Grantee Research Project Results
2006 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, 2005 through August 31, 2006
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 1 of the project, we have collected significant data from our field site, including historical water quality data, high-resolution imagery, and topography data, and conducted extensive water quality sampling throughout the West Fork Watershed. We completed three synoptic sampling events in September 2005, February 2006, and June 2006. At each synoptic event, streamwater samples were collected from 54 sites in the West Fork Watershed (Figure 1). In addition, water samples have been collected on a weekly basis since November 2004 at seven sites within the West Fork Watershed and two sites on the Gallatin River. Sites were chosen to capture differing upslope land use and watershed characteristics and also to continue collection at sites with a historical record. We are in the process of analyzing all of the water quality samples for nitrate, nitrite, ammonium, and dissolved organic nitrogen. A portion of the synoptic water quality samples were sent to a laboratory for isotopic analysis to ascertain sources of streamwater nitrogen. The results of the isotopic analysis will aid in validating the nitrogen export model. In addition to the grab samples, stream flow, elemental carbon, and temperature were measured at each site. We installed four aquarods, one in the mainstem West Fork, and one in each of its three main tributaries. The aquarods continuously record stream stage. Stage-discharge curves will be calibrated and used to estimate flows during all water quality sampling events.
Figure 1. Streamwater Nitrate Concentrations (ppm) in the West Fork Watershed, September 2005.
High resolution satellite imagery and topography data were collected in the fall of 2005. We have just received the orthorectified QuickBird imagery and have recruited a quality graduate student, Natalie Campos, to focus on the remote sensing analysis of LULC change within the West Fork Watershed. She will put together a timeline of LULC change using the 2005 QuickBird and Landsat imagery dating back to before resort development. We have received the high-resolution Airborne Laser Swath Mapping topography data and will soon begin to use these data to delineate watershed flowpaths and travel times, which we believe will be a principal control in the timing and amount of nitrogen exported from the West Fork Watershed. Once we have analyzed and delineated land use and watershed characteristics, we will begin to calibrate our Nitrogen Export Model. We have recently hired a Master’s student, Becca McNamara, to concentrate on instream nitrogen processing, which will be a critical component of the Nitrogen Export model. We have installed a custom-built Campbell Scientific weather station in the West Fork Watershed in July 2006 to measure precipitation, temperature, relative humidity, wind direction and speed, soil moisture, and solar radiation. Weather data will be critical in modeling streamflow. Once calibrated, we expect the Nitrogen Export Model to identify LULC thresholds governing nitrogen export in developing mountain watersheds. We will improve methods to quantify impacts of LULC change on water quality by accounting for topographical characteristics and spatial distribution of LULC. Moreover, we will provide a tool and methodology for land managers to detect nitrogen thresholds in mountainous watersheds and predict streamwater nitrate export risk to help guide low-impact development and minimize water quality degradation of our nation’s headwaters.
Future Activities:
We will continue to collect water quality samples and stream flow measurements. Using QuickBird and Landsat imagery, we will create a timeline of LULC from starting before resort development in the West Fork Watershed to present day. Once we have the water quality data, LULC timeline, and watershed characteristics, we will begin to model the relationship between LULC, watershed characteristics, and streamwater nitrogen. The three purposes of the validated model are to: (1) construct a complete time series of streamwater nitrogen export by applying the relationships found between LULC, watershed characteristics, and streamwater nitrogen export; (2) determine whether resiliency for nitrogen absorption has been surpassed and a nitrogen threshold has been crossed within the West Fork Watershed; and (3) determine the spatial and temporal dynamics of LULC that drove the ecosystem to cross a nitrogen threshold.
Journal Articles:
No journal articles submitted with this report: View all 25 publications for this projectSupplemental 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,, RFA, Scientific Discipline, Ecosystem Protection/Environmental Exposure & Risk, Aquatic Ecosystems & Estuarine Research, Aquatic Ecosystem, Environmental Monitoring, Ecological Risk Assessment, Ecology and Ecosystems, 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:
http://landresources.montana.edu/watershed/ Exit
Progress 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.