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The Watershed Project

creek

Bugs Know Best | What Tiny Water Insects Can Tell You About Your Creek


By Drew Jack

How can you tell if a creek is healthy or not? One way is to look at the bugs living in the creek. These bugs are called Benthic Macroinvertebrates (BMIs)– Macro, because we can see them without a microscope and benthic or benthos, meaning bottom, because they live on the stream bottom. BMIs allow us to evaluate the health of a creek because they are an important link between lower level resources such as algae, leaves, woody debris, and water plants and organisms in higher level organisms such as fish, frogs, and birds.

If BMIs are missing then we can say that the creek might be polluted or degraded. Why can we say this solely based on the absence of BMIs? Not only because BMIs are the vital link between plants and animals, but also because they are also very sensitive to changes in the ecosystem. They can only live in well-balanced ecosystems with steady pH levels, dissolved oxygen, and water temperature. Human actions like fertilizer and pesticide use can cause the physical and chemical characteristics of a creek to fluctuate wildly. Therefore, these bugs allow us to identify creeks and streams that may be impaired as a result of human actions.


So, how do we use BMIs to determine the health of a creek ecosystem? First, we need to know which BMIs should be in a healthy creek. The types of BMIs vary from watershed to watershed and among locations in one stream itself. Fortunately, scientists have done much work regarding macroinvertebrate types. This work is compiled into an Index of Biological Integrity (IBI). An IBI describes which BMI types should be in the stream and the particular sensitivities of the BMI.

The next step to determine creek health is to actually sample the creek for the BMIs. Using a special net, called a kick net, that is placed flush against the stream bottom, the sampling team gently scrubs the rocks about a foot in front of the net which allows the macroinvertebrates to be swept downstream and collected in the net. This is usually performed several times in different sections of the stream to obtain a good representation of the stream. The captured BMIs are then placed in a sample jar which is taken to an expert taxonomist– a person trained to identify all of the BMIs.


The last step in a BMI survey is to compare the report from the taxonomist to the IBI for the creek. You must pay attention to dominant bugs and bugs that are scarce or missing altogether. If major differences are found between your sample and the IBI, then you can say that the stream is unhealthy or stressed.

The next time you are near local stream, take a look under a rock or two and see what kind of bugs you find, you might be surprised at what you find. If you are interested in participating in a BMI survey of a local creek, contact Juliana@thewatershedproject.org.

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What’s in Your Watershed? | The Dazzling Damselfly


By Diana Dunn

Dazzling damselflies dancing through the air seem to be heralding the arrival of long summer days. However, these prehistoric looking insects do not always bear their lacy wings which enable them to dart around so effortlessly. Surprisingly enough, damselflies spend a portion of their lives wingless and underwater!

Damselflies are aquatic insects, and can be found living near the sun dappled waters of our local creeks. As nymphs, damselflies emerge from their eggs, which females slyly conceal in the tissue of riparian vegetation. During their underwater, adolescent phase damselflies have three flat, leaf-like appendages attached to the end of their abdomen. These delicate structures are gills used for breathing, and the larvae spread them apart like a paper fan to capture dissolved oxygen in the water.


The larvae are not strong swimmers and must find their way to still or slow moving water. Even though damselflies are not the most efficient at traveling through the water they are far from being fragile and meek creatures. Damselfly nymphs are fierce predators with a voracious appetite. Damselfly larvae are able to shoot their lower jaws out from their bodies at nearby prey. Spine-like structures at the end of the extended jaw capture an unsuspecting victim and sweep the target up into the mouth of the damselfly where it’s swallowed whole. When the prehensile jaw is not being used, it is tidily folded across the face of the damselfly nymph, and for this reason is known as its “mask.”


After ten long months of living, hunting and feeding in pools along the creek bank, damselfly nymphs will molt and become adults with their recognizable large, veined, translucent wings. Unlike their relatives, dragonflies, which hold their wings outstretched to the side of their long slender bodies; adult damselflies hold their wings together outstretched above their bodies. One other noticeable difference is that dragonflies are considered better flyers, but adult damselflies can be frighteningly quick in order to capture prey with their long, slender legs. These subtle characteristics can help creek-goers distinguish the difference between dragonflies and damselflies.

Not only are damselflies unique and exquisite looking insects, but their presence or absence in a riparian habitat is a wonderful indicator of creek health. If damselfly nymphs are found in the pools of local tributaries it typically means that the water quality is good in that creek. Damselfly nymphs can be sensitive to pollution if the amount of dissolved oxygen in the water decreases. Increased nutrients, like nitrate and phosphate, usually decrease oxygen levels in creek water. Most frequently, high nutrient levels in creeks can be attributed to fertilizer runoff or a leakage in septic systems. By taking preventative actions within our own homes, we can improve the overall health of our local creeks and watersheds and also enjoy the sight of iridescent damselflies zipping back and forth in the warm breeze.

To help support our efforts to restore local creeks for damselflies and other riparian species, CLICK HERE to DONATE.

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Are Creeks Dangerous? | Tragic Loss Raises Concerns About Channelization

L.A. River
By Caitlin Bell

On Saturday, February 19, 2011, Gavin Powell and Matthew Miller climbed aboard an inflatable raft and set off down Walnut Creek, unaware that the flooded and fast-moving channelized river would prove to be too dangerous to handle. As the city of Walnut Creek mourns the loss of two vibrant, happy teenagers, residents look to the source of the tragedy: the channelization of the creek.

Bill Kier, a resident of Walnut Creek for more than 60 years, wrote a poignant letter in the San Francisco Chronicle. “Our hearts go out to the families” he wrote. “My heart aches, too, for the community for the loss of their creek… Reading the story of the boys’ deaths in a concrete channel with 20-foot vertical drops, you had to wonder what kind of crazed engineering had befallen Walnut Creek.” As more and more streams are channelized around the state and across the country, we must consider the impacts of hydro-engineering projects.

sausal creek
The modification of natural features is not done without reason. Indeed, hydro-engineering projects such as channelization or the installation of culverts are generally done to control natural hazards such as flooding or erosion that are impacting private or public property. Many of these projects are necessary to prevent the loss of land and even lives. But these projects also “harden” natural landscapes, making them foreign, unnatural, and off-limits to humans.

Current global environmental trends point to a stormy future. Typically, cities have dealt with increased precipitation levels through the use of engineered solutions. However, employing natural methods to control flooding is also an option. Increasingly, municipalities are choosing to return the landscape to a near-original state and allow nature to reactivate its flood control system. “Daylighting” enclosed culverts may not be an option in all situations, but when possible, restoring a creek to a more natural state not only redirects control to a time-tested, natural system, but also gives residents a chance to reconnect with part of their community.

strawberry creek
Creek restoration is an expensive and labor-intensive process that may or may not prove to be effective in addressing environmental hazards. In today’s economy, many urban planners are hard-pressed to justify the removal of existing culverts and channels. But as the economy improves and as older structures become expensive to maintain, opportunities will arise to choose a different, more natural path to flood control. It is critical for communities to seize these opportunities, and take a more holistic approach to urban planning. By including recreation and aesthetics in our design plans, we can hope to gain back our lost connection with nature, and avoid future tragedies.

Editor’s Note: After the publication of this article it was brought to our attention that Contra Costa County has begun to develop a public outreach campaign to educate citizens about the hazards of channelized creeks during periods of flooding. The Public Works Department has also addressed these dangers with a 50-year plan for the county’s existing engineered structures, which can be viewed via the link below.


Photos: Channelized stretch of Los Angeles River; Sausal Creek Daylighting Project, Portola Valley; Strawberry Creek Daylighting Project, Berkeley.

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From One Watershed to Four | Riparian Lab Sprouts A Future


By Andy LaBar

When The Watershed Project introduced the Riparian Lab after-school creek ecology program in 2008, it was an attempt at something new and different. The Riparian Lab pilot program has grown like a weed over the past year, expanding from one site to four, all in different watersheds.

The program started at Booker T. Anderson recreation center, located along Baxter Creek in Richmond. Staff alternated between conducting lessons in the classroom and outside at the creek. In anticipation of the drop-in nature of an after-school program, the lab blended hard science like water quality testing and erosion experiments with fun, environmentally-themed games like “Predator Prey” and a tag game focusing on Bioaccumulation.


We started the growth by working along Wildcat Creek as it runs through Davis Park in San Pablo. Last year, that program shifted to be a part of the official after school program at nearby Dover Elementary. Twenty students attended the eight-week session, which culminates in a creek clean up. The Wildcat Creek Riparian Lab is continuing this spring, charged with a new group of 20 students and city plans to continue beautifying the creek with the help of proposition 84 funding.

In partnership with Lincoln Elementary and OASES, the Riparian Lab also expanded into Oakland. We focus our outdoor piece on Lake Merritt and the channel that leads past Laney College into the San Francisco Bay. By developing curriculum that the OASES staff can help lead, the students participating in this program will receive up to 32 creek lessons, rather than the 8-10 of most other programs. Additionally, students are documenting and reflecting on their experience with the lake by taking photos and writing haikus.


A fourth watershed was added to the program this past fall when we partnered with SPAWNERS and the El Sobrante Boys & Girls Club, located on Appian Creek. This program allows students to drop-in so as not to discourage irregular after-school program attendees to join in the fun. The program also encourages older students to take a leadership role in many activities.

What started out as an untested pilot has blossomed into a successful, exciting and evolving program. At each site, one of the students’ primary goals is to leave their creek in better shape than when they started, allowing students in each subsequent group to continue the improvements. From one watershed to four and with passionate students in tow, the Riparian Lab is extending The Watershed Project’s mission.

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