Data analysis underway after workers able to get access to two 48-inch pipelines
Editor’s note: This article was updated late in the morning of Aug. 23 with additional information from the Public Works Department.
This week, the Sarasota County Public Works staff pursued measures to try to ascertain whether problems with two pipelines, each 48 inches in diameter, near the intersection of Lorraine Road and Palmer Boulevard in Sarasota, led to what the department’s director, Spencer Anderson, has referred to as “excessive flooding” from Tropical Storm Debby’s rainfall in the Laurel Meadows community.
However, based on an Aug. 20 county staff report, the result so far — as members of the U.S. Navy would say — has been “no joy.”
In an Aug. 18 video produced by county staff, Anderson explained that, as of that time, he and his colleagues still had not been able to visually examine the pipelines because they remained underwater.
He noted that each pipeline is 150 feet long; they run south to north.
“We really want to find out if these pipes have anything wrong with them,” he stressed.
The following day, on Aug. 19, he continued, staff planned to start creating berms on either side of a canal in the area of those pipelines, so the water could be pumped down to a level to allow access to the pipes.
In a follow-up county video on Monday, Aug. 19, Anderson stood in the foreground as an equipment operator worked on one of the berms.
Staff expected to be finished with the effort that day, Anderson said.
On Aug. 20, in one of the county Recovery newsletters, Communications Department staff wrote that Public Works personnel still were evaluating the data collected during the Aug. 19 inspection of the pipelines.
As of that time, the newsletter continued, nothing had been found in the pipes “that would have exacerbated flooding from Hurricane Debby” in the area of Palmer Boulevard and Lorraine Road.
On Aug. 21, the News Leader submitted a question to Public Works, asking whether any further information had been found that offered insights into the flooding at Palmer and Lorraine. The department replied in an email on the morning of Aug. 23: “Public Works staff will further evaluate data collected from the inspection of the pipes through engineering analysis, which will take several weeks. … Public Works staff will continue to evaluate areas of concern around the county to identify root causes of flooding from Hurricane Debby and potential means to mitigate future flood impacts.”
On Facebook citizens pages that The Sarasota News Leader has reviewed, a number of people have blamed overdevelopment in the county for the flooding that occurred in numerous areas where residents never before had experienced high levels of stormwater.
The U.S. Geological Survey (USGS) explains in a June 2018 article on its website, “As cities grow and more development occurs, the natural landscape is replaced by roads, buildings, housing developments, and parking lots.”
Focusing on the metro Atlanta region, the USGS noted that that area had “experienced explosive growth over the last 50 years, and, along with it, large amounts of impervious surfaces have replaced the natural landscape.
“Impervious surfaces,” the article continued, “can have an effect on local streams, both in water quality and streamflow and flooding characteristics.”
The article pointed out, “A significant portion of rainfall in forested watersheds is absorbed into soils (infiltration), is stored as groundwater, and is slowly discharged to streams through seeps and springs. Flooding is less significant in these conditions because some of the runoff during a storm is absorbed into the ground, thus lessening the amount of runoff into a stream during the storm.”
The article also explained, “As watersheds are urbanized, much of the vegetation is replaced by impervious surfaces, thus reducing the area where infiltration to groundwater can occur. Thus, more stormwater runoff occurs — runoff that must be collected by extensive drainage systems that combine curbs, storm sewers, and ditches to carry stormwater runoff directly to streams. More simply, in a developed watershed, much more water arrives into a stream much more quickly, resulting in an increased likelihood of more frequent and more severe flooding. Frequent flooding causes problems for residents and also the local government which has to clean up sand and sediment deposited after a flood.”
As the News Leader reported last week, Anderson explained how the county canal system works to drain the area around the Palmer Boulevard/Lorraine Road intersection, along with other communities in the eastern part of the county and around Bee Ridge Road.
Public Works did tell the News Leader, in a statement, that routine cleaning and maintenance of the canals has continued to take place over the years.