What could have been a scar on a hillside from years of mining, has been approved for development after a year of discussion.

Lakeside Development, which owns 120 acres adjacent to the Issaquah Highlands, got the green light from the Issaquah City Council for the zoning to be changed from mineral resources to urban village at the Dec. 17 city council meeting.

The Lee family has operated a family-owned mining business on the property for 58 years. It processes gravel, makes gravel products and recycles asphalt concrete.

Lakeside’s property is also a transfer of development rights (TDR) receiving site, one of the largest in the greater Seattle area. As it stands, 700 residential units are possible for the site, but using the TDR, an additional 500 units could be added for a total of 1,200 units.

The parcel will be divided into seven different neighborhoods.

Highlands Drive Northeast divides the land; the only piece to the east of Highland Drive, known as parcels “A1” and “A2” already has a party under contract to buy the land from Lakeside.

Keith Niven, the economic development director for the city said the interested party might have a plan for the property ready to bring to the table as soon as the end of January. Parcel A2 has been limited to three-stories from four, after public outcry, to provide parity with the Issaquah Highlands.

Each individual neighborhood will be required to have some sort of community space. The plan includes a multi-use trail to the valley floor.

There was a surprisingly high volume of testimony from the public over its concern for the aquifer which lies below the majority of Issaquah, including the Lakeside area.

“You contaminate the aquifer, and you’ve probably lost it forever,” said John Macduff of Issaquah.

Citizens are concerned that the groundwater supply will be contaminated by construction and development. Recharge of the aquifer in the Lakeside development area is possible, but the overwhelming concern was about pesticides and other harmful chemicals polluting the water that many citizens drink, including residents of Sammamish.

Dale Timmons of Issaquah, who identified himself as a hydrologist said surface water runoff is polluted not only with chemicals, but contaminants from animal waste which contains coliform. He said Lakeside needs to engage in very aggressive infiltration.

“The Lakeside proposal is too vague on ongoing compliance,” Timmons said. “It can take decades to clean up a polluted aquifer.”

The alternative would be for runoff to be directed to the North Fork of Issaquah Creek, or to a detention pond.

Niven said that the infiltration plan is very aggressive, and that surface water will be run through various types of filtration into an infiltration gallery, which can be equated to a bathtub with no bottom, above levels of different types of soil for the drainage to filter through.

Niven said the system will be monitored for years until any infiltration would be allowed, and if the water is not at an acceptable level, it will not be allowed to enter the aquifer. Furthermore, the Department of Ecology would have to issue any permits for storm water solutions, which would have to be compliant with code at the time of permitting.

The entire master drainage plan for Lakeside is on the city’s web site.

Timothy Lee, the CEO of Lakeside, said the agreement was good for his family and the city of Issaquah. Councilman Joshua Schaer expressed concern about schools with the possibility of 1,200 potential new homes, but he said if they didn’t go for the agreement, Issaquah would be left with an abandoned mining facility between the Highlands and the Valley floor.

And the city has earned $9.7 million dollars in advance from Lakeside for accumulated impact and other fees, which Niven said can be put to work on other projects such as improving local parks.