American Fork GRAMA responses below.
Partly what is learned here is that the worst sediment / heavy metal content went beyond the settling ponds, that what little that remains in the settling ponds is above the Human Health Screening Values, but mostly that DWQ has not located the worst stuff- should be a concern to everyone who used secondary irrigation water in August / September 2016 in cities of American Fork, Highland, Cedar Hills, Lehi.
We also learn that the sediment samples taken in parks, the engineering firm dug down 3-4″ inches, but protocols for lead sampling in this situation should have included sod and the top 1/2-1″. This means that there is lead down deeper and that its heading to the aquifer if sediments have acidic water (typical of rain) that the sediments will dissolve out the lead and take it to the aquifer.
Cedar Hills, Highland, Lehi should provide some sampling – they seem to be avoiding the fact. Utah County Health Department is also hands off, this should be a concern.
Work Order 17A0596 – Tibble Fork, NUCWCD