Grantee Research Project Results
2018 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, 2017 through August 31,2018
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 investigates 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 are 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 minimize the impact of wildfires on water quality and treatability.
Progress Summary:
There are three major components of this project: I) Controlled Studies, II) Experimental Watershed Investigations and III) Treatability Assessment, corresponding to watershed management, landscape processes, and water quality, respectively. For the controlled studies (Objective I), we conducted two field experiments to quantify the productions and exports of dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and nutrients (e.g., nitrate and ammonia) from forest detritus layers collected from field plots under different management practices, including annual dormant season burn (i.e., burn every winter), annual growing season burn (i.e., burn every spring or summer), and periodic growing season burn (i.e., burn every other 2 to 4 years in spring or summer). These practices were implemented at the experimental plots in the Tom Yakwey Wildlife Center Heritage Preserve located at Georgetown, South Carolina in 2015 and 2016. Fuel mass per unit area in the plots were determined before and after each management practice in order to determine their consequences in changing the forest fuel loading and detritus chemistry (Experiment #1). In addition, detrital materials from different burning regimes were collected for a one-year open field incubation study (Experiment #2). Dissolved organic matter (DOM) and disinfection by-product precursors (DBPs) leached from these detritus materials were extensively characterized to determine the temporal effects on drinking water quality after wildland fire. Both experiments were completed. One manuscript is under preparation.
The Experimental Watershed Investigation (Objective II) involves watershed scale studies in Santee Experimental Watershed and Clemson Experimental Forest. In April 2016, with support from US Forest Service, 155 ha of the first-order watershed in Santee Experimental Watershed was burned using aerial ignition. The biweekly grab sampling was conducted between January-December 2016. This sampling strategy enabled us to collect samples before and after the prescribed fire applied in April 2016. Water exported from this watershed and an adjunct control watershed were closely monitored (Experiment #3) through three different water sampling techniques, including bi-weekly grab sample, flow-proportion auto-sampler, and in-situ DOC sensors (Experiment #4). The biweekly grab sampling was completed in April 2017, one-year after the burn. The flow proportion auto-sampler and in-situ sensors is continually collecting water samples and recording the data until the end of the project in 2019. In addition to chemical parameters, we also evaluated water quality using biological indicator. Stream benthic macroinvertebrate samples were collected biweekly for one year from March 2016 to March 2017 to determine if prescribed fire practices can produce significant impacts on the aquatic biota, thus indicating changes in water quality (Experiment #5). Comparing the two fuel reduction techniques (i.e., mechanical thinning and prescribed burning) is the second part of the Experimental Watershed Investigations, and this study has been conducted in Clemson Experimental Forest. A prescribed burning was conducted in April, 2018. Based on monitored water quality parameters and treatability results with samples collected from the ephemeral stream and the subsurface flow, the prescribed burning did not lead to sudden or long-lasting impacts on NOM characteristics of the studied watershed. A tray leaching study with detritus collected before and after prescribed burning and leaves and woody fuels collected from a near forest after mechanical thinning will be continued to further explore these two fuel reduction techniques side by side (Experiment #6).
The Water Quality & Treatability Assessment (Objective III) is to characterize water and dissolved organic matter (DOM) samples collected for the Objectives I and II. 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 waters. In the first year of the study, our research team conducted a laboratory study to evaluate effects of black and white ash water extractable substances on the population growth of M. aeruginosa, as well as to evaluate quantitative and qualitative alterations of subsequent DBP precursors throughout algal life. This experiment was completed, a manuscript was prepared last year, and the results were published in the Environmental Science and Technology. (Experiment #7). In addition to the prescribed fires, we also evaluated the impact of wildfires on drinking water quality and DBP precursors in this project. During the first year, water samples from Wragg and Rocky Fires (2015) in California were collected in 2016 (January-May), when the burnt area regenerated surface run-off. In the second year, water samples from Cold Fire (2016) in California were collected in 2017 (January-April) and, we continued sample collection in 2017 from Wragg and Rocky fires to evaluate the long-term effect of the wildfires. Water quality parameters and DBP precursor`s concentration levels were measured from samples (Experiment #8). To be able to examine the effect of fire on the treatability of DOM and DBP precursors, extra water samples were collected from prescribed fire (experiments #1 and 2) and wildfire (experiment #8) studies. Initially, optimum dose determination tests (based on DOC removals) were conducted for all waters with alum and ferric. Then, waters were treated with optimum doses of alum and ferric to test the removal of water quality parameters and DBP precursors (Experiment #9). Finally, we also evaluated impacts of extreme flooding events, occurred in some portion of our study area, on DBP precursor dynamics and water treatability. In October 2015, large areas of coastal South Carolina were flooded by Hurricane Joaquin. This so-called “thousand-year” rainfall mobilized and flushed large amounts of terrestrial organic matter and associated pollutants (e.g., mercury) into source water, affecting water quality and safety of municipal water supply. To understand the dynamics of water quality and water treatability during this extreme flood, water samples were collected from Waccamaw River (a typical blackwater river in the southeastern US) during rising limb, peak discharge, falling limb, and base flow. The results were published in Chemosphere as cited in published manuscripts section.
Future Activities:
We will continue our study plan as stated in the original proposal. In 2018-2019, we will conduct two fuel management practices (i.e., mechanical thinning and prescribed fire) in several 1st 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.
References:
Olivares, C.I.; Zheng, W.; Uzun, H.; Erdem, C.U.; Majidzadeh, H.; Trettin, C.; Karanfil, T.; Chow, A. High-temporal resolution optical in-situ sensors capture dissolved organic carbon (DOC) dynamics after wildland fire in blackwater forest ecosystems. Submitted to International Journal of Wildland Fire (Oct 2018).
Karanfil, K., and Chow, A.T. (2018) Workshop Session in Sustainable Forested Watersheds. South Carolina Environmental Conference (SCEC) (Myrtle Beach, SC March 2018).
- Lecture 1: Effect of wildfires on water quality and precursors of disinfection byproducts.
- Lecture 2: Understanding the impacts of wildfires on source water treatment
- Lecture 3: Fuel reduction techniques as effective forested watershed management practices against wildfire; Drinking water quality aspects.
Journal Articles:
No journal articles submitted with this report: View all 39 publications for this projectSupplemental Keywords:
disinfection byproducts, wildland fireProgress 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.