Potomac Highlands Watershed School

Stream Cleaner Overview & Content

Stream Cleaner is an interactive program found on the blackboard in the middle and high school  classrooms.  Stream Cleaner explores the relationship between people's actions and their impact on the environment, and the issues raised by Stream Cleaner are the same issues that people throughout the Chesapeake Bay watershed are working on to help clean up their local rivers and the Chesapeake Bay.  In Stream Cleaner, a stream is polluted with excess nutrients (fertilizer) and sediment (dirt).  The user has access to a "tool kit" with five Best Management Practices they can use to reduce pollution.  Each tool has a cost associated with its use, and the student has $10,000 to spend to clean up the water. 

The Chesapeake Bay is a national and local treasure, and an important source of livelihood, recreation and cultural heritage for the region. However, after receiving pollution from the surrounding landscape for many years, the Bay is in trouble. The states in the Chesapeake Bay watershed (Delaware, Maryland, New York, Pennsylvania, Virginia, and West Virginia), the District of Columbia, and the U.S. Environmental Protection Agency are working together to clean up the Bay. They have determined that the key to restoring the Bayís health is reducing the flow of nutrients (nitrogen and phosphorus) and sediment flowing from each of the Bay States into the Bay. To accomplish this, they have set maximum amounts for nitrogen, phosphorus and sediment in each Stateís waters.  All of the states have developed Tributary Strategies that seek to reduce nutrient and sediment pollution while minimizing economic and social burdens on our communities.

Stream Cleanerís landscape is typical of many watersheds in the rural uplands of the Chesapeake Bay watershed. It has a small town with residential areas, some fallow lands, and roads, and farmland located in the river's bottomland, with cornfields, pastures, and a barnyard. Towns and farms can produce many kinds of pollution, including both non-point source and point source pollution (see Pollution Primer). To keep things fairly simple, the watershed in Stream Cleaner doesnít have any point sources of pollution, so we donít have to worry about sewage treatment plants, industry, or large factory farms. We are also ignoring many of the kinds of pollution that can come from non point sources, such as bacteria, pesticides, and motor oil.

In Stream Cleaner, the stream is polluted with the same pollutants that are of greatest concern to the Chesapeake Bay -- excess nutrients (fertilizer) and sediment (dirt).  In the activity; these pollutants are combined into a general "pollution" category.   The user has access to a "tool kit" with five ways - called Best Management Practices (or BMPs) - to reduce pollution: grass buffers, forested buffers, sediment ponds, nutrient management plans, and cover crops. Some of the tools work for urban problems, some for farm problems, and some for both. Each tool has a cost associated with installation, and is able to reduce "pollution" by a certain amount. In reality, different BMPs work differently with different kinds of pollution, but we simplified Stream Cleaner rather than trying to account for nitrogen, phosphorus, and sediment separately.  The following table compares Stream Cleaner's pollution reduction assumptions with those used by the Chesapeake Bay Program.

BMP & Cost

Pollution Reductions 

per Chesapeake Bay Program

Pollution Reductions 

per Stream Cleaner

Grassy Buffers.

$130. The cost for this BMP includes equipment time to prepare the ground in addition to grass seed.

The area of land (buffer width times its length) that is converted from the existing use to a grass buffer is accounted for as the difference between pollution generated by the existing use and the pollution generated by an unfertilized grass buffer. The efficiency of a grassy buffer in removing pollution from runoff and below ground water is applied to upland acres of twice the area of land that is converted to a buffer. Stream Cleaner's buffers don't have a specified width, and therefore no area can be calculated. Pollution reductions are simply equal to the pollution reduction factor times the pollution for the upland area. For example, if you put a buffer on a pasture, it reduces the pollution flowing from that pasture to the stream by 50%.

Forested Buffer.

$1000. Why are they so expensive? The cost for this BMP includes seedlings, and protection for young seedlings (wire cage or planting tube) and assumes some replanting will be needed.

The area of land (buffer width times its length) that is converted from the existing use to a forested buffer is accounted for as the difference between pollution generated by the existing use and the pollution generated by a forested buffer. The efficiency of a forested buffer in removing pollution from runoff and below ground water is applied to upland acres of twice the area of land that is converted to a buffer. Stream Cleaner's buffers don't have a specified width, and therefore no area can be calculated. Pollution reductions are simply equal to the pollution reduction factor times the pollution for the upland area. For example, if you put a buffer on a pasture, it reduces the pollution flowing from that pasture to the stream by 60%.

Cover Crop.

$30. Cost includes seed and equipment to broadcast the seed across the field.

The pollution reduction efficiency is applied to the entire field where it is used. The pollution reduction efficiency is applied to the entire field where it is used.

Sediment Pond.

$1500. The big cost item here is heavy equipment to build the pond and remove the spoil.

This practice could actually refer to a number of possible CBP BMPs. All of these practices size the pond, or infiltration area, based on the area being protected. A sediment pond protects the entire field where it is placed.

Nutrient Management Plan.

$19. This is inexpensive due to economies of scale - a NMP is usually prepared for a large land area. Plus, there are no material or equipment costs.

The pollution reduction efficiency is applied to the entire field where it is used. The pollution reduction efficiency is applied to the entire field where it is used.

Waste Management Plan.

$4000. Costs include construction, operation and maintenance of a manure storage area. In reality, this could be much more expensive if the feeding area had to be relocated.

The pollution reduction efficiency is applied to the entire field where it is used. The value used applied to livestock, not poultry. The pollution reduction efficiency is applied to the entire field where it is used. In Stream Cleaner, this applies only to the barnyard.
In Stream Cleaner, the player drags tools from the toolbox, drops them in different locations, and measures their effect.  The challenge is to reduce pollution in Stream Cleanerís watershed by the largest amount possible within the $10,000 budget.

Activity Notes:

  1.      It was necessary to simplify concepts to make this activity playable without a large amount of explanation. This creates a few technical problems. One of these is to have a credible basis for assigning relative amount of pollution from the various landscape sources. Stream Cleanerís landscape is simple, and one simplifying decision was to combine fertilizer and dirt into a generic "pollution" category. This was done by taking the percentages for Nitrogen, Phosphorus, and Sediment used in the Chesapeake Bay Model for the land uses in the Stream Fixer activity and rolling them into a cumulative "pollution" category for all three parameters. Hopefully, this reasonably corrects for the fact that each different landscape element (corn field, pasture, town, barn yard) has different potentials to deliver different kinds of pollutants. To ground this in our regional reality, this was done using the 2002 modeled data from the Chesapeake Bay Program for the North Branch, the South Branch, and the Cacapon watersheds of West Virginia. The amount of land in row crop for these three segments was increased from 1% to 4% and pasture/hay decreased from 22% to 19%; this was done to emphasize the potential for pollution from row crops.
  2.      Using data developed by the Chesapeake Bay Programís Water Quality Model will give some people real heartburn.   The CBP Model takes information from many small studies, and extends it to apply to the whole Chesapeake Bay Watershed, and to smaller areas such as the Potomac Highlands. While some consider the information generated by this program as the best tool currently available for understanding some very complex problems, others see it as fatally flawed.  Nobody thinks it is absolutely "right," but many think it is the best tool we have at present.  

    • One of the sources of contention about The Model concerns how much total pollution there is, and how much comes from different parts of our landscape.  Long-term water-quality studies are being conducted throughout the Chesapeake Bay Watershed to see how closely the Model simulates reality.  

    • Another issue concerns how much pollution is actually reduced by using different Best Management Practices. The best evidence right now is that the CBP Model actually overestimates how well these BMPs work.  In Stream Cleaner, that could mean that you didnít clean up the stream as well as the game said you did. In the real world, it could mean that, after spending millions or even billions of dollars to clean up our streams and the Bay, the job may not be done.

 

Stream Cleaner Content

The Problem

Have you ever seen a river full of long green algae? Or looked back as you walked across a stream to see mud swirling up from the bottom where you stepped? Or fallen into the water because the river rocks are covered with "slime." In West Virginia, these are often signs of a stream that might need fixing.

The way we live, and the way we use the land, can cause these kinds of problems. While natural resources, such as forests and other vegetation, provide a balanced amount of nutrients necessary to our streams, an overabundance of nutrients are due to human impact. For example, the fertilizers (like nitrogen and phosphorus) that we use to help plants grow can do damage when they end up in our streams. Long green algae and slimy rocks are good signs that we may be using too much fertilizer.

In the same way, an overabundance of sand and dirt in the stream could be coming from natural sources, but more likely comes from excess erosion caused by the way people manage their land. For example, a large amount of dirt can quickly wash off a construction site where vegetation covering the ground has been removed and erosion control systems have not been installed.

It would be hard to imagine calling dirt pollution when it is in a field, or calling fertilizer pollution when it is used to help plants grow. They only become pollution when they end up in places where they donít belong. 

A stream doesnít have to be unhealthy just because people live and work nearby. There are many "tools" that people can use to allow healthy streams and people to live side-by-side.

The Stream Cleaner Toolkit

Hereís your chance to clean-up a stream. Like any fix-it project, youíll need some tools to get the job done. Just as you can build a wall with a hammer, a few boards and some nails, these cleaning tools will allow you to build barriers between the pollution that we produce (we all do it) and our stream. In other words, our tools will be used to keep precipitation (rainfall and snowmelt) from washing dirt, fertilizer, and other pollution into the stream.

What do we mean by tools? Another term for the kind of tools we will use is Best Management Practices (BMP). They fall into three categories Ė tools that hold dirt and fertilizer in place, tools that act as a barrier to stop dirt and fertilizer from washing into a stream, and tools that reduce the amount of fertilizer we use in the first place.

Best Management Practice Toolkit

Cover Crop

Grass can be used to hold soil and nutrients on agricultural land, construction sites, and bare ground so rainfall canít wash it away. So our tool kit includes planting grass on bare ground. When used on a farm itís called a Cover Crop, and is often used on cropland to keep the land from eroding over the winter months.

Grass Riparian Buffer

By planting wide strips of grass and other non-woody vegetation along rivers and streams, and by allowing it to grow tall, we can filter nutrients, sediment and other pollutant from runoff. Thick vegetation slows the runoff water down, allowing some pollutants in the water to settle to the ground, and cleaner water to flow to the stream. We call this a Grass Riparian Buffer.

Forested Riparian Buffer

By planting wide strips of trees along rivers and streams, we can filter nutrients, sediments and other pollutants from runoff as well as remove nutrients from groundwater. Thick vegetation and dead leaves slow the runoff water down, allowing some pollutants in the water to settle to the ground, and cleaner water to flow to the stream. This is called a Forested Riparian Buffer.

Sediment Pond

Our fourth tool is a Sediment Pond. A sediment pond captures and temporarily stores stormwater runoff before allowing the water to either soak into the ground or flow slowly out toward our stream. Because the pond slows the water down, some of the pollutants in the water settle to the bottom of the pond and cleaner water can then flow out of the pond into the stream.

Nutrient and Waste Management Plan (NMP)

Some people use more fertilizer than they really need to grow the plants they planted, and the excess fertilizer can get carried into streams. Our last tool is called a Nutrient and Waste Management Plan (NMP).  A Nutrient Management Plan helps people use just the right amount of fertilizer. For a farmer, homeowner or a golf course manager, a NMP describes the optimum use of nutrients to both help plants to grow and also minimize fertilizer loss.

In a barnyard, a Waste Management Plan prevents the nutrients in concentrated animal wastes from running into a stream. This may involve relocating an animal feeding area away from a stream, or building a structure that contains the animal wastes.

Where the Pollution is Coming From

Here is a typical West Virginia watershed.  From the pie chart, you can see that forested hillsides cover 70 percent of the landscape, with farms accounting for a little less than 20 percent of the land, and with a small headwaters town and nearby fallow lands covering about 8 percent of the land area.

Nutrients, such as phosphorus and nitrogen, occur naturally in soil, water and the atmosphere. They are required for the growth of plants and for aquatic life. We donít consider nutrients and dirt from the forested area to be pollution because the forest is a natural source. Excess fertilizer and dirt (from now on, weíll just call that pollution) comes from the town and farm areas. In the town, this pollution comes from bare ground and over-fertilized lawns. Also, water that hits surfaces like roads and rooftops canít soak into the ground and actually gains speed as it runs across the ground Ė which causes erosion. On the farm, the sources are the barnyard, the cornfield and the pasture. The pie chart shows how much pollution is coming from each of these sources. Take a close look, and you might notice that the largest land areas do not necessarily contribute the most pollution.

 

Details, Details

Now you know about the landscape, the problem, the tools you can use to fix the problem, and the sources of pollution. The only thing you donít know is that some tools cost more to use than others and they reduce pollution by different amounts. The numbers you now see beside each tool in the toolkit tell you, for example, that a forested buffer costs $1000 for every field and removes 60 percent of the pollution that moves through it. To keep things fairly simple, Stream Cleaner assumes that each of the fields in our landscape has the same footage of land bordering the stream.

Your goal in Stream Cleaner is to reduce the amount of pollution entering the stream to the greatest amount possible before spending all your money.  Click Next to start the game.

Time to cleanup the stream

You have a total of $10,000 to spend. To use a tool, just drag and drop it over the area where you want to use it. If you try to use a tool in a place where it doesnít make sense, the computer will ask you "Do you really want to do that?" If you try to use a tool in a place where you have already used it, the computer will tell you "You have already done that." After you place a BMP in a field or in town, you will see a change in your bank account gage (when its on empty, youíre out of money and done), and also a change in the pollution level gage. Your goal is to get the pollution level as low as you can before you run out of money.

Your challenge will be to balance how well the different tools work, how much its costs to install the tools, and how big the different sources are -- with how much money you have to spend. Ready?