Intense Rainfall Tests Scarsdale's Storm Water Management System

How did the Village's new storm water management system perform during the heavy rainstorms on Tuesday December 9th? We asked Village Manager Al Gatta and Department of Public Works Supervisor Benedict Salanitro for a report on areas that have flooded in the past and here is what they shared:

From Village Manager Al Gatta:
"The first issue was the amount of rainfall. The Public Works Department reports that 3.16" of rain fell with great intensity over a 12-hour period, not the 24-hour period which was the design standard for the improvement projects. Also the Village-wide drainage system was still retaining water from rainstorms on the previous Saturday that decreased the amount the system could hold on Tuesday.

The improvements at George Field Park performed as expected with a small amount of flooding on the north end, across Eton Road. The rain garden at Cooper Green, opposite the public safety building also performed as designed and there were no problems.

However, at Brewster Road we had flooding in the high school parking lots but the road was open. We believe the flooding was caused by excess water in the watercourse from the rains on Saturday and the rain intensity on Tuesday. The 3.16" of rainfall entered the system too quickly, causing the parking areas to flood.

The Hutchinson River area had little flooding, but had some discharge from the sanitary sewers. We are looking at this issue with the County and the Village may have to undertake an Inflow/infiltration Study to determine the amount of rainwater that is getting into the sanitary sewer system and causing the backups. We are also working on a project with New Rochelle and the County to determine if the incidence of flooding can be reduced in the Hutchinson River area."

From Benedict Salanitro, Supervisor of the Department of Public Works:
"The very intense rainfall accumulation in a relatively short period of time (3.16 inches in 12 hours- as reported by Westchester County in Mamaroneck), was a perfect recipe for flooding and nuisance water to accumulate in low lying areas. This intensity together with about an inch of rain accumulation from the previous Saturday, (into part of Sunday) caused excessive saturation of the ground and the water was able to sheet flow off of the lawn( mimicking blacktop surface runoff) with greater velocity than normal.

The areas around Brewster Road (High School) was one of the first areas that experienced water related issues around 10 am, because the flows were so high. Many folks were not expecting to see the type of flooding that occurred and expressed concerns about the drainage system not being able to handle the rain, but in fact the conditions that we experienced was in-line with the expectations based upon the actually rainfall and duration.

The time that it took for these areas to recede was also an indicator for us of how well the system does in fact work, given the limitations of the amount of rainfall. All in all, while there were many areas of concern, understanding the storm characteristics puts everything into perspective."

Asked about homes near Cayuga Pond in Heathcote, Salanitro added, "There was flooding on some properties along Seneca and Cayuga that surprised some people, but we believe that the improvements worked as expected."