Grantee Research Project Results
2008 Progress Report: Land Use Land Cover Change Governing Watershed Nitrogen Threshold And Stream Water Quality
EPA Grant Number: R832449Title: Land Use Land Cover Change Governing Watershed Nitrogen Threshold And Stream Water Quality
Investigators: McGlynn, Brian , Patten, Duncan T. , Schmitz, Denine , Shanley, James , Gardner, Kristin
Current Investigators: McGlynn, Brian , Patten, Duncan T. , Shanley, James , Gardner, Kristin , Schmitz, Denine
Institution: Montana State University
EPA Project Officer: Packard, Benjamin H
Project Period: September 1, 2005 through August 31, 2007 (Extended to August 31, 2009)
Project Period Covered by this Report: September 1, 2007 through August 31,2008
Project Amount: $293,397
RFA: Exploratory Research: Understanding Ecological Thresholds In Aquatic Systems Through Retrospective Analysis (2004) RFA Text | Recipients Lists
Research Category: Aquatic Ecosystems , Water
Objective:
The objective of this research project is to quantify the impact of recreational and exurban development on streamwater quality in a characteristic mountain west watershed. It will be the first study to integrate terrain analysis and spatial variability of land use/land cover (LULC) change to improve model quantification of past and future nitrogen thresholds and nitrogen saturation status of subwatersheds. Our study site is the Big Sky resort community in southwestern Montana, which is characteristic of early stage resort development in mountainous regions.
Progress Summary:
In Year 3, we continued to collect streamwater samples (biweekly instead of weekly) at 9 sites and streamflow measurements on the West Fork and its three main tributaries. Water quality analysis was completed for all weekly and synoptic samples for NO2-, NO3-, NH4+, and DON, major anions and cations, and DOC. All of the spatial water chemistry was put into the STORET database. Land use/ land cover delineation was completed. Seventeen nutrient addition experiments were performed to compare nutrient uptake lengths across environmental and land use gradients. Approximately, two thirds of the uptake lengths have been quantified. Preliminary results suggest that nitrogen (N) uptake lengths (amount of N removed from a system) do vary across the watersheds depending on ambient N levels, stream size and season. Nutrient diffusing substrata experiments were performed in streams draining watersheds with a range of land use and environmental gradients in October, April, and July as a secondary source of information on seasonal patterns of nutrient limitation. Preliminary results indicate a general trend in the seasonal patterns of instream nutrient limitation: P limitation in winter switching to N limitation in the summer. Weathering experiments were conducted on geologic materials represented in the West Fork watershed to compare nitrate production. Preliminary results of the weathering experiments indicate that there are significant differences between rock types in the amount of N produced. This result suggests that certain types of rocks may be a source of streamwater N and therefore, watershed geology should be considered for estimation and/or prediction of streamwater N. Geostatistical modeling of the spatial streamwater N was performed to explore seasonal influences of land use on streamwater chemistry. The results of the spatial modeling indicate that streamwater nitrate concentrations were spatially correlated for longer distances during the dormant season than during the growing season, suggesting the importance of biological processing on streamwater N concentrations. In addition, modeling results show that anthropogenic sources most influence streamwater nitrate in the dormant season, while variables describing biological processing were most influential in the growing season. These results demonstrates the importance of 1) incorporating spatial relationships into water quality modeling, and 2) investigating streamwater chemistry across seasons to gain a more complete understanding of development impacts on streamwater quality.
Future Activities:
In Year 4, we will wrap up the data analysis of the N uptake experiments to determine if there is a pattern of instream N uptake. We will then use the N uptake experiment results to build a N export model to incorporate the relationship between land use/ land cover, watershed characteristics and instream nitrogen processing to predict streamwater nitrogen. The validated model will be used to: 1) construct a complete time series of streamwater nitrogen export by applying relationships found between LULC, watershed characteristics, and streamwater nitrogen export; (2) determine whether a nitrogen threshold has been crossed within the in West Fork watershed, and 3) determine the spatial and temporal dynamics of LULC that drove the ecosystem to cross a nitrogen threshold.
Journal Articles on this Report : 1 Displayed | Download in RIS Format
Other project views: | All 25 publications | 1 publications in selected types | All 1 journal articles |
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Type | Citation | ||
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Gardner KK, McGlynn BL. Seasonality in spatial variability and influence of land use/land cover and watershed characteristics on stream water nitrate concentrations in a developing watershed in the Rocky Mountain West. Water Resources Research 2009;45:W08411. |
R832449 (2008) |
Exit Exit |
Supplemental Keywords:
watersheds, ecological effects, land use, aquatic ecosystem, indicators, hydrology, ecology, biogeochemistry, water quality monitoring, nitrogen, terrain analysis, Northern Rockies, recreation, ecosystem protection/environmental exposure and risk, scientific discipline, ecosystems, environmental monitoring, anthropogenic impact, anthropogenic stress, ecological thresholds, ecosystem indicators, ecosystem response, ecosystem stress, environmental history, estuarine research, land use, landscape change, modeling ecosystem change, nitrogen cycling, riverine ecosystems, trophic interactions, , Ecosystem Protection/Environmental Exposure & Risk, Scientific Discipline, RFA, Aquatic Ecosystems & Estuarine Research, Ecological Risk Assessment, Aquatic Ecosystem, Ecology and Ecosystems, Environmental Monitoring, water quality, ecosystem indicators, riverine ecosystems, environmental history, estuarine research, land use, anthropogenic impact, trophic interactions, nitrogen cycling, aquatic ecosystems, anthropogenic stress, ecosystem stress, ecosystem response, ecological thresholds, landscape change, RFA, Scientific Discipline, Ecosystem Protection/Environmental Exposure & Risk, Aquatic Ecosystems & Estuarine Research, Aquatic Ecosystem, Environmental Monitoring, Ecology and Ecosystems, Ecological Risk Assessment, anthropogenic stress, estuarine research, landscape change, ecological thresholds, nitrogen cycling, anthropogenic impact, ecosystem indicators, modeling ecosystem change, aquatic ecosystems, water quality, ecosystem stress, riverine ecosystems, trophic interactions, ecosystem response, environmental historyRelevant Websites:
Montana State Watershed Hydrology LabProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.