Levee work needed at Lake Waconda detailed. Excerpts from an SID #1 Board of Directors’ statement provide details issued in the Cassgram.
The engineers from the US Army Corps of Engineers as well as those from TD2 have met, walked the levees and made assessments as well as recommendations for action. There are four main areas Waconda is dealing with:
Boils in the lake continue to be a problem mostly at the north end near the river. The issue with these is that as water levels in the river are higher than the lake level, the water is forcing its way under the levee through sand layers below the surface of the lake; The greater the differential, the higher the velocity of flow. Remedies include the lake level controlled at a higher level than normal and fighting the boils by either sandbagging or placing aluminum culvert tubes vertically over the boils.
On the south part of the earthen levee that runs east toward the river, there is wave erosion. This will be addressed by placing riprap (rock) along this stretch on the river side of the levee.
The landward side of the levee from Bullfrog Bay to approximately Lot #1 (East Boat Ramp) or 2200 feet is exhibiting seepage. A combination of very high ground water and water saturating the ground at the base of the levee places the levee in jeopardy of sloughing.
The plan to address this calls for over 15,500 ton of gravel, the equivalent of 1000 dump trucks.
On Sunday, the ground between the levee and the lake on both sides of Bullfrog Bay Rd. exhibited the same signs as #3.
The method for fighting #3 and #4 is the same, and work started Sunday. An erosion mat is placed on the ground and covered with 3 feet of sand/gravel/rock. This allows the water to get away from the levee toe and to evaporate, and the mass of the sand and rock strengthens the levee to prevent sloughing.
SID #1 urges that no one except authorized emergency volunteers working with Larry Hathaway (Waconda manager) should be at the lake between sunset and sunrise. Cass County Emergency Management Agency has advised that while the levee is being strengthened and stabilized anyone at the lake should be alert for changing conditions and that it is not safe for anyone to be sleeping there.
“We are committed to do all that we can to protect our levees, our community, and of course our investments. We will continue to do this until we are told to cease.”SID Board statement said.