Morro Bay's Marina Street outfall becomes
a foamy mess with very little rainfall.
It's
a good illustration of how a small amount
of rain carries surface pollutants into the estuary.
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Rains, the Watershed and Pollution -- Part 2
from the Morro Bay National Estuary Program
Last month, part one of this article explored watersheds and how geography plays a role in the unfortunate potential for rain to compound water quality problems. (Read that article here.)
This month, in part two, we'll dig deeper into what those pollution threats are and some opportunities to help solve them.
Urban runoff, also known as stormwater runoff, is generally considered to be one of the leading causes of water quality contamination in many areas, but what exactly is it? In short, it is the water traveling over our roofs, city streets, and walkways after a rainstorm. Naturally, there"s a good deal more to the concept than this simple answer provides.
At the heart of the problem are "impervious surfaces." Generations of urban designers were taught to quickly shunt excess water away from populated areas in the interest of avoiding flooding. Our rooftops and streets are designed to shed water, not absorb it. When it rains, the water falling onto these surfaces must go somewhere. A network of gutters, drains, and pipes works to quickly whisk this surplus surface water away to prevent flooding. Unfortunately, this rapidly moving water carries with it any surface pollution.
On the Central Coast, most of our precipitation falls between October and May, followed by a long dry period. As soon as the last storm of the season has passed, pollutants begin building up on streets, driveways, and in our storm drainage system. A small oil leak from an automobile, failing to pick up after a pet or over fertilizing landscaping all contribute to this build-up until it is all washed into the drainage system by the first storm of the season.
This highly concentrated pollution load from the first storm of the season is known as "First Flush." As the rainfall courses over streets and sidewalks to the drainage system, it picks up all of these pollutants and deposits them in the body of water at the end of the line. Many people erroneously believe that storm drains lead to a treatment facility or filtration system to remove pollution. In Morro Bay and Los Osos, this is not the case. Stormwater (as shown in the photo) drains directly into the Morro Bay estuary without any prior treatment, carrying with it bacteria, sediment, heavy metals, and litter.
Since 2005, the Estuary Program has been regularly sampling First Flush runoff. The results show that stormwater is polluting the Morro Bay Estuary.
These pollutants include:
Oil and Grease: from a variety of sources including soaps, foods, and cars.
Nitrates: Commonly found in fertilizers.
Dissolved Metals: Primarily generated by tire and brake wear from cars, as well as architectural features. Zinc and copper are two of the most concentrated metals.
E. coli bacteria: E. coli is an indicator of fecal contamination by people or animals.
What is also clear from the data is that natural waters are not safe for swimming immediately following a storm.
Swimmers and surfers are advised to stay clear of the water for at least 72 hours following a storm. While people can avoid this surge of pollution by staying out of the water, the fish and wildlife in the Morro Bay Estuary cannot, and we need your help to protect them.
Stormwater runoff is a "nonpoint source" pollution problem. This means that no single person, business, or agency is directly responsible for creating the problem. In fact, everyone who lives in the community plays a role in creating stormwater pollution, and everyone can help solve this problem.
How do we clean this water up? Make sure only rain goes down the storm drain!
1. Don't wash your car in your driveway.
Oil and grease from carwash soaps, copper from brake dust, zinc from tires, and phosphates from soaps will all go straight to the stormdrains. If you take your car to a coin wash or commercial car wash, the wash water is treated onsite to remove pollutants.
2. Avoid applying fertilizer, herbicides, or pesticides to lawns and gardens when there is any chance of rain.
There's no way to know if it will rain a half an inch or three inches. Apply fertilizer when you can control the amount of watering and runoff through an irrigation system.
3. Support street sweeping efforts by your city or community services district.
Street sweeping literally vacuums up stormwater pollutants. Sweeping removes not only large pieces of litter (like cigarette butts or food wrappers) but can also retain smaller particles from automotive wear and tear.
4. Pick up pet waste.
Animal droppings left on the street are both unsightly and a source of bacteria.
5. Take the next step.
* Learn about catchement systems which capture runoff from your roof and other impervious surfaces on your property. Making use of this water for landscape irrigation can save on your water bill and recharge our groundwater!
* Naturalize your landscaping. Replacing hard surfaces with natural groundcovers and porous paving allows rainfall to soak into the ground, recharging the aquifer and preventing runoff.
* Conduct a water audit at your home and cut out the waste. Sending less water into treatment plants can help alleviate over taxed systems and save money.
More information on this and other estuary related topics can be found at the Morro Bay National Estuary Program website.
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