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Research about Grand County, Colorado

Source-linked reports with geographic coverage including Grand County, Colorado.

13 recordsLinked to original sources
USGS2022

Living with wildfire in Grand County, Colorado: 2021 data report

Wildfire affects hundreds of wildland-urban interface communities each year, and yet most communities lack data reflecting the conditions before an event. This study was conducted before the devastating 2020 East Troublesome Fire1, which spread across 193,812 acres and resulted in two lives lost and 366 homes and 214 other structures burned. The fire’s dramatic run threatened over 7,000 structures and led to a mandatory evacuation of over 35,000 people in Grand and Larimer Counties. The data reported here serve as baseline data to aid in understanding the parcel and social conditions before the fire. This report presents results from WiRē Rapid Wildfire Risk Assessment (WiRē RA) data, collected from 1,162 private residential properties in six communities in five fire protection districts (FPDs), the majority (72%) of which were characterized as high, very high, or extreme risk. This report also presents results from household surveys sent to homeowners in the study area. Household survey respondents underestimated their risk compared to the conditions observed through the professional risk assessment. Respondents consistently overestimated the amount of defensible space and the distance from their homes to nonvegetative combustibles. Respondents also overestimated the availability of driveway clearance that would enable access for response vehicles and for safe passing of residents evacuating and responders arriving to their homes.

Colorado↗
USGS2019

sUAS-based remote sensing of river discharge using thermal particle image velocimetry and bathymetric lidar

This paper describes a non-contact methodology for computing river discharge based on data collected from small Unmanned Aerial Systems (sUAS). The approach is complete in that both surface velocity and channel geometry are measured directly under field conditions. The technique does not require introducing artificial tracer particles for computing surface velocity, nor does it rely upon the presence of naturally occurring floating material. Moreover, no prior knowledge of river bathymetry is necessary. Due to the weight of the sensors and limited payload capacities of the commercially available sUAS used in the study, two sUAS were required. The first sUAS included mid-wave thermal infrared and visible cameras. For the field evaluation described herein, a thermal image time series was acquired and a particle image velocimetry (PIV) algorithm used to track the motion of structures expressed at the water surface as small differences in temperature. The ability to detect these thermal features was significant because the water surface lacked floating material (e.g., foam, debris) that could have been detected with a visible camera and used to perform conventional Large-Scale Particle Image Velocimetry (LSPIV). The second sUAS was devoted to measuring bathymetry with a novel scanning polarizing lidar. We collected field measurements along two channel transects to assess the accuracy of the remotely sensed velocities, depths, and discharges. Thermal PIV provided velocities that agreed closely (R^2 = 0.82 and 0.64) with in situ velocity measurements from an acoustic Doppler current profiler (ADCP). Depths inferred from the lidar closely matched those surveyed by wading in the shallower of the two cross sections (R^2 = 0.95) but the agreement was not as strong for the transect with greater depths (R^2 = 0.61). Incremental discharges computed with the remotely sensed velocities and depths were greater than corresponding ADCP measurements by 22% at the first cross section and < 1% at the second.

Colorado↗
USGS2014

Mapping mountain pine beetle mortality through growth trend analysis of time-series landsat data

Disturbances are key processes in the carbon cycle of forests and other ecosystems. In recent decades, mountain pine beetle (MPB; Dendroctonus ponderosae) outbreaks have become more frequent and extensive in western North America. Remote sensing has the ability to fill the data gaps of long-term infestation monitoring, but the elimination of observational noise and attributing changes quantitatively are two main challenges in its effective application. Here, we present a forest growth trend analysis method that integrates Landsat temporal trajectories and decision tree techniques to derive annual forest disturbance maps over an 11-year period. The temporal trajectory component successfully captures the disturbance events as represented by spectral segments, whereas decision tree modeling efficiently recognizes and attributes events based upon the characteristics of the segments. Validated against a point set sampled across a gradient of MPB mortality, 86.74% to 94.00% overall accuracy was achieved with small variability in accuracy among years. In contrast, the overall accuracies of single-date classifications ranged from 37.20% to 75.20% and only become comparable with our approach when the training sample size was increased at least four-fold. This demonstrates that the advantages of this time series work flow exist in its small training sample size requirement. The easily understandable, interpretable and modifiable characteristics of our approach suggest that it could be applicable to other ecoregions.

Colorado↗
USGS2014

Characterizing recent and projecting future potential patterns of mountain pine beetle outbreaks in the Southern Rocky Mountains

The recent widespread mountain pine beetle (MPB) outbreak in the Southern Rocky Mountains presents an opportunity to investigate the relative influence of anthropogenic, biologic, and physical drivers that have shaped the spatiotemporal patterns of the outbreak. The aim of this study was to quantify the landscape-level drivers that explained the dynamic patterns of MPB mortality, and simulate areas with future potential MPB mortality under projected climate-change scenarios in Grand County, Colorado, USA. The outbreak patterns of MPB were characterized by analysis of a decade-long Landsat time-series stack, aided by automatic attribution of change detected by the Landsat-based Detection of Trends in Disturbance and Recovery algorithm (LandTrendr). The annual area of new MPB mortality was then related to a suite of anthropogenic, biologic, and physical predictor variables under a general linear model (GLM) framework. Data from years 2001–2005 were used to train the model and data from years 2006–2011 were retained for validation. After stepwise removal of non-significant predictors, the remaining predictors in the GLM indicated that neighborhood mortality, winter mean temperature anomaly, and residential housing density were positively associated with MPB mortality, whereas summer precipitation was negatively related. The final model had an average area under the curve (AUC) of a receiver operating characteristic plot value of 0.72 in predicting the annual area of new mortality for the independent validation years, and the mean deviation from the base maps in the MPB mortality areal estimates was around 5%. The extent of MPB mortality will likely expand under two climate-change scenarios (RCP 4.5 and 8.5) in Grand County, which implies that the impacts of MPB outbreaks on vegetation composition and structure, and ecosystem functioning are likely to increase in the future.

Colorado↗
USGS2014

Evaluation of the Raven sUAS to detect and monitor greater sage-grouse leks within the Middle Park population

Staff from the U.S. Geological Survey Fort Collins Science Center and the Colorado Parks and Wildlife Hot Sulphur Springs Office began discussions in 2011 for a proof of concept study to test the Raven RQ-11A small Unmanned Aircraft System (Raven sUAS) for its suitability to detect and monitor greater sage-grouse (Centrocercus urophasianus) breeding sites (leks). During April 2013, the Raven sUAS was flown over two known lek sites within the Middle Park population in Grand County, Colorado. Known sites were flown to determine the reaction of the greater sage-grouse to the aircraft and to determine if the technology had potential for future use of locating new leks and obtaining population counts on known, active lek sites. The Raven sUAS is a hand-launched reconnaissance and data-gathering tool developed for the U.S. Department of Defense by AeroVironment, Inc. Originally designed to provide aerial observation, day or night, at line-of-site ranges up to 6.2 miles (10 kilometers), the Raven sUAS has a wingspan of 4.5 feet (1.38 meters) and weighs 4.2 pounds (1.9 kilograms). A 60-minute lithium-ion rechargeable battery powers the system which also transmits live video (color or infrared imagery), compass headings, and location information to a ground control station. The Raven sUAS is typically operated by a three-person flight crew consisting of a pilot, mission operator, and a trained observer.

Colorado↗
USGS2011

Responses of soil and water chemistry to mountain pine beetle induced tree mortality in Grand County, Colorado, USA

Pine forest in northern Colorado and southern Wyoming, USA, are experiencing the most severe mountain pine beetle epidemic in recorded history, and possible degradation of drinking-water quality is a major concern. The objective of this study was to investigate possible changes in soil and water chemistry in Grand County, Colorado in response to the epidemic, and to identify major controlling influences on stream-water nutrients and C in areas affected by the mountain pine beetle. Soil moisture and soil N increased in soils beneath trees killed by the mountain pine beetle, reflecting reduced evapotranspiration and litter accumulation and decay. No significant changes in stream-water NO 3 - "> NO 3 - or dissolved organic C were observed; however, total N and total P increased, possibly due to litter breakdown or increased productivity related to warming air temperatures. Multiple-regression analyses indicated that % of basin affected by mountain pine beetles had minimal influence on stream-water NO 3 - "> NO 3 - and dissolved organic C; instead, other basin characteristics, such as percent of the basin classified as forest, were much more important.

Colorado↗
USGS2009

Hazards management in Grand County, Colorado— Fire fuels characterization

The USGS Fire Science Initiative is designed to identify potential wildfire risks and related hazards and to mitigate their effects on people, property, and natural resources. The USGS Rocky Mountain Geographic Science Center (RMGSC) plays an integral role in the fire science demonstration project targeting Grand County, Colo., which uses remote sensing imagery, other geospatial data, and advanced classification techniques to produce inventories and assessments of the current state of the ecosystem. The data gathered - extent of tree mortality and insect infestation, changes in fire fuels, susceptibility to post-fire effects, distribution of wildland-urban interface areas, etc. - will give much needed information to decisionmakers on the Federal, State, and local levels.

Colorado↗
USGS2004

Water-quality characteristics and ground water quantity of the Fraser River watershed, Grand County, Colorado, 1998-2001

The U.S. Geological Survey, in cooperation with the Grand County Board of County Commissioners, conducted a 4-year study to assess ground- and surface-water-quality conditions and ground-water quantity in the 302-square-mile Fraser River watershed in north-central Colorado. The Fraser River flows north about 28 miles from the headwaters near the Continental Divide, through the towns of Winter Park, Fraser, Tabernash, and Granby, and is one of the major tributaries to the Upper Colorado River. Increasing urban development, as well as the seasonal influx of tourists, is placing more demands on the water resources in the Fraser River watershed. A ground-water sampling network of 11 wells was established to represent different aquifer systems (alluvial, Troublesome Formation, Precambrian granite), land uses (urban, nonurban), and areas with or without individual septic disposal system use. The well network was sampled for ground-water quality on a semiannual basis from August 1998 through September 2001. The sampling included field properties and the collection of water samples for analysis of major ions, trace elements, nutrients, dissolved organic carbon, bacteria, methylene blue active substances, and radon-222. One surface-water site, on the Fraser River just downstream from the town of Tabernash, Colorado, was sampled bimonthly from August 1998 through September 2001 to assess the cumulative effects of natural and human processes on water quality in the upper part of the Fraser River watershed. Surface-water-quality sampling included field properties and the collection of water-quality samples for analysis of major ions, trace elements, nutrients, organic carbon, and bacteria. Ground water was a calcium-bicarbonate type water and is suitable as a drinking-water, domestic, municipal, industrial, and irrigation source. In general, no widespread ground-water-quality problems were indicated. All pH values and concentrations of dissolved solids, chloride, fluoride, sulfate, nitrite, and nitrate in the ground-water samples met or were substantially less than U.S. Environmental Protection Agency drinking-water standards and health advisories or State of Colorado water-quality standards. Federal standards for turbidity and concentrations of iron, manganese, methylene blue active substances, and radon-222 were not met in water samples from at least one well. The only ground-water-quality concern assessed by this study is radon-222, which was detected in all radon- analyzed samples from 10 wells at levels exceeding the proposed U.S. Environmental Protection Agency drinking-water standard of 300 picocuries per liter. Concentrations of chloride, magnesium, and sulfate were statistically different (higher) in ground-water samples from wells completed in the alluvial aquifer, urbanized areas, and areas with individual septic disposal system use than those from wells completed in the Troublesome Formation, nonurban areas, and areas without individual septic disposal system use. Dissolved organic carbon concentrations were statistically higher in ground-water samples from wells completed in the alluvial aquifer and areas without individual septic disposal system use than those from wells completed in the Troublesome Formation and areas with individual septic disposal system use. Differences in dissolved organic-carbon concentrations between the latter category and areas without septic systems likely had no environmental significance. Surface water at the site Fraser River below Crooked Creek at Tabernash was a calcium-bicarbonate type water and is suitable as a drinking-water, residential, commercial, and irrigation resource. All pH values and concentrations of dissolved oxygen were within the State of Colorado instream water-quality standards, and all concentrations of chloride, sulfate, iron, manganese, un-ionized ammonia, nitrite, nitrate, and fecal coliform bacteria met State standards. Seasonal changes in the values or conc

Colorado↗
USGS1975

An occurrence of disseminated uraninite in Wheeler Basin, Grand County, Colorado

Disseminated uraninite occurs in Wheeler Basin, Grand County, Colo., about 5 mi (8 km) southeast of Monarch Lake, in Precambrian metamorphic rocks consisting of migmatized gneiss and mixed gneiss and pegmatite. An intrusion of Precambrian Y Silver Plume Granite lies within 400 ft (122 m) of the occurrence. The disseminated uraninite is confined to parts of the host rock that are rich in biotite; highest grade found was 0.73 percent uranium. The disseminated uraninite occurs as cubes and grains, generally from 0.1 to 0.3 mm across. Unit cell edge of the uraninite, ≈ 5.48 A, suggests its pegmatitic origin. The origin of the uraninite disseminations is attributed by us to remobilization and concentration of elements during metamorphism caused by the intrusion of Silver Plume Granite. Uranium and lead isotopic analyses by K. R. Ludwig of uraninite and monazite from biotite concentrations confirm an apparent age of 1,450±20 m.y. for these minerals. This age is equivalent to that reported for the Silver Plume Granite. Although the Wheeler Basin occurrence is small in size, it has many similarities to the Rossing uranium deposit in South-West Africa.

Colorado↗
USGS1975

Absolute age of disseminated uraninite in Wheeler Basin, Grand County, Colorado

Uranium and lead isotopic analyses of monazlte and uraninite from the disseminated uraninite occurrence at Wheeler Basin, Grand County, Colo., indicate that these minerals formed 1,446±20 m.y. ago. This time correlates well with intrusion of the Silver Plume Granite. The uraninite and monazite were also affected by a later disturbance at 880±130 m.y., but show essentially no effects of subsequent events. This secondary disturbance may have been due to intrusion of dikes related to the Pikes Peak batholith, dated at 1,041±13 m.y. ago.

Colorado↗