Parks staff says splash pad at Harbor Island would double in size; commission asks for stormwater calculations

Parks general foreman Jeff Ahn told the Harbor and Coastal Zone Management Commission that preliminary plans call for roughly doubling the size of the Harbor Island Park splash pad, keeping it in the same location at Harbor Island Beach and using the same poured-in-place rubber surface. "What we're basically looking to do is we're basically looking to double the size of the splash pad," Ahn said during the July 17 meeting.

Commissioners pressed staff for technical details, particularly on stormwater and drainage. The chair noted the expansion appears to be within a 100-foot wetland buffer and asked whether the existing drains can handle the additional impervious surface. Ahn said the enlarged pad would continue to discharge into the same two drains that serve the current spray ground—a 2-foot-by-8-foot trench leading to a 12-inch pipe under the sand—and acknowledged he did not have volume calculations at the meeting. "I do not," Ahn said when asked for a calculation of what the drains handle now versus with the new, 1,200-foot surface.

The commission also questioned water-supply capacity and peak flows. Commissioners referenced published equipment figures near 97 gallons per minute; Ahn said the splash pad's equipment cycles—so not all features run at once—and that the existing domestic 2-inch supply line would remain. He noted a splash feature that periodically dumps water will create short bursts of higher drainage but said the system is designed to avoid upsizing the supply line.

On environmental and visual impacts, Ahn said there would be no impact to nearby trees or the overall harbor appearance and that the only nearby vegetation is planted seagrass. He described the existing fence line as unchanged. Commissioners asked about timing; Ahn said construction would begin after the beach season so work could occur in fall and winter, with the hope of reopening before the next season.

The commission agreed staff should draft an advisory letter to the Board of Trustees assessing consistency with local standards and asked staff to include stormwater calculations in that draft. The chair said he had enough information to begin a draft and sought a volunteer to prepare the first version of the splash pad advisory letter; staff later confirmed they would start the draft and circulate it under the circulation limitations explained by the chair.

The presentation concluded with Jason Pinto, superintendent of recreation, thanking the commission and reiterating the splash pad's popularity. "It is one of the most popular things that we have in the park," Pinto said.