State Water Resources Research Institute Program (WRRI)

Details for Project ID 2011CO245G, 2011

Water Quality Impacts of the Mountain Pine Beetle Infestation in the Rocky Mountain West: Heavy Metals and Disinfection Byproducts

Institute: Colorado
USGS Grant Number: G11AP20213
Start Date: 2011-09-01 End Date: 2014-08-31
Total Federal Funds: $140,162 Total Non-Federal Funds: $140,259

Principal Investigators: John McCray, Reed Maxwell

Abstract: The Mountain Pine Beetle (MPB) is the primary cause of insect-induced mortality in pine forests in western North America. The MPB’s range encompasses most of western North America, from the Mexico to British Columbia, and from the Pacific Coast to South Dakota. The Rocky Mountains are the source-water region for more than 60 million people. The current epidemic is severe: lodgepole forests are expected to experience more than 90% tree mortality. Two important potential watershed impacts are changes in the hydrologic cycle and water quality. While impacts on the hydrologic cycle have recieved considerable attention; the impacts of this phenomenon on water quality are not well understood. This proposal addresses two potential MPB impacts on water quality: increased metal concentrations with ecotoxicological and human health ramifications and the potential formation of disinfection byproducts (DBPs) in downstream drinking water supplies. Dissolved organic carbon (DOC) increases in waters below impacted pines forests are expected based on fundamental biogeochemical mechanisms resulting from sources such as tree stress, litter fall, and decay. This increased DOC can result in enhanced metal transport to natural waters as well as increased potential for the formation of DBPs (e.g., trihalomethanes and nitrosamines) during disinfection of natural waters used for drinking water supplies. Municipal water suppliers are concerned about the impact of MPB infestation on drinking water quality and the potential need for costly treatment process modifications to meet public health mandates. These concerns persist over the entire Rocky Mountain West, but are currently based on anecdotal evidence that has not been sufficiently analyzed and documented using systematic and mechanistic studies. The proposed research strongly addresses the NIWR research priority regarding vulnerability and resilience assessment of public water supplies. Specifically, results from this project will enable water managers to better understand the vulnerability of their water supplies to MPB outbreaks and implement a plan to ensure current and future resilience of the water supplies. The proposed research aims to answer 3 primary questions with an integrated approach that includes synthesis and analysis of data collected by municipal water suppliers over the past fifteen years, a field investigation, and supporting laboratory experiments. These questions are as follows: (1) can DBP formation potential and metal loading be estimated based on forest, hydrologic, geographic or geologic factors that represent the watershed’s vulnerability (or resiliency) to MPB impacts; (2) will surface waters associated with MPB impacted lodgepole pines will see an increase in TOC and DBP formation potential that corresponds with the degree of infestation and tree mortality; (3) do soils associated with MPB-impacted trees have an increased potential for metal leaching and release of DOC than will soils associated with healthy lodgepole pines? This research proposal represents a strong collaboration with an existing USGS study in Rocky Mountain National Park (RMNP) related to hydrologic and water quality impacts (primarily nutrients) associated with MPB infestation. If funded, the research will provide training for a PhD graduate student, an early-career professor, 6 non-thesis MS students, and approximately 60 undergraduates. A well-rounded plan is provided for transferring results to the science community, water managers, and the public, including K-12.