Article 2

The Ground water Source: Notes from the Supply Side

By John Jansen, Aquifer Science and Technology
Published in the Wisconsin Ground Water Association Newsletter, Spring, 2000

As many of you are probably aware, water supply issues are getting more attention in Wisconsin. The “Groundwater Resources of Southeastern Wisconsin” conference held at UWM in January highlighted many of these issues and got reasonably good coverage in the news papers. In addition to the conference, several other water quality issues are also getting public attention.

Summaries of the presentations given at the UWM conference are planned to be included in this news letter. Though all the presentations were relevant, perhaps the issues with the most immediate impact had to do with water quality in the sandstone aquifer and the recharge rates of the major aquifers. Tim Grundl, Robert Taylor, Daniel Feinstein, and I gave presentations that described the changes in water quality and head in the sandstone aquifer and described geophysical efforts to map the distribution of saline water. These presentations all gave consistent indications that salinity and gross alpha levels are rising in the sandstone aquifer in several areas of eastern Wisconsin, apparently in association with the significant decline in head near major pumping centers.

Doug Cherkauer discussed the differences in storage and recharge conditions of the major aquifers at the conference. The sandstone aquifer has a relatively large volume of water in storage, but receives relatively little recharge, making the aquifer susceptible to mining. A first order analysis was presented that indicated that some of the suburbs of Milwaukee may be mining over half of their sandstone aquifer pumpage from storage. By contrast, the sand and gravel and dolomite aquifers have relatively low storage but receive much more recharge. This makes them more amenable to sustained development. Unfortunately, this also means that these aquifers are more closely connected to surface water and surface sources of contamination. As a result, wells in these aquifers must be protected from contamination. In addition, poor well placement or over pumpage can cause negative impacts to surface water. Doug presented some innovative research to map the recharge of the shallow aquifers in southeastern Wisconsin.

In addition to the issues presented at the UWM conference, several other ground water issues have been getting public attention. One of the most prominent is the distribution of naturally occurring arsenic in northeastern Wisconsin. The USEPA is overdue on proposing a new drinking water standard for arsenic. The current standard is 50 ppb. The new standard is expected to be somewhere between 3 and 10 ppb, with 5 ppb as the most likely level. Arsenic is known to cause skin diseases and has been linked to cancer of the skin, lungs, liver, kidneys, and bladder as well as to neurological disorders. If the new standard is set at 5 ppb, an estimated 28,000 private wells will exceed the standard. In addition, over 400 public water supply wells in 48 counties will exceed the standard.

The arsenic problem covers much of the state, but is concentrated in Brown, Outagamie and Winnebago Counties. The arsenic is associated with oxidation of naturally occurring sulfide minerals and may be getting worse due to regional declines in the sandstone aquifer which is exposing sulfide minerals to air during pumping cycles.

Another issue getting attention in the media has been the proposed Perrier spring water bottling facility near the Mecan Springs Wildlife Area in Waushara County. The facility would use a well on private land to divert spring water from the spring orifice on state land. Water that meets FDA bottling requirements for spring water commands a premium price on the bottled water market. Although the WDNR and local groups were concerned about the plan, they found that the existing Wisconsin well codes did not allow the permit to be denied based on surface water impacts. This has exposed a significant gap in the NR811 and NR812 well codes; they fail to protect surface water from ground water extraction. This has been a contentious issue in many states and has been the subject of multi-million dollar litigation between states such as Kansas and Colorado and Kansas and Nebraska. It is an issue that will have to be resolved in Wisconsin as well.

These high profile stories have highlighted the rapid changes occurring in the water supply industry in eastern Wisconsin. The changing water quality and declining heads in the sandstone is causing many communities to look to the sand and gravel or dolomite aquifers for new supply. This is a trend that is likely to continue for the foreseeable future, causing an increase demand on the shallow aquifers.

The connection of the shallow aquifers to surface recharge is causing water utilities to take wellhead protection more seriously. Several utilities are scrutinizing environmental sites near their well fields more closely. This has caused several professionals to question the strong political push for Remediation by Natural Attenuation (RNA) as the first choice for most environmental sites. The slower pace of many environmental investigations has also become a concern.

In addition to the greater risk of contamination, the water balance of the shallow aquifers will need to be understood. The old concept of sustainable yield which balanced extraction and recharge does not leave water for base flow to streams, putting surface water resources at risk. This management philosophy has caused many perennial streams in western Kansas to dry up over the last 20 years. Some way of distributing the available recharge between ground water extraction, base flow, and surface runoff must be established to protect our environment. Perhaps the day of artificial or enhanced recharge is not far off.

In summary, water supply issues are becoming increasingly important to the long term economic and environmental future of the state. The issues are beginning to get the public attention they deserve. WGWA, as the leading ground water association of the state should be involved. As the largest group of experts on ground water, we should be helping to set reasonable standards for assessing surface water impacts from ground water extraction. We also should be advocating rational use of RNA to protect shallow ground water resources. I’ll bet we can all think of examples where RNA was approved for sites where reasonable people would be concerned about the long term consequences on ground water. We are moving into an age where we will soon bump into the limits of our resources. Our future prosperity and well being will depend on how well we learn to live with what we have and use those resources wisely.