would be lowered as much as eight to nine feet in some areas to temporarily hold rain water under a proposal presented by the village's engineering consultants Monday night.
The concept of a storm water retention facility as a way to reduce surface flooding in the area. The village later in the year to design a storm water management plan in the area, which is roughly bordered by Ardmore Avenue on the east, Henry Clay Street on the north, Shoreland Avenue on the west and Glendale Avenue on the south.
The plan would not affect the tennis courts or playground equipment on the west end of the park, but would lower the western portion of the park to hold rain water. The northern end of the grassy park area would be lowered eight to nine feet. Further to the south, between the baseball diamond and the playground equipment, the ground would be lowered two to three feet.
Softball diamond would be lost
Under this preliminary first draft the rain water would be diverted away from the high school baseball diamond, which would still meet WIAA standards. The park would lose some level surface on the perimeter, allowing four feet of slope per each foot lost in elevation. The softball field would no longer meet traditional standards.
Kathy Huegel said the loss of the softball field and other useable green space concerned her because the village has limited green space.
"That park is full of kids every single day, from April, May, June and July," she said.
Some residents at the meeting suggested retaining the softball field by lowering the entire park to the same depth, but that would jeopardize the baseball field's compliance with WIAA regulations, the consultants said. The Whitefish Bay varsity softball team plays on the high school grounds and Cahill is used primarily for junior varsity games.
Assistant Village Engineer Aaron Jahncke said the design is similar to the soccer field area at the , which drains 24 to 48 hours after a rain.
The plan would cost $11 million to implement, $5 million of which would go toward storm water management in Cahill and $6 million of which would go toward remaining utility and road costs. The plan would be implemented over the course of nine years.
A more cost-effective option
These storm water improvements designed to reduce surface flooding were included in a . The price tag for the larger, more comprehensive project ranges from $108 million to $134 million, but village officials hope to shave that price by focusing on the six most flood-prone areas of the village.
The added storage space would reduce the amount of rain water in the surrounding area and lessen the rain water load for storm sewer pipes to handle downstream.
"The flows are being reduced here. ... By letting it back up (in the park) and releasing it slowly we prevent from having to put those larger pipes in downstream, which are much higher cost," said Village Engineer Dan Naze.
Crispell-Snyder engineer Troy Hartjes said the storm water facility is the most efficient, cost-effective means of reducing surface flooding.
"This is one of the more economical solutions," he said. "This is the biggest bang for your buck."
Storm water pipes in the 4700 blocks from Ardmore to Santa Monica Boulevard will also be upgraded as part of the $11 million plan.
The excess water would drain into the storm sewer at Sheffield Avenue, then through Hampton storm sewers and eventually outflowing to Estabrook Park.
Currently the southwestern drainage basin can manage 2.6 inches in a 24-hour period, and with the Cahill plan and new pipe upgrades, the basin could handle 3.6 inches in a 24-hour period, or 5.9 inches in a 24-hour period with street ponding.
The village has applied for a $4 million hazard mitigation grant through the Federal Emergency Management Agency, and the village is expected to hear back later this fall if it is selected for an award.
This is the consultants' first draft, so the plan could be modified in the future, but it may require a new FEMA application if the design is significantly different.
Going forward, Trustee James Roemer said the Village Board will contact local sports programs, the Whitefish Bay School District and other stakeholders to further talk about the design of the project.