Grantee Research Project Results

Final Report: Egret - A LIDAR Sensor for Storm Water Monitoring

EPA Contract Number: 68HERC22C0007
Title: Egret - A LIDAR Sensor for Storm Water Monitoring
Investigators: Johnson, William
Small Business: Michigan Aerospace Corporation
EPA Contact: Richards, April
Phase: I
Project Period: December 1, 2021 through May 31, 2022
Project Amount: $99,992
RFA: Small Business Innovation Research (SBIR) Phase I (2022) RFA Text |  Recipients Lists
Research Category: SBIR - Water , Small Business Innovation Research (SBIR)

Description:

This Phase I SBIR aimed to deploy and evaluate the potential of the Egret sensor in a relevant environment.  The Egret, a short-range LiDAR sensor that can monitor stormwater from above the water surface, collected surface height and turbidity data autonomously under solar power on a retention pond outlet in Ann Arbor, MI.  A collection of rain events was captured over a five day period where the Egret was able to demonstrate measurements of high resolution surface height measurements as well as turbidity measurements from above the water surface.  Turbidity data was collected when practical simultaneously with a commercial turbidity sensor (YSI Exo 1 Sonde).  Excellent agreement was found between the commercial submerged sensor and the Egret.

Summary/Accomplishments (Outputs/Outcomes):

It was found the Egret can measure surface heights with a resolution of 0.1 inches and agrees well with commercial turbidity sensors.  During weeks of field testing, a five day period that included two rain events was recorded with the results of the surface heights and turbidity values shown in the figure below.

The top chart shows the surface height data where gaps in the time series represent when data collection was paused to manually retrieve data from the Egret and confirm the unit was still fully function.  The lower graph shows the time series of turbidity values measured by the Egret in blue compared against a commercial submerged sonde in orange.  

Conclusions:

Under this Phase I SBIR the Egret achieved a key milestone in its product development by demonstrating it could collect stormwater data in a relevant environment through storm events while operating on solar power alone.  Surface height measurement resolution was found to be on par with USGS streamgage resolution requirements and the turbidity values were found to be in excellent agreement with a standard water quality sonde. 

The Egret sensor is non-contact water quality monitoring solution.  The Egret can make its measurements from above the water surface without the need for ground power making it well suited to applications requiring easy installation and operation in remote environments.  A variety of potential markets have been identified for the Egret including stormwater management, wastewater surveillance, wastewater treatment, commercial brewing, and streamgage monitoring.  By avoiding the need for continuous submersion the Egret avoids issues of biofouling and damage often encountered in rugged wastewater and stormwater monitoring environments.