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The dance to healthy lakes

Jetstream express

Watershed wisdom

Inquiry into Inle Lake

We want to introduce you to The Watershed Waltz and The Sammamish Swing, an environmental manual designed to teach homeowners how to “dance their way to healthier lakes and streams in 25 simple yet elegant steps.” The manual was originally designed for distribution to residents of the Lake Sammamish watershed but the information is applicable to any northwest lake. The manual explains and illustrates day-to-day alternatives that will reduce most lake’s primary source of pollution—high levels of phosphorus originating from our everyday activities.

To order a copy of the manual call or email the Pomegranate Center at (425) 557-6412.


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Wet weather

La Nina’s continued influence was felt in King County as volunteer lake monitors recorded heavy springtime precipitation (Figure 1). Rainfall totals measured well above Sea-Tac Airport’s historic average (346 mm) for the January-March quarter. Exceptions include lakes Cottage, Joy, Star, and Twelve where volunteers were not able to collect data for the full quarter. Precipitation totals at seven of the 37 lakes were above the 1999 regional average of 546 mm and 31 of the lakes were above the 1998 regional average of 415 mm. The regional average was calculated from a rain gauge just north of Sea-Tac Airport at Lake Reba.

Click here to see Figure 1 in greater detail

Stormy weather

Many of our lake volunteers had difficulty collecting data this spring because of high winds and stormy weather throughout the sampling quarter. This period coincides with the National Weather Service reporting that “a very strong jetstream” across the North Pacific generated an active winter storm pattern for the Pacific Northwest.

Two jetstreams influence our local weather: the Pacific Jetstream and the Polar Jetstream. A jetstream is a stream of strong wind concentrated within a narrow zone of the atmosphere. Many forces lead to the creation and flow pattern of jetstreams, including rotation of the planet and heat exchange from the earth’s surface to the atmosphere. Jetstreams usually flow from west to east, including the westerlies from east Asia that jetstream to the Pacific Northwest.

So as winter turns to spring, and icy-cold blasts turn to mild breezes, think about the jetstream high in the atmosphere that is flowing your way. To learn more about jetstreams and global climate patterns checkout the great El Nino/La Nina tutorial at the Climate Prediction Center Website.


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One place to start living in harmony with your watershed is in the garden. Take this quiz to find out if you are doing "The Watershed Waltz & The Sammamish Swing" (see cover article).

A. Have some of your plantings been selected specifically for drought tolerance?
Yes, some (+5)
None (0)
We don't have droughts in the Pacific Northwest (-10)

Drought tolerant plants, such as Purple Coneflower (Echinacea purpurea), require less water and maintenance.

B. What percentage of your landscape is native Northwest plants?
100% (+15)
70% (+10)
30% (+5)
Don't know (0)

Bunchberry (Cornus canadensis) is an elegant, native groundcover that grows well in shady areas.

C. How do you respond to the appearance of weeds?
Give them little name tags (0)
Icy indifference (+5)
Rip them from the earth with my bare hands(+5)
Blast them with chemicals (-10)

Weeds, such as dandelions, are best pulled by hand or ignored when living near a lake.

10 to 25 points: Your landscape is a symphony
5 to 10 points: Your landscape can hum a few bars
less than 5 points: Your landscape is singin' the blues


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Inle Lake is situated in Nyaungshwe Township, southern Shan State in Burma. It is the second largest lake in Burma at about 14 miles long and 7 miles wide (about twice the size of Lake Sammamish). The Inle region is characterized by a large, flat valley running north to south which is surrounded by mountain ranges averaging 4000 feet in elevation. The lake averages 2915 feet above sea level. Over 200 villages border the lake and inhabit the surrounding watershed.

The depth of the lake fluctuates with seasons. The average depth in the summer is four meters and in the rainy season, seven meters. The lake bed is comprised of fine silt deposited by the surrounding streams which flow through the plateau's limestone. Thirty streams flow into the lake: 17 from the east, 12 from the west, and one from the north. Inle lake has one outlet which flows south, entering the Thanlwin River.

Fishes and birds

Sixteen species of fish inhabit Inle Lake, including carp, catfish, and snakehead fishes. Inle is rich in birds with 57 species of forest birds and 43 species of water birds. Several species of egret, sea gull, commorant, wild duck, and magpie are abundant in northwest Inle. Migratory birds usually live in Inle wetlands from October to May.

Nga-phane, a symbol of Inle

The Inle carp, Cyprinus carpio intha or Nga-phane, plays an important role in local food supply as well as the cultural symbol of ethnic Intha. The carp breed year-round with clean and clear water. However, because of poor water quality, the Nga-phane population has become surprisingly scarce.

Inle flora

Native aquatic plants include pondweeds (Potamogeton), coontail (Ceratophyllum), bladderwort (Utricularia), stonewort (Nitella), muskgrass (Chara), and elephant grass (Saccharum spotaneum). People use elephant grass to make mats while pondweeds are used for food by both people and fish.

Invasive plants in Inle Lake

Water hyacinth (Eichornia crassipes) was introduced to the lake about 60 years ago as an ornamental plant. Although the plant is used for gas production, paper, and bag making, the over abundant population obstructs waterways along the lake.

The pollution problem

The main business of the Inle Lake region is floating garden agriculture. Tomatoes, the primary cash crop, comprise two-thirds of the region's agriculture. The remaining one-third consists of flowers, vegetables, and sugarcane plantations. The farmers use pesticides and fertilizers for their crops.

The Inle area is also well-known for its textile products. In eight villages, major textile industries use chemical dyes as well as natural dyes. In addition to the floating gardens and textiles industries, waste and garbage from households, lack of proper sanitation system, and live stock breeding contribute to poor water quality.

Excess siltation

In the western area of the Inle Lake watershed, deforestation is a big issue. Slash and burn agricultural practices on the adjacent hills contribute to soil erosion. Expansion of the villages throughout the watershed has also increased siltation. The addition of silt blocks or hinders the proper flow of water.

Preservation activities

In Burma, Inle Lake is a major tourist attraction. When the military regime promoted tourism in 1996, the government became aware of local efforts to preserve Inle Lake. In 1997, the Inle Lake preservation project was launched by the government. The project's executive committee includes members from Shan State Peace and Development Council, Nyaungshwe Township local authorities, and Government sector personnel (Irrigation, Agriculture, and Forestry departments). The preservation project continues as lake management is performed by multiple interests. Public awareness and participation will continue to play a vital role in Inle Lake's preservation.

Thanks to Myint Su, University of Washington Humphrey Fellow, for this article.


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Webster defines “nutrients” as something that nourishes or as a food ingredient. The primary nutrients for plants (including algae) are phosphorus and nitrogen. The more nutrients available to plants, the better they grow.

In most fresh water systems, phosphorus is less abundant than nitrogen (phosphorus limited). When the phosphorus supply runs out, plant growth slows or stops. When the phosphorus supply increases, plant growth increases. This increase in growth, left unchecked in a lake or stream, can result in unsightly and nuisance algal blooms. Subsequently, limnologists study ways to manage phosphorus levels in lakes.

Where Does Phosphorus Come From?

Phosphorus is found naturally in soil, plants, and animal tissue and occurs in several forms. Level II volunteers collect samples which are analyzed for total phosphorus (TP). This form includes all phosporus that is bound in plant or animal tissue, attached to soil particles, or dissolved in the water. Soluble phosphorus (SRP) is the form of the nutrient which is dissolved, making it readily available to be utilized by plants.

Phosphorus binds readily with iron in soils and can become a problem for lakes that stratify. When bottom waters become low in oxygen, the iron-phosphorus bond is broken and phosphorus is released into the water column. When the lake mixes during the fall, the phosphorus becomes available throughout the water column, sometimes causing new algal blooms. Aquatic plants (and algae) die back and decay in late autumn as the growing season ends. Phosphorus in the plant tissue is then released back into the water column.

Other Sources of Phosphorus

Phosphorus contained in animal feces can be a troublesome source of nutients to a lake (Figure 1). For example, when a population of waterfowl becomes too large or when large animals such as horses and cattle have free range near a stream or lake, fecal runoff enters nearby surface waters. Pets can contribute nutrients with their “droppings” when this waste is left to wash into surface waters. Human feces also contribute phosphorus when septic systems fail.