East Lyme — The Inland Wetlands Agency is seeking more answers from the companies building a solar farm on Grassy Hill and Walnut Hill roads before it will lift a cease-desist-and-correct order related to runoff from the site.

Failures to the stormwater management system and overflow during a heavy rainstorm in March had caused silting in wetlands areas and sedimentation deposits in a stream that travels into Cranberry Meadow Brook. A second rainstorm last week also raised concerns over turbid water.

At a show cause hearing Monday, the Inland Wetlands Agency asked the companies to present a clearer portrait of the areas with silting and seek permission from nearby property owners, including the East Lyme Land Conservation Trust, that the silting potentially affects. It also requested a study of the downstream waterways to detect if silting there stemmed from the site.

The companies are also supposed to present more information on using a binding agent, based on the site’s soil characteristics, that would make the water discharge, from the stormwater management system, clear.

Greenskies Renewable Energy and Centerplan Construction Co. are to submit the information at the next meeting on June 9 when the commission will consider lifting the order it issued last month.

A remediation plan, presented Monday by Michael Klein, an environmental scientist hired by the company, calls for vacuum-removal of areas with thick sediment — some as much as 8 inches deep — during the drier, summer months. Areas with shallower sediment  will be left alone, because Klein said vegetation would still be allowed to grow and removing the sediment could be more damaging.

Klein said the event occurred during a two-day rainstorm with about 4 inches of rain falling on the already-saturated ground.

Inland Wetlands Agency Chairwoman Cheryl Lozanov called into question the timeline and planning of the project, particularly having an area clear cut in the rainy season, rather than proceeding in stages and at a different season. She asked if the companies could take this into consideration for future projects.

Centerplan CEO Bob Landino said he appreciated the comments, but the company had followed state and federal guidelines and “best practices.” He said such an event was very rare and had to do with a “perfect storm” of heavy rain pouring down on an already-saturated construction site.

The commission also wanted the companies to investigate the silting in watercourses and take responsibility for their portion. Commission member Joe Mingo said he saw mud in watercourses, including down to the fish ladder at Latimer Brook.

Klein said it would be difficult to determine how much silting came from the site since there was turbid water across the state from rainstorms, but Lozanov said there would be ways to determine the likelihood that it came from the site by observing the color and texture of the sedimentation.

Although the cease-desist-and-correct order stemmed from a March rainstorm, a heavy rainstorm last week again raised concerns about the sedimentation and erosion controls at the solar farm.

During a public comment period added to the regular meeting since the hearing was not a public hearing, resident Mark Christensen said, following the heavy rainstorm last week, he saw mud in Cranberry Meadow Brook down to the fish ladder at Latimer Brook.

“I’ve never seen it that brown ever,” he said, commenting that there must have been hundreds or thousands of tons of materials released into Latimer Brook. He added that it was not difficult to understand that a site of open, unseeded land would cause that kind of disturbance.

The siting council again inspected the site on Friday, after the second major rain raised some concerns, said the council’s executive director Melanie Bachman in an email interview. The council found that the erosion and sedimentation controls “were repaired and reinforced since the last rain event in accordance with our recommendations to install redundant fencing, check dams and swales in a letter to the project developer dated April 7, 2014.”

“These E&S controls were working properly during the rain event last week; however, in some areas, turbid water escaped the outlets due to the sheer volume of water produced by the rain event,” she wrote.

k.drelich@theday.com