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1999 Progress Report: Stress of Increased Sediment Loading on Lake and Stream Function
EPA Grant Number: R825433C028Subproject: this is subproject number 028 , established and managed by the Center Director under grant R825433
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: EERC - Center for Ecological Health Research (Cal Davis)
Center Director: Rolston, Dennis E.
Title: Stress of Increased Sediment Loading on Lake and Stream Function
Investigators: Goldman, Charles R. , Reuter, John E.
Current Investigators: Goldman, Charles R. , Hatch, Lorin , Reuter, John E. , Stubblefield, Andrew P.
Institution: University of California - Davis
EPA Project Officer: Levinson, Barbara
Project Period: October 1, 1996 through September 30, 2000
Project Period Covered by this Report: October 1, 1998 through September 30, 1999
RFA: Exploratory Environmental Research Centers (1992)
Research Category: Center for Ecological Health Research , Targeted Research
Description:
Objective:To investigate suspended sediment loading from individual watersheds within the Lake Tahoe Basin.
Progress Summary:At Lake Tahoe, adaptive watershed management is replacing management based solely on regulation. By themselves, water quality standards and thresholds are not adequate to assess lake and watershed management alternatives. At Lake Tahoe we need to know (1) what are the sources and relative contribution of sediment and nutrients to the lake, (2) how much of a reduction in loading is necessary to achieve the desired water quality, and (3) how will this reduction be achieved? The answers to these and other questions must be evaluated within a dynamic framework based on scientific knowledge.
Mr. Andrew Stubblefield is the graduate student currently working on this project. During the water year 1999, his research focused on synoptic sampling of Ward Creek. The goals of the project were to (1) quantify sediment loading coming from small tributaries, channel bank erosion, and a steep denuded region referred to on USFS maps as "the Ward Badlands", (2) collect field data for the watershed hydrological model of Levant Kavvas' group, and (3) evaluate the use of turbidity and turbidometers as proxies for phosphorus and suspended sediment.
Weekly sampling trips during the snowmelt season and during storm events were augmented by continuous turbidity readings. Four infrared backscatter turbidometers were installed in the Ward Creek drainage. The instream turbidometers provided continuous readings to Campbell Scientific dataloggers. The turbidometer readings complemented the sampling trips in the following ways. The continuous record provided a background and context for the weekly sampling. Ecosystems with snowmelt-driven hydrology have huge seasonal, weekly and daily variation in water discharge and sediment and nutrient loading. Without a continuous record, it is not possible to be assured that the events sampled on a weekly basis are representative of the actual conditions prevailing during the rest of the week. The additional function of the turbidometer is to characterize temporal variation. The synoptic sampling is supposed to represent a snapshot of conditions at seven locations on Ward Creek. However, in snowy conditions it can take several hours to sample all of the locations. The turbidometer serves as assurance that the differences between locations are due to differences in sediment loading between the locations, not due to differences in the time of day that the samples were gathered.
During each sampling trip the turbidometers were cleaned and the data downloaded into a laptop computer. At each of the four turbidometer locations and three additional ones stream water was collected for total phosphorus, soluble reactive phosphorus, turbidity (lab measurement), and total suspended sediment. The stream discharge was determined with a flow meter at each location, except for the three locations that have continuous USGS stream gages.
A series of regressions were calculated to determine the relationships between the measured parameters and to calibrate the instream turbidity readings. Instantaneous loads were calculated by multiplying concentration times discharge. Yearly loads will be calculated with the help of the turbidometer record. Excellent correlations were found between turbidity and total suspended sediment (r2= 0.95). The correlations with turbidity were good for total phosphorus (r2= 0.69). and poor for soluble reactive phosphorus (r2= 0.10).
The average of the synoptic sample turbidity measurements was calculated for each location. The mouth was 8.5 normalized turbidity units (NTU). The mid and confluence stations were 7.1 and 7.2 NTU respectively. The South Fork and North Fork were 5.8 and 3.2 NTU respectively and the two measured tributaries were 4 NTU for the upper and 1 NTU for the lower. The South Fork is the location of the badlands. The lower tributary is a smaller watershed and has significant wetland areas. It is likely that the reduced turbidity is from sediment trapping characteristics of the wetland areas. The turbidity did not seem to increase with distance downstream, although the discharge increased. Instantaneous loading calculations provide a better view of this relationship. The average instantaneous load for the mouth was 135 gm/s. For the mid and confluence stations it was 122 and 60 gm/s respectively. The South and North Forks were 40 and 17 gm/s respectively and the tributaries were less than 4 gm/s. Thus the tributaries do not appear to have a significant fraction of the total loading. However since they are not gauged, further monitoring will increase our confidence in this finding. The effect of the badlands is apparent in the higher loading from the South Fork.
Sampling or installation of a turbidometer further into the South Fork, closer to the badland region will focus on this effect. When instantaneous loading is calculated the channel appears to be gaining sediment with downstream distance. Interestingly, when the loading calculations are viewed by discrete events a pattern emerges. During low and medium loading events (below 120 gm/s) the loading decreases with downstream direction. The lower reaches act as sediment sinks. However during large loading events (above 120 gm/s) the lower reaches act as source areas, increasing the sediment load. At this point it is unclear whether this loading is coming from channel bank erosion or instream storage of sediment.
Future Activities:Future work will take the next step in narrowing in on sediment sources in Ward Creek. Storm and snowmelt sampling will continue. Laser particle size analysis will be performed on all sample collections. This information will improve our understanding of the correlation between turbidity and total suspended solids (TSS) and nutrients. It will also help pinpoint crucial events and sources for the delivery of fine, less than 10 micron sediment. This coming year a network of erosion pins, cross-sections and sampling of instream storage will elucidate the question of whether channel bank erosion or instream storage is the source of sediment loading from lower reaches. In addition, nutrient and particle size analysis of sediment taken from the badlands region, channel bank materials and forest soils will add another line of evidence to the analysis. A fifth turbidity sensor will be installed further upstream in the South Fork in order to more precisely quantify the contribution of the badlands region. For the water year 2000, the storm and snowmelt sampling will include samples of overland flow and subsurface collected in conjunction with Dr. Levant Kavvas' hydrological monitoring station in Ward Canyon.
Other projects include the channel bank erosion budget and the Lake Tahoe Interagency Monitoring Program (LTIMP) database analysis. Mr. Stubblefield will continue analysis of aerial photographs and surveyed river cross sections in Blackwood Canyon, General Creek and the Upper Truckee River for the purpose of estimating the total suspended sediment loading from channel bank erosion for these watersheds. An event by event analysis of the LTIMP database for Ward Creek will correlate river stage and discharge, precipitation, snowpack with TSS and nutrient loading. The analysis will shed light on the types of events producing the bulk of fine sediment and nutrient loading and give insights into the mechanism and source regions.
Supplemental Keywords:Ecosystem Protection/Environmental Exposure & Risk, Water, INTERNATIONAL COOPERATION, Scientific Discipline, RFA, ECOSYSTEMS, Water & Watershed, Restoration, Aquatic Ecosystem Restoration, Aquatic Ecosystems & Estuarine Research, Terrestrial Ecosystems, Aquatic Ecosystem, Biochemistry, Environmental Microbiology, Fate & Transport, Watersheds, Monitoring/Modeling, Ecology and Ecosystems, ecological impact, fate and transport, watershed management, watershed restoration, ecological research, ecology assessment models, aquatic habitat protection , stream function, land use, wetland restoration, aquatic ecosystems, environmental stress, sediment transport, watershed sustainablility, hydrology, Sierra Nevada, watershed influences, restoration strategies, ecosystem stress, integrated watershed model
Progress and Final Reports:
Original Abstract
Final Report
Main Center Abstract and Reports:
R825433 EERC - Center for Ecological Health Research (Cal Davis)
Subprojects under this Center:
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R825433C001 Potential for Long-Term Degradation of Wetland Water Quality Due to Natural Discharge of Polluted Groundwater
R825433C002 Sacramento River Watershed
R825433C003 Endocrine Disruption in Fish and Birds
R825433C004 Biomarkers of Exposure and Deleterious Effect: A Laboratory and Field Investigation
R825433C005 Fish Developmental Toxicity/Recruitment
R825433C006 Resolving Multiple Stressors by Biochemical Indicator Patterns and their Linkages to Adverse Effects on Benthic Invertebrate Patterns
R825433C007 Environmental Chemistry of Bioavailability in Sediments and Water Column
R825433C008 Reproduction of Birds and mammals in a terrestrial-aquatic interface
R825433C009 Modeling Ecosystems Under Combined Stress
R825433C010 Mercury Uptake by Fish
R825433C011 Clear Lake Watershed
R825433C012 The Role of Fishes as Transporters of Mercury
R825433C013 Wetlands Restoration
R825433C014 Wildlife Bioaccumulation and Effects
R825433C015 Microbiology of Mercury Methylation in Sediments
R825433C016 Hg and Fe Biogeochemistry
R825433C017 Water Motions and Material Transport
R825433C018 Economic Impacts of Multiple Stresses
R825433C019 The History of Anthropogenic Effects
R825433C020 Wetland Restoration
R825433C021 Sierra Nevada Watershed Project
R825433C022 Regional Transport of Air Pollutants and Exposure of Sierra Nevada Forests to Ozone
R825433C023 Biomarkers of Ozone Damage to Sierra Nevada Vegetation
R825433C024 Effects of Air Pollution on Water Quality: Emission of MTBE and Other Pollutants From Motorized Watercraft
R825433C025 Regional Movement of Toxics
R825433C026 Effect of Photochemical Reactions in Fog Drops and Aerosol Particles on the Fate of Atmospheric Chemicals in the Central Valley
R825433C027 Source Load Modeling for Sediment in Mountainous Watersheds
R825433C028 Stress of Increased Sediment Loading on Lake and Stream Function
R825433C029 Watershed Response to Natural and Anthropogenic Stress: Lake Tahoe Nutrient Budget
R825433C030 Mercury Distribution and Cycling in Sierra Nevada Waterbodies
R825433C031 Pre-contact Forest Structure
R825433C032 Identification and distribution of pest complexes in relation to late seral/old growth forest structure in the Lake Tahoe watershed
R825433C033 Subalpine Marsh Plant Communities as Early Indicators of Ecosystem Stress
R825433C034 Regional Hydrogeology and Contaminant Transport in a Sierra Nevada Ecosystem
R825433C035 Border Rivers Watershed
R825433C036 Toxicity Studies
R825433C037 Watershed Assessment
R825433C038 Microbiological Processes in Sediments
R825433C039 Analytical and Biomarkers Core
R825433C040 Organic Analysis
R825433C041 Inorganic Analysis
R825433C042 Immunoassay and Serum Markers
R825433C043 Sensitive Biomarkers to Detect Biochemical Changes Indicating Multiple Stresses Including Chemically Induced Stresses
R825433C044 Molecular, Cellular and Animal Biomarkers of Exposure and Effect
R825433C045 Microbial Community Assays
R825433C046 Cumulative and Integrative Biochemical Indicators
R825433C047 Mercury and Iron Biogeochemistry
R825433C048 Transport and Fate Core
R825433C049 Role of Hydrogeologic Processes in Alpine Ecosystem Health
R825433C050 Regional Hydrologic Modeling With Emphasis on Watershed-Scale Environmental Stresses
R825433C051 Development of Pollutant Fate and Transport Models for Use in Terrestrial Ecosystem Exposure Assessment
R825433C052 Pesticide Transport in Subsurface and Surface Water Systems
R825433C053 Currents in Clear Lake
R825433C054 Data Integration and Decision Support Core
R825433C055 Spatial Patterns and Biodiversity
R825433C056 Modeling Transport in Aquatic Systems
R825433C057 Spatial and Temporal Trends in Water Quality
R825433C058 Time Series Analysis and Modeling Ecological Risk
R825433C059 WWW/Outreach
R825433C060 Economic Effects of Multiple Stresses
R825433C061 Effects of Nutrients on Algal Growth
R825433C062 Nutrient Loading
R825433C063 Subalpine Wetlands as Early Indicators of Ecosystem Stress
R825433C064 Chlorinated Hydrocarbons
R825433C065 Sierra Ozone Studies
R825433C066 Assessment of Multiple Stresses on Soil Microbial Communities
R825433C067 Terrestrial - Agriculture
R825433C069 Molecular Epidemiology Core
R825433C070 Serum Markers of Environmental Stress
R825433C071 Development of Sensitive Biomarkers Based on Chemically Induced Changes in Expressions of Oncogenes
R825433C072 Molecular Monitoring of Microbial Populations
R825433C073 Aquatic - Rivers and Estuaries
R825433C074 Border Rivers - Toxicity Studies