The Dredge Report Card 11/8/2011

Tuesday, November 8, 2011

The Dredge Report Card


Until a few weeks ago, the flow into the lake was controlled by a contraption consisting of a Stop sign wrapped in a plastic bag. Low-concept; low-design; very effective. As the dozens of residents witnessed on October 30 with the turning of the red wheel (see photos below), the city now has something even better than a Stop-In-A-Bag: three separate valves that attenuate water flow into the lake and the creek.
Temporary Sign

The Old Temporary Sign

Stop in a Bag - Water Flow Control

Effective, Cheap and Ugly Stop in a Bag Water flow control

"New" Technology for Water Flow Control

"New" Technology for Water Flow Control

However, the time it takes to fill the lake will depend on several factors. If the weather is wet, not only will the rain contribute water to the lake bed but it will also keep the stream flowing at a rate that doesn’t require turning off the valves to ensure stream health. Here’s a description from Paul Simpson, our project engineer:

The rate at which the lake will fill is dependent on several factors. First and foremost of course is the weather. This is the driest time of the year so that the flow in Snapfinger Creek is very low. As we are filling the lake, the State requires that the flow in the creek be maintained to at least minimum levels known as the “7Q10”. This equates to what is known as the “base flow” conditions in the stream. If we were to pull too much flow from the creek, it would harm the ecosystem of the creek, which of course we do not want to do. Our maintenance crews will be checking frequently on the flow in the creek and the inflow to the lake and will be adjusting the flows as needed to maintain the proper stream flow.

Meanwhile, there are many tasks that remain on the “punch list,” including:
*the landscape architect finishing the design of our banks and berms
*general clean-up and restoration of swings, signs, and debris
*AND the re-opening of the road by the end of the week