Sediment Budget and Sediment Source Apportionment Study for Plum Creek

Purpose

Plum Creek is part of the Total maximum Daily Load (TMDL) and watershed management plan for total phosphorus (TP) and total suspended solids (TSS) in the Lower Fox River basin. The Lower Fox River Green Bay AOC has proposed BUI targets for eutrophication and undesirable algae based on achieving the load reductions identified in the TMDL for 7 subbasins, including Plum Creek. Based on SWAT model output, agricultural land in Plum Creek is estimated to contribute 94 to 95 percent of annual loading of TP and TSS, respectively. However, recent stream inventories of Plum Creek by Outagamie County indicate that 24 of the 43 miles inventoried had actively eroding banks. Preliminary estimates are that these banks could be contributing 45 percent of the TSS annual loading measure at the USGS gauge. If stream processes are producing almost half of the annual loading of TSS, the proposed TMDL goal to reduce TSS by 70 percent will not be achievable through upland soil conservation practices alone.

Objective

One of the first steps in the sediment TMDL process along with identifying targets is to identify the major sources of sediment. A stream corridor-based sediment budget and source apportionment study is needed to quantify the proportion of the TP and TSS loading originating from in-stream sources of bank and channel erosion compared to soil erosion. Gullying associated with headward extension of stream networks also needs to be quantified as a possible TP and TSS source. This proposal describes a combined sediment budget/fingerprinting approach that will help identify the proportion of annual loading of TP and TSS originating from stream corridor sources. The results from this study will be compared to expected field contributions based on RUSKE2 calculations and measured TP and TSS loading from the USGS water quality monitoring stations. The source assessment results can be used in all subsequent steps of the TMDL process, including monitoring and targeted implementation of the plan.

Outcome

Products from this study will include GIS maps and spreadsheets of stream corridor sources and sinks of sediment and TP. A presentation will be given and made available to project partners and local watershed groups. A journal article will be published with the results, with submittal to a journal (to be selected with input from partners) at the end of year 2.

Study Design

This study will build off of previous stream corridor inventories of sediment sources conducted by Outagamie County and additional sampling activities by others that are being conducted in the Plum Creek watershed. This study will take two years to complete, the first year for writing a QAPP, compilation of existing data, watershed reconnaissance of geomorphic setting, and collection of field data. The second year is needed for laboratory analyses, data workup, and publishing results. As part of the sediment budget approach, the USGS will conduct an inventory of sediment sources and sinks using a river walk approach aerial photo analyses.

Related Reports

Run Project Summary Report
View Umbrella-Projects
View Related-Projects

Great Lakes Restoration Initiative
Toxics and Areas of Concern
GBF1603_PlumCreek
2016
Active
 
Reports and Documents
Publication of findings from Sediment Fingerprinting on Plum Creek
Presentation at SEDHYD Conference on the Source Apportionment in Plum Creek
Proceedings Paper - Stream Corridor Sources of Suspended Sediment and Phosphorus from an Agricultural Tributary to the Great Lakes
USGS' quarterly report for 2018 Q2 for the Sediment Budget and Sediment Source Apportionment Study for Plum Creek.
Presentation of draft results of sediment fingerprinting
USGS' quarterly report for 2018Q1 for the Sediment Budget and Sediment Source Apportionment Study for Plum Creek.
USGS report of project activities to date
Official EPA approval of QAPP
Project Plan with DNR approvals
Statement of work for Plum Creek project.
Final Scope of Work for USGS for the Sediment Source Apportionment Study for Plum Creek in the Lower Green Bay Fox River Area of Concern (AOC).