Esther Simplot Park cleanup done. Cost: $6.5 million

The city of Boise will end up paying at least $4 million and is likely to pay $4.5 million to clean up the Esther Simplot Park site, city engineer John Tensen said.

The Simplot family, which is paying to develop the park named for Esther Simplot, the philanthropist and arts benefactor who was married to Idaho agriculture giant J.R. Simplot, will cover the rest of the cost.

In the 1940s, some of the land where the park is being built was used as an airfield to train student pilots. Sometime later, a concrete company pastured horses on it. In 1964, Consolidated Concrete bought the land and put a concrete plant there.

Discovery last spring of the contamination has slowed park construction. Excavation crews unearthed a variety of debris and industrial waste at the 55-acre site between Whitewater Park Boulevard and the Boise River just north of Quinn’s Pond. They found a variety of pollutants, including a Volkswagen Beetle — year unknown — petroleum contamination, discarded concrete, steel rebar, tires and a cement-mixing drum.

At first, the city expected to pay no more than $2.5 million for the cleanup. But the deeper workers dug, the more stuff they found.

Potential contamination of the nearby river “was always a concern as we were digging it out but there was no evidence whatsoever that anything we did at the project got into the river,” Tensen said.

The city will continue to monitor the river and ponds at the future park to make sure contamination isn’t leaking into them, Tensen said.

The city is paying its portion of the cleanup cost out of its solid waste fund, an account that collects money from residents' payments for garbage and recycling collection.

The total $6.5 million cost of the cleanup may have come as a shock, but considering the Simplots are paying to develop the park, the city’s still pretty happy, spokesman Mike Journee said.

“At the end of the day, we’re going to have an amazing new park along our Greenbelt,” Journee said. “And we’re very appreciative of the Simplots for making that happen, despite the challenges we’ve had.”

The park will have 17 acres of ponds as well as 13 acres of grassy and planted space; a series of ponds where people can swim and fish; a playground with wood obstacles and features designed to encourage imagination and creativity; beaches; a stream connecting the ponds to Quinn’s Pond to the south; a pathway through a natural wetlands area and “Friendship Island” — a place for children to explore the natural Boise River surroundings.

The Simplots have not disclosed how much they’re spending to develop the park. Boise Parks and Recreation Director Doug Holloway said a park of this magnitude would cost the city somewhere between $9 million and $12 million to build.

This story was originally published January 13, 2016 at 12:49 PM with the headline "Esther Simplot Park cleanup done. Cost: $6.5 million."