October 15, 2020

Morrow Dam Reservoir Drawdown -10/12/2020 Stakeholder Update

In an effort to improve communications with stakeholders, STS Hydropower (STS) is providing regular email updates on the status of the Morrow Dam spillway gate replacement project necessary to ensure dam and public safety, and the associated reservoir drawdown. This is the sixth bi-weekly email status update. 


Gate Replacement Project Status 

We continue to make good progress and remain on schedule to complete the installation of new spillway gates in December 2020.  

Our construction contractor, J.F. Brennan Company, has completed mobilization activities and is progressing with critical pre-construction activities. The contractor has completed installation of a temporary access road and crane pad. Next week, we are scheduled to receive delivery of the project crane and other materials and equipment. Our gate fabricator has received all out-sourced materials and fabrication of the replacement gates is nearing completion.   

We continue to consult with Regulatory Agencies regarding the timing of refilling the reservoir and returning to normal project operations.   Recently the Michigan DNR completed a review of STS’s proposal to initiate reservoir refill operations immediately upon completion of the gate replacement and determined that immediate commencement of refill operations would be appropriate. STS expects that reservoir refill operations will occur over an approximate 30-day timeframe starting in December 2020.  



Sediment Control Plan 

On September 28th, we completed the installation of 600 ft of additional sediment curtain upstream of the dam and 600 ft in the immediate downstream vicinity of the dam.  To date we have installed a total of 3,800 feet of turbidity curtain and/or shoreline protection in four separate phases.   Based on turbidity monitoring data and visual observations, these measures are having a positive effect on the ongoing sediment transport and turbidity issues. However, sediment continues to move in the system.    

STS scheduled a site visit with EGLE and the U.S. Environmental Protection Agency (EPA) on October 6th to discuss and determine the need for additional sediment controls up and downstream of Morrow Dam.  Based on this consultation, STS is preparing to deploy a 5th phase of sediment control measures.  Phase 5 will consist primarily of 4,000 to 5,000 ft of additional shoreline stabilization and sediment curtain deployed upstream of the dam.  Mobilization will occur on October 14th and we expect the work will be completed within 10 days.  


Long Term Characterization and Mitigation Activities 

On October 1, 2020, STS submitted a draft Field Investigation Plan to Regulatory Agencies for review and approval. The Plan describes the activities that STS proposes to conduct this Fall to assess the volume, location, depth, and composition of sediments downstream of the dam that were mobilized by the drawdown of Morrow Lake.  STS is currently working with the Resource Agencies to finalize the Plan and expects that data collection activities will commence later this month.   


Please feel free to forward this status update to others that may be interested.  If you know of stakeholders who would be interested in receiving updates, please ask that they contact Melissa Sonnleitner at so that they can be added to our stakeholder list.  

If you have any questions or concerns, please contact me directly via email at