On Mar. 17, reader Deren Ash posted a complex comment on the MauiTime Facebook page to my Mar. 16 cover story “The County of Maui is already in hot water over sewage in the ocean off West Maui, but a new study says that the Kihei coast is far worse.” The story detailed recent study published in Marine Pollution Bulletin concerning the possibility that treated sewage injected into the ground at the Kihei Wastewater Reclamation Facility was migrating to near shore waters, specifically around Cove Park and Kalama Beach, and potentially killing coral there. Specifically, Ash found fault with the notion that the injection wells were a source of the pollution found in ocean off Kihei.
Here are Ash’s comments:
The article authors clearly don’t know the difference between storm water runoff and effluent from injection wells, and it makes a huge difference in deciding how we spend our resources fixing it. It doesn’t seem like they are able to understand more than one variable. They talk about sediment and turbidity it causes, but that’s not from sewage effluent, that’s from stormwater runoff. Is there a nutrient loading problem from injection wells? Maybe, but nothing in the article indicates that. In Lahaina, they were able to make the determination based on nitrogen isotope studies. The fact that there *is* high turbidity indicates there is most certainly nutrient loading from stormwater runoff, so actually contradicts the hypothesis of the high nitrogen being from injection wells. However, injection wells could certainly still be adding to it, but without a nitrogen isotope study how much it contributes is nothing more than a guess.
Note that just because it’s from stormwater runoff does not mean humans aren’t at fault (we probably are or at least contribute significantly to it) or that we can’t or shouldn’t mitigate it. But what we do to mitigate matters *a lot.*
Given the science involved with all this, I asked Mailea Miller-Pierce and Neil Rhoads–the authors of the study I wrote about–to respond to Ash. It took them a few days, but they formulated a response. Here it is:
Daren makes some good points and has some misconceptions–ones that many people might also share.
One goal of our research was raise awareness of the publicly available water quality data collected by the Hawaii Department of Health which exists for Kihei and Lahaina. We acknowledge and state in the paper that there are multiple sources which may be responsible for nutrient loading, not just the WWRFs.
The isotope studies done by [Charles] Hunt and [Sarah] Rosa clearly show the presence of wastewater effluent mixed with ground water emerging in the Cove Park and Kalama Park nearshore environment. The wastewater includes man-made chemicals such as fire retardants, fabric brighteners, and pharmaceuticals which are not found in nature and can therefore be used as intrinsic tracers. Hunt and Rosa analyzed the tracers and the isotopes and show rather conclusively the magnitude and location of the effluent.
If you visit our web site www.EcoOak.org you will be able to see diagrams showing the boundaries of the effluent plumes for Kihei and Lahaina as determined by isotope and tracer studies. If you want to go into the details yourself, we also have downloadable copies of those studies as well as others, such as isotope studies by [researcher Meghan] Dailer et al which also show that the locations of the WWRFs coincide with some of the highest concentrations of pollutants observed.
As for turbidity, sadly we do not know of any comprehensive studies covering Maui’s coasts. Those of us who live here see the evidence for ourselves. Bad storms can result in massive runoff that takes weeks to clear. High surf events occurring months or years later can stir up and re-suspend old sediment and reduce visibility to a matter of feet. The shallow water near Cove Park does not seem to exchange well with the deeper water hundreds of yards from shore. We could not find an aerial photo of runoff at Cove Park, but our web site does have photos of runoff near Lipoa Street and Kalepolepo Park. (If you have such photos please share them with us.)
Another goal of our study was to encourage further, more detailed research into what effects these pollutants are having and take constructive action. Community involvement is also essential and we hope the diagrams, charts, and interactive maps on our website will be a good resource. Suggestions on policy decisions or how government resources should be spent is beyond the scope of our research and is up to the policy makers, stakeholders, and the public.
Click here to read our original article.
Photo of Cove Park in Kihei from 2006: Forest & Kim Starr/Wikimedia Commons