The stretch of Left Hand Creek located within the City of Longmont is an engineered channel designed to pass 100-year flood flows. Sediment deposition had not been an issue in Left Hand Creek until the September 2013 flood event.
The 2013 flood caused extensive damage to Left Hand Creek. These damages included bank erosion and sediment deposits. After the 2013 flood, the City repaired the embankments and removed approximately 30,000 cubic yards of sediment in the reach of Left Hand Creek located within the City.
Additional damage to Left Hand Creek, including additional sediment deposits and bank erosion, occurred during the 2015 heavy spring runoff. These damages will require channel repair and sediment removal to maintain the channel capacity needed for flood control.
The City will be repairing Left Hand Creek bank erosion and removing sediment deposited in Left Hand Creek from the 2015 heavy spring runoff.
The City will also be performing a study on ways to mitigate future sediment deposits in Left Hand Creek. (This study is not funded by FEMA grants.)
The sediment removal project is a partnership between the City of Longmont and the Federal Emergency Management Agency (FEMA).
The City has been awarded a FEMA grant to fully fund improvements for this project. Cost for the project is estimated at $886,700.
Final design has been completed for the Left Hand Creek Sediment project. FEMA has approved the design, and the U.S. Army Corps of Engineers has issued the necessary permits. Colt & Steel Corp. has been awarded the contract to complete the work.
Construction to remove sediment and repair embankments is scheduled to begin in mid-January 2018. The work is expected to take approximately three months to complete.
Project Manager Bill Taylor, Sr. Civil Engineer