Grantee Research Project Results
2016 Progress Report: Fuel Reduction Techniques as Effective Forested Watershed Management Practices against Wildfire: Drinking Water Quality Aspects
EPA Grant Number: R835864Title: Fuel Reduction Techniques as Effective Forested Watershed Management Practices against Wildfire: Drinking Water Quality Aspects
Investigators: Karanfil, Tanju , Chow, Alex
Institution: Clemson University
EPA Project Officer: Packard, Benjamin H
Project Period: September 1, 2015 through August 31, 2018 (Extended to August 31, 2019)
Project Period Covered by this Report: September 1, 2015 through August 31,2016
Project Amount: $1,260,408
RFA: National Priorities: Systems-Based Strategies to Improve The Nation’s Ability to Plan And Respond to Water Scarcity and Drought Due to Climate Change (2014) RFA Text | Recipients Lists
Research Category: Water
Objective:
This research project will investigate the consequences of different fuel reduction techniques, as watershed management practices against wildfire, on the exports of dissolved organic matter (DOM) from forested watersheds and associated biogeochemical processes and impacts on drinking water supplies. Specifically, the temporal variations of DOM exported from watersheds under prescribed burn or mechanical thinning will be examined and compared to determine how they form regulated and emerging carbonaceous and nitrogenous disinfection byproducts (DBPs) with DOM from unmanaged watersheds. The overarching goal of this project is to identify the best forest management practices to protect our source waters due to climate change.
Progress Summary:
There are three major components in this project: (1) controlled studies, (2) experimental watershed investigations, and (3) treatability assessment, corresponding to watershed management, landscape processes, and water quality, respectively. In the controlled studies (Objective 1), we conducted two field experiments in the first year to quantify the productions and exports of dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and nutrients from forest detritus layers under different management practices, including annual dormant, annual growing, and periodic growing season prescribed burns. Experimental plots at the Tom Yakwey Wildlife Center Heritage Preserve in Georgetown, South Carolina, were implementing these practices in 2015 and 2016. Fuel mass per unit area in the plots were determined before and after each treatment to determine the consequences of management practices in changing the forest fuel loading and detritus chemistry. In addition, detritus materials were collected for a 1-year field incubation study. Chemical constituents leached from these detritus materials were fully characterized to determine the temporal effects on drinking water quality after wildland fire. Field investigations demonstrated that the fuel loading or the thickness of detritus layer in forest floor were reduced after prescribed burn treatments, but the overall chemical compositions, in terms of percentage of lignin, aromatic, polysaccharide, etc, were not different from unburned materials. Also, preliminary results of the field incubation study showed the changes of water quality parameters were only observed in the first major rainstorm event after the prescribed fire treatments. No obvious differences among treatments were observed in later rains.
The Experimental Watershed Investigation (Objective 2) involves watershed scale operations in Santee Experimental Watershed and Clemson Experimental Forest. In April 2015, with support from U.S. Forest Service, 155 ha of a first-order watershed in Santee Experimental Watershed was burned using aerial ignition. Water exported from this watershed and an adjunct control watershed were closely monitored through three different water sampling techniques, including biweekly grab sample, flow-proportion auto-sampler, and in-situ DOM sensors. The biweekly grab samples will be end in April, 2017, 1-year after the burn. The flow proportion auto-sampler and in-situ sensors will continue to collect water samples and record the data until the end of this project in 2018. In addition to chemical parameters, we also evaluate water quality using biological indicator. Sediment samples were collected every 2 weeks for 1 year to determine any changes of macroinvertebrate community due to the prescribed fire practice. Preliminary results demonstrated that burned watershed (WS77) showed lower DOC levels compared to the unmanaged watershed (WS80), supporting our hypothesis that fuel reduction practice in forested watershed can reduce DOM and DBP precursor exports to source water. Regarding the sampling techniques, continuous monitoring revealed that there were large deviations between DOC determined by grab samples compared to the total organic carbon equivalents detected by the in situ sensors. Further investigations and analyses are ongoing to confirm these findings.
Comparing the two fuel reduction techniques (i.e., mechanical thinning and prescribed burns) is the second part of the Experimental Watershed Investigations and this study will be conducted in Clemson Experimental Forest in Spring 2017. Currently, we are installing field sampling devices and collect water samples as pre-treatment and base line data.
The Water Quality & Treatability Assessment (Objective 3) is to characterize water and DOM samples collected in the Objectives 1 and 2. In addition to conventional water treatment such as coagulation and DBP formation tests, our research team conducted laboratory studies to evaluate any photochemical and microbial transformations of DOM in source water. In the first year of the study, our research team conduct a laboratory study to evaluate algal responses on thermally-altered DOM. Preliminary results show DOM and nutrients leaching from thermally altered detritus materials could support growth of algae, and exudates of algae from different growth phases can result have different DBP formation potential. Our research team will conduct photochemical transformation in the second and third year. Apart from the prescribed fire, our research team is also taking extra efforts to evaluate the impacts of wildfire on drinking water quality. Samples from 2015 Wragg and Rocky Fires in California were collected for DBP formation test. Initial results showed that turbidity, DOC, SUVA254, total dissolved nitrogen, and bromide of waters collected in the first rainstorm from the downstream of burned watershed were higher than those waters collected from non-burned watershed. Currently. we are planning another season wildfire sampling, including for the 2016 Cold fire in California and Pinnacle Mountain Fire in South Carolina to confirm the findings.
Future Activities:
We will continue our study plan as stated in the original proposal. In 2016-2017, we will conduct two fuel management practices (i.e., mechanical thinning and prescribed fire) in several first order forested watersheds in Clemson Experimental Forest. Water exported from these watersheds and an adjunct control watershed will be closely monitored and fully characterized for its treatability and DBP formation. In addition to water samples from managed watersheds, we are planning field sampling for few recent wildfire, including for the 2016 Cold fire in California and Pinnacle Mountain Fire in South Carolina.
Journal Articles:
No journal articles submitted with this report: View all 39 publications for this projectSupplemental Keywords:
Disinfection byproducts, wildland fire, watershed management, drinking water, water quality;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.