2012

How Evapotranspiration And Deep Percolation Impact The Precipitation-Runoff Response, Aquifer Recharge And Linked Nutrient-Cycling In A High-Elevation Catchment In Colorado

Anonymous — Fri, 17 Aug 2018 18:26:33 +0000

How Evapotranspiration And Deep Percolation Impact The Precipitation-Runoff Response, Aquifer Recharge And Linked Nutrient-Cycling In A High-Elevation Catchment In Colorado Anonymous (not verified) Fri, 08/17/2018 - 12:26 Morgan Zeliff

Zeliff, Morgan ¹ ; Williams, Mark ² ; Cowie, Rory ³ ; Knowles, John ⁴ ; Burns, Sean ⁵

¹ University of Colorado
² University of Colorado
³ University of Colorado
⁴ University of Colorado
⁵ University of Colorado

Here we evaluate how evapotranspiration (ET) and deep percolation (DP) impact the precipitation-runoff response, aquifer recharge, and linked nutrient-cycling at the 536 ha sub-alpine Como Creek drainage in the Colorado Front Range. ET is measured continuously using eddy covariance, soil moisture (SM) is measured using 2-m vertical sensor arrays, groundwater (GW) by a series of piezometers, and precipitation (P) is measured daily along with snow-water equivalent (SWE). Wet precipitation chemistry from a 25 year record collected by the National Atmospheric Deposition Program and hydrochemistry from surface water, groundwater and snowpack are analyzed from the Como Creek catchment as well as an adjacent, higher-elevation catchment.

From 2004 to 2009, annual P averaged 813 mm and ET averaged 590 mm, with ET thus representing 72.5% of annual P. Using multiple linear regression analysis, discharge (Q) was found to be modeled reasonably well with the independent variables of ET (p < 0.01), P (p < 0.01), and SM (p < 0.01). The final linear model had a reasonable fit (r2=0.57) indicating ET, P and SM to be good predictors of Q, with ET and SM having positive coefficients, and somewhat surprisingly, P having a negative coefficient. We found ET to be positively correlated with summer P (r2=0.45), but not well correlated with annual or winter P. Our vertical soil moisture arrays show that summer precipitation over 5 years never penetrated more than 50 cm in depth. Thus, during the summer, water flux in the root zone becomes decoupled from the ground water system and subsequent precipitation does little to contribute to streamflow for the current year, but serves to offset ET, which may explain the decrease in Q with increasing P. The newly installed piezometers (12, at depths ranging from 5 to 30 m) provide evidence that this portion of the basin is largely a losing reach during snowmelt, with GW in the piezometers increasing 5-7 m. After peak snowmelt however, the reach starts gaining again with piezometer levels dropping. Time series plots reveal a strong relationship between SWE and Q with larger SWE often resulting in larger Q. Thus, surface-groundwater interactions are tightly coupled during snowmelt, with snowmelt first replenishing the subsurface water deficit before contributing to discharge. Over the 1.5 years of monitoring, the deepest two piezometers (18 and 27 m) were not showing any significant water level declines, suggesting that water loss to DP is a potential important component of the water balance in the Como Creek catchment. Groundwater and Como Creek nutrient levels contrast with the surface water and snowpack hydrochemisty from higher-elevations where there has been a trend of increasing inorganic nitrogen (Williams & Tonnessen 2000). The reason may be that snowmelt first infiltrates into the subsurface, where ammonium and nitrate are assimilated in the densely forested Como Creek catchment.

Williams, MW and Tonnessen,KA, 2000, Critical loads for inorganic nitrogen deposition in the Colorado Front Range, USA: Ecological Applications, v.10, p. 1648-1665.

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Drainage Evolution In North America Since The Last Glacial Maximum

Anonymous — Fri, 17 Aug 2018 18:25:47 +0000

Drainage Evolution In North America Since The Last Glacial Maximum Anonymous (not verified) Fri, 08/17/2018 - 12:25 Andrew D. Wickert

Wickert, Andrew D. ¹ ; Anderson, Robert S. ² ; Mitrovica, Jerry X. ³

¹ University of Colorado
² University of Colorado
³ Harvard University

Glacial cycles modified North American river systems by drastically changing drainage basin areas, patterns of precipitation, and meltwater delivery to channels. We reconstruct drainage basins and river discharges in North America from 20,000 years ago to present by combining the ICE-5G ice sheet reconstruction [Peltier, 2004] with a state-of-the-art model of sea level that includes isostatic, gravitational, and rotational solid Earth response to changing ice and water loads [Mitrovica and Milne, 2003; Kendall et al., 2005] and a paleoclimate general circulation model [Liu et al., 2009]. We present the histories of these rapidly-evolving drainage systems, which are responsible for shaping the modern river networks of North America.

Kendall, R. A., J. X. Mitrovica, and G. A. Milne (2005), On post-glacial sea level--II. Numerical formulation and comparative results on spherically symmetric models, Geophysical Journal International, 161(3), 679-706.
Liu, Z. et al. (2009), Transient simulation of last deglaciation with a new mechanism for Bolling-Allerod warming., Science, 325(5938), 310-4.
Mitrovica, J. X., and G. A. Milne (2003), On post-glacial sea level: I. General theory, Geophysical Journal International, 154(2), 253-267.
Peltier, W. R. R. (2004), Global Glacial Isostasy and the Surface of the Ice-Age Earth: The ICE-5G (VM2) Model and GRACE, Annual Review of Earth and Planetary Sciences, 32(1), 111-149.

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Catalog And Interpretation Of Seismically Induced Water Level Fluctuations At Devils Hole, Death Valley National Park, California-Nevada

Anonymous — Fri, 17 Aug 2018 18:25:01 +0000

Catalog And Interpretation Of Seismically Induced Water Level Fluctuations At Devils Hole, Death Valley National Park, California-Nevada Anonymous (not verified) Fri, 08/17/2018 - 12:25 Matthew Weingarten

Weingarten, Matthew ¹ ; Ge, Shemin ² ; Cutillo, Paula ³

¹ University of Colorado
² University of Colorado
³ National Park Service

Devils Hole, a fluid-filled cavern in the Amargosa Desert, southern Nevada, USA, is a fault-dissolution depression in carbonate rock, and is habitat for the only naturally occurring population of the endangered Devils Hole Pupfish, Cyprinodon Diabolis. The pool lies at the intersection of several small aperture, northwest-trending, high-angle normal faults and a one-meter aperture, northeast-trending, high-angle reverse fault. In addition to being sensitive to solid earth tides and atmospheric pressure, the pool is highly sensitive to seismic sources, with continuous water level records from 1989 to the present recording hundreds of seismically induced water level oscillations. A catalog of seismically induced, high-frequency water level oscillations is presented. The pool’s sensitivity to seismically induced volumetric strains is on the order of 10^-11, which is three orders of magnitude less than the theoretical limit to coseismic strain sensitivity. Preliminary results suggest that the sensitivity of Devils Hole varies seasonally with seismically induced water level oscillations in the Fall averaging 50% larger volumes when compared to winter oscillations. In addition, frequency domain analyses of seismically induced water level oscillations utilizing 15-second frequency pressure transducer data from the past four years indicate response patterns in azimuthal direction, distance and magnitude of earthquake epicenters in relation to Devils Hole. The hypothesis that these patterns in seismic source sensitivity are directly related to the orientation of faults present at Devils Hole is tested.

Montgomery, D.R., and Manga, M., 2003, Streamflow and water well responses to earthquakes: Science, v. 300, p. 2047-2049.
Robertson, G., Ge, S., and Cutillo, P., 2007, An investigation of regional tectonic strain on water levels in Devils Hole: Journal of Geophysical Research, v. 34, L23308, 5 PP.

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Challenges To The Implementation Of Decentralized Water Reuse Technologies In Boulder, Colorado

Anonymous — Fri, 17 Aug 2018 18:24:10 +0000

Challenges To The Implementation Of Decentralized Water Reuse Technologies In Boulder, Colorado Anonymous (not verified) Fri, 08/17/2018 - 12:24 Katie Spahr

Spahr, Katie ¹

¹ University of Colorado

One of the easiest and most practical ways to address future freshwater needs is to implement water conservation. By improving the efficiency of current infrastructure, communities become more resilient to water demand changes like drought and population growth. For urban areas, like Boulder, Colorado, where the majority of water is used for indoor residential purposes, the implementation of residential-level water conservation programs can prove to be one of the most effective means for demand management. One way residences can experience water savings is by installing fixtures like low flow showerheads, faucet aerators, and/or water smart dishwashers, which can result in a reduction of indoor water use of up to 35%.

When evaluating indoor residential water use, the highest use is for toilets, which account for approximately 30% of all indoor uses in Boulder. Reducing the amount of potable water used to flush toilets can result in the biggest “bang for your buck” water savings. Toilet flushing was one of the most consistent and predictable water uses found during a residential water use study in Boulder. While installing more efficient toilets can reduce the amount of potable water used to flush and can result in significant water savings, the overall conundrum of using drinking water quality water to flush away human waste still remains. To optimize toilet water use, flushing water can be augmented with treated graywater. Graywater is typically defined as the wastewater from bathtubs, showers, sinks, and laundry machines. This water can be treated to an appropriate quality and reused inside a residence. Replacing graywater for potable water in toilets would convert the 30% indoor use to 30% savings.

Williams Village North is a 500-bed residence hall on the east end of the University of Colorado of Boulder Campus provides a case study for a large-scale recirculation system. Graywater is collected from the 65 sinks and 45 showers in the northwest wing and piped to a water treatment train. The graywater is then treated to a high quality and fed through purple pipes to flush the entire building’s 105 toilets. Given the installed system and existing supportive plumbing infrastructure, this presentation will addresses some of the non-technical components of starting and operating a graywater recirculation system in the setting of Boulder, Colorado. These components include water use estimates, evaluation of prior appropriation water rights, and the evaluation of environmental impacts of graywater recirculation and, conversely, demand management.

"Water Use Statistics." Drinktap.org. American Water Works Association. Web. 12 Mar. 2012. http://www.drinktap.org/consumerdnn/Home/WaterInformation/Conservation/WaterUseStatistics/tabid/85/Default.aspx.
Mayer, Peter W., et al. Residential End Uses of Water. Tech. Denver: AWWA Research Foundation, 1999. Print.

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Soil Moisture Monitoring Network Using Multi-Sensor Capacitance Probes In A Thick Vadose Zone Under Riparian Vegetation

Anonymous — Fri, 17 Aug 2018 18:21:57 +0000

Soil Moisture Monitoring Network Using Multi-Sensor Capacitance Probes In A Thick Vadose Zone Under Riparian Vegetation Anonymous (not verified) Fri, 08/17/2018 - 12:21 Jose A Solis

Solis, Jose A ¹ ; Rajaram, Harihar ²

¹ University of Colorado, Boulder
² University of Colorado, Boulder

Soil moisture profile measurements are an integral component of water balance estimation networks, especially in thick vadose zones and fine-grained soil environments. At field sites with silty and stiff clayey soils, installation of sensors at multiple depths poses a challenge. One approach that has gained popularity is a multi-sensor capacitance (EniroSCAN) probe system manufactured by Sentek technologies. This requires only a single borehole where a 56.5 mm PVC access tube is installed. A very attractive feature of this system is that the sensors can be positioned at different depths without having to disturb the soil since the sensors are located on a cartridge unit that rides within the access tube and can be moved in 10 cm increments.

We report the design and installation of a distributed soil moisture sensor network in a riparian zone within the Whitewater Basin in Central Kansas. The soil-moisture monitoring network used in this study is compromised of 6 profilers (each covering a depth of 2 m) with 4-5 sensors per profile, located at different depths. The network is connected to a centralized data logger, from which it can be accessed remotely through a telemetry system in real-time. The network obtains distributed soil moisture measurements every 15 minutes. All profilers exhibit a rapid response to precipitation events at depths < 1m. During the leaf-out stage, sensors at depths < 1.5 m exhibit diurnal fluctuations in response to plant water uptake. The temporal trends and response to rainfall/plant uptake is significantly different at the different profile locations, illustrating the significant heterogeneity at the site. The moisture profiles clearly demonstrate the gradual replenishment of soil moisture both by precipitation and capillary rise during fall and winter, followed by depletion (with diurnal variations superimposed) during the leaf-out stage of riparian vegetation.

We describe the calibration efforts needed to convert the dielectric permittivity measurements obtained by the capacitance sensors to moisture content values. A two point calibration (measurement in nonsaline water, Fw; and in air Fa) was found to be adequate for accurate estimation of soil moisture changes. However, more detailed calibration functions were necessary for accurate estimates of absolute water content. Characterization of unsaturated soil properties was done using the HYPROP system manufactured by UMS (Umewlt Measurement Systeme). This system determines both soil water retention and unsaturated hydraulic conductivity curves. Significant heterogeneity in unsaturated soil properties is indicated from measurements on soils at different depths and locations. The soil moisture measurements and soil properties are being used for water budget estimation at the site across a range of time scales.

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Investigation Of The Applicability Of An Adapted Data Fusion Technique Combining ERS SAR Radar Data With Optical Imagery For Flood Extent Monitoring

Anonymous — Fri, 17 Aug 2018 18:21:15 +0000

Investigation Of The Applicability Of An Adapted Data Fusion Technique Combining ERS SAR Radar Data With Optical Imagery For Flood Extent Monitoring Anonymous (not verified) Fri, 08/17/2018 - 12:21 Jessica Seersma

Seersma, Jessica ¹

¹ University of Colorado at Boulder

Routine and recurrent flooding has been experienced in many areas of the world since the time of the first flood of record (God). Flooding can serve to replenish groundwater supplies, preserve wetland habitats, and provide irrigation. However, excessive or recurrent flood inundation destroys crops, causes the temporary and permanent displacement of residents, results in the incurrence of economic losses resulting from property damage and loss of operating revenue. Techniques that combine multi-temporal and multi-spectral optical passive sensor with active sensor derived synthetic aperture radar (SAR) data allow for an adequate representation of the landform and background information while providing information about flood extents during and just subsequent to floods. Fourteen weeks of sustained rainfall beginning in mid-September of 2000 resulted in extensive fluvial flooding in England, Wales, and part of Northern Ireland and Scotland.

The flood inundation area extents resulting from these floods that occurred along the River Severn extending from the southern portion of Worcester, Worcestershire to a downstream location southwest of Gloucester, Gloucestershire were evaluated through the use of a data fusion technique adapted from (Yonghua, 2007). A comparative analysis was performed to assess the overall effectiveness in the determination of the flood extents resulting from the data fusion technique using Normalized Difference Vegetation Index (NDVI), maximum likelihood classification, and histogram thresholding applied to optical imagery taken after the flood. ERS SAR images sampled to a resolution of 10 meters, and 20 meter resolution HRVIR SPOT 4 optical imagery were used to perform the analysis.

The fusion technique was applied to the ERS radar data taken after the flood and the SPOT imagery taken before and after the flood, respectively. In the fused images the distribution of water and non-water was non-homogenous with the exception of the river and floodplain areas, Figure 1. Therefore, there wasn’t a significant correlation in the spatial distribution of the water and non-water classified areas between the fused images and the images produced using only the SPOT imagery taken after the flood. Although, the boundaries of the flood inundation areas were not clearly defined in the fused image that was produced using the SAR data taken after the flood and the SPOT imagery taken before the flood, the boundaries were clearly defined in the fused image that was produced using the SAR data taken after the flood and the SPOT imagery taken after the flood. It was also shown that between 74% to 82% of the area classified as water using only the SPOT imagery taken after the flood were classified as water in the fused images, Figure 2.

God. New International Version Genesis 7: 11-12. Retrieved July 19, 2011, from Bible Gateway http://www.biblegateway.com/passage/?search=Genesis%207&version=NIV
Yonghua, S. X. (2007). A Study on Optical and SAR Data Fusion for Extracting Flooded Area. Institute of Electrical and Electronics Engineers, 3086 - 3089.

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Seasonality Of Vertical Structure In Radar-Observed Precipitation Over Southern Switzerland

Anonymous — Fri, 17 Aug 2018 18:20:34 +0000

Seasonality Of Vertical Structure In Radar-Observed Precipitation Over Southern Switzerland Anonymous (not verified) Fri, 08/17/2018 - 12:20 James V Rudolph

Rudolph, James V ¹ ; Friedrich, Katja ²

¹ Univeristy of Colorado - ATOC
² University of Colorado - ATOC

Operational radar data reveals that precipitation systems occurring on the southern side of the Alps near Locarno, Switzerland follow seasonal patterns of vertical structure. Storms occurring in summer are more convective than winter season storms as indicated by more frequent observation of reflectivity at higher altitudes during summer. Individual precipitation events occurring year-round are classified by comparison to average seasonal vertical structure. Seasonal classification of individual storms reveals a transition between winter and summer-type storms during spring and fall that follows changes in average daily surface temperature. In addition to distinct vertical structure, summer and winter-type storms have differences in duration, intensity, and interval between storms. Although summer and winter-type storms result in similar amounts of total precipitation, summer-type storms have shorter duration, and therefore greater intensity. The dependence of storm type on temperature has implications for intensification of the hydrologic cycle due to climate change. Warmer winter, spring, or fall surface temperatures may affect average precipitation intensity by increasing the number of days per year that experience more intense convective precipitation while decreasing the probability of less intense stratiform precipitation.

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Analysis Of Snowpack Of Boulder’s Watershed On Niwot Ridge: 2011 Versus 2012

Anonymous — Fri, 17 Aug 2018 18:19:49 +0000

Analysis Of Snowpack Of Boulder’s Watershed On Niwot Ridge: 2011 Versus 2012 Anonymous (not verified) Fri, 08/17/2018 - 12:19 Katherine Rosa

Rosa, Katherine ¹ ; Kerr, Christopher ² ; Meleyco, Nicholas ³ ; Rideout, Keeley⁴ ; Williams, Tyson ⁵ ; Willard, Ryan ⁶

¹ �鶹��Ѱ��Boulder
² �鶹��Ѱ��Boulder
³ �鶹��Ѱ��Boulder
⁴ �鶹��Ѱ��Boulder
⁵ �鶹��Ѱ��Boulder
⁶ �鶹��Ѱ��Boulder

The responsibility of the Snow Hydrology Interns is to travel into the Boulder watershed to sites along Niwot Ridge as part of a 30-year ecological research project. The intern’s role within the project is to collect samples and data necessary for analysis of snow properties. At each site, a snow pit is dug to the ground where samples are taken and tests are administered. The interns collect data on key properties of the snowpack, such as the stratigraphy, a density profile, and a temperature profile. While in the laboratory, the interns analyze the chemistry of the snow samples gathered from the field, testing for levels of various chemicals and elements critical to water quality as well as examining conductivity and pH levels. The analysis of this year’s snowpack allows for the estimation of the amount of water held in Boulder’s watershed and the quality of the water. The larger implication of this research is data collected from the individual layers of the snowpack that can be equated to snow quality and snow conditions. The avalanche danger in areas around Colorado has been at a high level and will most likely persist for the majority of the season, due to how the snowpack layers have been formed. Evidence of this can be found in the properties of the layers (snow grain size, shape, hardness, etc.) in which the interns analyze at the site. In comparison to last year’s snowpack that had higher snow volume and more stability, this year’s snow pack has less volume and is less stable: explaining the high avalanche danger. The snowpack is a dynamic system that needs to be monitored in order to have an accurate analysis of Boulder’s watershed and to keep the snow as a safe source of recreation.

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Soil Carbon Links To Soil Water Cycling In Ecosystems In The Colorado Front Range

Anonymous — Fri, 17 Aug 2018 17:57:00 +0000

Soil Carbon Links To Soil Water Cycling In Ecosystems In The Colorado Front Range Anonymous (not verified) Fri, 08/17/2018 - 11:57 Katherine M Powell

Powell, Katherine M ¹ ; Blanken, Peter D ² ; Anderson, Dean E ³ ; Stannard, David I ⁴ ; Thienelt, Thomas ⁵

¹ University of Colorado
² University of Colorado
³ U.S. Geological Survey
⁴ U.S. Geological Survey
⁵ Martin-Luther-Universitaet Halle-Wittenberg

Near surface soil-water content is crucial to the sustainability of an ecosystem. Additionally, the feedbacks between soil water and soil carbon improve the ability to predict carbon sequestration rates. Organic-carbon content in surface soils influences soil texture and, subsequently, water holding capacity. Preliminary research for two growing seasons (2010 and 2011) compares soil water, temperature, heat flux, and evapotranspiration (ET) with soil organic carbon content at several sites in the Colorado Front Range. Continuous measurements of precipitation, soil moisture and temperature, and energy fluxes were conducted from eddy covariance flux towers at three sites around metropolitan Denver: one urban site and two adjacent sites, a montane forest (Flying J Ranch Open Space), and a native tallgrass prairie (Rocky Flats National Wildlife Refuge (NWR)). Irrigation data were obtained for the Denver urban site and added to its precipitation to obtain total water inputs. Soil samples (0-5cm) were collected at each tower site and analyzed for bulk density, volumetric water content, and organic carbon content. Soil water inputs and losses (as ET) were analyzed for each site and compared to soil organic carbon content. The tallgrass prairie soils contained the highest organic carbon content, with a mean value of over 13 percent (N=18, σ=2.44), the montane site had a mean of 7.5 percent (N=24, σ=3.56), and the urban contained a mean organic carbon content of 5.9 percent (N=29, σ=1.18). Comparing grassland sites, the urban soil received much more water than the soil at the tallgrass prairie, 5 times higher water input (600mm, more than half from irrigation) in 2010, and approximately 3 times higher water input (840mm, 3 quarters from irrigation) in 2011. Despite less water input, the tallgrass prairie site developed more soil organic carbon. Research is focusing on the soil moisture conditions through the season that are more favorable to organic carbon accumulation and what conditions may be limiting soil carbon formation in irrigated urban soils. Plans include expanding the use of ecosystem process models to increase predictability under different land management and climate scenarios.

Amundson, R., 2001, The carbon budget in soils, Annual Review of Earth and Planetary Sciences, v. 29, p. 535-562.
Craine, J. M. and T. M. Gelderman, 2011, Soil moisture controls on temperature sensitivity of soil organic carbon decomposition for a mesic grassland, Soil Biology and Biochemistry, v. 43, no.2, p. 455-457.
Pouyat et al., 2008, A comparison of soil organic carbon stocks between residential turf grass and native soil, Urban Ecosystems, v. 12, p. 45-62.

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Engineered Injection And Extraction For Enhanced Mixing In Groundwater To Improve In-Situ Remediation

Anonymous — Fri, 17 Aug 2018 17:54:58 +0000

Engineered Injection And Extraction For Enhanced Mixing In Groundwater To Improve In-Situ Remediation Anonymous (not verified) Fri, 08/17/2018 - 11:54 Amy Piscopo

Piscopo, Amy N ¹ ; Neupauer, Roseanna M ² ; Mays, David C ³

¹ �鶹��Ѱ��
² �鶹��Ѱ��
³ University of Colorado Denver

Creating favorable mixing conditions in aquifers has the potential to improve the efficiency of in-situ remediation of groundwater. In current practice of in-situ remediation, the treatment solution, containing chemical or biological amendments, is either drawn through the aquifer using a downgradient extraction well or left to travel with ambient groundwater flow. Neither of these scenarios provides opportunity to enlarge the interfacial area between the treatment solution and the contaminated groundwater where degradation reactions occur. We hypothesize that by sequentially injecting or extracting clean water at multiple wells in the aquifer, the interface between the treatment solution and the contaminated groundwater can be stretched and folded to create unique geometries that provide additional surface area for reaction, thereby accelerating the treatment process. This strategy of injection and extraction is expected to be feasible for practical application since the pumping duration is limited as compared to other methods of injection and extraction, for example the pulsed dipole approach investigated by others. Simulations are conducted to model the reaction that occurs during a particular sequence of injection and extraction in both homogeneous and heterogeneous media. The results are compared to the reaction that occurs during a typical in-situ remediation scenario, where the treatment solution travels with ambient groundwater flow.

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