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Research about Anchorage, Alaska

Source-linked reports with geographic coverage including Anchorage, Alaska.

At least 37 records · Page 2Linked to original sources
USGS2006

Ground-water quality beneath solid-waste disposal sites at anchorage, Alaska

Studies at three solid-waste disposal sites in the Anchorage area suggest that differences in local geohydrologic conditions influence ground-water quality. A leachate was detected in ground water within and beneath two sites where the water table is very near land surface and refuse is deposited either at or below the water table in some parts of the filled areas. No leachate was detected in ground water beneath a third site where waste disposal is well above the local water table.

Alaska↗
USGS2006

Ground water in the Anchorage area, Alaska: Meeting the challenges of ground-water sustainability

Ground water is an important component of Anchorage's water supply. During the 1970s and early 80s when ground water extracted from aquifers near Ship Creek was the principal source of supply, area-wide declines in ground-water levels resulted in near record low streamflows in Ship Creek. Since the importation of Eklutna Lake water in the late 1980s, ground-water use has been reduced and ground water has contributed 14-30 percent of the annual supply. As Anchorage grows, given the current constraints on the Eklutna Lake water availability, the increasing demand for water could place an increasing reliance on local ground-water resources. The sustainability of Anchorage's ground-water resources challenges stakeholders to develop a comprehensive water-resources management strategy.

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USGS2003

Identification of linear and threshold responses in streams along a gradient of urbanization in Anchorage, Alaska

We examined biotic and physiochemical responses in urbanized Anchorage, Alaska, to the percent of impervious area within stream basins, as determined by high-resolution IKONOS satellite imagery and aerial photography. Eighteen of the 86 variables examined, including riparian and instream habitat, macroinvertebrate communities, and water/sediment chemistry, were significantly correlated with percent impervious area. Variables related to channel condition, instream substrate, water chemistry, and residential and transportation right-of-way land uses were identified by principal components analysis as significant factors separating site groups. Detrended canonical correspondence analysis indicated that the macroinvertebrate communities responded to an urbanization gradient closely paralleling the percent of impervious area within the subbasin. A sliding regression analysis of variables significantly correlated with percent impervious area revealed 8 variables exhibiting threshold responses that correspond to a mean of 4.4-5.8% impervious area, much lower than mean values reported in other, similar investigations. As contributing factors to a subbasin's impervious area, storm drains and roads appeared to be important elements influencing the degradation of water quality with respect to the biota.

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USGS2003

Effects of implanted radio transmitters with percutaneous antennas on the behavior of Canada Geese

We examined whether surgically-implanted radio transmitters with percutaneous antennas affected behavior of Lesser Canada Geese (Branta canadensis parvipes) in Anchorage, Alaska. We implanted either a 26-g VHF radio transmitter or a larger VHF radio that was the same mass (35 g) and shape as a satellite transmitter in the coelom of adult females captured during molt in 2000. A control group of females was marked with leg bands. We simultaneously observed behavior of radio-marked and control females from 4-62 d following capture. We observed no differences in the proportion of time birds in different treatments allocated among grazing, resting, comfort, walking, and alert behavior. Females in different treatments spent a similar proportion of time in the water. Implantation of radio transmitters did not affect the frequency of agonistic interactions. We conclude that coelomic radio transmitters with percutaneous antennas had minimal effects on the behavior of Canada Geese.

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USGS2001

Effects of urbanization on benthic macroinvertebrate communities in streams, Anchorage, Alaska

The effect of urbanization on stream macroinvertebrate communities was examined by using data gathered during a 1999 reconnaissance of 14 sites in the Municipality of Anchorage, Alaska. Data collected included macroinvertebrate abundance, water chemistry, and trace elements in bed sediments. Macroinvertebrate relative-abundance data were edited and used in metric and index calculations. Population density was used as a surrogate for urbanization. Cluster analysis (unweighted-paired-grouping method) using arithmetic means of macroinvertebrate presence-absence data showed a well-defined separation between urbanized and nonurbanized sites as well as extracted sites that did not cleanly fall into either category. Water quality in Anchorage generally declined with increasing urbanization (population density). Of 59 variables examined, 31 correlated with urbanization. Local regression analysis extracted 11 variables that showed a significant impairment threshold response and 6 that showed a significant linear response. Significant biological variables for determining the impairment threshold in this study were the Margalef diversity index, Ephemeroptera-Plecoptera-Trichoptera taxa richness, and total taxa richness. Significant thresholds were observed in the water-chemistry variables conductivity, dissolved organic carbon, potassium, and total dissolved solids. Significant thresholds in trace elements in bed sediments included arsenic, iron, manganese, and lead. Results suggest that sites in Anchorage that have ratios of population density to road density greater than 70, storm-drain densities greater than 0.45 miles per square mile, road densities greater than 4 miles per square mile, or population densities greater than 125-150 persons per square mile may require further monitoring to determine if the stream has become impaired. This population density is far less than the 1,000 persons per square mile used by the U.S. Census Bureau to define an urban area.

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USGS2000

Radar structure of earthquake-induced, coastal landslides in Anchorage, Alaska

Ground-penetrating radar (GPR) was used to investigate the internal structure of two large landslides in Anchorage, Alaska that resulted from the great 1964 earthquake. The Government Hill and Turnagain Heights landslides occurred in similar stratigraphic and geographic settings, yet the style of ground deformation is different at each site. GPR data are compared with previous investigations and are shown, under certain conditions, to have utility in the identification of ancient landslides. Reflection surveys accurately reproduced the subsurface geometry of horst and graben structures and imaged finer scale features such as ground cracks and fissures. Where more complete disintegration of the bluff occurred, GPR reflections from within the slide mass are generally chaotic and include no recognizable evidence of the original stratigraphy. Common midpoint surveys estimated GPR velocity in the sediment and allowed the conversion of travel times to depths.

Alaska↗
USGS2000

Nitrate source indicators in ground water of the Scimitar Subdivision, Peters Creek area, Anchorage, Alaska

A combination of aqueous chemistry, isotopic measurement, and in situ tracers were used to study the possible nitrate sources, the factors contributing to the spatial distribution of nitrate, and possible septic system influence in the ground water in the Scimitar Subdivision, Municipality of Anchorage, Alaska. Two water types were distinguished on the basis of the major ion chemistry: (1) a calcium sodium carbonate water, which was associated with isotopically heavier boron and with chlorofluorocarbons (CFC's) that were in the range expected from equilibration with the atmosphere (group A water) and (2) a calcium magnesium carbonate water, which was associated with elevated nitrate, chloride, and magnesium concentrations, generally isotopically lighter boron, and CFC's concentrations that were generally in excess of that expected from equilibration with the atmosphere (group B water). Water from wells in group B had nitrate concentrations that were greater than 3 milligrams per liter, whereas those in group A had nitrate concentrations of 0.2 milligram per liter or less. Nitrate does not appear to be undergoing extensive transformation in the ground-water system and behaves as a conservative ion. The major ion chemistry trends and the presence of CFC's in excess of an atmospheric source for group B wells are consistent with waste-water influences. The spatial distribution of the nitrate among wells is likely due to the magnitude of this influence on any given well. Using an expanded data set composed of 16 wells sampled only for nitrate concentration, a significant difference in the static water level relative to bedrock was found. Well water samples with less than 1 milligram per liter nitrate had static water levels within the bedrock, whereas those samples with greater than 1 milligram per liter nitrate had static water levels near or above the top of the bedrock. This observation would be consistent with a conceptual model of a low-nitrate fractured bedrock aquifer that receives slow recharge from an overlying nitrate-enriched surficial aquifer.

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USGS1987

Pumpage data from public supply wells at Anchorage, Alaska, 1957- 1985

Tables of data for each well include monthly and yearly pumpage totals, average monthly pumpage for each year, and monthly (January-December) average pumpage for the period of record. Total monthly pumpage for each well is also portrayed graphically. The data are also accessible on computer files at the U.S. Geological Survey 's Alaska District Office in Anchorage.

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USGS1987

Ground-water levels in Anchorage, Alaska, 1985

Water-level data collected during 1985 for 146 Anchorage wells deeper than 40 feet are presented. Hydrographs of water levels in 20 wells for the period 1970 through 1985 are also given. The report describes groundwater conditions and seasonal fluctuations in water levels, and includes pumpage figures and well-construction data.

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USGS1987

Quantity and quality of urban runoff from the Chester Creek basin Anchorage, Alaska

Urbanization has affected both the flow characteristics and water quality of streams in the Chester Creek basin, of Anchorage, Alaska. Peak flows are higher in the urban rather than rural parts of the basin, and the percent of effective impervious area has a significant effect on storm runoff volumes and peaks. Water quality in the Chester Creek basin varies according to season and flow conditions. During low or base-flow conditions, concentrations of most water quality constituents measured are within State of Alaska drinking water standards, except for fecal coliform bacteria. During periods of high flow due to snowmelt or rainfall, concentrations of trace metal lead usually exceed recommended maximum levels. The primary sources of trace metal lead and suspended sediments are commercial areas , while the primary source of nutrients and fecal coliform bacteria is residential areas. Streamflow and water quality data collected at five sites representing different land-use categories were used to calibrate and verify three U.S. Geological Survey computer-based models: the Distributed Routing Rainfall-Runoff Model-Version II (DR3M-II), the Multi-Event Urban Runoff Quality Model (DR3M-QUAL), and the Precipitation Runoff Modeling Systems (PRMS). The PRMS can be used to simulate the effects of increased urbanization on daily flows. The DR3M-II can be used to simulate storm effects on small basins of < 40 acres. The DR3M-QUAL can be used to estimate seasonal loads of suspended sediment from basins of < 40 acres. (Lantz-PTT)

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USGS1987

Evaluation of ground failure susceptibility, opportunity, and potential in the urban area of Anchorage, Alaska : final technical report

This study was conducted as a part of the U.s. Geological Survey's Earthquake Hazards Reduction Program. The goal of this program is a reduction of earthquake hazards through the incorporation of research findings on these hazards into land-use planning decisions. An important objective of the Earthquake Hazards Reduction Program is assessment of the potential for earthquake-induced ground failure in areas of high seismicity.

Alaska↗
USGS1980

Effects of artificial-recharge experiments at Ship Creek alluvial fan on water levels at Spring Acres Subdivision, Anchorage, Alaska

A subdivision developer encountered water while digging trenches associated with developing property at Spring Acres Subdivision, Anchorage, Alaska, during the summer of 1975. He reported encountering water at a depth of about 8 feet in June 1975 and also reported a rise in water level to approximately land surface by early August. Neither incident was expected by the developer. The U.S. Geological Survey, in cooperation with the Municipality of Anchorage, had conducted an artificial-recharge experiment approximately 9,000 feet northeast of Spring Acres Subdivision from May 20 through September 19, 1975. Recharge experiments were also conducted in 1971, 1973, and 1974. The proximity of the 1975 recharge experiment to the subdivision caused speculation on the possible connection between the experiment and the water problems encountered by the developer. The effect of the artificial-recharge experiments on water levels at Spring Acres Subdivision was evaluated by using two digital-computer models constructed to simulate the water-level rises induced by the artificial recharge. The models predicted that the artificial recharge would have caused water levels in the aquifer immediately underlying Spring Acres Subdivision to rise approximately 0.2 foot from May 20 to August 7, 1975. The models also predicted a total rise in ground-water levels of 1.1 feet at this location from July 16, 1973, to August 7, 1975, as a result of the artificial-recharge experiments. Water-level data collected for auger holes in March 1975 by a consulting firm for the contractor indicated a depth to water of 6 to 7 feet below land surface at Spring Acres Subdivision at this time. Water levels measured in and near Spring Acres Subdivision several years before and after the 1973-75 artificial-recharge experiments showed seasonal rises of 2 to 12.4 feet. A depth to water below land surface of 2.6 feet was measured 600 feet from the subdivision in 1971 and in the subdivision in 1977. Average depth to water in the area was 7.0 feet from early 1976 to September 1979.

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USGS1977

Artificial recharge experiments on the Ship Creek alluvial fan, Anchorage, Alaska

During the summers of 1973 and 1974, water from Ship Creek was diverted at an average rate of approximately 6 cubic feet per second to an 11-acre recharge basin. Maximum sustained unit recharge for the basin was approximately 1.4 feet per day. Dur-ing 1975 a second basin of 8 acres was also used for recharge, and the total diversion rate was increased to as much as 30 cubic feet per second. The second basin was never completely filled, but the unit recharge rate was estimated to be at least four times as great as that in the first basin. During 1973 and 1974, when only one recharge basin was in operation, a maximum rise of 18 feet was observed in the ground-water table near the basin. In 1975, when both basins were being used, the maximum rise was 30 feet in the same area. During 1973 and 1974, the water-level rise was 12 and 8 feet in the unconfined and confined systems, respectively, at a point 4.400 feet downgradient from the basins; in 1975 the rise at the same point was 31 and 16 feet, respectively. It was originally believed that because of the location of the recharge ponds within the natural recharge zone of the area's confined aquifer system, the source of the major portion of Anchorage's public water supply, most of the artificially recharged water would enter that system. However, water-level data and changes in saturation conditions interpreted from borehole geophysical logs indicate that most of the recharged water remained in the unconfined aquifer. In addition, the potentiometric rise that was achieved in the confined aquifer during summer operation of the recharge basins was quickly dissipated when diversion stopped and the basins drained. Thus the benefits of recharge would not persist into late winter, the critical period of water availability in Anchorage, unless diversion to the basins could be continued until January or February.

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USGS1976

Geohydrology of the lowland lakes area, Anchorage, Alaska

Unconsolidated deposits, chiefly of glacial origin, make up the surficial geologic materials in the Anchorage lowland lakes area , the western part of the Anchorage glacial outwash plain. Postglacial accumulation of peat, commonly 5 to 10 feet thick, and the presence of ground water at or very near the surface combine to create the swamp-muskeg terrane of much of the area. Deeper, confined ground water is also present beneath thick silt and clay layers that underlie the surficial deposits. Domestic water supply for the lowland lakes area is provided largely by public-supply wells completed in the deep, confined aquifers. No large perennial streams traverse the area, thus streamflow is not a major parameter in the area 's natural water balance. The major uses of surface water are recreational, including fishing and boating at several of the larger lakes, and private and commercial aircraft operations at Hood-Spenard Lakes floatplane base. The hydrology and water balance of these lakes is complex. Water levels in some lakes appear to be closely related to adjacent ground-water levels. Other lakes are evidently perched above the local water table. The relation of lake level to adjacent ground-water level may vary along the shoreline of a single lake. The effect of residential development practices on lake basin water balance is not completely understood. At Sand Lake, the largest lake in this area of rapid urbanization, the water level has declined about 6 feet since the early 1960's. (Woodard-USGS)

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USGS1975

Hydrology for land-use planning: The Hillside area, Anchorage, Alaska

Rapid residential growth of the Hillside area, Anchorage, Alaska, may cause depletion of aquifers and a change in quality of water resources as a result of extensive development of small-lot tracts. Ground-water yields are low and may be locally inadequate for single family requirements where wells produce from bedrock in the eastern Hillside region. At lower altitudes single family water requirements of 3 to 10 gallons per minute or 0.2 to 0.6 litre per second usually can be obtained, but aquifers capable of being pumped at larger yields for public supplies are uncommon. However, in a few localities, wells do produce 40 to 300 gallons per minute or 2.5 to 19 litres per second from sand and gravel aquifers lying within thick sequences of glacial till. Streamflow within the Hillside area is inadequate as a significant source of water for public supply. Springs, swamps, and water-logged surficial sediments in the Hillside area are mainly caused by hilly terrain and low permeability of surficial materials. The relative vulnerability of streams, lakes, and ground water to pollution caused by the discharge of liquid waste, particularly from onsite sewage-disposal systems, is moderate to high in about half the study area. At higher altitudes contamination of bedrock aquifers may occur if discharge of liquid wastes is not regulated. The deep sedimentary aquifers at lower altitudes are less susceptible to contamination. However, shallow groundwater bodies may become polluted by discharge of sewage effluent and, consequently, some deep wells may be contaminated by seepage down the outside of casings or through leaky casing joints and underground seals.

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