Measuring the Effectiveness of Stacked Nutrient Reduction Practices

Date: 
Feb 2014

Issue

Detecting water quality improvements from best management practices (BMP) at the landscape scale has been difficult. Insufficient monitoring and the inability to link BMPs to monitored results may be to blame.

Objective

A paired watershed study design could overcome these issues. Two watersheds are monitored for a calibration period, then one serves as a control while improvements are implemented on the other.

Approach

Two sub-watersheds of Rapid Creek will be used for this research. Nutrient reduction BMPs, including cover crops, bioreactors, wetlands and filter/buffer strips will be “stacked” in one sub-watershed, with a similarly sized sub-watershed serving as the control. Sensors that continuously monitor and transmit water quality and stream-stage data will be installed and calibrated in the two sub-watersheds in fall 2014. Working with producers and landowners, stacked BMPs will be installed in 2015 in the treatment sub-watershed. Discharge and nitrate concentrations will be monitored during the calibration, treatment and post-treatment period to evaluate the effectiveness of stacking multiple BMPs to achieve water quality benefits.

Project Updates

December 2015

FINAL REPORT

The objectives of this project were to work with Johnson County Soil and Water Conservation District to establish multiple NO3-N reduction practices within a sub-watershed of Rapid Creek; deploy stream-stage sensors and NO3-N probes at the outlets of the treatment sub-watershed and a control sub-watershed; and monitor continuous discharge and stream concentrations at the outlets of the paired sub-watersheds during a three-year deployment period to measure the effectiveness of stacked nutrient reduction practices to reduce NO3-N loads at the watershed scale. Bridge (stage) sensors and water quality sensors (NO3-N and turbidity) were purchased and installed at the outlets of treatment and control subbasins in Rapid Creek watershed. Water quality data collected are displayed on the Iowa WQIS web page (http://iwqis.iowawis.org/app/). The stage and water quality monitoring data collection effort will continue in 2016 and 2017 as the data is leveraged with the Rapid Creek watershed project managed by the Johnson County Soil and Water Conservation District.

September 2015

Research funds have been used to establish sensor technology to evaluate nutrient loads in paired sub-watersheds over a three-year period. Sensors that continuously monitor and transmit water quality and stream-stage data have been installed and are being calibrated in two sub-watersheds of Rapid Creek. Stacked nutrient reduction practices will be implemented in one sub-watershed, with the other used as a control for this research. The goal is to use the sensor technology to measure the effectiveness of practices to reduce nitrate loading at the watershed level.

June 2015

Last fall, sensors that continuously monitor and transmit water quality and stream-stage data were installed and calibrated in the two sub-watersheds of Rapid Creek, then removed for the winter season. The sensors are back in place. The project team continues to work with landowners in the treatment basin to identify BMPs that would address nutrient and sediment reductions. A grass waterway on one property will be installed, and cover crops are being discussed with this landowner. Preliminary designs for a possible saturated buffer on another property are being developed. 

March 2015

Two sub-watersheds of Rapid Creek are being used for this project that focuses on detecting water quality improvements that result from the use of best management practices (BMP). Sensors that continuously monitor and transmit water quality and stream-stage data were installed and calibrated in the two sub-watersheds, then removed in November for the winter season. The sensors will be reinstalled this spring. The project team is working with six key landowners and producers in the treatment basin to identify BMPs that would address nutrient and sediment reductions to deploy on their properties in 2015.

December 2014

Detecting water quality improvements from best management practices (BMP) at the landscape scale has been difficult. Insufficient monitoring and the inability to link BMPs to monitored results may be to blame. A paired watershed study design could overcome these issues. Two sub-watersheds of Rapid Creek are under study for this project. Nutrient reduction BMPs, including cover crops, bioreactors, wetlands and filter/buffer strips will be “stacked” in one sub-watershed, with a similarly sized sub-watershed serving as the control. Sensors that continuously monitor and transmit water quality and stream-stage data have been installed and calibrated in the two sub-watersheds, and measurements are being collected.

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