I can't remember your dimensions.
How big is the pond? Length and height of the dam?
Pumping out the water and repairing the existing dam might be much cheaper than building a second dam. However, you do lose one year on your pond.
Building the second dam adjacent to the first dam might be a little dangerous with water seeping though the first dam. While you are working on the core trench you would have saturated, unstable soils above you. Trench collapses kill lots of construction workers.
If you are building a second dam, is there enough room to move farther down your waterway and make it a second pond?
If the elevations work out, then the leak in your first pond would only drain the water level down to the water level of the second pond. As long as your second dam is well sealed, then your first pond will also hold water.
Just spitballin' ideas to get your creative juices going since I expect you are chomping at the bit to get your pond fixed!
Good luck!
