- Art has a double face, of expression and illusion, just like science has a double face: the reality of error and the phantom of truth. - Rene Daumal

Despite my history background, I have long been interested in medicine and am fascinated that treating patients is as much art as science. Think about it. The first thing we do when we visit a doctor is complete a personal medical history, including a family health history. This helps tell the doctor and us, as patients, what might be in store for us as we get older. Next we have our vital signs - blood pressure and temperature - taken and our lab work done. These real-time indicators provide clues to the doctor about our relative health or illness. All these things provide a context for the doctor to diagnose our health problems and to try different solutions to help us return to good health.

Imagine if instead of treating patients, though, we used this approach for restoring water quality. Instead of making one aspect of our evaluation - the total maximum daily load - the centerpiece of all we do with water quality, we in Arizona try to use this more comprehensive approach in dealing with impaired waters.

The first step is to study the landscape, something akin to taking a family health history. We map the geography, inventory the land uses, and identify the resource characteristics and the demographics of the lands surrounding and adjacent to the impaired water. This not only gives us a good picture of what current and historic land uses have been but also sets out the point-source/nonpoint-source relationships. It also gives us a good idea of the people who live and work in the surrounding areas, which is key to the implementation process. We look at the uses we have designated for these waters and the standards that apply to them. We evaluate both their adequacy and relevance against the watershed characterization.

Next we identify the problems. We examine the source waters, surface water-quality issues. and land-use runoff. We use a water assessment checklist that captures such qualitative data as appearance and smell. We evaluate the currency and adequacy of our monitoring data, and if we believe more is required, we dispatch a kind of monitoring SWAT team to perform targeted monitoring. We have created a small team to perform just this kind of monitoring to make sure we have reliable indicators of a water's overall health. This is not unlike taking its vital signs.

If - after characterizing the watershed, assessing its specific health, and accepting the uses and standards are appropriate - we still find the water is impaired, then we begin to craft the solutions. Not until this step does the TMDL analysis come into consideration.

The TMDL framework is really nothing more than a problem-solving approach, which models various discharge and discharge reduction scenarios. We use these models to create pictures of the relationships among sources of impairment, and we try to determine the assimilative capacity for that water body. Through this process, we assign allocations to point sources and nonpoint sources and create a margin of safety for the water because this work, despite the trappings of precision, is really not precise at all.

While it's a bit frustrating to have the wrong piece of the puzzle be so dominating, on the other hand, it has grabbed our attention. And here is its uncertain promise: Court-ordered schedules and EPA work-plan agreements have made counting this "bean" so important to all of us that we have jumped right into it. And even though we are beginning at the wrong place and not looking at the most important things first - such as uses and standards - we are looking at it in various ways.

In Arizona, the generic term TMDL is evolving into a wider framework for evaluating water quality. The result is that, while the statutory and regulatory requirements for a TMDL define it narrowly as a quantitative formula of wasteloads and loads, it is implemented in Arizona as a wider, more comprehensive process.

Implementation plans, which are dynamic, are essential products of this evaluation. They are well-considered efforts to fairly reduce pollutants. In many cases, early intervention is more important than the more detailed proposed solution. It also makes sense to start small and work your way up the "diagnosis" progression rather than spend lots of money when a simple cure might do just as well.

The path to water-quality protection and restoration is a dynamic one. While certainty begets certainty in writing permit conditions, uncertainty requires more care and consideration. Just as in medicine, the rule here should be "First, do no harm."

We need to look comprehensively at the water body in its context and take its vitals. We need to diagnose and prescribe solutions we think will work. And we need checkups on a regular basis to help keep the water healthy. What we cannot and must not do is ignore the problem.

Karen L. Smith, Ph.D., is director of water quality at the Arizona Department of Environmental Quality. She serves as president of the Association of State and Interstate Water Pollution Control Administrators in 2003.

SW July/August 2003