2015 Progress Report: Role of land use and BMPs in reducing the effect of extreme magnitude events on sediment and pollutant transport in the SE US Coastal Plain and Mississippi Alluvial ValleyEPA Grant Number: R835186
Title: Role of land use and BMPs in reducing the effect of extreme magnitude events on sediment and pollutant transport in the SE US Coastal Plain and Mississippi Alluvial Valley
Investigators: Hatten, Jeffery A
Institution: Oregon State University
EPA Project Officer: Hiscock, Michael
Project Period: April 1, 2012 through March 31, 2017
Project Period Covered by this Report: April 1, 2015 through March 31,2016
Project Amount: $363,258
RFA: Extreme Event Impacts on Air Quality and Water Quality with a Changing Global Climate (2011) RFA Text | Recipients Lists
Research Category: Global Climate Change , Air Quality and Air Toxics , Water and Watersheds , Climate Change , Air , Water
The overall objective of this research is to determine the role of best management practices (BMPs) and land use decisions in affecting water quality in the face of extreme events and climate change. Two objectives have been developed to guide this research:
Objective #1. Determine the capacity of BMPs to reduce large event caused delivery of sediment in a lake with small agricultural watershed in the Mississippi Alluvial Valley (MAV).
Objective #2. Determine the role that BMP development and landuse decisions have had on event associated sedimentation rates in a lake with a large watershed (Loon Lake in the Oregon Coast Range).
The planned objectives for this period were to focus on sample analysis (biomarker), data analysis, writeup, and application for additional funds. We have developed the analytical model that will statistically analyze sedimentation trends in the cores collected from Loon Lake (Oregon) and are currently writing up those results. We analyzed the sediment accumulation rate in the recent portion of our sediment cores (1939-2013) and found evidence that the Oregon Forest Practices Act (OFPA) was significantly (p = 0.0028) associated with lower sedimentation rates. Pre-OFPA sediment accumulation rates were 0.82 g cm-2 yr-1 and post-OFPA rates were 0.61 g cm-2 yr-1 after accounting for climate. This suggests that the BMPs instituted in OFPA were effective at reducing sediment influx from the surrounding watersheds relative to historical harvesting practices. We then compared the pre- and post-OFPA period to the pre-settlement period (550-1780AD) and found that the pre-settlement period had a lower sedimentation rate (0.41-0.46 g cm-2 yr-1). This suggests that either contemporary harvesting practices contribute additional sediment to the watershed or that sediment deposited by historical practices in proximal sources are contributing to the elevated loads. This issue will be elucidated through our analysis of stable isotopes and biomarkers.
During the next year, one student will defend her thesis this December (2016) examining the sedimentation rates pre-settlement, pre-OFPA, and post-OFPA and in event layers in the sediment cores of Loon Lake. Furthermore, we will begin to analyze the isotope and biomarker data to elucidate the sediment source within Loon Lake. We also will begin data analysis of sedimentation rates in relation to BMP implementation in the Beasley Lake watershed and examine the source of sediment using elemental and stable isotopic composition of sediment within the core.