Optical in-situ sensors capture dissolved organic carbon (DOC) dynamics after prescribed fire in high-DOC forest watersheds


Olivares C. I. , Zhang W., Uzun H. , Erdem C. U. , Majidzadeh H., Trettin C., ...More

INTERNATIONAL JOURNAL OF WILDLAND FIRE, vol.28, no.10, pp.761-768, 2019 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 28 Issue: 10
  • Publication Date: 2019
  • Doi Number: 10.1071/wf18175
  • Title of Journal : INTERNATIONAL JOURNAL OF WILDLAND FIRE
  • Page Numbers: pp.761-768
  • Keywords: first-order watershed, forest management, prescribed burn, Santee Experimental Forest, South Carolina, WILDFIRE, MATTER, QUALITY, CATCHMENTS, DISCHARGE, EXPORT, TIME, FLOW

Abstract

Fires alter terrestrial dissolved organic carbon (DOC) exports into water, making reliable post-fire DOC monitoring a crucial aspect of safeguarding drinking water supply. We evaluated DOC optical sensors in a pair of prescribed burned and unburned first-order watersheds at the Santee Experimental Forest, in the coastal plain forests of South Carolina, and the receiving second-order watershed during four post-fire storm DOC pulses. Median DOC concentrations were 30 and 23 mg L-1 in the burned and unburned watersheds following the first post-fire storm. Median DOC remained high during the second and third storms, but returned to pre-fire concentrations in the fourth storm. During the first three post-fire storms, sensor DOC load in the burned watershed was 1.22-fold higher than in the unburned watershed. Grab samples underestimated DOC loads compared with those calculated using the in-situ sensors, especially for the second-order watershed. After fitting sensor values with a locally weighted smoothing model, the adjusted sensor values were within 2 mg L-1 of the grab samples over the course of the study. Overall, we showed that prescribed fire can release DOC during the first few post-fire storms and that in-situ sensors have adequate sensitivity to capture storm-related DOC pulses in high-DOC forest watersheds.