The Secret Service did it to ensure the security of the second family. Via NYT:
"Anthony Guglielmi, a Secret Service spokesman, said that for security reasons, the agency asked the U.S. Army Corps of Engineers to temporarily increase water flow from Caesar Creek Lake, which is connected to the river.
The boats used by the Secret Service for security or an emergency evacuation are usually motorized and need deeper waters to operate, he said. Smaller boats like the ones the Vances were using, such as kayaks and canoes, can operate in shallower waters.
Mr. Guglielmi also said that the Service and local public safety officials conducted a scouting mission ahead of the excursion. During that time, one of the local public safety boats ran aground, an indication that the water level was too low for that vessel.” [0]
Readit News
"Anthony Guglielmi, a Secret Service spokesman, said that for security reasons, the agency asked the U.S. Army Corps of Engineers to temporarily increase water flow from Caesar Creek Lake, which is connected to the river.
The boats used by the Secret Service for security or an emergency evacuation are usually motorized and need deeper waters to operate, he said. Smaller boats like the ones the Vances were using, such as kayaks and canoes, can operate in shallower waters.
Mr. Guglielmi also said that the Service and local public safety officials conducted a scouting mission ahead of the excursion. During that time, one of the local public safety boats ran aground, an indication that the water level was too low for that vessel.” [0]
0: https://www.nytimes.com/2025/08/07/us/politics/secret-servic...
Thankfully we all have your superior reasoning skills to help us navigate these frought waters.