Quantifying Stream Restoration Benefits

IRIS researcher Dr. Rod Lammers builds on stream restoration crediting programs

Writer: Cammie Caldwell

Contact: Dr. Roderick Lammers; rod.lammers@uga.edu

The United States and the nation’s streams and rivers have an uneasy history: we need clean water to drink, to irrigate our agriculture, and for industry—not to mention the myriad of other species that rely on freshwater resources to survive—but increasing pollution, nutrient overloads, which can cause algal blooms and decreased water quality, erosion and deforestation put new demands on streams under worsening conditions.

However, Dr. Roderick Lammers, Research Scientist at the University of Georgia, is developing a way for industry and other organizations to even the debt with our freshwater resources through stream restoration crediting programs.

Specifically, Lammers has worked alongside Wright Water Engineers, an engineering firm in Denver, and other UGA researchers to create methods for quantifying benefits that stream restoration activities may provide to regions seeking to improve water quality. These methods are applicable to stream restoration projects everywhere, but are receiving the most attention in parts of the country with significant water quality challenges.

With an estimated 51 billion gallons of water flowing into it on a daily basis, and runoff from five states, the Chesapeake Bay receives large amounts of pollutants, and it serves as an excellent starting point for developing these crediting approaches.

The states that contribute to run off in the Chesapeake have been aiming to improve water quality by encouraging stream restoration and other projects, making it a source of innovation in the field. In fact, Lammers has adapted many of the methods originally developed by the Chesapeake Stormwater Network.

His project is intended specifically to help state and regional agencies set up their own crediting programs.

“This document is targeted mainly to state or regional agencies who are responsible for setting up crediting programs having to do with stream restoration,” Lammers said.

Stream restoration projects are often taken on with a lack of understanding and measurements about the possible benefits they could provide. This is due to the fact that monitoring of stream restoration projects can take extensive time and money to perform.

“We want to develop a database around performance of stream restoration projects. Currently, few of these restoration projects are monitored and it is often unclear how well they work. We want to be able to quantify how much nutrient reduction one of these stream restoration activities would cause,” Lammers said.

To combat this gap in knowledge, Lammers is setting out to create quantification methods that focus on four major types of stream restoration strategy, each with its own formula.

The first, bed and bank stabilization, helps to prevent erosion and the release of phosphorus into the stream. Lammers is able to estimate the benefits of this type of project by measuring levels of erosion before and after the project, then calculating the amount of phosphorous reduced by stopping said erosion.

Next, the creation of riparian buffers traps sediment and pollutants within natural vegetation along streams before they can reach the water. These are assessed based on the size of the buffers and estimates of how many nutrients they can remove from an area.

“Another strategy is stream enhancement, which involves putting structures in the streams like rocks, logs, or anything to stabilize the channel,” Lammers explained. “These projects are assessed by how well they improve the filtering capacity of the stream and their contribution to water quality.”

The last is floodplain reconnection, which works to make the stream channel and floodplain act as a unit to reduce erosion and improve water quality. To measure the benefits of this strategy, Lammers calculates how much water moves through the connected floodplain and how much pollution removal has been removed.

The methods and databases that Lammers is working on can connect to small, regional projects but also to wider goals as well, having to do with policy and large-scale water quality standards.

When it comes to the Chesapeake Bay region, these four quantification methods, as well as others, are being incorporated to understand the best ways the area can reduce their excess nutrient levels. There are many other potential benefits of stream restoration besides than nutrient reduction that Lammers is not focusing on but finds important, such as benefits for fish, animals, flooding, insects, recreation, and more.

“This information can also provide a platform for water quality trading programs. We want to know how we can create a marketplace to encourage the most effective ways of improving water quality. For example, if a wastewater treatment plant is unable meet EPA limits on the amount of nutrients they can discharge, it may be cheaper for them to pay for stream restoration projects that could result in improved water quality in a more efficient way, rather than installing expensive upgrades at their facility,” Lammers said.

This work was made possible thanks to the Water Research Foundation.