HYDROGEOLOGY IN SUPPORT OF LITIGATION: INFLUENCING POLICY WITH HYDROGEOLOGY

Nitrate in Iowa’s streams has steadily increased in the absence of regulations or policies to reduce headwater sources. In 2014, a suit filed in U.S. District Court requested two rulings: 1- require drainage districts (DDs) to pay to reduce nitrate in their discharge; and 2- clarify the Clean Water Act (CWA) that has been interpreted to exempt agricultural from pollution permit requirements.

The DMWW holds a unique geographic position to argue hydrological principles before courts: 1-it is a large municipal water supply; 2- its primary source is the Raccoon River, one of the nation’s most nitrate-polluted streams; 3- the Raccoon River discharge is dominanted by groundwater from quasi-governmental DDs; and 4- the DMWW is required to spend substantial sums to reduce nitrate below 10/mg/L. The suit asked the court for financial compensation, actions to reduce nitrate discharge from DDs to less than 10 mg/L and require DDs to obtain permits to discharge nitrate pollution.

DMWW requested a report answering three questions: 1- what is the effect of DDs on nitrate in the North Raccoon River? 2- how and why do DDs convey nitrate into the North Raccoon River? and 3- is DD discharge primarily “... stormwater discharge?”. A technical report answering these questions provided the basic information for many of the facts in the suit.

The report included analysis and opinions about shallow geologic materials; processes affecting nitrate in groundwater; and how DDs accelerate the discharge of nitrate and groundwater. DDs selected are unaffected by urban water and discharge directly to the North Raccoon River. This discharge is upstream of USGS discharge and nitrate monitoring. The report compiled literature and data to establish that nitrate is transported by groundwater, not “stormwater" and nitrate concentrations frequently exceed 10 mg/L in discharge to natural and artificial streams from drainage district pipes.

The Federal court referred several questions about awarding compensation to the Iowa Supreme Court. The State court ruled that compensation could not be paid, and the suit was dismissed in federal court without ruling on the critical issues associated with interpretations of the U.S. Clean Water Act.