resources Division, U.S. Geological Survey and the U.S. Fish and Wildlife Service (FWS) to provide National Wildlife Refuge (NWR) managers guidance on the selection and evaluation of habitat management strategies to meet stated objectives. The FWS recently completed a handbook on writing refuge management goals and objectives (U.S. Fish and Wildlife Service 1996a). the National Wildlife Refuge System Improvement Act of 1997 requires that National Wildlife Refuge System (NWRS) lands be managed according to approved Comprehensive Conservation Plans to guide management decisions and devise strategies for achieving refuge unit purposes and meeting the NWRS mission. It is expected that over the next several years most refuges will develop new or revised refuge goals and objectives for directing their habitat management strategies. This paper outlines the steps we recommend in selecting and evaluating habitat management strategies to meet specific refuge habitat objectives. We selected two examples to illustrate the process. Although each refuge is unique and will require specific information and solutions, these two examples can be used as guidance when selecting and evaluating habitat management strategies for other refuge resources: Example 1. Management of floodplain woods habitat for forest interior birds. The biological recourse of concern is the quality and quantity of floodplain woods habitat for eastern forest interior birds in the Cypress Creek NWR (U.S. Fish and Wildlife Service 1996b). Example 2. Management of habitat for biodiversity: Historical landscape proportions. The biological resource of concern is the change in diversity associated with man-induced changes in the distribution and abundance of habitat types at the Minnesota Valley NWR (U.S. Fish and Wildlife Service 1996c).
This dataset, termed "GAGES II", an acronym for Geospatial Attributes of Gages for Evaluating Streamflow, version II, provides geospatial data and classifications for 9,322 stream gages maintained by the U.S. Geological Survey (USGS). It is an update to the original GAGES, which was published as a Data Paper on the journal Ecology's website (Falcone and others, 2010b) in 2010. The GAGES II dataset consists of gages which have had either 20+ complete years (not necessarily continuous) of discharge record since 1950, or are currently active, as of water year 2009, and whose watersheds lie within the United States, including Alaska, Hawaii, and Puerto Rico. Reference gages were identified based on indicators that they were the least-disturbed watersheds within the framework of broad regions, based on 12 major ecoregions across the United States. Of the 9,322 total sites, 2,057 are classified as reference, and 7,265 as non-reference. Of the 2,057 reference sites, 1,633 have (through 2009) 20+ years of record since 1950. Some sites have very long flow records: a number of gages have been in continuous service since 1900 (at least), and have 110 years of complete record (1900-2009) to date. The geospatial data include several hundred watershed characteristics compiled from national data sources, including environmental features (e.g. climate – including historical precipitation, geology, soils, topography) and anthropogenic influences (e.g. land use, road density, presence of dams, canals, or power plants). The dataset also includes comments from local USGS Water Science Centers, based on Annual Data Reports, pertinent to hydrologic modifications and influences. The data posted also include watershed boundaries in GIS format. This overall dataset is different in nature to the USGS Hydro-Climatic Data Network (HCDN; Slack and Landwehr 1992), whose data evaluation ended with water year 1988. The HCDN identifies stream gages which at some point in their history had periods which represented natural flow, and the years in which those natural flows occurred were identified (i.e. not all HCDN sites were in reference condition even in 1988, for example, 02353500). The HCDN remains a valuable indication of historic natural streamflow data. However, the goal of this dataset was to identify watersheds which currently have near-natural flow conditions, and the 2,057 reference sites identified here were derived independently of the HCDN. A subset, however, noted in the BasinID worksheet as “HCDN-2009”, has been identified as an updated list of 743 sites for potential hydro-climatic study. The HCDN-2009 sites fulfill all of the following criteria: (a) have 20 years of complete and continuous flow record in the last 20 years (water years 1990-2009), and were thus also currently active as of 2009, (b) are identified as being in current reference condition according to the GAGES-II classification, (c) have less than 5 percent imperviousness as measured from the NLCD 2006, and (d) were not eliminated by a review from participating state Water Science Center evaluators. The data posted here consist of the following items:- This point shapefile, with summary data for the 9,322 gages.- A zip file containing basin characteristics, variable definitions, and a more detailed report.- A zip file containing shapefiles of basin boundaries, organized by classification and aggregated ecoregion.- A zip file containing mainstem stream lines (Arc line coverages) for each gage.
Little St. Germain Lake is a 978-acre, multibasin lake in Vilas County, Wisconsin. In the interest of protecting and improving the water quality of the lake, the Little St. Germain Lake District initiated several cooperative studies with the U.S. Geological Survey between 1991 and 2004 to (1) document the water quality and the extent of winter anoxia in the lake, (2) evaluate the success of aerators at eliminating winter anoxia, (3) develop water and nutrient budgets for the lake, and (4) assess how the water quality of the lake should respond to changes in phosphorus loading. This report presents the results of these cooperative studies with special emphasis on the water quality in the lake since 2000, including the effects of winter aeration and the importance of ground-water contributions of phosphorus to the productivity of the lake. Measurements collected during these studies indicate that the water quality in Little St. Germain Lake was consistently different among basins. The West Bay consistently had the best water quality, the South Bay had intermediate water quality, and the East and Upper East Bays consistently had the worst water quality. The water quality in each of the basins was relatively stable from 1991 to 2000; however, since 2001, the West Bay has changed from oligotrophic to mesotrophic, the South Bay has changed from mesotrophic to eutrophic, and the East and Upper East Bays have changed from eutrophic to eutrophic/hypereutrophic. Winter anoxia frequently occurred throughout most of the lake, except in the West Bay and just below the ice in the East Bay. To eliminate winter anoxia, coarse-bubble line aerators were installed and operated in the Upper East, East, and South Bays. The aerators in the Upper East and South Bays were very successful at eliminating winter anoxia; however, the aerator in the East Bay had little impact on the dissolved oxygen concentrations throughout its basin. Detailed water and phosphorus budgets computed for the lake indicated that inflow from Muskellunge Creek was the major source of phosphorus to the lake and that ground water was the secondary source. Results from a detailed ground-water-flow model indicated that ground water flows into the lake from all sides, except the south sides of the West and Second South Bays. Most of the phosphorus appears to come from natural sources, such as ground water and surface water flowing through relatively undeveloped areas surrounding Little St. Germain Lake and Muskellunge Lake. Several empirical water-quality models were used to simulate how the East and Upper East Bays of the lake should respond to reductions in phosphorus loading from Muskellunge Creek. Simulation results indicated that reductions in tributary loading could improve the water quality of the East and Upper East Bays. Improving the water quality of these bays would also improve the water quality of the South and Second South Bays because of the flow of water through the lake. However, even with phosphorus loading from Muskellunge Creek completely eliminated, most of the lake would remain borderline mesotrophic/eutrophic because of the contributions of phosphorus from ground water.
Background The Federal Emergency Management Agency (FEMA) developed a plan in 1997 to modernize the FEMA flood mapping program. FEMA flood maps delineate flood hazard areas in support of the National Flood Insurance Program (NFIP). FEMA's plan outlined the steps necessary to update FEMA's flood maps for the nation to a seamless digital format and streamline FEMA's operations in raising public awareness of the importance of the maps and responding to requests to revise them. The modernization of flood maps involves conversion of existing information to digital format and integration of improved flood hazard data as needed. To determine flood mapping modernization needs, FEMA has established specific scoping activities to be done on a county-by-county basis for identifying and prioritizing requisite flood-mapping activities for map modernization. The U.S. Geological Survey (USGS), in cooperation with FEMA and the Maine State Planning Office Floodplain Management Program (MFMP), began scoping work in 2006 for Penobscot County. Scoping activities included assembling existing data and map needs information for communities in Penobscot County, documentation of data, contacts, community meetings, and prioritized mapping needs in a final scoping report (this document), and updating the Mapping Needs Update Support System (MNUSS) Database with information gathered during the scoping process. As of 2007, the average age of the FEMA floodplain maps in Penobscot County, Maine, is 22 years, based on the most recent revisions to the maps. Because the revisions did not affect all the map panels in each town, however, the true average date probably is more than 22 years. Many of the studies were published in the mid-1980s. Since the studies were completed, development has occurred in many of the watersheds, and the characteristics of the watersheds have changed with time. Therefore, many of the older studies may not depict current conditions nor accurately estimate risk in terms of flood heights or flood mapping.
Data bases are essential for modern scientific research. The new and exciting work being done in the Mineral Resource Program in the U.S. Geological Survey (USGS) usually begins with the question, "Where are the known deposits?" A mineral-resource data base containing this type of information and more can be useful not just to USGS scientists, but to anyone who needs such data. Users of the data bases from outside the USGS include mining and exploration companies, environmental groups, academia, other Federal Agencies, and the general public. At present, the USGS has two large mineral-resource data bases, MRDS (Mineral Resource Data System) and MAS (Minerals Availability System). MRDS was built and is mamtained by the USGS, and MAS was built and maintained by the Bureau of Mines. In 1996, after the Bureau was abolished, MAS was transferred to the USGS. The two data bases were compiled for different purposes and contain very different mformation. For instance, MAS contains information on costs, details of mining methods, and feasibility studies. MRDS has mineralogical and geologic data that are not contained in MAS. Because they are both mineral-resource data bases, however, they contain some information in common, such as location, name(s) of sites, and commodities present. Both data bases are international in scope, and both are quite large. MRDS contains over 110,000 records, while MAS has over 220,000. One reason that MAS has more records is that it contains information on smelters, mill sites, and fossil fuel sites, as well as mineral- resource sites. The USGS is working to combine the information in both data bases. This is a large undertaking that will require some years to complete. In the interim, information from both data bases will still be available
The "National Atlas of the United States of America ® ", published by the U.S. Geological Survey (USGS) in 1970, is out of print, but many of its maps can be purchased separately. Maps that span facing pages in the atlas are printed on one sheet. Maps dated after 1970 and before 1997 are either revisions of original atlas maps or new maps published in the original atlas format. The USGS and its partners in government and industry began work on a new "National Atlas" in 1997. Though most new atlas products are designed for the World Wide Web, we are continuing our tradition of printing high-quality maps of America. In 1998, the first completely redesigned maps of the "National Atlas of the United States ® " were published.
The overall mission of U.S. Geological Survey (USGS) Beach Health Initiative is to provide science-based information and methods that will allow beach managers to more accurately make beach closure and advisory decisions, understand the sources and physical processes affecting beach contaminants, and understand how science-based information can be used to mitigate and restore beaches and protect the public. The USGS, in collaboration with many Federal, State, and local agencies and universities, has conducted research on beach-health issues in the Great Lakes Region for more than a decade. The work consists of four science elements that align with the initiative's mission: real-time assessments of water quality; coastal processes; pathogens and source tracking; and data analysis, interpretation, and communication. The ongoing or completed research for each of these elements is described in this fact sheet.
This map was prepared in cooperation with the U.S. Department of Energy's Western Gas Sands Project and was constructed to show the thermal maturity of the Upper Cretaceous Mesaverde Formation (or Group) in the Piceance Creek Basin. The ability of a source rock to generate oil and gas is directly related to its kerogen content and thermal maturity; hence, thermal maturity is commonly used as an exploration tool. This publication consists of two parts: a coal rank map for the basinwide Cameo and Fairfield or equivalent coal zone and three cross sections showing the variation in a coal rank for the entire Mesaverde. Structure contours on the map show the top of the Rollins Sandstone Member of the Mesaverde Formation and its equivalent the Trout Creek Sandstone Member of the Iles Formation of the Mesaverde Group, which immediately underlie the Cameo and Fairfield zone. The structure contours show the fairly strong correlation between structure and coal rank in the basin, suggesting that maximum overburden was the key factor in determining the coal ranks. Even in the southern part of the basin where extensive plutonism occurred during the Oligocene, coal ranks still generally follow structure; indicating that the plutons had little affect on the coals. On the cross sections both the top of the Rollins and Trout Creek, and the top of the Mesaverde Formation/Group are shown. A complete analysis of the entire Mesaverde in the basin would require more information than is presently available.
The U.S. Geological Survey developed a content metadata standard to meet the demands of organizing electronic resources in the marine sciences for a broad, heterogeneous audience. These metadata standards are used by the Marine Realms Information Bank project, a Web-based public distributed library of marine science from academic institutions and government agencies. The development and deployment of this metadata standard serve as a model, complete with lessons about mistakes, for the creation of similarly specialized metadata standards for digital libraries.
We conducted inventories for amphibians and reptiles, birds, and mammals; and summarized past inventories for vascular plants at Coronado National Memorial (NM) in Arizona. We used our data as well as data from previous research to compile species lists for the memorial, assess inventory completeness, and make suggestions on future monitoring efforts. There have been 940 species of plants and vertebrates recorded at Coronado NM (Table 1), of which 46 (5%) are non-native. The species richness of the memorial is one of the highest in the Sonoran Desert Network of park units, third only to park units that are two and one-half (Chiricahua National Monument), 19 (Saguaro National Park) and 70 (Organ Pipe Cactus National Monument) times larger in area. The high species diversities are due to the large elevational gradient, overlap of bigeographical regions, wide range of geology and soils, and diverse vegetation communities present at the memorial. Changes in species composition have occurred at the memorial over the last 20 years in all major taxonomic groups. These changes are likely due to increases in grassy plant species (both native and non-native) at the lower elevations of the memorial. We suspect that grassy plant cover has increased because of changes in grazing intensity, introduction of some non-native species, and a recent fire. All recent vertebrate inventories have yielded grassland obligate species not previously recorded at the memorial. Based on the review of past studies, we believe the inventory for most taxa, except bats, is nearly complete, though some rare or elusive species will likely be added with additional survey effort.
Nutrient and sediment data collected at 115 sites by Federal and State agencies from 1993 to 2004 were analyzed by the U.S. Geological Survey to determine trends in concentrations and loads for selected rivers and streams that drain into the northwestern Gulf of Mexico from the south-central United States, specifically from the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf Basins. Trends observed in the study area were compared to determine potential regional patterns and to determine cause-effect relations with trends in hydrologic and human-induced factors such as nutrient sources, streamflow, and implementation of best management practices. Secondary objectives included calculation of loads and yields for the study period as a basis for comparing the delivery of nutrients and sediment to the northwestern Gulf of Mexico from the various rivers within the study area. In addition, loads were assessed at seven selected sites for the period 1980-2004 to give hydrologic perspective to trends in loads observed during 1993-2004. Most study sites (about 64 percent) either had no trends or decreasing trends in streamflow during the study period. The regional pattern of decreasing trends in streamflow during the study period appeared to correspond to moist conditions at the beginning of the study period and the influence of three drought periods during the study period, of which the most extreme was in 2000. Trend tests were completed for ammonia at 49 sites, for nitrite plus nitrate at 69 sites, and for total nitrogen at 41 sites. For all nitrogen constituents analyzed, no trends were observed at half or more of the sites. No regional trend patterns could be confirmed because there was poor spatial representation of the trend sites. Decreasing trends in flow-adjusted concentrations of ammonia were observed at 25 sites. No increasing trends in concentrations of ammonia were noted at any sites. Flow-adjusted concentrations of nitrite plus nitrate decreased at 7 sites and increased at14 sites. Flow-adjusted concentrations of total nitrogen decreased at 2 sites and increased at 12 sites. Improvements to municipal wastewater treatment facilities contributed to the decline of ammonia concentrations at selected sites. Notable increasing trends in nitrite plus nitrate and total nitrogen at selected study sites were attributed to both point and nonpointsources. Trend patterns in total nitrogen generally followed trend patterns in nitrite plus nitrate, which was understandable given that nitrite plus nitrate loads generally were 70-90 percent of the total nitrogen loads at most sites. Population data were used as a surrogate to understand the relation between changes in point sources and nutrient trends because data from wastewater treatment plants were inconsistent for this study area. Although population increased throughout the study area during the study period, there was no observed relation between increasing trends in nitrogen in study area streams and increasing trends in population. With respect to other nitrogen sources, statistical results did suggest that increasing trends in nitrogen could be related to increasing trends in nitrogen from either commercial fertilizer use and/or land application of manure. Loads of ammonia, nitrite plus nitrate, and total nitrogen decreased during the study period, but some trends in nitrogen loads were part of long-term decreases since 1980. For example, ammonia loads were shown to decrease at nearly all sites over the past decade, but at selected sites, these decreasing trends were part of much longer trends since 1980. The Mississippi and Atchafalaya Rivers contributed the highest nitrogen loads to the northwestern Gulf of Mexico as expected; however, nitrogen yields from smaller rivers had similar or higher yields than yields from the Mississippi River. Trend tests were completed for orthophosphorus at 34 sites and for total phosphorus at 52 sites. No trends were observed in abo
The Citizen Potawatomi Nation needs to characterize their existing surface-water and groundwater resources in and near their tribal jurisdictional area to complete a water-resource management plan. Water resources in this area include surface water from the North Canadian and Little Rivers and groundwater from the terrace and alluvial aquifers and underlying bedrock aquifers. To assist in this effort, the U.S. Geological Survey (USGS), in cooperation with the Citizen Potawatomi Nation, collected water-quality samples at 4 sites on 3 streams and from 30 wells during 2012 and 2013 in and near the Citizen Potawatomi Nation Tribal Jurisdictional Area in central Oklahoma. Stream samples were collected eight times on the North Canadian River at the upstream USGS streamflow-gaging station North Canadian River near Harrah, Okla. (07241550); at the downstream USGS streamflow-gaging station North Canadian River at Shawnee, Okla. (07241800); and on the Little River at the USGS streamflow-gaging station Little River near Tecumseh, Okla., (07230500). Stream samples also were collected three times at an ungaged site, Deer Creek near McLoud, Okla. (07241590). Water properties were measured, and water samples were analyzed for concentrations of major ions, nutrients, trace elements, counts of fecal-indicator bacteria, and 69 organic compounds. The highest concentrations of dissolved solids and chlorides were measured in stream-water samples collected at the Little River near Tecumseh station. The Secondary Maximum Contaminant Level (SMCL) for dissolved solids in drinking water of 500 milligrams per liter (mg/L) was exceeded in 7 of 8 stream-water samples, with a median concentration of 844 mg/L at that station. The 250-mg/L SMCL for chloride was exceeded in 5 of the 8 stream-water samples collected at that station. Median concentrations of total dissolved nitrogen were about an order of magnitude higher in stream-water samples collected at the two stations on the North Canadian River than concentrations in stream-water samples collected at the Little River near Tecumseh station and the Deer Creek site. Median concentrations of total dissolved nitrogen were 4.36 and 2.89 mg/L in stream-water samples collected at the two North Canadian River stations, 0.35 mg/L in stream-water samples collected at the Little River near Tecumseh station, and 0.76 mg/L in stream-water samples collected at the Deer Creek site. Similar to nitrogen, median concentrations of total dissolved phosphorus were higher by about two orders of magnitude in stream-water samples collected at the two stations on the North Canadian River than concentrations in stream-water samples collected at the Little River near Tecumseh station and the Deer Creek site. Median concentrations of total dissolved phosphorus were 1.05 and 0.805 mg/L in stream-water samples collected at the two North Canadian River stations, 0.007 mg/L in stream-water samples collected at the Little River near Tecumseh station, and 0.032 mg/L from the Deer Creek site. Dissolved concentrations of total nitrogen, nitrate-nitrogen, orthophosphorus, and total phosphorus were highest in stream-water samples collected at the two North Canadian River stations at low streamflows, indicating that wastewater effluent may have been a notable source of these nutrients. Concentrations of most trace elements increased with increasing streamflow in stream-water samples collected at the two North Canadian River stations, indicating that most trace elements are washed into the river by runoff from the land surface or resuspended from streambed sediments. In general, most trace-element concentrations were below respective Maximum Contaminant Levels (MCLs) for public drinking-water supplies, except for one stream-water sample with an arsenic concentration of 10.1 micrograms per liter (µg/L) collected from the North Canadian River and one stream-water sample with a barium concentration of 2,690 µg/L collected from the Little River. At least one stream-water sample from each of the four stream sites sampled in this study contained a lead concentration exceeding the SMCL of 15 µg/L. All of these samples were collected during high streamflows. A greater number of organic compounds were detected in stream-water samples collected at the two stations on the North Canadian River than in stream-water samples collected at the Tecumseh station and Deer Creek site. In the 8 stream-water samples collected at the upstream Harrah station, 213 detections of organic compounds were measured, whereas in 8 samples collected at the downstream Shawnee station, 203 detections of organic compounds were measured. In contrast, 59 detections of organic compounds were measured in the 8 stream-water samples collected at the Tecumseh station, and 25 detections of organic compounds were measured in the 3 stream-water samples collected at the Deer Creek site; however, the 8 detections of 7 organic compounds in the 2 equipment-blank samples is problematic for evaluating these data, especially for the Deer Creek and Little River samples because of the comparatively low detection frequency and should be taken into consideration when evaluating these results. Groundwater samples also were collected once from 30 wells producing water from the Garber-Wellington aquifer; Admire, Chase, and Council Grove Groups; the Vanoss Formation; and the terrace and alluvial aquifers along the North Canadian River. Water properties were measured, and samples were analyzed for concentrations of major ions, nutrients, trace elements, and selected radionuclides in groundwater. Of 30 wells sampled for this study, 26 were completed in bedrock aquifers, and 4 were completed in terrace and alluvial aquifers. In general, groundwater in the study area is very hard, with a median concentration of 180 mg/L as calcium carbonate in water samples collected from the 30 wells. Concentrations of sulfate exceeded the 250-mg/L SMCL in two groundwater samples, and dissolved solids concentrations exceeded the 500-mg/L SMCL in nine groundwater samples. Trace-element concentrations did not exceed respective MCLs in the 30 groundwater samples collected for this study. Concentrations of the radionuclide uranium ranged from 0.03 to 79.5 µg/L, with a median concentration of 1.9 µg/L in the 30 groundwater samples collected. Two of the groundwater samples collected for this study had uranium concentrations exceeding the MCL of 30 µg/L, with concentrations of 79.5 and 31.1 µg/L. Generally, uranium concentrations were highest in water samples collected from wells completed in the Wellington Formation and the Chase, Council Grove, and Admire Groups in the southern and eastern parts of the study area.
In 1980 Santa Rosa Dam began impounding water on the Pecos River about 7 miles north of Santa Rosa, New Mexico, to provide flood control, sediment control, and storage for irrigation. Santa Rosa Lake has caused changes in the groundwater flow system, which may cause changes in the streamflow of the Pecos River that cannot be detected at the present streamflow gaging stations. Data collected at these stations are used to measure the amount of water available for downstream users. A three-dimensional groundwater flow model for a 950 sq mi area between Anton Chico and Puerto de Luna was used to simulate the effects of Santa Rosa Lake on groundwater flow to a gaining reach of the Pecos River for lake levels of 4,675, 4,715, 4,725, 4,750, 4,776, and 4,797 feet above sea level and durations of impoundment of 30, 90, 182, and 365 days for all levels except 4 ,797 feet. These simulations indicated that streamflow in the Pecos River could increase by as much as 2 cu ft/sec between the dam and Puerto de Luna if the lake level were maintained at 4 ,797 feet for 90 days or 4,776 feet for 1 year. About 90% of this increased streamflow would occur < 0.5 mi downstream from the dam, some of which would be measured at the streamflow gaging station located 0.2 mile downstream from the dam. Simulations also indicated that the lake will affect groundwater flow such that inflow to the study area may be decreased by as much as 1.9 cu ft/sec. This water may leave the Pecos River drainage basin or be diverted back to the Pecos River downstream from the gaging station near Puerto de Luna. In either case, this quantity represents a net loss of water upstream from Puerto de Luna. Most simulations indicated that the decrease in groundwater flow into the study area would be of about the same quantity as the simulated increase in streamflow downstream from the dam. Therefore, the net effect of the lake on the flow of the Pecos River in the study area appears to be negligible. Model simulations indicated that effect of lake levels below 4 ,750 feet on water levels in observation wells completed in the San Andres Limestone could not be distinguished from the effects of other hydrologic stresses. (Author 's abstract)