By Marguerite Huber
I like beginnings. They are a fresh start and influence our lives further down the road. Just like how we have new beginnings, all rivers have influential beginnings too. In a network of rivers up in the mountains, headwater streams are the uppermost streams furthest from the river’s endpoint or merger with another stream. They are the very beginning of miles and miles of rivers and have a great impact on what flows downstream.
Headwater streams and their catchments, or drainage basins, are necessary for the maintenance of healthy and productive streams and rivers. Headwater catchments also provide numerous ecosystem services to humans and the surrounding environment. These benefits include biodiversity, climate regulation, recreation, timber and crop production, and water supply and purification.
EPA researchers studied the importance of headwater catchments by focusing on the quantity and value of a few ecosystem services, and then projected that importance from a regional to national scale. They focused on three ecosystem services (water supply, climate regulation, and water purification) for 568 headwater streams and their catchments.
To assess the potential economic value of headwater catchments’ ecosystem services, researchers used published economic value estimates based on commodity price (water supply), market value (climate regulation), and damage cost avoidance (water purification).
They found the economic value of each ecosystem service as follows:
- $470,000 – The average yearly value of water supplied through each headwater catchment.
- $553, 000 – The average yearly value of climate regulation (through carbon sequestration) of each headwater catchment.
- $29,759,000 – The average yearly value of improving water quality by reducing nutrient pollution.
Overall, the weighted average economic value for headwater catchments in the United States was $31 million per year per catchment. It is essential to note that the national importance of headwater catchments is even higher since the 568 catchments studied are only a statistical representation of the more than 2 million headwater catchments in the continental United States. I think it’s safe to say these beginnings provide some serious benefits!
About the author: Marguerite Huber is a Student Contractor with EPA’s Science Communications Team.