Years and years of rainfall runoff wash silt into ponds. Average depths become shallower. The pond is less productive. It’s a fact of Nature. How do you restore the youthful vitality of your treasured resource?
If you have clay soils that hold water, plus a watershed to fill a larger pond, it may be more practical and less expensive to raise the dam on an existing pond than digging out old silt. This is a big “if”, so consult a professional to be ABSOLUTELY sure soil and watershed potential meet all requirements beyond any doubt. While digging out old silt in the main lake basin, you run the risk of puncturing porous soils and creating a leak. Excavating a cubic yard of dirt increases water capacity by a cubic yard. Raising the dam one cubic yard backs water into a much larger area.
Raising a dam or levee requires more engineering than simply piling fresh dirt on top of an old dam. Earthmovers must blend new material from the old dam into new dirt to avoid a layering affect. Dirt added to the firm surface of an existing dam must be mixed and compacted or it almost certainly will leak. Be aware, new soil adds new weight. The foundation of an existing dam must be able to support that weight. The entire dam base may need widening to support more material, depending on how much it’s raised.
Some ponds don’t lend themselves to raising the dam. They may be too close to a land boundary and push water off your property. In his book, “Perfect Pond…Want One?”, Bob relates a success story of a client who enlarged his aging three-acre pond to a productive six-acre honey hole. He also shares consequences of a landowner who didn’t perform proper due diligence. This publication is a must read if you’re considering lake construction or renovation. The small cost could save hundreds or thousands in project costs. You can order at www.pondboss.com.