Groundwater at Odana exceeds standards for salt



The Cogeneration plant on the west side of the UW campus is allowed to withdraw large amounts of water from Lake Mendota, based on a complicated swap agreement with DNR.

That agreement called for an infiltration field at the Odana Hills Golf Course, where up to 60 million gallons a year of stormwater are pumped into the soil.  Background.

One of the problems with this agreement is that the water being pumped into the soil is rather salty, due to overuse of road salt in the area. Several test wells in the area show levels of salt over the Enforcement Standard.  In other words, the groundwater is starting to become polluted with salt.

The following is a DNR explanation of what the standards and terms mean (the underlines are mine):

"The preventive action limit represents a lesser concentration of the substance than the Enforcement Standard. The PAL is either 10%, 20%, or 50% of the enforcement standard... based on the health-related characteristics of the particular substance. Ten percent is used for cancer-causing substances, 20% for substances with other health effects and 50% for substances having aesthetic or other public-welfare concerns.

The preventive action limit serves two purposes. First, the PAL must be used in design codes for facilities (e.g., landfill design) and management practices (e.g., pesticide use regulations) so that contamination is prevented through use of stringent designs code regulations to assure that they conform to the PALs to the extent technically and economically feasible.

The second purpose of the PAL is to serve as a "trigger" for remedial actions. Exceeding a preventive action limit creates the possibility that some regulatory response may be necessary. Where a preventive action limit is attained or exceeded, the regulatory agency is required to evaluate the situation and take action necessary to reduce the concentration of the substance below the preventive action limit or at the lowest concentration feasible. When preventive action limits are exceeded, a regulatory agency may prohibit continuation of the activity, which is the source of the problem. However, to do so the agency would be required to meet specific statutory requirements. Preventive action limits are intended to provide regulatory agencies time to take preventive measures to ensure that the enforcement standard is not attained or exceeded.

Enforcement standards define when a violation has occurred. When a substance is detected in the groundwater in concentrations equal to or greater than its enforcement standard, the activity, practice or facility that is the source of the substance is subject to immediate enforcement action.  Unlike a PAL, when an enforcement standard has been attained or exceeded, a regulatory agency must prohibit the continuation of the activity from which the substance came, unless it is demonstrated to the agency that an alternative response will achieve compliance with the enforcement standard."

Some quotes from NR 140 Groundwater Quality:

"Although a preventative action limit is not intended to always require remedial action, activities affecting groundwater must be regulated to minimize the level of substances to the extent technically and economically feasible, and to maintain compliance with the preventative action limits unless compliance with the preventative action limits is not technically and economically feasible."

Clearly, through a salt reduction program, reduction of salt in Odana Pond is technically and economically feasible.  My observations in March show that salt use on the West Side is excessive and could be reduced.

My reading of these documents is that the PAL is where enforcement activities kick in.  If the ES level is reached, then the enforcement is still more severe.  One of the key things we have to determine is where (i.e. which well) is the measurement point that has to meet the goundwater standards--the two wells downstream, or the well within the infiltration field.

The full text of Chapter 140. Groundwater Quality
History and explanation of the Odana project