The promise of summer fun in the sun and water at Esther Simplot Pond has been a big disappointment for most of the summer. E. coli is to blame and finding the source of the contamination has proved harder than anyone imagined.

It's the most recent addition to Boise's Ribbon of Jewels, riverside parks named for prominent local women, but lately it's lost some of its shine.

The reason, according to Boise Parks and Recreation, can be traced to a retention pond located right next to Esther Simplot Pond.

Weeks ago tests came back with high levels of E. coli, which was linked to dog and geese feces.

So the city banned dogs and have tried to rid the area of geese, but readings were still high.

Boise Parks and Recreation Director Doug Holloway said they determined the issue was because this basin wasn't draining as it was designed to do and was seeping into the swimming pond just yards away.

So, Boise Parks and Recreation came in with pumps to empty it.

During the last three-week stretch contaminant numbers have been well above the 236 the state requires to be a safe level, and at some point it was peaking around 1,200. But they have seen significant improvements lately.

“Since the dogs have been gone, since we've been managing the geese, since we've been flushing the water, it's just been, it's consistently coming down, it keeps coming down, and now it's been down for a few days,” said Holloway.

Bottom line is the numbers are improving. However, Holloway says they want more consistency with the numbers for longer time periods before they open back up again. The hope is that will happen before the end of summer.

So the issue will continue to be the retention basin. Holloway says it’s not meant to hold water, but retain it and drain it off quickly. He says a design flaw didn't allow that to happen.

Now they are in discussions with the Ada County Highway District about how and when it gets fixed.

A spokesperson for ACDH told us there is even some dispute about who owns the property, the city of Boise or ACHD, and therefore, who is responsible to fix it.