This letter is about creating a new Capitol Lake that includes a natural estuary. The idea would be to build a containment wall to form a smaller freshwater lake in the east half of the north basin, and let everything to the west and south revert back to tidal flows. In short, it’s a Dual Estuary/Lake Idea (DELI).
While this idea has been reviewed and rejected before, I contend the review was biased and the rejection not valid. Here’s why.
The engineer’s report rejecting a containment wall built of piled rock (rubble mound) was severely tweaked to make it expensive. First, they estimated for a 25 foot height when only 15-20 feet is really needed. When building a 3:1 sloped mound of piled boulders, that’s a significant difference in material required.
Second, they bid the rock at $70-plus per cubic yard back in 2006 when local access via Black Lack Quarry would do it today for under $25. That brings the cost down even more.
Finally, they dismissed the idea that piling boulders across the substrate would result in a stable condition that wouldn’t settle and distort, even though the railroad embankment at Marathon Park is built on exactly this same material.
Building a containment wall to impound a new Capitol Lake will cost less than the roadway reconfigurations needed to open up the estuary. And supplying a new lake with the abundant artesian groundwater available here will create a clean, swimmable condition that will complement our downtown, urban environment.