Committee holds groundwater mapping bill for interim study after data concerns

Representative Kohler introduced HB 533 (second substitute), a study proposal to examine groundwater recharge and the connections between irrigation returns, septic or secondary water returns, and basin groundwater that ultimately supports surface flows to the Great Salt Lake.

Theresa Wilhelmsen, State Engineer, told the committee that many historic decrees assumed upper‑basin diversions would saturate the ground and return flows downstream; she and other witnesses said existing groundwater data are sparse and that more study is needed before policy changes are made. Dr. Ronald Mortensen and Warren Peterson urged careful study, with Mortensen noting localized aquifer declines and the risk of saltwater intrusion in some districts.

Representative Kohler and several committee members described the proposal as important but likely more appropriate for interim study to develop better data and model recharge dynamics. Representative Colford moved to hold the bill and send it to interim study; the committee approved the motion by voice vote.