Lowell commission approves three-townhouse floodplain plan at 535 Pawtucket Blvd with operations condition

April 23 — The Lowell Conservation Commission voted unanimously to grant a standard Order of Conditions to Huynh Properties LLC for work at 535 Pawtucket Boulevard, allowing demolition of an abandoned single‑family home and construction of three elevated, flow‑through townhouses located in the 100‑year floodplain.

The commission’s approval included a condition requiring an updated operation and maintenance (O&M) plan for the project’s porous pavement system, with biannual vacuuming, and language requiring O&M responsibilities to be recorded in the condominium association documents.

Matt Hammer of Lamplex Engineering and Surveying, the project’s civil engineer, told the commission the filing responds to Department of Environmental Protection comments and includes a detailed compensatory storage worksheet showing the cutting and filling for the site. “We feel as though, no, no, we feel we we know that this site will meet the performance standards for bordering land subject to flooding per the Wetlands Protection Act,” Hammer said during his presentation. He described the proposal as three elevated townhouses with flow‑through foundations, porous pavement drives and minimal grading; proposed site grades are generally around elevation 98, while the floodplain maximum elevation at this location is 100.4 (NAVD 88).

Hammer said the compensatory storage calculations break each unit into discrete components (columns, utility chase, stairs) and that the conservative estimate used for the stairs and chase results in roughly 38 cubic feet per vertical foot per unit (114 cubic feet for three units) when summed with the site grading calculations. He said the porous pavement design is appropriate for the local sandy soils and that the project reduces overall impervious area by removing an existing curb cut and some pavement.

Commission members pressed for detail on whether stair chases and walls were included in the compensatory storage calculations after DEP requested more specificity. Hammer agreed to double‑check that the stair and adjacent walls are included in the submitted worksheet and confirmed he has sent the expanded calculations to DEP. He also said that an O&M provision for twice‑annual vacuuming of the porous pavement will be added and placed in homeowners’ association documents to be recorded at the registry of deeds.

A resident who said they visited the site told the commission the wetlands were “only 2 feet from the road,” and expressed concern about access during high water events. Commission discussion acknowledged that the area floods during high‑flow events (members referenced the city’s Merrimack River and Clay Pit Brook influences and the Mother’s Day flood), and commissioners noted that the proposal raises site living floors above the flood elevation so that living spaces would not be reached by typical floodwaters while preserving or improving compensatory storage compared with removal of the existing structure.

Hammer said sewer and water plan revisions would be submitted to the Planning Board, where the applicant must next seek approval. The commission added the O&M requirement to the Order of Conditions and voted to grant the standard Order of Conditions with that addition. The commission also required the updated O&M plan to specify the biannual cleaning schedule for the porous pavement and confirmed the condition will be included in the recorded condominium documents.

The project record for the filing includes DEP file number 2060844; the commission’s approval is conditioned on addressing outstanding DEP comments and subsequent regulatory signoffs and Planning Board review.