Lesson 19: Land Use and Nitrogen

Background:

Not everyone lives next to a stream or river, but all of us live in a watershed. A watershed is defined as a region of land that drains ultimately to a particular body of water. Whether you live right on the water--or, like most Marylanders, within a half mile of your neighborhood stream--your actions on the land can effect water quality in the streams and rivers that feed the Chesapeake Bay.

Together, a group of these watersheds will combine to make up a tributary (river) basin. In Maryland, 94% of the land drains to the Chesapeake Bay, with the remaining land draining to the Maryland Coastal Bays and the Ohio River. The Maryland land that comprises the Chesapeake Bay watershed has been divided into ten major tributary basins.

Here in Maryland, major cleanup actions are now underway using a watershed approach for these ten tributary basins to control pollution and the nutrients (nitrogen and phosphorus) that find their way into our streams and rivers from widely scattered sources on the land. Excess fertilizers from farm fields and suburban lawns, sewage from septic systems, and sediment from construction projects all can wash off the land and into our waterways every time it rains.

These excess nutrients cause damaging effects as they enter our waterways. Excess nitrogen causes algal blooms that deplete the oxygen needed by fish, shellfish and other bay creatures. They also shade out the light needed by Bay grasses. Therefore, the way we manage growth in our towns and cities, where we choose to locate development and the strategies we use to compensate for land conversion and development all affect water quality.

Developing a pollution control plan unique to each watershed, its population and its land-use patterns is no small task. Among the pollution control options being implemented in each tributary basin are upgrades to wastewater treatment plants, the planting of stream-side forests to absorb nutrient runoff, best management practices to reduce agricultural runoff and "smart growth" plans aimed at concentrating new development and protecting open spaces and natural habitat.

In this lesson, students will examine the challenges of balancing development and land conversion with the fiscal, technical and political challenges of addressing nutrient loading. They will have the opportunity to examine these issues based on real data and maps from their own watersheds. The students will examine the impact of development on nitrogen loads (pounds of nitrogen runoff from the land that is entering the Bay) In Activities 1 &2 students will compare the nitrogen loads when development occurs inside and outside the Growth Area, and on differing wastewater treatment options (e.g. central sewer versus septic systems). In Activity 3, Students will select best management practices (BMPs) and set implementation targets based on available acres within their Tributary basin in order to offset the impacts of new development and meet nitrogen goals. Finally, in Activity 4, students will discuss their recommendations for reducing nitrogen in their tributaries in the face of future growth, and discuss the feasibility, cost and political acceptability of these options

Activity 1: Impact of Development Patterns on Nitrogen Load

In this activity, students will calculate the nitrogen load before and after development, both within and outside the growth area. Students will compare the nitrogen loads generated by each scenario and draw conclusions regarding development patterns on the generation of nitrogen load.

Have students review background material, nitrogen load bar chart (Student Handout #2) and Side Two of the National Geographic Maryland Smart Growth Map. Use the tributary basin map to identify the basin where the school is located. Have students complete Student Handouts 3 & 4. Students will need to refer to the Watershed Profiles (Student Handout #1) and the Tributary basin maps for information.

Discussion Questions:

What are the differences in nitrogen load before and after development for inside the growth area?
What are the differences in nitrogen load before and after development for outside the growth area?
What are the differences in nitrogen loads after development for inside and outside the growth area?
Do development patterns affect nitrogen loading? Why ?

Activity 2. Impact of Wastewater Treatment Options on Nitrogen Load

In this activity, students investigate the nitrogen load impact of the people who will move into the new houses. Students then examine different wastewater treatment options to remove the nitrogen load. Students compare results of development inside and outside a growth area.

Have students complete Student Handout #5.

Discussion Questions:

Which wastewater treatment option is the most expensive? Which is the least expensive?
Which wastewater treatment option provides the most environmental benefit? Which provides the least?
What are the implications of these costs for how a county might choose to develop?
What policy approaches might counties adopt to address the information you have discovered?

Examples:

Counties might encourage most development on central sewer to avoid nitrogen
problems from septic systems.
Counties might charge a fee to people on conventional systems to help pay for
nitrogen removal elsewhere.
Counties might require new septic systems to install nitrogen removal, regardless of
cost.
Students may add other options.

Activity 3: Using Best Management Practices to Reduce Nitrogen Loads

In this exercise, students will take the nitrogen load generated by the new development and choose a set of one or more best management practices to zero out the new nitrogen load. Students will calculate how much the plan will cost, and decide what government policies to put in place to see that the nitrogen reduction plan is carried out. Note that there are many more BMPs for nutrient reduction than those listed in this lesson.

Have students fill out Student Handout #6(a) and #6(b). Students will need to refer to the Watershed Profiles (Student Handout #1) and Tributary Basin Locator Map.
Select a set of practices from the “Best Management Practices Chart” that will reduce to zero your new nitrogen load from development. Look at BMP options for all sources. For example, even if you only develop within the growth area, you may use agricultural practices to offset the nitrogen loads from new development so that, across the whole watershed, you have no new nitrogen loads.
Calculate the cost of your plan in acres and dollars.
Devise plans that will deal with the development scenarios for both inside and outside growth area development.

Discussion Questions:

Which BMPs did you select? Why?
How much (how many acres or systems) of each BMP will you apply?
What is the total cost of your plan?
In your plan, who would be responsible for reducing the largest load of nitrogen? (farmers, water treatment, homeowners, landowners)
Compare your plan with others.
What are the pros and cons of various systems that are presented?

Activity 4: Process for Developing a Nitrogen Reduction Plan

Currently, Maryland, Virginia, Pennsylvania and the District of Columbia are working to develop nitrogen reduction plans in order to restore the water quality in the Chesapeake Bay for living resources. Plans address both point sources (wastewater treatment plants and industrial sources) and nonpoint sources (runoff from agricultural, urban and suburban land managed through BMPs). The costs of these plans are expected to exceed the current funds available. Currently, practices are paid for through a variety of means, for example:

Homeowners pay water and sewer bills to pay for wastewater treatment
State taxpayers pay for programs through the State, like grants to wastewater treatment plants and farmers, to defray the costs of nitrogen reduction
Farmers pay a portion of the costs needed to install best management practices (the rest is paid for by State grants, or cost-share)
Federal taxpayers pay for programs through the Federal government to reduce nitrogen (like those through the Farm Bill)
Developers pay for stormwater management on new development as part of the cost of developing a new subdivision.

Writing Exercise: Have students draft a mock memo to a local elected official about the proposed nitrogen reduction strategy. Student should include the following elements:

Why is reducing nitrogen important for the health of the Bay?
What are three advantages to the proposed plan ?
What are the costs and obstacles to the plan?
Have students anticipate and provide answers to three questions that elected officials would ask about the plan.

Discussion Questions:

What criteria do you think are most important for reducing nitrogen loads (cost effectiveness, fairness, feasibility, etc)? What recommendations would you make to help achieve nitrogen reductions and maintain them in the face of future growth?
How can State and local governments most effectively achieve nitrogen reduction goals for your tributary? Think about both BMPs and Smart Growth policies. What approaches do you think will be most accepted by the public? Which approaches do you think will be more controversial, and why?
Who should pay for nitrogen reduction in your tributary? What are the potential impacts of different decisions about who pays on residents within your tributary?

Extending the Lesson:

Examine the bar charts to determine the major source of Nitrogen pollution in your Tributary basin. Design a set of BMPs that would reduce the load from the major source. What would you do, where would it go, how much will it cost, how effective is it?
Compare your tributary nitrogen numbers with other tributary basin. Locate similar and different watersheds. Is the major source of nitrogen the same for all?
Using the summary of Smart Growth policies and programs, which ones do you think would be most important in protecting the Bay and its tributaries?
Examine the tributary basin growth, preservation area and land use maps. What does this tell you about how your tributary basin has grown? What does it tell you about where future development and preservation are targeted?
Contact your tributary team to learn more about what is being done in your basin to control nutrient loads.
Visit “Eyes on the Bay” to learn more about current water quality conditions around the bay. www.eyesonthebay.net

Additional Resources:

Maryland Tributary Teams, www.dnr.state.md.us/bay/tribstrat/index.html
Center for Watershed Protection, www.cwp.org
Eyes on the Bay, www.eyesonthebay.net
Chesapeake Bay Program, www.chesapeakebay.net
Learn more about nitrogen and the Bay: Bay Grasses in Classes, http://www.dnr.state.md.us/bay/sav/bgic/grass_class.html
"From the Skies to the Sea: Air Pollution and the Bay", http://www.dnr.state.md.us/education/envirothon/, found in the aquatics training packet