Water For Our Future Award
Monterey County Science and Engineering Fair, 2013
This year’s winner is ninth grade student, McKenna Gibson, of York School in Monterey, California. The title of her project: Copper Concentration in Stormwater Runoff South of Carmel.
McKenna’s project measured copper in two creeks flowing into the ocean from the Carmel Highlands. The locations of these creeks are shown on the map in Figure 1. McDougall Creek is a small stream running through the middle of the Highlands community. Mal Paso Creek begins in the mountains and flows along the community’s southern edge. This watershed has few roads and homes compared to McDougall Creek.
Why would we be interested in copper found in stormwater? First, copper is toxic to aquatic animals. It impairs a fish’s ability to reproduce. It creates a range of stress symptoms, including elevated cortisol levels. In the case of rainbow/steelhead trout, excessive copper has been shown to lower their ability to smell or taste chemical cues in the water. This could prevent fish from finding their way back to natal streams to spawn.
Another reason this project is interesting – stormwater is an alternative water source for California. In some parts of the State, it is being recycled for irrigation. Many believe stormwater will one day become part of our municipal supply. Recently, Pacific Grove announced that the city was considering stormwater to irrigate the local golf course. Because copper can be toxic to plants, we need to know if the water is safe before it is used. There are ways to remove copper from stormwater. But first, we must have the science that documents whether or not there is a copper problem before we spend the money to clean it up. This is why monitoring studies, like McKenna’s, are so important.
As our communities turn to ocean desalination for a future water supply, documenting copper levels in stormwater flowing into the sea presents another point of concern. Although reverse osmosis can remove this metal, it will be concentrated in the brine waste which, for now, is slated to be discharged back into the ocean. This may cause an even bigger problem for marine life.
The primary sources of copper in urbanized areas come from rain gutters and roofing on our homes, as well as brake pads on our cars. During storms, copper is washed into rivers, streams, and storm drains where it eventually makes it’s way offshore. Chronic exposure to copper is not only harmful to marine fish, but excess copper is now being linked to toxic algal blooms too, as suggested by another contending project for this year’s award.
Stormwater monitoring has been ongoing for nearly a decade. Each year, citizen scientists volunteer with the Monterey Bay National Marine Sanctuary to collect water samples during the first heavy rains (“First Flush”). Typically, these storms contain high amounts of pollutants, which make the chemicals easier to detect with simple, inexpensive tests.
Data from “First Flush” monitoring is publically available online . Thus, if you wanted to study pollutant levels from a location that has never been monitored before and compare it to areas already in the database, it would be easy to do. This is exactly what McKenna did.
In her study, McKenna hypothesized that less urbanized areas would have less copper in stormwater compared to more developed sites. To show this, she analyzed levels in McDougall and Mal Paso Creeks on four separate occasions; once before the rains began (September), next during the First Flush event (October), and again in November and January. She then compared her results to sites in the First Flush database. Her conclusion provided a humbling reality for our community: urban development is linked to higher copper levels in storm runoff.
Water quality objectives for stormwater are based on California’s Central Coast Basin Plan. For copper, limits are set at 30 parts per billion (30 micrograms/liter). To highlight the growing concern over copper, McKenna cites a study from 2011 in which half of all monitored sites around Monterey Bay exceeded copper limits, including four of five sites monitored in Carmel. Her study on two new sites south of Carmel gives us a glimpse of what copper runoff in Carmel used to be and what Carmel Highlands could become as the area continues to grow.
After the first rains in October, McKenna’s data showed copper levels in McDougall Creek dropped dramatically to safe levels and stayed there. The consistently low levels observed in Mal Paso Creek were best explained by less urbanization. In the Discussion, she noted that the easiest way to control copper was to stop it at the source; that is, to simply make car brakes, gutters, and roofing materials without it.
What we, as judges, saw in McKenna’s well-referenced, statistically analyzed study was sound evidence for why stormwater cleanup is so important. We were impressed. Once again, Monterey County’s young scientists are exploring ways that can solve a water shortage. For our future, I continue to be very hopeful.
The Water For Our Future Award was created by Dr. Carol Reeb at Stanford’s Hopkins Marine Station and is sponsored by CSUMB’s Watershed Institute. It seeks to encourage young scientists to think now about future ways to solve a water shortage at home, at school (work), or on the farm. Apologies for the late posting of this year’s winner. I had a major project report to finish, myself.