Natural Resources and Environmental Science

Student Name: Erin Carroll-Moore

Major Professor and Institutional Affiliation: Dr. Wally Miller, Department of Natural Resources and Environmental Science, University of Nevada, Reno

Graduate Program: Natural Resources and Environmental Science

Graduation Date: August 2006

Title of Research Project: Applications of Spatial Analysis in Sierran Systems: Hydrologic Balance, Nutrient Budget, and Erosion

Key Findings of Research Project: A surface water model was developed integrating Geographic Information Systems (GIS), Doppler radar, and field measurements to simulate the hydrologic balance of the Russel Valley watershed in order to better define total overland flow water and nutrient contributions to stream flow. Comparisons of the GIS model outputs to estimated Boca Reservoir inflow from Russel Valley watershed found most input to Boca reservoir occurs during spring snowmelt. The estimated area of collection for surface runoff collectors was found to be comparable to previous findings of about 1,000 to 10,000 cm2 during the dry season with larger areas of collection during the wet season. Estimates of surface and infiltrated waters’ nutrient concentrations found surface runoff concentrations had the potential to surpass Truckee River standards, especially for nitrate/nitrite and ortho-phosphate, while soil water was typically well within limits. Using relative percentages of total input to Boca Reservoir contributed by surface water and infiltration, as determined by the GIS model, the model indicated overall output from Russel Valley watershed to be primarily in the form of base flow, and therefore have nutrient concentrations approximating the lower concentrations of soil water. This model, however, was limited by potential errors in snowmelt quantity and the potential for widespread decreases in infiltration rate due to winter freeze/thaw and biomass removal treatment. In the event of extensive freezing of soils and hydrophobicity induced by biomass removal treatments or wildfire, the system could be largely surface water dominant and therefore contribute large nutrient quantities to outflow via surface runoff, thereby exceeding water quality standards. A better understanding of these issues is needed to determine the true influence of surface runoff nutrient concentrations under these conditions.

High intensity wildfire due to long-term fire suppression led to the 2002 “Gondola” wildfire, located just southeast of Lake Tahoe, NV-CA, which was followed two weeks later by a severe hail and rainfall event that deposited 7.6 to 15.2 mm of precipitation over a 3-5 hr time period. This resulted in a substantive upland ash and sediment flow with subsequent down-gradient riparian zone deposition. Geographic Information Systems (GIS) software was applied to point data to spatially assess source area contribution and the extent of ash and sediment flow deposition in the riparian zone. An estimated average depth of 10.1 mm of surface material eroded from the upland source area. Compared to previous measurements of erosion during rainfall simulation studies, the erosion of 1,800 to 6,700 g m-2 mm-1 determined from this study was as much as four orders of magnitude larger. Wildfire, followed by the single event documented in this investigation, enhanced soil water repellency and contributed 17-67% of the reported 15-60 mm ky-1 of non-glacial, baseline erosion rates occurring in mountainous, granitic terrain sites in the Sierra Nevada. High fuel loads now common to the Lake Tahoe Basin increase the risk that similar erosion events will become more commonplace, potentially contributing to the accelerated degradation of Lake Tahoe’s water clarity.

Overall, it was found that spatial analysis software is an extremely useful tool that is really only limited by gaps in data, lack of complete understanding of the forces involved in natural processes, and the operator’s imagination. Gaps in knowledge identified by this investigation included extent of winter freeze/thaw of soils, hydrophobicity of soils immediately post biomass removal treatment, and velocity effects on surface runoff collector viability.

Publications from Graduate Research:

Carroll, Erin M., Wally W. Miller, Dale W. Johnson, Laurel Saito, Robert G. Qualls, and Roger E. Walker. 2007. Spatial Analysis of a Large Magnitude Erosion Event Following a Sierran Wildfire. Journal of Environmental Quality, 36:4, pp. 1105-1111.

Miller, W.W., D.W. Johnson, T. Loupe, E. Carroll, J. Murphy, R.F. Walker, and D. Glass. Wildfire and Runoff Water Quality in Lake Tahoe Basin. California Agriculture, 60:2, pp.65-71.

Miller, W. Wally, Dale W. Johnson, Theresa M. Loupe, James S. Sedinger, Erin M. Carroll, James D. Murphy, Roger F. Walker, and Dallas Glass. 2006. Nutrients Flow from Runoff at Burned Forest Site in Lake Tahoe Basin. California Agriculture, 60:2, pp. 65-71.

Murphy, J.D., D.W. Johnson, W.W. Miller, R.F. Walker, E.M. Carroll, and R.R. Blank. 2006. Wildfire Effects on Soil Nutrients and Leaching in a Tahoe Basin Watershed. Journal of Environmental Quality, 35:2, pp.479-489.

Saito, L., W.W. Miller, D.W. Johnson, R.G. Qualls, P. Szameitat, and E. Carroll. Fire Effects on Stable Isotopes Signatures in Soils and Forest Floor Residue. Submitted to Journal of Environmental Quality.

Loupe, T.M., W.W. Miller, D.W. Johnson, E.M. Carroll, D. Hanseder, D. Glass, and R.F. Walker. Inorganic N and P in Sierran Forest O Horizon Leachate. Journal of Environmental Quality. NAES #52055642 In Revision.

Poster Presentations:

Carroll, E.M., W.W. Miller, D.W. Johnson, L. Saito, P. Szameitat, and R.F. Walker. Spatial Analysis of an Ash/Sediment Flow Following a Sierran Wildfire. 97th Annual Meetings of the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, November 6-10, 2005, Salt Lake City, UT.

Loupe, T., W.W. Miller, D.W. Johnson, E.M. Carroll, D. Hanseder, D. Glass, and R.F. Walker. Nutrient Content in O-Horizon Leachate from a Mixed Conifer Sierran Forest. 97th Annual Meetings of the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, November 6-10, 2005, Salt Lake City, UT.

Johnson, D.W., W.W. Miller, and R.F. Walker, Pls; J.D. Murphy, C.M. Stein, T. Loupe, and E. Carroll, Grad Students. Forest Fire Studies at University of Nevada, Reno. Senator Ensign 2003 Lake Tahoe Summit, Lake Tahoe, NV.

 

Student Name: Joseph Ferguson

Major Professor and Institutional Affiliation: Dr. Robert G. Qualls, Department of Natural Resources and Environmental Science, University of Nevada, Reno

Graduate Program: Natural Resources and Environmental Science

Graduation Date: August 2005

Title of Research Project: The Bioavailability of Sediment and Dissolved Organic Phosphorus Inputs to Lake Tahoe

Key Findings of Research Project: Phosphorous is generally the factor that limits the growth of phytoplankton in Lake Tahoe and suspended sediments in

tributary streams are one of the most important inputs of P. However, not all of this P may be available for algal uptake.

No more than 50% of the P in suspended sediments was available for algal growth, and the variation between streams makes it important to consider bioavailability in ranking the importance of various sources in eutrophication of Lake Tahoe.

Publications from Graduate Research:

Joseph Ferguson. 2005. The Bioavailability of Sediment and Dissolved Organic Phosphorus Inputs to Lake Tahoe. Masters Thesis. University of Nevada, Reno, NV, August, 2005.

 

Student Name: Nicole Gergans

Major Professor and Institutional Affiliation: Dr. Wally Miller, Department of Natural Resources and

Environmental Science, University of Nevada, Reno

Graduate Program: Natural Resources and Environmental Science

Graduation Date: December 2008

Title of Research Project: Effects of a Sierran Stream Environment Zone and an Unpaved Road on Runoff Water Quality

Key Findings of Research Project: Sierran stream environment zones are ineffective at intercepting inorganic nutrients from upland overland flow. Value of Graduate Degree in Career Development: As an Environmental Program Advocate, I use the knowledge I gained through my graduate education to influence policy decisions in the Tahoe Basin relating to sediment and nutrient loading.

Publications from Graduate Research:

Effects of a Sierran Stream Environment Zone and an Unpaved Road on Runoff Water Quality (Thesis) Runoff Water Quality from a Sierran Upland Forest, Transition Ecotone, and Stream Environment Zone (JEQ, submitted June 2008)

 

Student Name: Kim Gorman

Major Professor and Institutional Affiliation: Dr. Wally Miller, Department of Natural Resources and Environmental Science, University of Nevada, Reno

Graduate Program: Environmental and Natural Resource Science

Graduation Date: December 2003

Title of Research Project: The Isolation of Dissolved Organic Phosphorus in Aqueous Solutions of Lake Water, Soil Leachate, and Plant Extracts

Key Findings of Research Project: With regards to algal growth Lake Tahoe is primarily Phosphorus (P) limited. Extensive bioassays performed by UC Davis indicate that the dissolved P fraction is what algae utilize as a primary food source. The inorganic dissolved P (PO4) is believed to account for between 75-90% of bioavailable P. My research was to extract the dissolved organic P (DOP) fraction from aqueous solutions and then perform bioassays to determine the bioavailability of DOP. The methods used were not completely successful in isolating the DOP fraction; however we did observe that the DOP fraction behaved chemically – very similar to the inorganic PO4 fraction – suggesting it too is bioavailable to some degree.

Publications from Graduate Research: The Isolation of Dissolved Organic Phosphorus in Aqueous Solutions of Lake Water, Soil Leachate, and Plant Extracts

 

Student Name: Elizabeth Harrison

Major Professor and Institutional Affiliation: Dr. Dale Johnson, Department of Natural Resources and Environmental Science, University of Nevada, Reno

Graduate Program: Natural Resources and Environmental Science

Graduation Date: May 2007

Title of Research Project: An Analysis of Lake Tahoe Nutrient Budgets (Professional Paper)

Key Findings of Research Project: This project was initiated to determine whether updates to the nutrient budgets published in the 2000 Lake Tahoe Watershed Assessment (LTWA) (Reuter and Miller, 2000) were warranted based on the significant amount of research conducted in the Tahoe Basin since its publishing. Three sources of nutrient contributions were evaluated; atmospheric deposition, upland sources and groundwater loading. Due to the large variability in reported data and in some cases large data gaps, it was deemed appropriate to utilize averages of nutrient source categories calculated in this project to compare to estimates reported in the LTWA. The estimate of total N (TN) reported in this study was 80 MT yr-1 higher than the estimate reported in LTWA, while estimates of total phosphorus were quite similar. This project revealed that significant gaps in data still exist for calculations of N and P in atmospheric deposition and groundwater loading to Lake Tahoe. It was intended that the budget developed as part of this project be used as a tool for identifying data gaps and informational needs that should be the focus of future research efforts.

 

Student Name: Marcy Kamerath

Major Professor and Institutional Affiliation: Dr. Sudeep Chandra, Department of Natural Resources and

Environmental Science, University of Nevada, Reno

Graduate Program: Natural Resources and Environmental Science

Graduation Date: December 2008

Title of Research Project: Distribution, Impacts, and Bioenergetics modeling of warm water nonnative fish

Key Findings of Research Project: Warmwater nonnative fish are prevalent in Lake Tahoe at 58% of survey locations. Warmwater nonnative fish are predating and competing with the last remaining native forage fishes of Lake Tahoe which could further alter Lake Tahoe’s food web.

Publications from Graduate Research:

Kamerath, M., S. Chandra, and B.C. Allen. 2008. Distribution and impacts of warm water invasive fish in Lake Tahoe, USA. Aquatic Invasions 3: 35-41.

 

Student Name: Scott A. Burcar

Major Professor and Institutional Affiliation: Dr. Wally Miller, Department of Natural Resources and Environmental Science, University of Nevada, Reno

Graduation Date: December 1992

Graduate Program: Natural Resources and Environmental Science

Title of Research Project: Seasonal preferential flow and nutrient transport in selected Sierra Nevada soils

Key Findings of Research Project:

Preferential flow does occur in the soils studied, however,

the applied nutrients (ammonium and nitrate) do not pass

through these preferential paths unabsorbed.

Publications from Graduate Research:

Thesis: Burcar, Scott Anthony, Seasonal preferential flow

and nutrient transport in selected Sierra Nevada soils.

University of Nevada, Reno, 1992.

S. Burcar, W. W. Miller, D. W. Johnson, and S. W. Tyler. Seasonal Preferential Flow in Two Sierra Nevada Soils under Forested and Meadow Cover. Soil Sci Soc Am J 1994 58: 1555-1561.

S. Burcar, W. W. Miller, S. W. Tyler, and R. R. Blank. Moist- and Dry-Season Nitrogen Transport in Sierra Nevada Soils. Soil Sci Soc Am J 1997 61: 1774-1780.

 

Student Name: Dave Rios

Major Professor and Institutional Affiliation: Dr. Sudeep Chandra, Department of Natural Resources and Environmental Science, University of Nevada, Reno

Graduate Program: Natural Resources and Environmental Science

Graduation Date: Spring 2009

Title of Research Project: Vegetation communities in natural and constructed wetlands in the Lake Tahoe Basin. Pre-restoration hydrologic conditions in a small urban watershed in Lake Tahoe.