Floods, Pandemic and Material Shortages
Kissick Construction Company Inc., (KCC) was awarded the contract to make repairs to the Blacksnake Creek Outfall structure at the discharge point to the Missouri River at the mouth of the Blacksnake Creek. The original work assigned to KCC was to address the needed repairs and maintenance to the Blacksnake Creek sewer outfall structure by constructing a linear concrete channel structure with energy dissipating features. A Notice to Proceed was issued in mid 2018 and some of the work was completed prior to the flooding in 2019. However, due to the flooding, work was ceased until the waters receded. This became a constructibility issue because several flood peaks changed the topography of the site requiring the engineering of the outfall to be re-examined.
An alternative design was developed by the city and approved by the United States Corp of Engineers (USACE), which will allow the city to easily maintain the area by creating a channel like the Roy’s Branch section constructed in the near surface conveyance phase of the Blacksnake Project. This redesign utilized the initially constructed temporary tieback walls, making them into permanent shotcrete walls. In addition, following all the special conditions set forth by USACE, this redesign created an engineered channel utilizing a series of sheet pile walls located at various locations along the channel’s length. The channel bottom and sides were also reshaped and armored to remain as an intact unit while acting to slow water and dissipate energy through the channel.
Currently to date, all the above improvements have been installed and completed except for the new flood gate. The old gate, destroyed during the flood conditions, was redesigned and approved for assembly in March 2021. The gate is currently scheduled to be installed later this fall due to material and labor shortages brought on by the ongoing issues connected to the pandemic. The city has been granted a project extension tied to the delivery and installation of the gate until November 2021.