Effectiveness of forestry related Best Management Practices in the Trout Creek Watershed, Colorado

This report was accepted as Thesis in partial fulfillment of the requirements for the Masters of Science for Nani Bay Teves in Spring 2005.June 2005.Includes bibliographical references (pages 79-83).In multiuse forests the majority of nonpoint source pollution is typically sediment. Best management practices (BMPs) are implemented to reduce or prevent this pollutant, however little research has been done to quantify the effectiveness of individual types of BMPs. The overall goal of this project was to evaluate the effectiveness of three BMPs implemented to reduce sediment in Trout Creek: cattle fences, off-road vehicle signs, and road culverts. The effectiveness of the combined BMPs in the land use area was evaluated by comparing water quality and Wolman pebble counts with an upstream reference area. The reference area was selected based on soil type, vegetation type, elevation, and absence of cattle grazing and off-road vehicle use. Despite the difficulty of finding an exact reference area, the study results suggest that fences and culverts are effective, but signs are ineffective.United States Department of the Interior, Geological Survey, Contract number 01HQGR0077

Ecological integrity and western water management: a Colorado perspective

Sept. 1995.Includes bibliographical references

Forests and water: a state-of-the-art review for Colorado

Includes bibliographical references (pages 65-75).Forests occupy 22.6 million acres in Colorado, or 32 percent of the land area, and nearly three-quarters of the forest lands in Colorado are in public ownership. About 55 percent of the forested area is considered suitable for forest harvest. National forests comprise nearly half of the forested area and approximately 60 percent of the area is considered suitable for forest harvest. There are no significant, privately-owned, industrial forest lands in Colorado. Historic photographs, forest stand records, and other data indicate that forest density in Colorado is generally greater than in the mid to late 1800s. This increase in forest density, attributed to suppression of forest fires, reduced grazing, and lower rates of forest harvest for timber, fuel, and other products, are generally believed to have decreased annual water yields. Annual water yields from the 1.34 million acres of national forest lands in the North Platte River basin are estimated to have decreased by approximately 8 to 14 percent or 135,000 to 185,000 acre-feet per year, depending on the assumed stand history for the spruce-fir forests. Hydrologic models indicate that average annual water yields could be increased in the North Platte River basin by about 55,000 acre-feet per year if all 502,000 acres designated as suitable for timber harvest were regularly harvested on a sustained yield basis. Similar data are not available for other river basins in Colorado, although the overall trends are probably similar. This research looked at how reducing forest canopy affects the rate of spring snowmelt and water yield, how it affects evapotranspiration, what happens when the forest regrows, whether reducing forest density affects water yields if annual precipitation is a factor, the effects on water quality, and the necessity for water storage facilities to store the increased runoff. The report does not attempt to address the myriad of other issues that must be considered when evaluating various management alternatives for forested lands. Some of these issues include the numerous laws and regulations that affect land management, economic considerations, the downstream uses of water and water storage capacities, and the effects of forest management on recreation, local communities, aesthetics, and other plant and animal species.Sponsored by: Colorado River Water Conservation District, Colorado Water Resources Research Institute, Denver Water, Northern Colorado Water Conservancy District and financed in part by the U.S. Department of the Interior, Geological Survey, through the Colorado Water Resources Research Institute and Grant no. 01HQGR0077

Monitoring the effects of timber water yield harvest on annual

Abstract Paired catchment studies have been used as a method to assess the effects of vegetation removal (timber harvesting) on streamflow responses including lowflows and peakflows, but particularly annual water yield. Paired catchment studies in the United States reporting on the effects of timber harvesting on annual water yields were compiled. In general, changes in annual water yield from forest cover reduction (or catchment area harvested) of less than 20% could not be determined by hydrometric or streamflow measurement methods. The catchment studies were discriminated by hydrologic region, defined by temperature and precipitation regimes. This regionalization suggested that as little as 15% of the catchment area (or basal area) could be harvested for a measurable increase in annual water yield at the catchment level in the Rocky Mountain region as compared with 50% in the Central Plains, although system responses are variable. Given changing world-wide objectives for forest land management, hydrologists will be asked to develop monitoring programs to assess the effects of multiple and temporally and spatially distributed land use activities on water resources. Less catchment area will be disturbed, thus monitoring programs must be carefully designed to obtain useful information. The concept of hydrologic recovery, i.e. return to pretreatment condition tends to be based on annual water yield, but also needs the evaluation of streamflow generation and routing mechanisms including lowflows and peakflows when compared with the pretreatment condition

Applicability of trophic status indicators to Colorado plains reservoirs

Includes bibliographical references (pages 80-83).The recent proposed change in Cherry Creek Reservoir TMDL brought to light several issues about using a trophic status index (TSI) for water quality in Colorado reservoirs. Concerns range from applicability to interpretation. Off channel storage reservoirs along the South Platte River downstream of Denver, Colorado are often filled with river water that may contain high concentrations of nitrogen and phosphorous. This study measured reservoir nutrient concentrations from April through October 2001 in Jackson, Prewitt and North Sterling Reservoirs. Median total nitrogen (TN) concentrations were as follows: Jackson (2,550 mg/L), Prewitt (3,100 mg/L) and North Sterling (3,550 mg/L). Median total phosphorous (TP) concentrations were as follows: Jackson (208 mg/L), Prewitt (267 mg/L) and North Sterling (183 mg/L). An analysis of the applicability of common Trophic Status Index (TSI) models suggested that all reservoirs are eutrophic - hypereutrophic based upon chlorophyll-a, TP and Secchi depth measurements. Models using chlorophyll-a generally resulted in a lower trophic designation than those based upon TP. Model precision analysis (correlation coefficients, 95% confidence intervals, and average and percentage error) was used to evaluate 24 common models that predict chlorophyll-a from nutrient concentrations. Using precision analysis, models based upon TP were the best at Prewitt Reservoir, while models using TN and TP were best at Jackson and Sterling Reservoirs. This study suggested that one model does not fit all reservoirs. Based on precision analysis and model selection methods, nitrogen and phosphorous concentrations should be used when assessing off channel storage reservoir trophic status.Financed in part by the U.S. Department of the Interior, Geological Survey, through the Colorado Water Resources Research Institute and Grant no. 01HQGR0077

AGU hydrology days 2004

24th annual AGU hydrology days was held at Colorado State University on March 10-12, 2004.Includes bibliographical references.To determine the potential hydraulic connection of Turquois Lake to water movement in and through the mines and related fractures of the Sugar Loaf mining district, 166 moles of the gas sulfur hexafluoride (SF₆) were injected into Turquoise Lake in July 2003. High lake levels were long suspected for contributing to the growth and appearance of wetlands developed at the mouths of several area dewatering tunnels, including the Dinero and Bartlett. The tracer effectively tagged the reservoir with detectable concentrations lasting over 4 months. SF₆ was detected in the Bartlett tunnel 45 days after the injection, suggesting a flow rate of 13 m day⁻¹ for water moving from the lake. The detection at the Bartlett tunnel confirms a hydraulic connection to the water of Turquoise Lake. Although a similar response was expected at the Dinero tunnel, no tracer was ever detected. Degassing along the flow path is suspected for loss of the SF₆

GLEES (Glacier Lakes Ecosystem Experiments Site) Snow Depth Data Measured Annually at Peak Accumulation from 2005 to 2014

Point measurements of snow depth data were collected at approximately peak snow accumulation each winter for a 10-year period from 2005 to 2014 (2005-04-20; 2006-05-02; 2007-04-17; 2008-04-24; 2009-04-30; 2010-05-06; 2011-04-28; 2012-04-10; 2013-05-02; 2014-05-01) around the West Glacier Lake Watershed at GLEES (Glacier Lakes Ecosystem Experiments Site) (41.37255627, -106.2676067; 41.38350614, -106.2505978). Data were collected as part of the research by Dr. Douglas M. Hultstrand (https://mountainscholar.org/handle/10217/233658; https://mountainscholar.org/handle/10217/232572) and others. Snow depth was measured with an anodized aluminum depth probe and the location was measured with a hand-held Garmin Global Positioning System (GPS) unit. The data were collected by the Colorado State University (CSU) in conjunction with the United States Department of Agriculture U.S. Forest Service Rocky Mountain Research Station

Snowpack Distribution Using Topographical, Climatological and Winter Season Index Inputs

A majority of the annual precipitation in many mountains falls as snow, and obtaining accurate estimates of the amount of water stored within the snowpack is important for water supply forecasting. Mountain topography can produce complex patterns of snow distribution, accumulation, and ablation, yet the interaction of topography and meteorological patterns tends to generate similar inter-annual snow depth distribution patterns. Here, we question whether snow depth patterns at or near peak accumulation are repeatable for a 10-year time frame and whether years with limited snow depth measurement can still be used to accurately represent snow depth and mean snow depth. We used snow depth measurements from the West Glacier Lake watershed, Wyoming, USA, to investigate the distribution of snow depth. West Glacier Lake is a small (0.61 km2) windswept (mean of 8 m/s) watershed that ranges between 3277 m and 3493 m. Three interpolation methods were compared: (1) a binary regression tree, (2) multiple linear regression, and (3) generalized additive models. Generalized additive models using topographic parameters with measured snow depth presented the best estimates of the snow depth distribution and the basin mean amounts. The snow depth patterns near peak accumulation were found to be consistent inter-annually with an average annual correlation coefficient (r2) of 0.83, and scalable based on a winter season accumulation index (r2 = 0.75) based on the correlation between mean snow depth measurements to Brooklyn Lake snow telemetry (SNOTEL) snow depth data