A Spreadsheet Tool to Quantify Stream Functional Lift and Loss
Will Harman, PG
Cidney Jones, PE
Ecosystem Planning and Restoration
*Students should bring a laptop.
There is an increasing need within the stream restoration industry to show the functional lift of reach-scale projects. Stream mitigation projects are required to show that the post-restoration condition/function is better than the pre-restoration condition. This difference is called functional lift and is also the definition of a stream mitigation credit. On the other side of the ledger, permitted impacts are required to quantify the conditional/functional loss resulting from their permitted activity. This is called a debit. Ultimately, the functional lift from stream mitigation projects (credits) must offset the functional loss from permitted impacts (debits).
Currently, the vast majority of stream mitigation programs lack a quantitative method for determining functional loss and lift. Most programs use rapid, qualitative methods to estimate stream condition at an impact site and then assume a loss based on the impact activity. On the mitigation side, many protocols assign credits simply based on changes to channel geometry or assume that a certain activity will create functional lift. These methods do not adequately capture lift and loss and make it virtually impossible to determine if the credit equals the debit.
Beyond mitigation, many stream restoration programs are interested in documenting the benefits from stream restoration practices. There is also a need to improve the site selection process so that limited funding can go to the project sites that can generate the most lift.
This workshop will introduce the Stream Quantification Tool (SQT), a spreadsheet tool that can be used to quantify the functional lift at stream restoration sites (or proposed sites) and the functional loss at proposed impact sites. The tool requires a combination of desktop information and field data collection. Where feasible, both rapid and detailed field-data collection methods are provided; however, both are quantitative. The workshop will provide the logic behind the tool, examples of how to enter data, and case study examples showing how the tool works.