WWETAC Projects

Project Title: ICWater sediment transport module

Principal Investigator: Douglas F. Ryan,  USDA Forest Service, Pacific Northwest Research Station

dryan01[at]fs.fed.us
                                               
Collaborators and Affiliations: William B. Samuels, SAIC Corp.; William J. Elliot, USDA Forest Service, Rocky Mountain Research Station (RMRS); Deborah Martin, USGS, Boulder; Kevin Hyde, RMRS

Key Issues/Problems Addressed:

Wildland fire can threaten public drinking water and critical aquatic habitat by introducing high levels of contaminants into surface water. This study examined whether three models could be linked to predict what could not be predicted before.  Incident Command Tool for Protecting Drinking Water (ICWater) is a tool used to help incident responders assess risk of waterborne contaminants to drinking water. This project investigated the feasibility of linking a sediment fate and transport model and a model of post-fire soil erosion to ICWater to make predictions of impacts to water quality related to hydrology, soil erosion and sediment delivery generated by wildfire.

Setting and Approach:

After a literature review of sediment fate and transport models, the Contaminant Transport and Fate Model for Streams (CMS), developed by the US Army Corps of Engineers, was recommended for integration into ICWater. The data fields which are common to both ICWater and CMS (stream reach length, width, depth, cross section area, and flow rate) create the linkage between the two models. A proof-of-concept study investigated whether the Water Erosion Prediction Project (WEPP) soil-erosion model and the CMS model could be compatibly linked to ICWater for use forecasting of suspended sediment concentrations in streams draining watersheds after severe wildland fires.

Key Findings:

  • Transport models of sediment and contaminants differ in the way they handle space and time dimensions, as well as how they model the fate and transport processes.
  • ICWater can be compatibly linked with the WEPP post-fire surface erosion model and the CMS sediment fate and transport model for use forecasting suspended sediment impacts on water quality in streams following wildland fires.

Impacts/Applications:
Integrating CMS and WEPP with ICWater develops the capability for ICWater to simulate the transport of suspended sediments, a major category of post-fire water contamination. ICWater is available online at http://eh2o.saic.com/SectionProjects/Transport/Surface/ICWater/ICWater.aspx

Report

SAIC, 2009. Sediment Transport, Toxic Fate, and Forest Fires: US Forest Service Requirements for ICWater Application to Wildland Fire. Unpublished Report of TSWG Task PS-IP-121I, to Contract W91CRB-08-C-0038. (unpublished report on file with WWETAC)

WWETAC Project ID:  FY08JB50

Figure 1: Wildland fire threats to water supply values-at-risk.

 

Figure 2: Wildland fire threats to critical aquatic habitat as a value-at-risk.

 

Figure 3. Schematic of the proposed tool for predicting impacts of wildland fire on public drinking water and fish for emergency decision makers in government agencies and utilities.  This project addresses transport of suspended sediment from burned landscapes to drinking water and fish downstream (pathway shaded in yellow).  Specifically it develops the capability for ICWater to simulate the transport of suspended sediments, a major category of post-fire water contamination.