That portion—featured in the image above—would cut down on the nutrients Lilly Run deposits into the bay and address flooding issues in locations around town, according to John Van Gilder, project coordinator and city spokesman.
The holding area would be a re-created stream bed, with man-made turns to allow for sediment and nutrients to settle out. The area surrounding the stream would be graded out into a bowl shape to allow for flood water to build up behind a weir, which Van Gilder described as a reverse dam—allowing normal stream conditions to flow unimpeded, but higher water to back up, creating a temporary pond.
"Most people see this and think it's going to be standing water all the time, and a mosquito pond and whatever," Van Gilder said. "It's going to be a winding stream, and if it ever does fill up to this point, it's very temporary. In eight hours, 10 hours, whatever, it's going to be dry again and back to its level."
That function should prevent flooding downstream in the Juniata and Otsego street corridor, Van Gilder said.
On most days, the area behind the weir will be a picturesque and effective natural filter for the water.
By utilizing strategic planting of grasses and trees, the water coming into the holding area section, where it will meander through man-made turns, will be cleaner on the way out.
"It's going to spend a little more time in there. There are certain plants that really absorb things," Van Gilder said.
Building habitats for local species—including platforms for osprey and other wildlife—is also under consideration, Van Gilder said.
The path from Lewis Lane near the middle school and activity center that extends to the high school would be re-routed over a new walkway, complete with an observation platform.
The pathway would also ring around the holding area, and cross Lilly Run at the weir behind the grandstand at James R. Harris Stadium. From there, the walkway would parallel the Amtrak line and link the Lewis Lane area with the city's downtown district.
The culvert under the former stadium field—which is a primary pinch-point for the flow of Lilly Run during heavy rains—would be replaced, Van Gilder said. That element of the project would help to alleviate flooding along Revolution Street near Bloomsbury Avenue, which, conceivably, would improve the flow of water back into the Baybrook neighborhood.
The holding area proposal would eliminate the field that borders Lilly Run—currently used for high school field hockey. It would be replaced by a new multi-purpose field, to be built along Lilly Run between the 90-foot baseball field and the middle school.