USDA’s Natural Resources Conservation Service has developed a new web-based tool to help producers easily calculate the quality of water flowing off their fields.

It’s called the Water Quality Index for Agricultural Runoff, or WQIag for short, and this is how it works: Producers input variables about their field, such as slope, soil characteristics, nutrient and pest management, tillage practices, and, finally, conservation practices.

Then, as NRCS National Water Quality and Quantity team leader Shaun McKinney explains, “The WQIag takes the complex scientific information of these variables and synthesizes them into a single number.”

Though some variables – such as slope and soil – won’t change, producers can adjust others for a quick estimate of how conservation impacts water quality. A few clicks calculate the consequences, in terms of water quality, of using less tillage, less fertilizer, natural pest management techniques and other conservation practices.

“Water quality is complex,” says McKinney. In the past, “experts have usually focused on one aspect of water quality – such as temperature, nutrients or pesticide content –instead of thinking about a more complete picture.”

When experts do talk about the complete picture, their common vocabulary is math and science. It’s not always easy to get producers on board with improving water quality, in part because conversations on this topic often quickly become highly technical, leaving most non-scientists behind.

“This is a problem,” McKinney says. “How can we talk to producers about improving water quality, when we can’t explain it in a clear way?”

The Water Quality Index for Agricultural Runoff addresses this problem with two features that set it apart from previous measures of water quality: simplicity and accessibility. First, the WQIag simplifies the result into a 10-point rating everyone can understand; second, it’s available to anyone with an internet connection.

Before the WQIag, there was no simple way to rate water quality. Experts installed monitoring stations that tested water as it flowed off fields. These stations provide actual measurements, but they’re expensive and interpreting the measurements requires a scientific background.

“Our solution was inspired by the Dow Jones Index[es],” says team member and Environmental Engineer Harbans Lal, referring to the well-known system that tracks investments like mutual funds and stocks. “We wanted to represent something very complex with a single, easy-to-understand number.”

“The WQIag is still in the pilot phase, but we’re getting a lot of useful feedback. We’re using that feedback to fine tune the software and make it even better,” says Lal. “We hope to eventually offer the WQIag as a free smartphone app.”