Construction of Wetlands - 1992-93



The Students: Autumn Gestrin, Kyra Guest, Jerimi Paul, and Jennifer Reif

The Teacher: Clinton A. Kennedy

Awards: 1993 Seiko Youth Challenge West Region Semi-Finalist - Wetlands to the Rescue



Wetlands To The Rescue

Summary Page

Cascade Reservoir was built for irrigation purposes in 1942. In the early 1970's it was discovered that the water quality was getting poor, as a result of reoccurring algae blooms. Little has been done to improve the situation. This is do to roadblocks such as diplomacy, irrigation water rights, obsolete laws that protect those rights, and financial shortage.

The tourist industry has given us reason to examine possible solutions to the problem of phosphorous loading. Much of the business conducted in Cascade is a direct result of tourism. Cascade needs the tourist industry to provide jobs and income for its occupants.

After considering several solutions, including BMP's, (best management practices) land application of sewage, alternate sewage treatment, dredging algae, and wetland benefits, we decided that the best option was wetland usage. Our decision was made after much chemical and biological research concerning the lake. We ran several tests on the lake water to determine water quality. Our conclusion was that the quality is good to fair. We also collected and examined organisms form the lake to cross-check the results that we got from the chemical tests. Our diversity index indicated that the water quality was fair to poor.

To get more information on the lake we asked speakers to come to our class. The speakers ranged from scientists, engineers, and forest and land managers. The promoter of the Valbois ski resort also accepted our invitation to speak to the class.

We also went on a field trip to Boulder Creek, which is a tributary of Cascade Reservoir. During this trip we gained more information on wetlands and BMP's. Another field trip found us being filmed for a state-wide television program known as "Incredible Idaho." We were shown on television three weeks later.

There are several reasons for our choice of building a wetland as a solution. Overall, wetlands would have the best effect on the environment with fewer drawbacks. A wetland is the same treatment nature uses to assist lakes. There's no unplanned and damaging side-effects that might be the case with a biological/chemical solution. It would filter for phosphorous, and help reduce nutrient loading, (not to mention offer an appealing physical appearance).

A wetland on Mud Creek would significantly drop the amount of phosphorous and other nutrients that enter Cascade Reservoir. Therefore, it would be the best and most logical solution.



Wetlands to the Rescue

As we attempted to come up with a hook (fish hook) for this project, we were abruptly snagged by an idea. What was that idea, again? Oh no! We couldn't remember. We'd all been netted by amnesia and couldn't seem to "gut" what the idea had been. We were engulfed with a humid mist of a rotten stench. No matter how hard we pulled, we couldn't reel in a line of the idea from our heads. The ground underneath us started writhing, and a worm's voice shrieked, "Help! Get me off the hook and outta' this god forsaken lake!" We all got up to run, but unfortunately we took off in opposite directions. . .towards each other. CLUNK. After a lot of moaning and rubbing our bruised skulls, we decided to help the worm by helping the lake. Thus, began the Biowired (that?s us. . . every super hero has a secret identity, you know) crusade to save the Cascade Reservoir. It's also how we got involved in the glorious Seiko Youth Challenge (insert applause here). Okay, okay, back to reality. The Seiko Youth Challenge was brought to our attention by the devoted Advanced Biology Teacher, Mr. Kennedy. Our class performed several labs and projects to learn about the Cascade Reservoir.

The Reservoir is approximately twenty-one miles long. Its width varies form one to four miles across. The lake is fairly shallow, with an average depth of 26.5 feet. It supports one of the biggest fisheries in Idaho, putting out anywhere from 300,000 to 400,000 game fish annually. Construction of the Reservoir began in 1942, but was interrupted by World War II, It then resumed in 1946, and was completed two years later by the Bureau of Reclamation. The lake was intended for use as a hydroelectric and irrigation facility. It was first filled to top capacity in 1957. The Reservoir has become very important for recreational use. It brings in a large amount of tourism business. About 255,000 people came to the reservoir in 1988 to swim, boat, camp, and fish. Increased use has caused environmental damage and higher demands on the limited water. One of the may problems we decided to tackle is phosphorous loading. Before we could attempt a solution, we needed to learn more about through research and by running a few tests.

To test the water quality of the lake, we ran a variety of tests using LaMotte and Hach kits. The tests helped to determine oxygen, carbon dioxide, pH, phosphate, nitrogen, temperature, and turbidity of the reservoir. To get water samples, two people went out on the lake in a canoe, and dropped a bottle secured to a brick. Once the contraption hit bottom, one person pulled a rope (that was connected to the cork) and the cork was released from the bottle's mouth. The water in the bottle was used to run tests on. The sample bottles were sealed while they were still under the water in order to prevent additional oxygen from entering them. The tests were run on site so the readings would be accurate. (Gases come out of solution if the temperature raises, and will go into solution if it drops. The tests had to be run before the temperature of the sample changed.) The depth of the water was measured with a rope marked off in meters. The depth was important because it can be used to find the thermocline level and to determine if one actually had occurred. It was also useful in finding the oxic level and the approximate level at which the lake became anoxic.

After testing for oxygen, we discovered that we had a wide range of measurements. This is probably because of algae. During the day, algae produces an excess of oxygen through photosynthesis, but during the night, it uses up an equal amount of oxygen, through respiration. The fact that we took samples at different times of the day, probably accounts for the difference between measurements.

As with most projects, there were some draw-backs to our procedures, but we found solutions to them. During our first attempt at measuring temperature, the thermometer was lowered to the bottom layer of water by a string. It was then pulled up. However, the thermometer reading wasn't accurate after passing through different temperature levels (strata). We then filled a container with water from the hypolimnion (bottom density layer) and measured it?s temperature. This worked much better, and was tremendously more precise.

After leaving the site, we returned to the classroom. In order to accurately check the amount of phosphate, we used the spectrophotometer. To do this, we first had to test different known concentrations of phosphate, and plotted absorbency/concentration graphs. We used the Lambert-Beer Law (which states that for a given concentration range the absorbency is directly proportional to the concentration of solute molecules) to create a linear plot used to determine unknown concentrations.

A month was spent observing, sizing, and identifying organisms that had been collected from the Reservoir. We were able to classify the water in the lake by using the organisms as indicators of water quality. The diversity index (a measure and distribution of organisms in an ecosystem) of a body of water gives a general idea of water quality. A variety of organisms were found. Some indicated good water quality, such as daphnia, snails, and euglena. Others indicated poor water quality: annelids, mosquito larva, bryozoan, tubifex, and blue-green algae. Most of the organisms lived in moderate water, such as crustaceans, arthopods, musses, bristle worms, sideswimmers, and dragonflies. The assignment didn't include observing fish, but we knew about different species located in the reservoir. These species also helped us to determine water quality. For example, trout are found in clean, cold water. There were also suckerfish, squawfish, and catfish, which are usually located in poor water. Perch, Crayfish, and Bluegill live in moderate water. All of the above fish reside in the Cascade Reservoir. With this information about the organisms, we can, with some accuracy, state that the Cascade Reservoir has moderate to poor water quality.

Many factors could have influenced our conclusion and caused errors. For example, the samples were gathered during the months of fall, which could have had a major effect on the types of organisms that were collected. There is seasonal variation in the numbers and types of organisms. The fact that the organisms some samples were taken before, and some during turnover, probably had an influence, as well. Turnover occurs when stratified layers reach the same temperature (four degrees) and therefore the same density. This causes the layers to mix and distribute nutrients uniformly throughout the lake. Samples were collected at different areas of the reservoir in order to gain a fairly wide range of organisms.

We learned that the lake did thermostratify. When thermostratification occurs (temperature layering), density is affected, along with gases in the lake. As the density/temperature increases, the gases become less efficient at mixing thus, less oxygen is available for organisms. The top layer (epilimnion) isn?t getting any oxygen to the other layers, and the hypolimnion is anaerobic. The different layers caused by changes in temperature which affect density. The epilimnion moves down as the hypolimnion moves up, thus cramming fish into a single layer and decreasing their ability to move effectively. (This puts a lot of stress on the fish, obviously, and therefore lessens their chance of survival.)

Algae located in the epilimnion sinks to the bottom and starts to decompose (using up the oxygen that the fish need). This algae (organic snow), is decomposed by bacteria located on the bottom of the lake oxygen is taken from PO4, SO4, NO3, and CO3. (Algae is also the source of the Red Tide, which is a toxin that is harmful to aquatic organisms.) The carbon dioxide given off by bacteria forms carbonic acid when it combines with the water, so the pH of the water is lowered and nutrients are able to go into solution easier. The increased nutrients cause algae blooms to occur, and wave action dissolves more nutrients and sediments, causing even greater algae growth. Additional nutrients are gained form point sources (sewage/irrigation pipes) and nonpoint sources (grazing cattle, recreation, timber and harvest, road construction, etc.). These aren't the only cause of poor water quality though.

Cascade Reservoir is a draw-down reservoir. This means it's water level varies, which causes problems. Temperature changes, exposed spawning beds, reduction of space for organisms to live/increased competition among organisms are common difficulties of a draw-down reservoir. Another problem is the inability for a Riparian habitat to form. A Riparian habitat is the area around a body of water in which vegetation and other organisms flourish (sort of like the Garden of Eden...It even has the snakes). A Riparian Zone provides cover in the form of overhanging vegetation. The vegetation provides shade for the water which in turn lowers the temperature of the water (which benefits cold water aquatic organisms). The Riparian habitat is also a place where fish lay their eggs and live. The Riparian Zone provides food for land animals, as well. Deer and other herbivores eat the surrounding vegetation and use it as protective cover. A Riparian area stabilizes stream banks to reduce erosion and helps block solar radiation. The mud around the zone is the heart and soul of a lake because it stores and recycles nutrients back into the lake. A draw-down reservoir, such as Cascade's, will not develop a Riparian Zone because of the fluctuating water level. Since the Cascade Reservoir lacks a Riparian zone, it has none of the advantages of one.

Field trips provided further information for the benefit of our project. Michael Ingham (Idaho Division Environmental Quality), David Blew (Idaho Soil Conservation Commission), Nancy Blew (Idaho soil conservation Commission), Kathleen Menke (Valley Soil Conservation District) and Dewey Worth (Department of Environmental Quality) took us on a field trip to Boulder Creek (a tributary of Cascade Lake). Boulder Creek contributes five to twenty percent of the phosphorous load (thirty percent of it comes from agricultural activity and twenty-two percent comes from forest activity). In a 1986 test of the creek, total Fecal Coliform bacteria counts were high. There were significantly higher amounts of total phosphorous, and two samples showed a violation of water quality standards (this does not bode well for the lake). We participated in biological samplings of the creek (we scraped bugs off the bottom of rocks). We also took part in observing and discussing wetlands. We studied the diversity of its insects, riparian zones, and the projects for improvement currently taking place, as well.

Another adventurous field trip was to the Cascade Reservoir Association meeting. Many of the speakers talked about problems concerning the lake, like Nitella, the most common plant species found there. This plant grows in thick masses that cover the surface of the water, causing transportation on the lake to become difficult; and nearly impossible when it becomes entangled in a boat's propeller. Some ideas for a solution were brought up, but many were too expensive to implement and would cause complaints from people such as fishermen. For example, and idea such as draining the lake, cleaning it out, adding a sand bottom, and refilling it, was one suggestion.

The news of our project involving the lake spread quickly, and a state-wide television program ("Incredible Idaho"), asked if they could film us in action. The film crew came to our school and went with us to the Goldfork site (on the north end of Cascade Reservoir). The crew spent most of the time interviewing various individuals who spoke about the lake's problems. They followed us back to the classroom. Once there, they filmed us using the spectrophotometer to examine the water. Three weeks later, the program aired on a popular channel across the state. Later, there was a special segment shown on the news about our class.

We asked several people to come and talk to our class about the lake. Don Anderson was one speaker that accepted our invitation. Rather than give a lecture, he answered our questions about Cascade Reservoir. When asked about whether stratification (heat layering) occurred in the reservoir, he said that he believed it did. He said that the lake is anoxic throughout the summer and that "anoxia is worst in the summer. . . .algae are floating around and wind pushes them to shore. During the nighttime oxygen sags, perch kills are fairly common and severe, and the fact that the lake does smell bad, indicates that the bottom is anoxic." He also said that "Right now, it looks like 14% of the lake will support trout during summer stratification, and even those trout are stressed out." That statement shows how desperate the situation is at Cascade Reservoir. Obviously, the water quality is poor and getting worse.

He stated that in the dam area, stratification won't occur if the water level is under 20 feet deep, and that right now, not all lot of stratification occurs there. According to Anderson, "Cascade Reservoir recycles most of its nutrients, and 15% of the nutrients come from internal recycling, (yet some believe it is more). Increasing the amount of oxygen in the lake will have a short term impact. Some oxygen can be added by bringing the four degree water to the top layer of ice during winter, which will cause the ice to melt. (One problem being the fishermen that happen to be standing on the ice at the time.) Only by removing the phosphorous, will there be any long term impact though, and Goldfork and Boulder Creek are significant sources of the phosphorous loading (they've gone over the state limit)."

Jim Messerli (a former U.S. Fish and Wildlife Biologist) accompanied Don Anderson to our class. Messerli joined the discussion with us about some possible solutions for the problem of water quality (such as: wetlands, land application, and BMP?s). Messerli coughed and passionately spewed, "I think a big problem is going to be in withholding water from irrigators. . .water rights in Idaho are fighting words!"

Dennis Taggart, the proposer of the Valbois ski resort, spoke to our night class about land application of sewage, wetlands, and ponds. One of his top engineers accompanied him and spoke of wetland benefits. He lectured on the impact of the proposed Valbois resort on the surrounding area, as well. All of the speakers that were gracious enough to speak to us helped tremendously. They offered information and suggestions for our possible solution to reducing phosphorous loading of Cascade Lake.

Our solution is to build a wetland. Dennis Taggart offered us three to four acres (it has to be at least half an acre to be considered a wetland) of land near the Mud Creek are to build this wetland. According to Don Anderson, the only drawback is that it's difficult to build. "Wetlands are a pain." However, there are several very vital ways that wetlands benefit the area surrounding them. If water goes through a wetland before it is put in the lake, then the wetland would reduce the amount of phrosion by blocking wind. The roots help bank stability by holding soil in place. The phosphorous that wetlands efficiently trap provide food for plant species there. The nutrients are used by vascular plants and so taken out of the water.

The level of water in a wetland is one factor that determines what plants will grow there. Plants have specific water heights that they can grow at, these heights are called hydroperiods. Deep water prevents short plants from getting sunlight, and shallow water exposes too much of the tall plants to weather and animals. Some floating plants found in wetlands, include duckweed (which has a high tolerance to nutrients such as phosphorus), and lilies which are adapted to floating and change in water levels. Usually there's plenty of plant diversity in wetlands, but sometimes one of two types of plants take over. For example, cattails are nutrient competitive and can out-compete other plant species. This causes problems. If the plants are monotypic (meaning only one of two different species rather than several) then a single bug of disease can easily wipe out the whole lot of them. Sometimes the leaves of plants are observed to check how healthy they are. Leaves indicate the nutrient content and selectivity that the plants use. A vegetation analysis can be run in which the chlorophyll content can be taken (the more dense the chlorophyll, the higher the content of nutrients) to determine to plants' well-being.

The trapped water is stored and used by wildlife, such as moose, deer, and beavers as a source for food and water. Willows growing near the wetland are a protein source for such animals. Overhanging vegetation maintains cool water conditions, as well as providing shade and shelter for fish and other aquatic organisms. In order to benefit fowl nesting, water height needs to be equal to both the wetland and dam. Insects and midges feed off the detritus (organic material at the bottom of the wetland).

Midges are insect larva that mature in water. Many are benthic (bottom dwellers) dipterons (two wings) that burrow in the mud and feed off detritus, thereby using up nutrients. There can be as many as ten-thousand per square meter and can grow to be one and a quarter inch long. They are one key to wetland treatment. They also become available for the fish in (and around) Cascade Lake would build up the population and help stabilize it. After metamorphosis, insects carry off some of the excess nutrients, further aiding the wetland's function.

The specific wetland we propose will be located on the west side of the lake, near Mud Creek. We chose to build near Mud Creek because it is a major contributor of phosphorous to the reservoir. A wetland on Mud Creek could be used to monitor nutrient loading, and indicate the efficiency of the wetland. If this "prototype" wetland is effective, then it can be used to promote the building of other wetlands near the lake. It will be placed below the proposed Valbois recreation site, on the three to four acres of land donated by Dennis Taggart (to our Advanced Biology class). This is a project that will actually be carried out. Mr. Taggart has made a commitment by donating the land. The monitors and builders of the wetland will be none other than our Advanced Biology class, (with the help of Valbois, of course). We plan to start this coming summer. Normally, the cost of building a wetland is anywhere from $500 to $50,000 per acre. Since the land was donated to us free of cost, and we will constructing it ourselves, that cost will be significantly less. We also hope to get the use of the equipment donated. (We found someone that may be willing to donate the use of some heavy machinery.) There will be relatively no cost in maintaining the wetland because it should be self-maintained. Transferring and pumping water is also an expense that we won't need to worry about. The water will be brought to the wetland by Mud Creek. We?ve already called the Army Corp. of Engineers for information, and all that remains.

In order to build the wetland, we need to clear and reshape the land around the area. The ground needs to be conditioned to retain water, because we don't want the wetland to dry; other wise nutrients would be able to collect. The ground will also have to be fairly permeable in order for the wetland to act efficiently. The creek will be diverted from the lake to a series of sedimentation ponds.

The purpose of these ponds will be to slow down the flow of the water so that particles settle out and are trapped. We plan to use three sedimentation ponds. The first will be surrounded by cattails and other phosphorous competitive plants. This way, most of the phosphorous is pulled out during the first step, reducing the chance of it entering the lake. The pond will be fairly deep, (around ten feet), so that it isn't quickly filled up by the sediment it collects. The second will contain floating plants,propellers.) The depth of this pond will be around five feet, in order to support the floating plants. This section will slow the water even more, to trap the finer sediments that the first pond did not. It's important to allow the sediment to settle out; that?s the main function of a wetland, "Stop the sediment and you stop the phosphorous." (Don Anderson). There will be and effort to keep the third pond free of floating plants, for reasons we've established. This pond will have a variety of plants, including cattails, and possibly willows. It will be around ten feet deep, in order to insure enough time for the water to cool off and deposit the rest of the sediments. Hopefully, all of these ponds will be inhabited with a variety of midges to further eliminate nutrients and feed surrounding wildlife. In ideal conditions, much of the nutrient load is removed from the water by developing midges. All of these aspects of the wetland make up a greater whole that needs to be monitored and maintained.

We need to focus on a few things when this wetland is built. Obviously, we're going to need to protect all of it's benefits. We need to make sure that development doesn't interfere with the wetland system and is designed around it. For several reasons, the system needs balance, stability, and movement, as well as a pleasing appearance. The balance of the system is important. If balance is not carefully monitored, it could be upset, making the problem difficult or impossible to correct. An example could be a certain type of midge that dominates all others until it becomes monotypic (the only type in the system). It would take strong action to control that midge and bring others back into the wetland. The environment around the wetland needs to be stable in order to survive stress and natural change. An unstable environment might not last through many years. A bad storm or erosion over a long amount of time could destroy it. Appearance will be an important factor to consider because the ponds will be built near a (proposed) resort. Few people would want to visit a resort that has a smelly, unkept wetland near it. The wetland will need to appear well-groomed and taken care of. As for movement, the water entering and leaving the area is perhaps the most important aspect of all. the water needs to move slow enough to drop off the sediments, but not so slow that it?s at a near stand-still and becoming stagnant. The water should be held a minimum of four days, but no longer. Otherwise,

Signs erected near the Mud Creek wetland could explain it's purpose, and help educate the public about its importance. Farmers, ranchers, and irrigators will be invited to watch and participate in the building of the wetland; this could help gain stronger support. The public will also be welcome to join in.

Improved water quality by the use of a wetland (or several of them) would be greatly advantageous to Cascade's recreation industry. For one thing, a lake that doesn't look like it's inhabited by several tons of green slime (also known as blue-green algae) would encourage fishermen to toss in a line or two. Boaters would appreciate the lack of Nitella, since it clogs their propellers. Swimmers would no longer fell threatened by the poisonous green tint of the water. Most importantly, the ecology will be improved. Fish and other species will appreciate improved water quality because they will have a greater chance at survival.

From our observation of the lake, it's obvious that it's in serious trouble. The fact that many of it's tributaries didn't pass Idaho's water quality standards, points to the need of definite, trustworthy programs. At least thirty percent of the phosphorous has to be reduced in order to achieve good water quality in the lake. One wetland may not make an enormous impact on the phosphorous load, but it's a start. There's no fast and easy cure for the lake. Building wetlands would have a long lasting effect on the improvement of water quality in the lake. If action isn't taken soon, then the lake won't be fit for human contact.

In conclusion, the Cascade Reservoir is in need of immediate assistance. A wetland built on Mud Creek would not only reduce the amount of phosphorous that enters the reservoir, but also encourage the idea of building more Wetlands don't disrupt nature's cycles, unlike other alternatives. We hope you're hooked on our idea. (The fish will thank you for it!)

Bibliography


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