Modeling Your Local Watershed and Nutrient Pollution

Abstract

Have you ever been unable to swim in a body of water because it was polluted? Have you ever wondered where the water came from, or what contributed to its pollution? In this science project, you'll learn how water drains to common areas to create bodies of water and how the land surrounding a waterway can contribute to its health and pollution.

Summary

Areas of Science

Environmental Science
Ocean Sciences

Difficulty

Method

Scientific Method

Time Required

Very Short (≤ 1 day)

Prerequisites

None

Material Availability

Readily available

Cost

Very Low (under $20)

Safety

No issues

Credits

Laura Ohl, PhD, Science Buddies Alumni

Inspired by Stroud Water Research Center. They developed this tool to model the local watershed.

Science Buddies is committed to creating content authored by scientists and educators. Learn more about our process and how we use AI.

https://www.youtube.com/watch?v=oWlPOl1oYMY

Objective

To understand the boundaries of local watersheds and potential major and minor sources of nutrient pollution to watersheds in your local environment. 

Introduction

Large bodies of water, like rivers, lakes, and oceans, come from water that drains from the surrounding land, called a watershed. A watershed includes all of the water over land, called surface runoff, and the underground water flow, called subsurface flow. These sources of water all flow to the lowest point in that region, where water collects, as seen in Figure 1. That is why a watershed is sometimes also called a water drainage basin. One large example of a watershed is the Mississippi River Basin in the United States. This large area of land channels water from 31 states into the Mississippi River, which eventually drains into the Gulf of Mexico. How do scientists take measurements from such a large watershed? Many of them use tools and modeling to predict what will happen to the watershed over time and use field measurements to validate the accuracy of these models. 

Image Credit: Laura Ohl, PhD / Science Buddies

Image of small lake waterway created from a watershed.

Why is monitoring a region's watershed important? Waterways can easily become polluted, which is problematic for everyday life because we drink the water from many of these water sources, use the fish and shellfish living in them as food sources, and enjoy these waterways for recreation, such as swimming and water sports. How do these waterways become polluted? One of the most common sources of pollution is nutrient pollution from the land within the watersheds. Nutrient pollution can come from fossil fuel burning, agriculture, urban development, and industry. Excess nutrients in our environment may result in the growth of harmful algae blooms and aquatic dead zones, where aquatic ecosystems are harmed or destroyed. In addition to creating hypoxic environments for wildlife, excess nutrients can also affect the usability of these waterways and ecosystems. For example, nitrates have been shown to have negative consequences on human health. Cleaning up these waterways and removing excess nutrients is essential for keeping them healthy and usable, but the process can be costly and time-consuming, as opposed to preventing nutrient pollution in the first place.  

What are the current solutions to nutrient pollution, and how can we better monitor, model, and remediate it before water sources are contaminated with excess nutrients that harm the environment? Effectively modeling the watershed is the first step to identifying which sources are major or minor contributors to nutrient pollution. In this science project, you will learn how to measure changes in a watershed to understand how runoff in a particular region is contributing to the transportation of excess nutrients. You will also look at sources of nutrient pollution (e.g., nitrogen and phosphorus) to better understand how different watersheds have different or similar sources of this type of pollution. 

Terms and Concepts

• Watershed
• Surface runoff
• Subsurface flow
• Nutrient pollution
• Harmful algae blooms
• Hypoxic 
• Nitrates
• Monitor
• Model

Questions

• What is a watershed? How is it measured?
• What causes nutrient pollution?
• What sources historically contribute the most to nutrient pollution? How do these contributors vary per geographical region?
• What are the ecological consequences of nutrient pollution?

Materials and Equipment

• Computer with internet access
• Lab notebook

This project follows the Scientific Method. Review the steps before you begin.

1. Go to https:/modelmywatershed.org/project.
2. Select the Get Started button.
3. On the Select Area page, use the dropdown menu to select your boundary.
   1. We recommend choosing USGS Watershed unit (HUC-10) to start. 
4. On the map, select your area of interest. This will highlight or brighten the area and darken the other unselected areas. 
   1. This model recommends using a more rural area. However, you can also compare urbanized areas to rural ones to compare sources of nutrient pollution in these different types of regions. 
5. There are three tabs: Analyze, Monitor, and Model. Select the model tab and select Watershed Multi-Year Model. This will model the daily watershed over a 30-year period. 
6. The model will compile the data, giving you information about the Hydrology and Water Quality of the selected watershed area. It should look similar to Figure 2.
7. Use the generated data from the model to answer the following questions:
   1. Select the Hydrology tab. 
      1. Surface runoff is a direct route of nutrient pollution. What is the average surface runoff per year for this region? What months have the highest surface runoff into the waterway? Put this data into Table 1. 
      2. Subsurface runoff can indirectly contribute to the transport of nutrient pollution. How much subsurface runoff is there yearly, and what months have the highest contribution? Put this data into Table 1. 
      3. Increased nutrient runoff can occur after extreme precipitation events. What is the average precipitation per year for this region? Put this data into Table 1. 
   2. Select the Water Quality tab.
      1. Sediment, nitrogen, and phosphorus levels can tell you a lot about a watershed's health. In the second table from the top of the page, there is a list of sources that contribute to excess nutrients entering the watershed, measured in mass (kg). What are the top sources that contribute to nutrient pollution? Rank them in order of highest to lowest contributor (highest to lowest number). Put at least the top three highest contributors to excess nutrient pollution into Table 2. 
8. Repeat this for another area, so you can compare the results. 
   1. Note: The closer the areas you choose are in proximity to each other, the more you will learn about a particular region's watershed. Choosing a location along the same waterway can also tell you about where the major nutrient pollution contributors may be along that watershed. 
9. What does this information tell you about the major contributors to nutrient pollution in these areas?
   1. Which area has a higher concentration of sediment, total nitrogen, or phosphorus (use mean annual concentration in mg/L to compare)?
   2. How do the top sources of excess pollutants vary per area? Are they similar or dissimilar? Are these sources connected or disconnected in their watershed coverage of the region?
10. Make conclusions about your overall analysis.
    1. What hydrology measures are most indicative of runoff in modeling a watershed?
    2. What sources contribute most to excess nutrients in the watershed? Does this vary by region?

Image Credit: Stroud Water Research Center

Image of user interface of model my watershed tool.

Figure 2. Image showing user interface of Model My Watershed tool.

Swipe left to see more

Table 1. Hydrology measurements from 30-year model.

Watershed Regions	Yearly average surface runoff (cm)	Rank order of months with the most surface runoff	Yearly average subsurface flow (cm)	Rank order of months with the most subsurface flow
Area 1:  __________		1. 2. 3.		1.  2. 3.
Area 2: __________		...		...

Swipe left to see more

Table 2. Water quality measurements from 30-year model.

Watershed Regions	Mean annual concentration of sediment (mg/L)	Rank order of top source of sediment (kg)	Mean annual concentration of nitrogen (mg/L)	Rank order of top source of excess nitrogen (kg)	Mean annual concentrations of phosphorous (mg/L)	Rank order of top sources of excess phosphorus (kg)
Area 1:  __________		1. 2. 3.		1. 2. 3.		1. 2. 3.
Area 2:  __________		...		...		...

Ask an Expert

Do you have specific questions about your science project? Our team of volunteer scientists can help. Our Experts won't do the work for you, but they will make suggestions, offer guidance, and help you troubleshoot.

Post a Question

Global Goals

The United Nations Sustainable Development Goals (UNSDGs) are a blueprint to achieve a better and more sustainable future for all.

This project explores topics key to Clean Water and Sanitation: Ensure access to water and sanitation for all.

Variations

Careers

If you like this project, you might enjoy exploring these related careers:

Soil and Water Conservationist

Log in to add favorite More Menu

• Read More

Career Profile

Soil and water are two of Earth's most important natural resources. Earth would not be able to sustain life without nutritive soil to grow food and clean water to drink. Soil and water conservationists foster the science and art of natural resource conservation. The scientists work to discover, develop, implement, and constantly improve ways to use land that sustains its productive capacity, and enhances the environment at the same time. Soil and water conservationists are involved in improving… Read more

Water & Liquid Waste Treatment Plant & System Operator

Log in to add favorite More Menu

• Read More

Career Profile

Have you ever wondered what happens to that soapy water from your kitchen sink or laundry room washer, or the waste water from your bathroom? What about the water that factories discharge after making products? Or the water that runs off of roads and farmlands after a big storm? Water and liquid waste treatment plant and system operators run the amazing water treatment plants that remove pollutants and other harmful materials from waste water, so that it can be safely returned to the… Read more

Water or Wastewater Engineer

Log in to add favorite More Menu

• Read More

Career Profile

When you think about a city that is a great place to live, what do you consider? Probably a community where the citizens are happy, healthy, and comfortable. Part of being all three is having a clean, safe, and constant water supply. Many of us take for granted that when we turn the faucet on we will be able to get a glass of water or that when we flush the toilet our waste will be carried away and treated somewhere. Well, that is what a water or wastewater engineer does. Their job is to design… Read more

Environmental Scientist

Log in to add favorite More Menu

• Read More

Career Profile

Have you ever noticed that for people with asthma it can sometimes be especially hard to breathe in the middle of a busy city? One reason for this is the exhaust from vehicles. Cars, buses, and motorcycles add pollution to our air, which affects our health. But can pollution impact more than our health? Cutting down trees, or deforestation, can contribute to erosion, which carries off valuable topsoil. But can erosion alter more than the condition of the soil? How does an oil spill harm fish… Read more

News Feed on This Topic

 

, ,

Explore Our Science Videos

Test and Change the Air Quality of Your Environment | Science Project

Build a Wind-Powered Car | STEM Activity

Improved Ion Wind Rotor | Science Project