Evaluating Risks: Turf v Grass

I've tried to develop a conceptual framework to help us with thinking about the risks and benefits associated with natural grass and artificial turf fields. Much of the discussion on artificial turf have focused on the potential health impacts due to the toxins in the crumb rubber infill or the positive benefit of more available field time. But there are lots of other risks/impacts that should be taken into consideration.

Below is a traditional risk matrix.The x-axis shows the likelihood of a risk occurring, from low to high. And the y-axis attempts to assess the impact if that risk occurs. Generally, you want to avoid the upper right quadrant -- highly likely that a risk will occur, and high impact if it does. You want, as much as possible, to be in the lower left: low risk of occurrence and low impact when it does.

The goal, is to try to find a way to conceptualize all the factors associated with artificial turf, and to work out a way to evaluate the 'apple and oranges' comparisons that are necessary. For example, how do we answer the following questions: Can the added playing time benefit offset the potential negative impact to the environment by the waste generation?

ARTIFICIAL TURF RISK ASSESSMENT

This chart shows my risk assessment for artificial turf. It's not perfect, there is a lot of perception and, admittedly, bias involved, but its a framework that might help the conversation. Whether or not the risk elements are located exactly right on the chart, this framework can help us plan to take action to either minimize the risk of occurrence or the potential impact. I've categorized the risks into 3 groups: Environment, Students and Costs. The size of the ovals represents uncertainty.

Students:

On top left, we see the low risk/high impact element Health. There is some risk that artificial turf components can have a long term impact on health. If it does, its serious. But there is also, the issue that many are not willing to take the risk, so whether a bad outcome is likely to happen, this issue needs to be considered thoughtfully.

There is some risk of Injury, as their is with all physical activity and there is some debate on whether artificial turf or well-managed grass turf is safer. I've rated this issue as medium risk, with low impact.

We know there will be days of high Heat and that they are likely to be more frequent in the future. In addition, turf fields get much hotter on warm days than grass fields do. Efforts can be taken to reduce the impact on students, more frequent breaks, and moving to a grass field when there are extreme temperatures. Of course, this option reduces the cost/benefit of having installed a turf field.

The Weather risk refers to the likelihood of wetter weather affecting the usability of the field. The impact of snow or rain will have a low impact on the artificial turf field's ability to be available for practices and games on the field.

Environment:

There is also a small risk, that the Well could be impacted. We could reduce this risk through engaging a hydrologist to assess the water movement on the site. We could more fully understand the contaminants in the field components. We could review the storm water design and implement best practice elements such as settling ponds.

In the upper right quadrant, we see Waste and Pellets. At the end of the 10 years of so, the field will need to reconstructed; we know this will happen so its a high risk. Typically in the US, the turf materials are landfilled or incinerated in a waste-to-energy facility. It is quite possible that the crumb rubber from this field would find its way to the Covanta waste-to-energy plant in Pittsfield. Environmentally, this is the worst scenario. There is some possibly for some materials to be recycled or reused but various reports indicate that this is rarely the case. To minimize environmental impact, the end-of-life plan for the materials should be determined prior to purchase, and an understanding of their environmental impact be developed.

The pellets will find their way to water resources. Its a challenge to quantify the impact of this occurrence that contributes to micro plastic pollution. Estimates of the quantity of pellets leaving the site vary widely but efforts can be made to minimize the likelihood. They include constructing a barrier around the field area to contain pellets, good maintenance practices associated with storing, and handling of these materials. Brush off protocols for users of the field.

There is also some risk that Storm Water could be contaminated with heavy metals in the crumb rubber. This contamination is likely to be small. The risk can be reduced to improved storm water engineering design and testing of the storm water.

The turf field will require virtually no Water for irrigation. So while there is some risk that water on site won't be available, there is no impact to field use.

Costs:

The capital cost of an artificial turf field is high. And if the field is damaged by overuse or poor maintenance practices the cost for repair can be significant. A thorough examination of the costs and maintenance required, as well as a maintenance fund can reduce the negative impact of cost overruns in annual budgets. Care must be taken so that taxes are not negatively impacted in future years, particularly if there is not broad community support for the field.

NATURAL GRASS FIELD

The risk assessment for sustainably managed natural grass field highlights several important differences from an artificial field.

STUDENTS:

The risk of a high Heat field is much lower since grass does not retain heat in the same way that artificial turf does. The field will be 30-50 F cooler on warm days than artificial turf. Since temperatures are predicted to rise and the frequency of high temperatures days will increase in the future, this benefit may become more important.

Health risks are impacted by the inability to use the field during bad

The risk and impact of Injury is assumed to be about the same as artificial turf.

The impact of inclement Weather on the usability of the field is higher. Early spring and rainy days will result in fewer days of use. This can be offset by alternative activities or more formal arrangements and bus transportation to shared existing turf fields.

ENVIRONMENT:

Since the field does not contain crumb rubber Pellets and does not need to replaced every 8-12 years, there is no risk/impact associated with these elements (Pellets, Well and Waste). There is some risk of impact on Storm Water if pesticides or chemical fertilizers are used on the field.

The grass field will require Water for irrigation. Since water on site is provided by wells with limited capacity there is a risk that water will not be available for irrigation. Consideration could be given to installing water storage facilities to capture rainwater for use when needed.

COSTS:

The capital costs of turf field are lower than an artificial turf field, there are virtually no end of life costs, and maintenance costs, while typically higher can be known in advance.

TAKING A LOOK AT BOTH FIELD OPTIO

Clearly, what these assessments don't do, is evaluate the importance to any element to the decision-makers. Turf fields are available more often for student use, but the sustainable natural grass field, has the lower negative impact on the environment. Whether we can develop alternative programs or approaches to foster active outdoor recreation to offset the loss of playing time and challenging rescheduling of events seems to be an important question to address.