Big Green Lake TWA WQM Plan 2017

Purpose

This study monitored the water quality of the Big Green Lake Watershed. This Targeted Watershed Assessment (TWA) involved collection of a baseline water quality assessment in the watersheds on the south side of Big Green Lake and Silver Creek, including total phosphorus (TP), habitat, fish, and aquatic macro invertebrates. Monitoring the Big Green Lake watershed will be used for comparison of future monitoring after watershed enhancements have been made to improve water quality in Silver Creek and reduce the nutrient and suspended solids load into Big Green Lake. Considerable creek restoration and watershed best management practice work was conducted and is projected for the future by multiple agencies, including Green Lake County Land Conservation Department (Green Lake County LCD) and Natural Resource Conservation Service (NRCS).

Objective

A secondary goal of this project was to determine Wisconsin Administrative Code ch. NR 102 (NR 102) phosphorus and temperature water quality criteria exceedances and degraded biological community and habitat impairments for USEPA Clean Water Act Section 303d (CWA 303d) listing purposes for the creeks in this watershed. In 2011, an assessment was conducted by DNR Water Resources staff on creeks that discharge into Big Green Lake (Johnson et. al. 2011). Three of the creeks (Roy Creek, Hill Creek, and Wuerches Creek) in that assessment are in the HUC 12 watershed on the south side of Big Green Lake. Overall, the monitoring conducted in 2014 filled in data gaps from the 2011 assessment.

Outcome

There are many options available to reduce the pollutants, phosphorus and sediment in Silver Creek and the Unnamed Tributaries. One option to reduce the sediment and nutrients is to conduct streambank restoration on eroding banks (Appendix C). Another option to reduce the cropland runoff is to increase flood storage capacity in the watersheds. Creating sedimentation ponds which capture runoff from cropland/uplands will provide flood storage, reduce sediment and nutrients reaching the creeks, and reduce high creek flow velocities which cause erosion. A third option to reduce nutrient and sediment loading while creating fish and aquatic life habitat is to re-meander channelized ditches which contain large amounts of organic material. Perched culverts and the Gothic Millpond Dam are partial or complete barriers to fish migration. Fish barriers, whether complete or partial, can limit the biotic integrity of a watershed. Replacing perched culverts with properly sized and designed culverts increases the available fish and aquatic life habitat and limits any risk to fish migration.Adding a fish passage component to the Gothic Millpond Dam would encourage fish migration by fish species such as brown trout and northern pike to spawning habitat upstream of the millpond. Increasing vegetative and forested buffer widths along the creeks in the Silver Creek Watershed can also have a positive impact on the sediment and nutrient load reaching the creeks. Recommended buffer widths vary significantly in published research (there is no one-size-fits all), but the majority of research recommends vegetative buffers >35’, with 35’ being on the lower end of recommended buffer widths. In general, as the land slope along a creek increases, the riparian buffer width recommendation increases. The type of vegetative buffer is also critical to reducing sediment and nutrients reaching the creeks of this project. A combination of forest and native grass buffers may result in greater nutrient reduction than strictly grassed buffers.

Study Design

Methods, Equipment and Quality Assurance: Collection of TP, habitat, fish, continuous temperature, and aquatic macroinvertebrates used standard DNR data collection methods and samples were sent to certified laboratories in the state. No specific in-field duplicates, replicates or blanks were collected for the study; however quality assurance sampling procedures were used in the collection and preservation of samples for all parameters.

QA Measures

Run Project Summary Report

Targeted Watershed Approach
Evaluation (TP SSC, Stressor, Bioassess)
East_TWA_1_2014
2014
Complete
 
Reports and Documents
Big Green Lake TWA WQM PLAN 2017
2011 Field Season
2013 NWQI Watershed Selection
Big Green Lake TWA WQM Plan 2017 [UF07] Presentation
An Example of Streambank Restoration on Roy Creek near County O (Green Lake LCD) 2014 (148200)
An Example of Unstable Banks on Roy Creek near County O (Green Lake LCD) (148200) 2017 photo
This Targeted Watershed Assessment (TWA) will address needs for baseline water quality monitoring of the watershed on the south side of Big Green Lake. This watershed discharges between 15-30% of the Total Phosphorus load into Big Green Lake. Considerable stream restoration and watershed BMP work has been done and is projected for the future by multiple agencies, including Green Lake County LWCD and NRCS.
This Targeted Watershed Assessment (TWA) will address needs for baseline water quality monitoring of the watershed on the south side of Big Green Lake. This watershed discharges between 15-30% of the Total Phosphorus load into Big Green Lake. Considerable stream restoration and watershed BMP work has been done and is projected for the future by multiple agencies, including Green Lake County LWCD and NRCS.
 
Activities & Recommendations
Monitor with Baseline Survey
This Targeted Watershed Assessment will address needs for baseline water quality monitoring of the HUC 12 watershed on the south side of Big Green Lake.
Water Quality Planning
Watershed based assessment and planning
Monitor Targeted Watershed Area (TWA)
Big Green Lake TWA 2014
 
Waters