Did you know?
As we gather at meetings, I have been emphasizing the critical issue of silt management—a topic that profoundly impacts our beloved lake. Allow me to provide a brief history and summary of the insights gained by the Dredge Committee in the past 6 months. In upcoming articles, we will delve into the comprehensive plan as well as an updated view of our road projects and the other major infrastructure.
Our Unique Position:
- Conversations with engineering firms, contractors, and even a metro area mayor have highlighted our Homes Association’s uniqueness. We own an extensive network of road miles, properties, the lake, and dam.
- Surprisingly, given our budget and staffing, we have managed remarkably well over the years. Kudos to the dedicated volunteers and staff who have worked tirelessly behind the scenes to shape our lake community.
- However, our commitment to affordability has sometimes led us to compromise on road and lake infrastructure maintenance, creating pressing issues that demand immediate attention.
Lessons from the Past:
- In 2016, Lamp Rynearson engineering firm conducted a study on our watershed and lake maintenance requirements.
- Key findings from that study remain relevant today. Unfortunately, we fell short on the maintenance plan over the past decade, leaving us with significant catch-up work to align with the study’s recommendations.
- The Dredge Committee is diligently crafting a catch-up plan, and we will soon present financing details to the Ways and Means committee to incorporate into 2025 and beyond budgets.
Silt Volume Insights:
- Back in 1984, the Soil Conservation Service estimated that a staggering 72,000-plus tons (or 3,000 cubic yards) of sediment entered the lake annually.
- Fast forward to 1996, and the silt volumes decreased due to development in Blue Springs and Lee’s Summit reducing farmland around us. Now, we face an estimated 62,000 tons (or 2,500 cubic yards) of silt. In addition, the increase development also increases volumes of water with heavy rains. This speeds water flow and tends to carry silt further into the lake structure.
- Remarkably, over 90% of this silt volume infiltrates through the five largest coves and bays: Sunset, Sunrise, Big Rock Bay, Quantrill Cove, and Waterfall, hence their need for more regular dredging.
Navigating the Silt Challenge: A Comprehensive Look at Dredging
Let us journey back to 1996—a pivotal year when we embarked on a significant dredging effort to improve the overall depths and navigation. Hydraulic and drag line dredging techniques were used to remove an estimated 210,500 cubic yards of silt (at an average cost of $2.47 per cubic yard, totaling $519,000). The target was to bring the lake to a Level 3 status—a minimum depth of 8 feet or the original bottom. We made tough choices leaving approximately 179,000 cubic yards in the lake, primarily in Sunrise and Sunset Bays. The cost considerations guided our decisions at that time ($420,000 for those curious).
Fast forward to 2001 when we invested in our own dredge machine with the objective of maintaining Level 3 status. Our silt basins proved useful for periodic extraction, but limitations emerged. Our basin designs were not optimized for swift drying and dirt removal, necessitating 3–5-year gaps between uses. Over time as we dredged, we accumulated 10’s of thousands of cubic yards around Basins #3 and #6—the workhorses of our silt removal efforts. This left our silt basins full and nowhere to move dirt effectively. We estimate over 80k cubic yards at a minimum for both basins.
The silt saga is ongoing. We face a daunting task: an estimated 404,000 cubic yards must be extracted to restore the lake to its coveted Level 3 condition including Sunset and Sunrise Bays. There are also areas where smaller coves are not in the original plans that will need work performed to make the numbers larger. Also, in the coves where the terrain tends to not collect silt, the back of those coves will still need excavation to regain depth and integrity.
Now, let us talk about some what-if numbers. If we rely solely on our dredge, aiming for 20–25 thousand cubic yards annually, it will take a staggering 16-plus years to catch up—assuming no new silt enters the lake. So, the previous target of that annual amount no longer meets the needs.
But there is more. Dredging costs have surged over the years, and that is without factoring in silt basin management. Assuming just the annual dredge operational costs double the 1996 rates, our current catch-up price tag exceeds $2 million. That translates to potentially an additional $1,850 per home—a necessary investment to safeguard our lake’s future. Knowing we must prepare the silt basins prior to dredging; we are looking at additional costs of up to an estimated $1 million.
In summary, the way we have managed silt since 1996 has created a situation where we have full silt basins that are surrounded by significant amounts of dirt from prior cleanouts and dredging operations. In 2025 we need to start a catch-up strategy that can in 3-5 years leave us at a Level 3 status for the entire lake along with a framework to properly maintain going forward.
To catch up we must both remove excess dirt (current activity at basin #3) and dig out the basins. Also, each basin has issues that need to be repaired as in the case of basin #3 that has a broken drain. We need to improve our basins’ design to remove more silt before water drains back to the lake as well as, where possible, increase capacity. In addition, we need to develop a setup that allows for rapid dirt dispersal in a way that 3rd parties can come and remove dirt economically.
Why Does It Matter?
- The major value of all our properties lies in the use of the lake.
- Silt does not sit still as recent mapping reveals depth loss throughout the lake, with a growing buildup at the dam.
- Long-term preservation requires keeping silt away from entry points to prevent further migration and impacts on fish habitat and lake use beyond the major coves and bays.
As stewards of this remarkable resource, we are committed to addressing these challenges. The road ahead involves strategic planning, collaboration, and a shared vision for preserving Lake Lotawana’s beauty and vitality.
Thank you for your continued support and commitment.
Warm regards,
Jeff Clemow
President